cliveb;538777 Wrote: > It's actually quite difficult to understand exactly what your test > involves, but looking at your linked page, I get the impression that > you are proposing this: > > 1. Take a file with a very low level signal (eg. -80dB). > 2. Play it without digital attenuation, and increase the analogue gain > until you can hear it. > 3. Now apply some digital attenuation and increase the analogue gain to > compensate (so the overall level is the same). > 4. There will be an audible difference. > > Is that what you're saying? If it is, then my response is: "hey, no > sh*t, Sherlock! Now tell us something we don't already understand". > > And then try and justify how this extremely unrealistic scenario > relates in any way to the normal listening experience. > Presumably you tried this test with a signal at normal levels (ie. not > artificially low) and failed to hear a difference? What does that tell > you about the real world? > > > And when you use analogue attenuation you are sliding the music out of > that range.
What it tells you is the limit of your DAC even in the MOST EXTREME UNREALISTIC WORLD. Even with 6dB (1 bit of attenuation you can EASILY) hear a difference in these unrealistic test files. But if you can HEAR any difference I assure you it will effect fine level detail of a real recording too. Then if your crazy enough to use digital attenuation for volume and subract like 24dB you are just tossing some serious resolution. You're not pushing it down into lower bits and having your amp bring it back up if your DAC can't resolve those low level bits. Most DACs are no where near 24bit even though they may accept 24bit format. If DACs were perfect to 24bits then it would not be a big deal using digital attenuation. This helps show what your DAC can and CAN'T do. I found in my system that even 3dB attenuation (due to another problem which I finally found a work around for) had a huge difference in performance. I also found problems in another system thinking I was getting 24bit but I was only getting 16. You'd never know unless you ran a test like this. Another person found he had a noise problem with this test. Effectively you are finding the noise floor of your system with this. It's crude but it works. -- mswlogo XP > Cat5 > Transporter/DuetController > SPDIF > Meridian G68 > DSP6000, DSP5500HC, DSP5000 XP > Cat5 > SB3 > SPDIF > Meridian DSP5000 XP > Cat5 > DuetReceiver > SPDIF > Meridian G91 > DSP5000 'My Transporter Setup' (http://forums.slimdevices.com/showpost.php?p=350741&postcount=45) 'Hitch Hikers Guide to Meridian' (http://www.meridianunplugged.com) ------------------------------------------------------------------------ mswlogo's Profile: http://forums.slimdevices.com/member.php?userid=9090 View this thread: http://forums.slimdevices.com/showthread.php?t=77725 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles
