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Show HN: I made a free app to calibrate your turntable by simply playing a song

452 points by okatbest 2y ago

Hey there! I made a little app that lets you to calibrate your turntable by putting on any record and tapping a button. It's called Grooved and it uses your phone's microphone to see how fast your platter is going, almost like magic. You can see what it looks like in action here: https://twitter.com/OKatBest/status/1795453042994680148 https://twitter.com/OKatBest/status/1795453042994680148 The app itself is free without ads, subscriptions, or trackers. It's a tool I built for myself, and I just thought someone else might want to use it too. I have never seen this technology being used before, all other apps require you to either print something and use the camera, or to place your phone on the spinning platter and use the accelerometer. You can grab it on the App Store, and I am working on an Android version I hope to release at some point in June. Would love to hear what you think about it! Ivan_

sans_souse 2y ago
thank you Ivan looking forward to an android version!
gen3 2y ago
Neat POC, are you doing a song fingerprint then comparing speed/stretch?
KeplerBoy 2y ago
That really is a lot of copywriting for a bunch of FFTs, but nicely done.
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echelon 2y ago
I'm not an expert on vinyl. The only record players I've interacted with have only had two speeds. Do most of them do variable spin rates? How frequently do the rates get out of sync? What causes it? Do they vary on an album by album basis?
- CaptainOfCoit 2y ago
  > I'm not an expert on vinyl. The only record players I've interacted with have only had two speeds. Do most of them do variable spin rates? Lots of turntables have variable speed, DJs can tell you more about it :) > How frequently do the rates get out of sync? What causes it? Do they vary on an album by album basis? When you're DJing, one of the main things you'd deal with, is making things be in sync, one way or another. I'm not sure how much value you'd get from an app like this that seems to be more "fire and forget" and not for on-the-fly matching. I'm guessing this app is for people who do their own maintenance, repairs and such of turntables, so they can easily verify their work.
  - hnlmorg 2y ago
    I don’t think this would be aimed at DJ turntables. It doesn’t matter if those things drift because you’re never playing anything locked in at a specific RPM. Plus DJ turntables tend to be direct drive, which should be pretty consistent. Where as consumer record players tend to be more belt drives. And I’m assuming those belts can stretch with time?
    - CaptainOfCoit 2y ago
      > I don’t think this would be aimed at DJ turntables I agree :) > Plus DJ turntables tend to be direct drive, which should be pretty consistent Indeed, but once you start doing repairs and/or modifications, things can get fuzzy. Maybe the app would help those people?
      - LM358 2y ago
        People who are serious about turntable repair have calibration records with sine waves for that purpose.
- beAbU 2y ago
  Fancy record players have a trim setting where you can fine adjust the speed up or down a semitone. But all of them have a built in stroboscope/calibrator to help get the speed right. I think the drag of the needle impacts the speed, hence the desire to tune it per record. Audioplebs need not apply.
patrakov 2y ago
Does it rely on the fact that music has a concept of notes with well-defined frequencies and that there is no such thing as 216 Hz (must be 207.6 or 220 Hz) when the music is played on a properly tuned instrument? Or does it use other heuristics?
- franky47 2y ago
  A "properly tuned instrument" still requires a base frequency (usually defined for A4). Whether to use 440Hz or another slightly different frequency is a fun debate to get into.
  - datpiff 2y ago
    Older recordings on analog media also can have timing error at the recording stage or duplication stages.
- astral303 2y ago
  I tried it out and the instructions have tips on what record to pick, they say to pick a well known version of a song (like not a live version etc), and preferably song with a beat, but it says it doesn’t use any 3rd party APIs or libraries, only Apple APIs. So my guess at to what it’s doing is using a ShazamKit recognition behind the scenes and looking at the frequencySkew value of the matched result. It also gives you one answer after listening, instead of a continuous gauge, which seems to corroborate song recognition. It probably won’t work with an obscure record that is not Shazamable. And so I don’t think it can measure wow & flutter as a result. Still pretty cool for those that need to calibrate a turntable, or verify 33 vs 45 PRM for a record.
  - netsharc 2y ago
    I guess a phone's camera can be used to count the RPM, e.g. by filming the label and counting how many milliseconds it needs to do a full rotation (1818ms for a 33 RPM record)
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tirthd 2y ago
Great copywriting. It's very rare that I read an entire paragraph without skipping a word.
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- empath75 2y ago
  I actually disagree. There's a lot of extraneous stuff about app stores that's probably appealing to app developers but are developers the audience or audiophiles?
- turnsout 2y ago
  Agreed—and it does feel like the Apple-inspired copywriting style the author is complaining about is feeling extremely (wait for it) played. Absolutely every site is like: "Lawn Order. The X900's diamond-tipped rotary blades cut your grass to within 50 microns of your desired length. Overkill? Absolutely. Because it's not just your lawn—it's our passion."
arytoriop 2y ago
This is really cool.
shiandow 2y ago
This just tells you the speed, not the variation in speed over time?
- okatbest 2y ago
  That's correct. The analysis takes a few seconds so even if I take more samples, it all gets averaged over time and won't be able to do instant read. If you're interested in measuring wow and flutter I think you'll need to look at more traditional calibration methods unfortunately.
gaudystead 2y ago
I'm just here to say that I enjoyed that intro you gave to the website, and although I hate unitaskers in the kitchen, that intro helped to remind me of the magical wonder of them in the early days of "The Modern Smartphone". Cool app and thanks for sharing! :D
nickthegreek 2y ago
Just put a record on yesterday and my wife said it was playing too fast. I thought she was wrong, then I see this post today! I grabbed the app and gave it a go, 3.5% too fast according to your app. Now I have to figure out how to adjust the damn thing. Really appreciate a free nonsense free app. update: youtube to the rescue. pretty common affordable turntable( Audio-Technica LP60), so I figure I would put the vid link here for others who might want to know - https://www.youtube.com/watch?v=d3PdS2V8Jz0 https://www.youtube.com/watch?v=d3PdS2V8Jz0
- okatbest 2y ago
  Hey that's awesome to hear, thanks for trying it out! This is exactly what I hoped for when building this app. Making a dead simple tool for people who want their records to sound better, but may not have the equipment or knowledge necessary to adjust it.
- kazinator 2y ago
  3.5% is a lot! One semitone is a bit shy of 6 percent.s It's between 59 and 60 cents: more than a quarter semitone. Exact value: 1> (* 1200 (log2 1.035)) 59.5569212695205 So 59.6 to 3 sig figs. Someone with a good pitch memory of a tune (hearing in their head how it should sound) would spot such a difference. Especially if they heard the tune recently.
  - criddell 2y ago
    So many recordings (especially before 2000) seem to be sped up a little. I can’t tell by listening to the song but when you try to play along with a guitar, it sounds terrible. Sometimes it helps to find a live version on YouTube.
    - taylodl 2y ago
      Correct. That was often done when mastering with tape. Record at one speed, playback at another to make it sound more "lively." There are songs that were sped up that way anywhere from 25 to 40 cents. It's another reason why live music so often doesn't sound like the recording. When using digital mastering, you can also adjust the playback speed, but you can correct the shift. You get more "liveliness" without the shift change. That's why you're not hearing the pitch shift so much in more recent music.
crazygringo 2y ago
This seems really clever -- kudos! I'm curious how it actually works? At first I assumed you were comparing the vinyl track to the reference digital track from some streaming service and either analyzing the frequencies with FFT or the timing of peaks. But I watched your demo video and you don't need to tell it anything about the song. Which makes me think you're rather doing an FFT and simply trying to match how well the frequencies align to the well-tempered scale based on A 440 hZ. Which then leads me to three questions: 1) Obviously this wouldn't work if you were playing a standup comedy album or something? Or the drum solo part of a song? 2) Are essentially all albums perfectly in tune with A 440 hZ? For example with classical music, I understand that 442 is also used, baroque is sometimes at 415, and 432 has been common as well? I don't know about pop but I can't help but wonder if some artists have intentionally chosen something other than 440 over the decades. 3) I assume this won't work if the turntable speed is off by more than 2.8%? Since the distance from A4 (440 hZ) to A-flat-4 (415.30 hZ) is a decrease of 5.6%, and so if the turntable is off by more than half of that you'd be trying to align to the wrong note?
- datpiff 2y ago
  > Are essentially all albums perfectly in tune with A 440 hZ? For example with classical music, I understand that 442 is also used, baroque is sometimes at 415, and 432 has been common as well? I don't know about pop but I can't help but wonder if some artists have intentionally chosen something other than 440 over the decades. No they are not all tuned to 440Hz. This is really evident if you play an instrument and want to play along with an album.
  - iaresee 2y ago
    Every. Rolling. Stones. Album.
- sambeau 2y ago
  My first thought was that it is listening to the scratches rather than the music, but I guess they speed up as the record gets played and the arm moves inwards. So, my second guess is that it's listening to the pitch of the notes being played. Of course, old albums (especially punk albums) are probably tuned to whatever worked on the day—maybe a tuning fork, possibly a piano, maybe just to one of the instruments.
lukko 2y ago
This is cool - not sure if it's possible, but it would great if you could determine other things, like is the needle weight correct, or is the cartridge aligned properly (maybe left / right channel would be louder / softer??). I found the copy on the site a bit gross - I'm not sure something like this needs a critique of modern copywriting, and for me it gives that same weird sense of over familiarity ('we get you') that I think it's trying to criticise.
mk_stjames 2y ago
So here's another method that doesn't rely on the song being detected or even a song at all: The gyroscope on your phone is accurate enough to measure RPM to about the first decimal place at 33 1/3 - 45 rpm's just by placing your phone on the turntable flat and letting it spin.
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sambeau 2y ago
Very cool. Great aesthetic and copy. No notes.
gcp123 2y ago
What a perfectly simple app! Going to try this out with my Technics SL1200 mk2 tonight. Thanks for sharing. P.S. Reading comments from a bunch of tech folks trying to wrap their heads around an app for calibrating analogue music playback device is very amusing. :-)
- bastardoperator 2y ago
  I assume this is for belt driven turntables, not direct drive. I also have a pair of 1200's. Most mixers these days have BPM built in, and before that you had red micro bpm counters and headphone amps to validate BPM. Never once on my 1200's did it read something outside of the producers BPM count when pitch was locked.
  - fmj 2y ago
    My MK2 was off by about 3% when the pitch adjust was in the detent. To be fair, it had a rough life before it ended up in my hands. If you have a frequency counter they're pretty easy to calibrate the correct way though.
    - CoffeeOnWrite 2y ago
      Did the delta show up on the strobe? Or is issue that the quartz is off and it’s feeding both the motor and the strobe? (Sorry if this is a dumb question. I don’t recall seeing speed calibration in the mk2 manual when I was setting up my secondhand decks)
      - fmj 2y ago
        I honestly can't remember if it showed up in the strobe or not, this was a few years ago. This procedure wouldn't be listed in the regular manual. It involves opening it up to adjust an internal potentiometer, and can't be reliably done without a frequency counter (I guess you could do it through trial and error, but it would take forever having to reassemble it and play a test disc after every adjustment,) so it is only in the service manual. You should be able to find a scan pretty easily though. Can't remember what frequency you need to hit, but it's low. If you don't have a proper frequency counter an Arduino will work just fine.
plastic3169 2y ago
Looks amazing and useful for me! The links don’t take me to the app store on my iphone and the app name is not in the heading I need to scroll past the copy to find what to search for. Minor annoyance but for some reason annoyed me a lot. That annoyance led me to hate the copy as I was searching for the app name and tried to skim the text. This is probably the first time I write any feedback to internet. I am usually not one that does that kind of thing haha. Ok, now I will search and install the app. I bet it’s great.
- okatbest 2y ago
  Hey that's very odd, would you mind telling me which country/region you are located in? I actually released the app yesterday but didn't post about it til today because it wasn't being indexed properly on the App Store yet, it's possible that it's still not live everywhere. I have an image link to the listing in the first section of the web page and if on iPhone it should show you the classic "this website has an app" banner at the top. If you're searching for it, "Grooved" has many results but if you accept the suggestion of "Grooved: turntable calibration" it'll come up. This is a direct link to the store page: https://apps.apple.com/app/grooved-turntable-calibration/id6479003866 https://apps.apple.com/app/grooved-turntable-calibration/id6... Please let me know if it still doesn't work and I can take a look... Thanks!
  - plastic3169 2y ago
    I figured that the site breaks with apple lockdown mode on. I think that appstore links usually work still, but might be that that’s one of the lockdown mode protections. The spinning animation also was not there so I didn’t see the app logo there.
    - okatbest 2y ago
      That's very good to know, I didn't even think to test it with lockdown mode! I'll see if I can add a fallback page if the content is missing. Thanks!
kazinator 2y ago
I'm skeptical; you have no idea whether a random song from a record player is in tune or not, without a reference copy of that song from digital media. Is this zeroing in on traces of 60 cycle hum in the recording? Or else, won't it adjust an out-of-tune song to be in concert pitch? (Mind you, that would be extremely useful if you're playing along with the track and don't want to adjust your instrument, or cannot do so.) To get it to the correct speed, I would go through my record collection and find a tune with long, sustained notes. Find the same tune on Youtube and get a pitch reference for the note using a digital tuner. Then adjust the record player to match the pitch on that note, down to 1/10 of a Hz precision. (In the first place, why would you have a record player without a built-in strobe light for adjusting the speed in 2024, when this was a common item even in lower income households in 1984.)
- echoangle 2y ago
  60 cycle hum probably would not work, europe uses 50hz
  - kazinator 2y ago
    That's a big enough discrepancy that the program could have heuristics to figure it out, particularly if the record player is in the right ballpark. Also west Japan is 50, east 60. The main problem is: (1) there isn't a lot of hum on professionally produced records; (2) but there may be hum from the equpiment itself.
- okatbest 2y ago
  Unfortunately a lot of mid-range tables nowadays don't have the strobe (mine included), most likely for aesthetic reasons... Even just looking at online shopping right now I only see a handful that do have it. As for being skeptical, good! That means I'm doing something great according to Clarke's third law. You can see me testing out the app on multiple records here: https://twitter.com/OKatBest/status/1795453042994680148 https://twitter.com/OKatBest/status/1795453042994680148 The results aren't 100% perfect, and they definitely won't be as good as matching specific frequencies, but it'll get you very close to the ideal RPM.
shudza 2y ago
I've used to use an app (there are many) which measures angular velocity using accelerometer and displays RPM (you place the phone on the turntable). I can't see why would anyone need something other than that.
- hobofan 2y ago
  Complete noob here, but wouldn't the phones weight (especially with how big phones are nowadays) have a significant impact on the RPM by slowing it down?
  - svantana 2y ago
    It's very possible, increased weight will increase friction in the bearing. However my iphone SE weighs almost the same as a 12-inch record (150g). BUT it is also more difficult to place symmetrically on the turntable, which also could affect friction.
peter_l_downs 2y ago
Strongly recommend updating your website to lead with some variation of "This is an offline iPhone app to help you calibrate your turntable's speed, all you need to do is play your records and the app will show you the current RPM" — wayyyyyyy too many words and other nonsense before I could figure out this is what it did. Embed the demo video (the tweet you linked) too! Looks great and if I still used records I would try it out! Congratulations on the launch. EDIT: keep the rest of the writing if you'd like, I have no objection to it and I thought it was funny. But lead with what the app is and what it does!
- gamegod 2y ago
  Yeah, but he gets great time-on-site engagement numbers by doing that. Somebody give this guy a job in Silicon Valley!
- berkes 2y ago
  Maybe they already changed it, but there's a chapter "As easy as 1-2-3." I'd personally move that way up. I had to scroll across all sorts of fluff and effects. I was sold by this (edit: this chapter, not the fluff) Maybe I'd personally even research how to make the entire website just that. Where maybe step 0 is "install the app" :D The (promised) simplicity of the app doesn't show in the communication of the website at least.
- joebergeron 2y ago
  I thought the copy was fun and don't mind a good soapbox every once in a while, but yeah, wouldn't hurt to slip in a few words about what exactly the product does earlier on. I'll definitely be trying this out on my decks before my next set :)
  - peter_l_downs 2y ago
    Updated my comment for clarification, agreed the extra copy is fun. Also hi joe :^)
- gchamonlive 2y ago
  > Let's be real, if this charade of a website was an actual startup, we'd probably wear t-shirts that say... It's intentional. The app is free. There is a statement about this whole corp mission mindset. This is the way it is. If people don't like it or push it away from the product, they are not the target audience. I think this is brilliant. I understood immediately what the app does and kudos for the courage in setting the website the way it is. Was also impressed with the aesthetic of the site. If only I had a turntable...
miah_ 2y ago
This is a neat idea. I don't know why it needs to be an app on a phone though. I guess you "know" a phone has a microphone and the setup is minimal and you have a api for everything? It being a phone app leads me to believe the 'no data collected' bit is temporary as all phone apps eventually gobble data to sell. I have an Android so I can't try this out, as its in 'private beta' on Android currently. Would love to see this as a open source project that I can install on Windows or Linux though.
- okatbest 2y ago
  Probably a smart idea to be suspicious of new apps, though I will say I am someone who care deeply about privacy. You can take a look at my previous project Boop ( https://boop.okat.best/ https://boop.okat.best/ ), which is open source and has been on the App Store for 6 years, yet I still don't have any analytics or data collection in it. I have no clue how many people use it beyond download figures I get from Apple. I have considered making this app open source, and it may still happen in the future, but I do want to release the Android version first. I'm worried that somebody will see my code, repackage it with a new name, beat me with better SEO (which would be easy considering how dumb the copy is on my website) and sell it for profit before I have a chance to reach a wider audience. This is something that did happen with Boop, not a hypothetical. The reality is that this app cannot collect anything valuable either way. It's a simple serving app that only uses your microphone for a couple of seconds at a time, and I assume most people will delete it once it serves its purpose. If I wanted to monetize it, the best way would be to add a "Pro" version with a subscription or to add ads, but I have no interest in doing either. This is a fun side project/portfolio piece, and I'd rather collect internet love distributing a ton of free copies, rather than sell a small fraction of that number of paid copies for $0.99 and have to deal with things like marketing, taxes, and customer support.
  - saganus 2y ago
    You are the Boop author!? Awesome! I use it and it's very handy. Thanks for creating useful no-nonsense tools!
    - 2y ago
thekegsi 2y ago
You can get apps where you place your phone on the turn table and it directly measures the turntable speed using either gyroscope or compass https://play.google.com/store/apps/details?id=com.vinylrpm&hl=en_IE&gl=US&pli=1 https://play.google.com/store/apps/details?id=com.vinylrpm&h...
- zamadatix 2y ago
  Here I was thinking it'd be smart to have the app use the camera to figure out how fast the middle label is spinning around but this seems way simpler now that you mention it.
- okatbest 2y ago
  This is how this project started! I thought I was super smart figuring out I could do that, then I realized there are many apps that already do the same thing. Eventually I decided to see if I could find a novel, more user-friendly approach that doesn't require you to put a thousand-dollars phone on a fast moving spinning thingie, and that's how Grooved came to be.
YawHawHawn 2y ago
[dead]
egypturnash 2y ago
All the turntables in my life as a kid had built-in calibration, in the form of four rows of repeating black/silver squares on the side of the wheel, a light flickering at the mains frequency, and a little dial to adjust the turning speed until the row of squares corresponding to your current combination of 50/60 hz DC and 33/45 RPM appeared to stop moving. It was a very clever trick.
- crazygringo 2y ago
  I never knew what the heck those squares were for! Just thought they were some funny aesthetic choice from the 70's and 80's. Thanks for giving me the definitive answer for something that has always seemed odd to me.
- hinkley 2y ago
  We have replaced a lot of stepper motors with a more refined version of this using stripes and a photoreceptor. Printers for instance. Surely there must be turntables doing the same thing?
- c5karl 2y ago
  I would think that any turntable that allows for adjustment of the speed of the motor would have this already (based on my limited experience with turntables from decades ago). So, nice little app, but if it shows you the error of a non-adjustable turntable, it won't have a lot of practical applications.
- taylodl 2y ago
  You had access to nicer turntables as a kid! That was a distinguishing feature between the more "serious" music hobbyist and the person who just wanted to play some tunes. I haven't messed around with a turntable in over 20 years but these days, only the supposed "serious" music hobbyist would be using a turntable and I'd think anyone making a turntable that didn't have this adjustment would be laughed out of the market. What are you going to tell me next - they're also using belt drive, a plastic needle, and a tone arm with a non-adjustable counterweight?! :)
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dmd 2y ago
I've tried this on a dozen or so records and all I get is "Please made sure your device can hear the music, and that you're using a modern song with a clearly defined beat." (There is definitely a very well defined beat.)
- okatbest 2y ago
  That's odd, could you share an example of a record you use? Are those fairly popular/common records? Also, do you see the little disk outline moving during the analysis? This would confirm that your phone can hear the sound coming out of your record player (just to be safe: you need to play the song out loud)
  - dmd 2y ago
    I've tried the White Album, Tiffany (I think we're alone now), and a bunch of songs on Cake Comfort Eagle. No, the disk is not moving at all! It's turned up pretty loud.
    - okatbest 2y ago
      That's super odd. So it's not even rotating? There might be an issue that occurs before the analysis starts. If you don't mind, do you have any special setting on? Lockdown mode or something? Are you able to play the music back if you use the Voice Memo app to record a bit of it? Sorry about all that, hopefully we can figure out what's wrong!
      - dmd 2y ago
        Yep, voice memo works fine, not on lockdown (not sure what that is).
        Omni5cience 2y ago
        Basically it's a setting for people who are concerned about being targeted by 0days. > Lockdown Mode is an optional, extreme protection that’s designed for the very few individuals who, because of who they are or what they do, might be personally targeted by some of the most sophisticated digital threats. https://support.apple.com/en-us/105120 https://support.apple.com/en-us/105120
strongpigeon 2y ago
Nice work! This looks really good. I'm not in the intended audience as I don't have a turntable, but if I had one I feel like I would be much more likely to use this if it was a web app. If I didn't know about this app beforehand, I'm pretty sure I'd be looking on Google rather than the App Store. That being said, you made this app for yourself and it looks great. Congrats on shipping!
virskyfan 2y ago
Great! In the past I've used the app that measures the turntable speed through its accelerometer...it's somewhat uncomfortable and weird to set the mobile on the turntable, start and stop once and again. Would love to see a comparison of measurements taken with your app and the one using the accelerometer...calibration is a huge thing in engineering.
- okatbest 2y ago
  I'm gonna be honest, using the accelerometer will definitely be more accurate because you can take more samples over a longer period of time. That's how this project started, but I also felt uncomfortable putting my brand new phone on a fragile player and even more so asking other people to do the same. Grooved is still very accurate, especially if you run multiple measurements to confirm on multiple songs/records. The threshold for "perfection" in the app is 0.01%, which to me anything beyond that is a rounding error and I could not tell the difference in my tests. This is equal to a drift of about a third of a second over an hour of listening.
chriscjcj 2y ago
So is this just a test to see if it's playing records at the right speed? Does it do anything else? Is it comparing it to a known-good recording of the song or is it measuring how many cents the song deviates from a natural key? If it's the latter, I can say that I have many many records don't play back in a natural key. I have several records (45's) in my collection whose hole is not punched perfectly in the center and the pitch wavers up and down as the record rotates. How would this app react to that and what suggestion might it make to mitigate?
- nomel 2y ago
  Oh, you could probably solve that concentricity error by looking at the subtle repetitive wobbles in the spectrum. Period of the wobble would be related to the radius from the center, and the amplitude of the spectral shift would be relative to the radius and the concentricity error. I suspect modern direct drive could handle the modulation of their speed. I suspect this has been done already.
verelo 2y ago
So this is super cool but i am questioning its reliability after playing a song from Spotify on my Sonos and then letting the app listen: the result was 0.1% too slow? I guess that’s a very small difference, what’s the degree of error to expect here?
- nickthegreek 2y ago
  I just played Bad Religion - Incomplete on YT Music through Sonos, app said "That's pretty much perfect". Played the same track on vinyl, app reported 3.5% too fast. Dev answered elsewhere on the post that .01% is required for the perfect message.
- okatbest 2y ago
  So this is an excellent question, because no joke I have noticed the same thing testing with Spotify. Apple Music does not have that issue. Makes me wonder: do different streaming services get different masters? Or, is Spotify having playback issues? To the app, they both should sound the same. I intend to do some research with that when the fog clears out a bit and the Android version is out.
kernal 2y ago
Made with Flutter?
Balgair 2y ago
Great idea! Thank you! However, I don't think I'll ever use it. My turntable doesn't have an adjustment for speed outside of 45s. So, if I find out that my table is too fast or slow, that's just going to bug me forever. So, I'd rather not know, seeing as I'm enjoying the music just fine as is. If you can, try selling this out to an adjustable turntable manufacturer in stock options, so that when all the people find out their turntable doesn't spin quite right and then go spend to buy a new one they can adjust, you'll make even more money.
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ThomasBb 2y ago
Very nifty; thanks for building this. Great excuse to put a record on my player. Mine was 0.2% slow apparently…
Object0541 2y ago
It would be exciting to try your app, cause I have 2 turntables to calibrate, but I don't use google play store. Could you make it available on f-droid?
criddell 2y ago
I wonder if this would work playing The Shaggs' Philosophy of the World record? It's notorious for having untuned guitars and the drummer doesn't seem to be following any kind of pattern.
Animats 2y ago
You can get test records which have a constant tone recorded. That's the right tool for this. Not only can you measure speed, you can see small speed variations - wow, flutter, etc.
czottmann 2y ago
I have zero use for this app (I own no turntable), but I absolutely dig the website. Well done on what you wrote, how you wrote it, and how good it all looks!
drewbeck 2y ago
This is cool although it very confidently asserted that a 45 rpm 12” single was a perfect! 33 1/3 rpm. Which suggests this is using song recognition and not discovering some underlying truth of the spinning platter.
- hunter2_ 2y ago
  Very good data point for the folks wondering if it's detecting the period of wow or scratches -- this likely proves that it's not (unless it can adapt to all common RPMs, but then it would show that). frequencySkew from ShazamKit, as mentioned elsewhere here, is my guess.
Lio 2y ago
Neat idea. For some reason I thought this might be for calibrating cartridge alignment. If someone can come up with an easier way to correct that it would be amazing.
coloneltcb 2y ago
this is very cool! Just tried this on my TT (Pro-Ject Carbon Debut EVO) and got a perfect 33 1/3 and had to brag thanks for making this, and in general I love digital experiences that match with analog media, please keep making more and lmk if you want any free ideas
Terr_ 2y ago
Random though from non-vinyl-aficionado here: Is there an easy way to temporarily leave a mark (and thus a sound) on the surface of the record, so that you can easily measure the time of each revolution without damaging the record or the needle? At first I thought of a small square of scotch-tape, although I expect that might "catch" and damage the stylus. Perhaps blu-tack? A big water droplet?
- jansan 2y ago
  There are weights with strobe patterns that you can put on.
  - Terr_ 2y ago
    I know you can buy strobe mats/discs and view them under a precisely flickering light (sometimes fluorescent lights with the right power-grid frequency) but I guess I was trying to think of something one could use in a pinch that wouldn't involve a separate purchase of things beyond household items. (Excluding the smartphone, which I assumed would be ubiquitous.)
smackeyacky 2y ago
Cool idea but for a surprising reason I don't need it. Towards the end of the classic era of Japanese hi-fi, even mid-fi turntables out of Japan made this app superfluous. There were quite a few "quartz locked" models which offer great speed fidelity without having to muddle around with anything. As an example, the Technics SL1400 Mk 2 is a quartz locked, direct drive table that has a little window so you can see the speed on the turntable markings AND has digital adjustment of the speed, not that you ever need to move it off 0 because it's already spot on. I also have a cheaper JVC table (QL-A2) which doesn't have the crazy adjustability of the Technics, but is still spot-on all the time. I can see this app being useful for cheap, modern belt drive garbage they are shovelling out now.
- lomase 2y ago
  You talk like belt drive turntables are something new. Most people had belt turntables. Direct drive and stroboscopic quartz are only a must for djs.
whynotkeithberg 2y ago
Wow really cool! I am going to be setting up my SL-1200 soon and I can't wait to test it out with this app.
- recursive 2y ago
  You'll have the calibration strobe markings built in which are at least as accurate.
ginkgotree 2y ago
This is awesome. As a fellow (dare I say luddite), technologist that hates the centralized greed digital internet tech has enabled with media, vinyl records are an outstanding hold out for individuals to still archive (and OWN!) their music. Thank you for investing in the movement with your valuable hours in making this app.
nhggfu 2y ago
sounds very niche and very useful. +1000 coo pints from me that you don't even try to monetize via BS. I hope that you have an option for happy customers to buy you a beer or make a donation!
rustdesk 2y ago
You are genius.
alecsandra 2y ago
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jzemeocala 2y ago
I wonder how this would behave with the two different speed versions of the Beatles song revolution
hilti 2y ago
Thank you for your work! I‘ll download it and calibrate my WEGA P3440 turntable as soon as I‘m back home.
emsign 2y ago
I don't like how it doesn't explain how it works.
belthesar 2y ago
I'm not a turntable owner myself, so the app doesn't offer a lot of value to me. In thinking about it though, this app reminds me of the early days of mobile apps, where folks made neat, useful little tools to make life better. It wasn't about making a platform, or figuring out how to make a six figure sum, just a neat little ecosystem of fun and useful tools made by folks that had a problem to solve, and thought someone else might find it useful. I see that it's free, but I feel like this could have easily been a $1 app. Grats on making a really neat little focused tool!
grantmuller 2y ago
This is fantastic. In the span of 5 minutes I had my old record player calibrated. Really great work.

452 points by okatbest 2y ago

sans_souse 2y ago

thank you Ivan looking forward to an android version!

gen3 2y ago

Neat POC, are you doing a song fingerprint then comparing speed/stretch?

KeplerBoy 2y ago

That really is a lot of copywriting for a bunch of FFTs, but nicely done.

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echelon 2y ago

I'm not an expert on vinyl. The only record players I've interacted with have only had two speeds. Do most of them do variable spin rates? How frequently do the rates get out of sync? What causes it? Do they vary on an album by album basis?

CaptainOfCoit 2y ago
> I'm not an expert on vinyl. The only record players I've interacted with have only had two speeds. Do most of them do variable spin rates? Lots of turntables have variable speed, DJs can tell you more about it :) > How frequently do the rates get out of sync? What causes it? Do they vary on an album by album basis? When you're DJing, one of the main things you'd deal with, is making things be in sync, one way or another. I'm not sure how much value you'd get from an app like this that seems to be more "fire and forget" and not for on-the-fly matching. I'm guessing this app is for people who do their own maintenance, repairs and such of turntables, so they can easily verify their work.
- hnlmorg 2y ago
  I don’t think this would be aimed at DJ turntables. It doesn’t matter if those things drift because you’re never playing anything locked in at a specific RPM. Plus DJ turntables tend to be direct drive, which should be pretty consistent. Where as consumer record players tend to be more belt drives. And I’m assuming those belts can stretch with time?
  - CaptainOfCoit 2y ago
    > I don’t think this would be aimed at DJ turntables I agree :) > Plus DJ turntables tend to be direct drive, which should be pretty consistent Indeed, but once you start doing repairs and/or modifications, things can get fuzzy. Maybe the app would help those people?
    - LM358 2y ago
      People who are serious about turntable repair have calibration records with sine waves for that purpose.
beAbU 2y ago
Fancy record players have a trim setting where you can fine adjust the speed up or down a semitone. But all of them have a built in stroboscope/calibrator to help get the speed right. I think the drag of the needle impacts the speed, hence the desire to tune it per record. Audioplebs need not apply.

patrakov 2y ago

Does it rely on the fact that music has a concept of notes with well-defined frequencies and that there is no such thing as 216 Hz (must be 207.6 or 220 Hz) when the music is played on a properly tuned instrument? Or does it use other heuristics?

franky47 2y ago
A "properly tuned instrument" still requires a base frequency (usually defined for A4). Whether to use 440Hz or another slightly different frequency is a fun debate to get into.
- datpiff 2y ago
  Older recordings on analog media also can have timing error at the recording stage or duplication stages.
astral303 2y ago
I tried it out and the instructions have tips on what record to pick, they say to pick a well known version of a song (like not a live version etc), and preferably song with a beat, but it says it doesn’t use any 3rd party APIs or libraries, only Apple APIs. So my guess at to what it’s doing is using a ShazamKit recognition behind the scenes and looking at the frequencySkew value of the matched result. It also gives you one answer after listening, instead of a continuous gauge, which seems to corroborate song recognition. It probably won’t work with an obscure record that is not Shazamable. And so I don’t think it can measure wow & flutter as a result. Still pretty cool for those that need to calibrate a turntable, or verify 33 vs 45 PRM for a record.
- netsharc 2y ago
  I guess a phone's camera can be used to count the RPM, e.g. by filming the label and counting how many milliseconds it needs to do a full rotation (1818ms for a 33 RPM record)
  - 2y ago

tirthd 2y ago

Great copywriting. It's very rare that I read an entire paragraph without skipping a word.

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empath75 2y ago
I actually disagree. There's a lot of extraneous stuff about app stores that's probably appealing to app developers but are developers the audience or audiophiles?
turnsout 2y ago
Agreed—and it does feel like the Apple-inspired copywriting style the author is complaining about is feeling extremely (wait for it) played. Absolutely every site is like: "Lawn Order. The X900's diamond-tipped rotary blades cut your grass to within 50 microns of your desired length. Overkill? Absolutely. Because it's not just your lawn—it's our passion."

arytoriop 2y ago

This is really cool.

shiandow 2y ago

This just tells you the speed, not the variation in speed over time?

okatbest 2y ago
That's correct. The analysis takes a few seconds so even if I take more samples, it all gets averaged over time and won't be able to do instant read. If you're interested in measuring wow and flutter I think you'll need to look at more traditional calibration methods unfortunately.

gaudystead 2y ago

I'm just here to say that I enjoyed that intro you gave to the website, and although I hate unitaskers in the kitchen, that intro helped to remind me of the magical wonder of them in the early days of "The Modern Smartphone". Cool app and thanks for sharing! :D

nickthegreek 2y ago

Just put a record on yesterday and my wife said it was playing too fast. I thought she was wrong, then I see this post today! I grabbed the app and gave it a go, 3.5% too fast according to your app. Now I have to figure out how to adjust the damn thing. Really appreciate a free nonsense free app. update: youtube to the rescue. pretty common affordable turntable( Audio-Technica LP60), so I figure I would put the vid link here for others who might want to know - https://www.youtube.com/watch?v=d3PdS2V8Jz0 https://www.youtube.com/watch?v=d3PdS2V8Jz0

okatbest 2y ago
Hey that's awesome to hear, thanks for trying it out! This is exactly what I hoped for when building this app. Making a dead simple tool for people who want their records to sound better, but may not have the equipment or knowledge necessary to adjust it.
kazinator 2y ago
3.5% is a lot! One semitone is a bit shy of 6 percent.s It's between 59 and 60 cents: more than a quarter semitone. Exact value: 1> (* 1200 (log2 1.035)) 59.5569212695205 So 59.6 to 3 sig figs. Someone with a good pitch memory of a tune (hearing in their head how it should sound) would spot such a difference. Especially if they heard the tune recently.
- criddell 2y ago
  So many recordings (especially before 2000) seem to be sped up a little. I can’t tell by listening to the song but when you try to play along with a guitar, it sounds terrible. Sometimes it helps to find a live version on YouTube.
  - taylodl 2y ago
    Correct. That was often done when mastering with tape. Record at one speed, playback at another to make it sound more "lively." There are songs that were sped up that way anywhere from 25 to 40 cents. It's another reason why live music so often doesn't sound like the recording. When using digital mastering, you can also adjust the playback speed, but you can correct the shift. You get more "liveliness" without the shift change. That's why you're not hearing the pitch shift so much in more recent music.

crazygringo 2y ago

This seems really clever -- kudos! I'm curious how it actually works? At first I assumed you were comparing the vinyl track to the reference digital track from some streaming service and either analyzing the frequencies with FFT or the timing of peaks. But I watched your demo video and you don't need to tell it anything about the song. Which makes me think you're rather doing an FFT and simply trying to match how well the frequencies align to the well-tempered scale based on A 440 hZ. Which then leads me to three questions: 1) Obviously this wouldn't work if you were playing a standup comedy album or something? Or the drum solo part of a song? 2) Are essentially all albums perfectly in tune with A 440 hZ? For example with classical music, I understand that 442 is also used, baroque is sometimes at 415, and 432 has been common as well? I don't know about pop but I can't help but wonder if some artists have intentionally chosen something other than 440 over the decades. 3) I assume this won't work if the turntable speed is off by more than 2.8%? Since the distance from A4 (440 hZ) to A-flat-4 (415.30 hZ) is a decrease of 5.6%, and so if the turntable is off by more than half of that you'd be trying to align to the wrong note?

datpiff 2y ago
> Are essentially all albums perfectly in tune with A 440 hZ? For example with classical music, I understand that 442 is also used, baroque is sometimes at 415, and 432 has been common as well? I don't know about pop but I can't help but wonder if some artists have intentionally chosen something other than 440 over the decades. No they are not all tuned to 440Hz. This is really evident if you play an instrument and want to play along with an album.
- iaresee 2y ago
  Every. Rolling. Stones. Album.
sambeau 2y ago
My first thought was that it is listening to the scratches rather than the music, but I guess they speed up as the record gets played and the arm moves inwards. So, my second guess is that it's listening to the pitch of the notes being played. Of course, old albums (especially punk albums) are probably tuned to whatever worked on the day—maybe a tuning fork, possibly a piano, maybe just to one of the instruments.

lukko 2y ago

This is cool - not sure if it's possible, but it would great if you could determine other things, like is the needle weight correct, or is the cartridge aligned properly (maybe left / right channel would be louder / softer??). I found the copy on the site a bit gross - I'm not sure something like this needs a critique of modern copywriting, and for me it gives that same weird sense of over familiarity ('we get you') that I think it's trying to criticise.

mk_stjames 2y ago

So here's another method that doesn't rely on the song being detected or even a song at all: The gyroscope on your phone is accurate enough to measure RPM to about the first decimal place at 33 1/3 - 45 rpm's just by placing your phone on the turntable flat and letting it spin.

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sambeau 2y ago

Very cool. Great aesthetic and copy. No notes.

gcp123 2y ago

What a perfectly simple app! Going to try this out with my Technics SL1200 mk2 tonight. Thanks for sharing. P.S. Reading comments from a bunch of tech folks trying to wrap their heads around an app for calibrating analogue music playback device is very amusing. :-)

bastardoperator 2y ago
I assume this is for belt driven turntables, not direct drive. I also have a pair of 1200's. Most mixers these days have BPM built in, and before that you had red micro bpm counters and headphone amps to validate BPM. Never once on my 1200's did it read something outside of the producers BPM count when pitch was locked.
- fmj 2y ago
  My MK2 was off by about 3% when the pitch adjust was in the detent. To be fair, it had a rough life before it ended up in my hands. If you have a frequency counter they're pretty easy to calibrate the correct way though.
  - CoffeeOnWrite 2y ago
    Did the delta show up on the strobe? Or is issue that the quartz is off and it’s feeding both the motor and the strobe? (Sorry if this is a dumb question. I don’t recall seeing speed calibration in the mk2 manual when I was setting up my secondhand decks)
    - fmj 2y ago
      I honestly can't remember if it showed up in the strobe or not, this was a few years ago. This procedure wouldn't be listed in the regular manual. It involves opening it up to adjust an internal potentiometer, and can't be reliably done without a frequency counter (I guess you could do it through trial and error, but it would take forever having to reassemble it and play a test disc after every adjustment,) so it is only in the service manual. You should be able to find a scan pretty easily though. Can't remember what frequency you need to hit, but it's low. If you don't have a proper frequency counter an Arduino will work just fine.

plastic3169 2y ago

Looks amazing and useful for me! The links don’t take me to the app store on my iphone and the app name is not in the heading I need to scroll past the copy to find what to search for. Minor annoyance but for some reason annoyed me a lot. That annoyance led me to hate the copy as I was searching for the app name and tried to skim the text. This is probably the first time I write any feedback to internet. I am usually not one that does that kind of thing haha. Ok, now I will search and install the app. I bet it’s great.

okatbest 2y ago
Hey that's very odd, would you mind telling me which country/region you are located in? I actually released the app yesterday but didn't post about it til today because it wasn't being indexed properly on the App Store yet, it's possible that it's still not live everywhere. I have an image link to the listing in the first section of the web page and if on iPhone it should show you the classic "this website has an app" banner at the top. If you're searching for it, "Grooved" has many results but if you accept the suggestion of "Grooved: turntable calibration" it'll come up. This is a direct link to the store page: https://apps.apple.com/app/grooved-turntable-calibration/id6479003866 https://apps.apple.com/app/grooved-turntable-calibration/id6... Please let me know if it still doesn't work and I can take a look... Thanks!
- plastic3169 2y ago
  I figured that the site breaks with apple lockdown mode on. I think that appstore links usually work still, but might be that that’s one of the lockdown mode protections. The spinning animation also was not there so I didn’t see the app logo there.
  - okatbest 2y ago
    That's very good to know, I didn't even think to test it with lockdown mode! I'll see if I can add a fallback page if the content is missing. Thanks!

kazinator 2y ago

I'm skeptical; you have no idea whether a random song from a record player is in tune or not, without a reference copy of that song from digital media. Is this zeroing in on traces of 60 cycle hum in the recording? Or else, won't it adjust an out-of-tune song to be in concert pitch? (Mind you, that would be extremely useful if you're playing along with the track and don't want to adjust your instrument, or cannot do so.) To get it to the correct speed, I would go through my record collection and find a tune with long, sustained notes. Find the same tune on Youtube and get a pitch reference for the note using a digital tuner. Then adjust the record player to match the pitch on that note, down to 1/10 of a Hz precision. (In the first place, why would you have a record player without a built-in strobe light for adjusting the speed in 2024, when this was a common item even in lower income households in 1984.)

echoangle 2y ago
60 cycle hum probably would not work, europe uses 50hz
- kazinator 2y ago
  That's a big enough discrepancy that the program could have heuristics to figure it out, particularly if the record player is in the right ballpark. Also west Japan is 50, east 60. The main problem is: (1) there isn't a lot of hum on professionally produced records; (2) but there may be hum from the equpiment itself.
okatbest 2y ago
Unfortunately a lot of mid-range tables nowadays don't have the strobe (mine included), most likely for aesthetic reasons... Even just looking at online shopping right now I only see a handful that do have it. As for being skeptical, good! That means I'm doing something great according to Clarke's third law. You can see me testing out the app on multiple records here: https://twitter.com/OKatBest/status/1795453042994680148 https://twitter.com/OKatBest/status/1795453042994680148 The results aren't 100% perfect, and they definitely won't be as good as matching specific frequencies, but it'll get you very close to the ideal RPM.

shudza 2y ago

I've used to use an app (there are many) which measures angular velocity using accelerometer and displays RPM (you place the phone on the turntable). I can't see why would anyone need something other than that.

hobofan 2y ago
Complete noob here, but wouldn't the phones weight (especially with how big phones are nowadays) have a significant impact on the RPM by slowing it down?
- svantana 2y ago
  It's very possible, increased weight will increase friction in the bearing. However my iphone SE weighs almost the same as a 12-inch record (150g). BUT it is also more difficult to place symmetrically on the turntable, which also could affect friction.

peter_l_downs 2y ago

Strongly recommend updating your website to lead with some variation of "This is an offline iPhone app to help you calibrate your turntable's speed, all you need to do is play your records and the app will show you the current RPM" — wayyyyyyy too many words and other nonsense before I could figure out this is what it did. Embed the demo video (the tweet you linked) too! Looks great and if I still used records I would try it out! Congratulations on the launch. EDIT: keep the rest of the writing if you'd like, I have no objection to it and I thought it was funny. But lead with what the app is and what it does!

gamegod 2y ago
Yeah, but he gets great time-on-site engagement numbers by doing that. Somebody give this guy a job in Silicon Valley!
berkes 2y ago
Maybe they already changed it, but there's a chapter "As easy as 1-2-3." I'd personally move that way up. I had to scroll across all sorts of fluff and effects. I was sold by this (edit: this chapter, not the fluff) Maybe I'd personally even research how to make the entire website just that. Where maybe step 0 is "install the app" :D The (promised) simplicity of the app doesn't show in the communication of the website at least.
joebergeron 2y ago
I thought the copy was fun and don't mind a good soapbox every once in a while, but yeah, wouldn't hurt to slip in a few words about what exactly the product does earlier on. I'll definitely be trying this out on my decks before my next set :)
- peter_l_downs 2y ago
  Updated my comment for clarification, agreed the extra copy is fun. Also hi joe :^)
gchamonlive 2y ago
> Let's be real, if this charade of a website was an actual startup, we'd probably wear t-shirts that say... It's intentional. The app is free. There is a statement about this whole corp mission mindset. This is the way it is. If people don't like it or push it away from the product, they are not the target audience. I think this is brilliant. I understood immediately what the app does and kudos for the courage in setting the website the way it is. Was also impressed with the aesthetic of the site. If only I had a turntable...

miah_ 2y ago

This is a neat idea. I don't know why it needs to be an app on a phone though. I guess you "know" a phone has a microphone and the setup is minimal and you have a api for everything? It being a phone app leads me to believe the 'no data collected' bit is temporary as all phone apps eventually gobble data to sell. I have an Android so I can't try this out, as its in 'private beta' on Android currently. Would love to see this as a open source project that I can install on Windows or Linux though.

okatbest 2y ago
Probably a smart idea to be suspicious of new apps, though I will say I am someone who care deeply about privacy. You can take a look at my previous project Boop ( https://boop.okat.best/ https://boop.okat.best/ ), which is open source and has been on the App Store for 6 years, yet I still don't have any analytics or data collection in it. I have no clue how many people use it beyond download figures I get from Apple. I have considered making this app open source, and it may still happen in the future, but I do want to release the Android version first. I'm worried that somebody will see my code, repackage it with a new name, beat me with better SEO (which would be easy considering how dumb the copy is on my website) and sell it for profit before I have a chance to reach a wider audience. This is something that did happen with Boop, not a hypothetical. The reality is that this app cannot collect anything valuable either way. It's a simple serving app that only uses your microphone for a couple of seconds at a time, and I assume most people will delete it once it serves its purpose. If I wanted to monetize it, the best way would be to add a "Pro" version with a subscription or to add ads, but I have no interest in doing either. This is a fun side project/portfolio piece, and I'd rather collect internet love distributing a ton of free copies, rather than sell a small fraction of that number of paid copies for $0.99 and have to deal with things like marketing, taxes, and customer support.
- saganus 2y ago
  You are the Boop author!? Awesome! I use it and it's very handy. Thanks for creating useful no-nonsense tools!
  - 2y ago

thekegsi 2y ago

You can get apps where you place your phone on the turn table and it directly measures the turntable speed using either gyroscope or compass https://play.google.com/store/apps/details?id=com.vinylrpm&hl=en_IE&gl=US&pli=1 https://play.google.com/store/apps/details?id=com.vinylrpm&h...

zamadatix 2y ago
Here I was thinking it'd be smart to have the app use the camera to figure out how fast the middle label is spinning around but this seems way simpler now that you mention it.
okatbest 2y ago
This is how this project started! I thought I was super smart figuring out I could do that, then I realized there are many apps that already do the same thing. Eventually I decided to see if I could find a novel, more user-friendly approach that doesn't require you to put a thousand-dollars phone on a fast moving spinning thingie, and that's how Grooved came to be.

YawHawHawn 2y ago

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egypturnash 2y ago

All the turntables in my life as a kid had built-in calibration, in the form of four rows of repeating black/silver squares on the side of the wheel, a light flickering at the mains frequency, and a little dial to adjust the turning speed until the row of squares corresponding to your current combination of 50/60 hz DC and 33/45 RPM appeared to stop moving. It was a very clever trick.

crazygringo 2y ago
I never knew what the heck those squares were for! Just thought they were some funny aesthetic choice from the 70's and 80's. Thanks for giving me the definitive answer for something that has always seemed odd to me.
hinkley 2y ago
We have replaced a lot of stepper motors with a more refined version of this using stripes and a photoreceptor. Printers for instance. Surely there must be turntables doing the same thing?
c5karl 2y ago
I would think that any turntable that allows for adjustment of the speed of the motor would have this already (based on my limited experience with turntables from decades ago). So, nice little app, but if it shows you the error of a non-adjustable turntable, it won't have a lot of practical applications.
taylodl 2y ago
You had access to nicer turntables as a kid! That was a distinguishing feature between the more "serious" music hobbyist and the person who just wanted to play some tunes. I haven't messed around with a turntable in over 20 years but these days, only the supposed "serious" music hobbyist would be using a turntable and I'd think anyone making a turntable that didn't have this adjustment would be laughed out of the market. What are you going to tell me next - they're also using belt drive, a plastic needle, and a tone arm with a non-adjustable counterweight?! :)
- 2y ago

dmd 2y ago

I've tried this on a dozen or so records and all I get is "Please made sure your device can hear the music, and that you're using a modern song with a clearly defined beat." (There is definitely a very well defined beat.)

okatbest 2y ago
That's odd, could you share an example of a record you use? Are those fairly popular/common records? Also, do you see the little disk outline moving during the analysis? This would confirm that your phone can hear the sound coming out of your record player (just to be safe: you need to play the song out loud)
- dmd 2y ago
  I've tried the White Album, Tiffany (I think we're alone now), and a bunch of songs on Cake Comfort Eagle. No, the disk is not moving at all! It's turned up pretty loud.
  - okatbest 2y ago
    That's super odd. So it's not even rotating? There might be an issue that occurs before the analysis starts. If you don't mind, do you have any special setting on? Lockdown mode or something? Are you able to play the music back if you use the Voice Memo app to record a bit of it? Sorry about all that, hopefully we can figure out what's wrong!
    - dmd 2y ago
      Yep, voice memo works fine, not on lockdown (not sure what that is).
      - Omni5cience 2y ago
        Basically it's a setting for people who are concerned about being targeted by 0days. > Lockdown Mode is an optional, extreme protection that’s designed for the very few individuals who, because of who they are or what they do, might be personally targeted by some of the most sophisticated digital threats. https://support.apple.com/en-us/105120 https://support.apple.com/en-us/105120

strongpigeon 2y ago

Nice work! This looks really good. I'm not in the intended audience as I don't have a turntable, but if I had one I feel like I would be much more likely to use this if it was a web app. If I didn't know about this app beforehand, I'm pretty sure I'd be looking on Google rather than the App Store. That being said, you made this app for yourself and it looks great. Congrats on shipping!

virskyfan 2y ago

Great! In the past I've used the app that measures the turntable speed through its accelerometer...it's somewhat uncomfortable and weird to set the mobile on the turntable, start and stop once and again. Would love to see a comparison of measurements taken with your app and the one using the accelerometer...calibration is a huge thing in engineering.

