Or instead of using the preamp, you could use an editing tool to digitally amplify the recording back to the original level before comparing to the control.
Going a little further with this... one might ask if we could compare a digital attenuator and an analog attenuator side-by-side, using audiodiffmaker. The answer is yes, except that you'll be limited by the noise floor of the ADC in the PC. There, you get an analogous situation due to the incorrect gain staging - since the ADC has a finite SNR / dynamic range, by attenuating that input signal (by any means) you will effectively lose SNR in the recording. This is an important difference between using a PC for audio measurements as compared to a professional measurement tool. Something like an AP or Dscope will have internal stepped analog gain controls in front of the ADC, allowing it to keep the signal closer to full-scale amplitude to maximize resolution. On my Dscope these are controlled automatically by relays, and I can hear them clicking as I change the input level. None of this is to say a PC is a poor tool for audio measurements - quite the contrary. But it does have this important limitation with respect to this particular type of test. -- seanadams ------------------------------------------------------------------------ seanadams's Profile: http://forums.slimdevices.com/member.php?userid=3 View this thread: http://forums.slimdevices.com/showthread.php?t=60041 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles
