seanadams;400273 Wrote: > 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.
An important distinction. On the FFT we use, there is an "idiot light" on the front panel that allows us to set the proper attenuation range. For very low noise measurements, we use an in-house designed preamp. This gets us below the noise floor of the FFT. We then adjust the FFT attenuator to its proper range. That sort of thing is hard to do on a PC-based system. Attempting to make a measurement w/o this feature can skew results. Pat -- ar-t http://www.analogresearch-technology.net ------------------------------------------------------------------------ ar-t's Profile: http://forums.slimdevices.com/member.php?userid=13619 View this thread: http://forums.slimdevices.com/showthread.php?t=60041 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/audiophiles
