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Newbie question: how do we know we can trust the microphone? It sounds like a chicken-and-egg problem to equalize speakers with an equalized microphone, but ma
by qbonnard 4y ago
Newbie question: how do we know we can trust the microphone?
It sounds like a chicken-and-egg problem to equalize speakers with an equalized microphone, but maybe microphones are simpler and can be assumed to be equalized ?
- tibbon 4y agoYou’ll need a calibration curve for the microphone. Even of the same model, there is a lot of variance.
- doctorhandshake 4y agoThere’s an example of doing this on the readme- scroll way down
- gh02t 4y agoMiniDSP makes some calibration mics that run about 60 bucks. I used them as a cheap instrument for some lab work where I needed a calibrated mic a while back and was very impressed with their performance for the price. They ship with a little code that you can use to retrieve the calibration curve from the factory, and I know a lot of people use them for hifi calibration with REW.
- willis936 4y agoAnyone interested in this area should also know that above ~2 kHz it doesn't matter what you do for magnitude equalization because you'll be dominated by sub mm variations in position and direction. The only way to get any amount of repeatability above 2 kHz is with IEMs.
- erdewit 4y agoThis is dealt with by smoothing the spectrum in a way to preserves the power density. The constructive and destructive interference then cancel each other out.
- Gracana 4y agoWhat does "smoothing the spectrum" mean? What operations are being performed?
- danuker 4y agoI'd guess: Fourier transform, a power density preserving blur convolution, then inverse Fourier transform. But I am not familiar with the field of signal processing.
- willis936 4y agoThat's my guess too but my hunch is that would sound like absolute crap. Intentional IMD. Something to experiment with.
- AndrewUnmuted 4y ago
- O__________O 4y agoNot an audiophile, but one way might be tuning forks. That said, I would be super surprised if this was needed for high-end microphones.
- amluto 4y agoA microphone’s ability to reliably identify a frequency is excellent, even if the microphone is cheap, crappy and uncalibrated. It’s almost entirely a function of whatever clock is used to digitize it, and oscillator chips that are just fine are ubiquitous. The issue is calibrating the amplitude response at a given frequency, and a tuning fork won’t help. edit: those quartz oscillator chips have a lot in common with tuning forks.
- brokenmachine 4y agoNow I'm imagining using thousands of tuning forks with calibrated knockers.
- pier25 4y agoThere are cheap calibrated mics available. There's one for about $20 from Dayton Audio.
- Schroedingersat 4y agoA microphone that is linear to a dB or so is far cheaper than a speaker that is linear to 6dB and room treatment that maintains that.