okatbest 2y ago
I'm gonna be honest, using the accelerometer will definitely be more accurate because you can take more samples over a longer period of time. That's how this project started, but I also felt uncomfortable putting my brand new phone on a fragile player and even more so asking other people to do the same. Grooved is still very accurate, especially if you run multiple measurements to confirm on multiple songs/records. The threshold for "perfection" in the app is 0.01%, which to me anything beyond that is a rounding error and I could not tell the difference in my tests. This is equal to a drift of about a third of a second over an hour of listening.

chriscjcj 2y ago

So is this just a test to see if it's playing records at the right speed? Does it do anything else? Is it comparing it to a known-good recording of the song or is it measuring how many cents the song deviates from a natural key? If it's the latter, I can say that I have many many records don't play back in a natural key. I have several records (45's) in my collection whose hole is not punched perfectly in the center and the pitch wavers up and down as the record rotates. How would this app react to that and what suggestion might it make to mitigate?

nomel 2y ago
Oh, you could probably solve that concentricity error by looking at the subtle repetitive wobbles in the spectrum. Period of the wobble would be related to the radius from the center, and the amplitude of the spectral shift would be relative to the radius and the concentricity error. I suspect modern direct drive could handle the modulation of their speed. I suspect this has been done already.

verelo 2y ago

So this is super cool but i am questioning its reliability after playing a song from Spotify on my Sonos and then letting the app listen: the result was 0.1% too slow? I guess that’s a very small difference, what’s the degree of error to expect here?

nickthegreek 2y ago
I just played Bad Religion - Incomplete on YT Music through Sonos, app said "That's pretty much perfect". Played the same track on vinyl, app reported 3.5% too fast. Dev answered elsewhere on the post that .01% is required for the perfect message.
okatbest 2y ago
So this is an excellent question, because no joke I have noticed the same thing testing with Spotify. Apple Music does not have that issue. Makes me wonder: do different streaming services get different masters? Or, is Spotify having playback issues? To the app, they both should sound the same. I intend to do some research with that when the fog clears out a bit and the Android version is out.

kernal 2y ago

Made with Flutter?

Balgair 2y ago

Great idea! Thank you! However, I don't think I'll ever use it. My turntable doesn't have an adjustment for speed outside of 45s. So, if I find out that my table is too fast or slow, that's just going to bug me forever. So, I'd rather not know, seeing as I'm enjoying the music just fine as is. If you can, try selling this out to an adjustable turntable manufacturer in stock options, so that when all the people find out their turntable doesn't spin quite right and then go spend to buy a new one they can adjust, you'll make even more money.

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ThomasBb 2y ago

Very nifty; thanks for building this. Great excuse to put a record on my player. Mine was 0.2% slow apparently…

Object0541 2y ago

It would be exciting to try your app, cause I have 2 turntables to calibrate, but I don't use google play store. Could you make it available on f-droid?

criddell 2y ago

I wonder if this would work playing The Shaggs' Philosophy of the World record? It's notorious for having untuned guitars and the drummer doesn't seem to be following any kind of pattern.

Animats 2y ago

You can get test records which have a constant tone recorded. That's the right tool for this. Not only can you measure speed, you can see small speed variations - wow, flutter, etc.

czottmann 2y ago

I have zero use for this app (I own no turntable), but I absolutely dig the website. Well done on what you wrote, how you wrote it, and how good it all looks!

drewbeck 2y ago

This is cool although it very confidently asserted that a 45 rpm 12” single was a perfect! 33 1/3 rpm. Which suggests this is using song recognition and not discovering some underlying truth of the spinning platter.

hunter2_ 2y ago
Very good data point for the folks wondering if it's detecting the period of wow or scratches -- this likely proves that it's not (unless it can adapt to all common RPMs, but then it would show that). frequencySkew from ShazamKit, as mentioned elsewhere here, is my guess.

Lio 2y ago

Neat idea. For some reason I thought this might be for calibrating cartridge alignment. If someone can come up with an easier way to correct that it would be amazing.

coloneltcb 2y ago

this is very cool! Just tried this on my TT (Pro-Ject Carbon Debut EVO) and got a perfect 33 1/3 and had to brag thanks for making this, and in general I love digital experiences that match with analog media, please keep making more and lmk if you want any free ideas

Terr_ 2y ago

Random though from non-vinyl-aficionado here: Is there an easy way to temporarily leave a mark (and thus a sound) on the surface of the record, so that you can easily measure the time of each revolution without damaging the record or the needle? At first I thought of a small square of scotch-tape, although I expect that might "catch" and damage the stylus. Perhaps blu-tack? A big water droplet?

jansan 2y ago
There are weights with strobe patterns that you can put on.
- Terr_ 2y ago
  I know you can buy strobe mats/discs and view them under a precisely flickering light (sometimes fluorescent lights with the right power-grid frequency) but I guess I was trying to think of something one could use in a pinch that wouldn't involve a separate purchase of things beyond household items. (Excluding the smartphone, which I assumed would be ubiquitous.)

smackeyacky 2y ago

Cool idea but for a surprising reason I don't need it. Towards the end of the classic era of Japanese hi-fi, even mid-fi turntables out of Japan made this app superfluous. There were quite a few "quartz locked" models which offer great speed fidelity without having to muddle around with anything. As an example, the Technics SL1400 Mk 2 is a quartz locked, direct drive table that has a little window so you can see the speed on the turntable markings AND has digital adjustment of the speed, not that you ever need to move it off 0 because it's already spot on. I also have a cheaper JVC table (QL-A2) which doesn't have the crazy adjustability of the Technics, but is still spot-on all the time. I can see this app being useful for cheap, modern belt drive garbage they are shovelling out now.

lomase 2y ago
You talk like belt drive turntables are something new. Most people had belt turntables. Direct drive and stroboscopic quartz are only a must for djs.

whynotkeithberg 2y ago

Wow really cool! I am going to be setting up my SL-1200 soon and I can't wait to test it out with this app.

recursive 2y ago
You'll have the calibration strobe markings built in which are at least as accurate.

ginkgotree 2y ago

This is awesome. As a fellow (dare I say luddite), technologist that hates the centralized greed digital internet tech has enabled with media, vinyl records are an outstanding hold out for individuals to still archive (and OWN!) their music. Thank you for investing in the movement with your valuable hours in making this app.

nhggfu 2y ago

sounds very niche and very useful. +1000 coo pints from me that you don't even try to monetize via BS. I hope that you have an option for happy customers to buy you a beer or make a donation!

rustdesk 2y ago

You are genius.

alecsandra 2y ago

[dead]

jzemeocala 2y ago

I wonder how this would behave with the two different speed versions of the Beatles song revolution

hilti 2y ago

Thank you for your work! I‘ll download it and calibrate my WEGA P3440 turntable as soon as I‘m back home.

emsign 2y ago

I don't like how it doesn't explain how it works.

belthesar 2y ago

I'm not a turntable owner myself, so the app doesn't offer a lot of value to me. In thinking about it though, this app reminds me of the early days of mobile apps, where folks made neat, useful little tools to make life better. It wasn't about making a platform, or figuring out how to make a six figure sum, just a neat little ecosystem of fun and useful tools made by folks that had a problem to solve, and thought someone else might find it useful. I see that it's free, but I feel like this could have easily been a $1 app. Grats on making a really neat little focused tool!

grantmuller 2y ago

This is fantastic. In the span of 5 minutes I had my old record player calibrated. Really great work.