creating a calibration tool

[tester]

Let say that a soundcard is a device, that records at 44.1kHz. But if the soundcard is wrongly calibrated and it's 44.1kHz is a little bit more or less? (is it possible anyway? I heard about external recorders that are able to produce few Hz differences between each other while recording a reference tone at the same time).

Question. If for some reason - these 44.1kHz are faster or slower than it should be... are the recording inputs, and playback outputs driven by the same clock? I mean - will both - input and output - have the same type of error? For example - increasing amount of samples per second (at 44kHz sampling rate) on recording/input and then on output/playback?

[KG_is_back]

Let say that a soundcard is a device, that records at 44.1kHz. But if the soundcard is wrongly calibrated and it's 44.1kHz is a little bit more or less? (is it possible anyway? I heard about external recorders that are able to produce few Hz differences between each other while recording a reference tone at the same time).

Question. If for some reason - these 44.1kHz are faster or slower than it should be... are the recording inputs, and playback outputs driven by the same clock? I mean - will both - input and output - have the same type of error? For example - increasing amount of samples per second (at 44kHz sampling rate) on recording/input and then on output/playback?

Yes, soundcards are always a little offset. Usually when you use multiple AD converters on one soundcard you have an option to sinc them (I'ts quite common on adat sound cards). In that case one serves as a clock source and other uses that external clock. I believe input and output use the same clock (I could be wrong though). At least multiple inputs use the same clock.

[tester]

My scenario: uncalibrated signal source + uncalibrated recording/playback device + probably reference file/algorithm (for 1kHz sine wave). Goal - to calibrate soundcard (having no other tools) and to know how good is the signal source.

If any of them would be stable over time - maybe it would be doable just by iterative sound measurements. But I'm starting thinking towards some sort of other internal clock source (bus clock or something like that? these MHz things).

Mad science.