darrenyeats wrote: > Some dodgy technical claims in recent posts. > > 1. DACs with ">16 bit performance" don't keep that performance when > employing digital volume control (to be clear I'm not arguing against > digital volume control, in fact I'm a fan, nevertheless the observation > stands). >
Yes, that is a false claim if stated as a generality with audibly significant consequences. I also can appreciate digital volume controls, and have some concerns related to audiophile paranoia about them. much of which seems to be based on misapprehension. Part of the problem seems to relate to the mistaken belief that resolution is infinite in the analog domain. > > 2. In audio recording and reproduction the signal passes through a long > chain of processes and components. Even if one component could be > transparent, it could still play its part in audible artifacts in an > ensemble. I can think of mic, mic preamp, ADC, studio digital effects > (multiple, perhaps many), mixing, mastering, downsampling, DAC, preamp, > amp, active crossover. That's 11 off the top of my head. Stack 11 > transparent windows upon each other, they may very well not be > transparent. Even if transparency was achievable for a component in > isolation, that's not actually good enough. > Agreed. Both theory and practice are well known that can be used to predict the aggregate performance of any chain of audio components if their individual detailed performance is known. At worst the deficiencies in the components add linearly, at best they cancel each other out. In other cases they add geometrically. It all depends on the details. BTW I'm not talking about spec sheet numbers, I'm talking about real world performance. A lot of noise and distortion can accrue when audio signals pass from component to component. There is a reason why for good pro audio gear, balanced I/O is a general rule. The unbalanced connections that are endemic in home audio gear can be a source of audible problems with ground loops and interference pickup, and the like. This can be one reason why an AVR that basically puts all the electronics in one box can be a better idea, because it avoids a lot of dodgy unbalanced interfaces that might exist between separates. Digital audio interconnections can avoid a lot of these issues. However, I see a general misapprehension about the degree of transparency of real world audio gear. There were pieces of audio gear that were on the market and in general use in the late 1960s that were sonically transparent. At that time the biggest problems were with analog recorders and players, whose performance may have been 20-40 dB worse than say a good preamp. The rule of the weakest link held sway and the weak links were impossible to avoid. The first generation digital gear performed better than a lot of contemporaneous amps and preamps, but not all. One rule of thumb is that any component or chain of components whose in-band artifacts are so many dB down or better, are sonically transparent. IOW the artifacts can be measured, but if you ABX them in comparison with the proverbial straight wire, all listeners will come up random guessing. The question is then about the actual quantity of "so many dB down". The answer is usually in the range of 60-70 dB. This is a readily achievable number for many individual pieces and reasonable combinations of modern audio gear. A more general rule is that if "so many dB down" is 90-100 dB, then forgeddabout it. ------------------------------------------------------------------------ arnyk's Profile: http://forums.slimdevices.com/member.php?userid=64365 View this thread: http://forums.slimdevices.com/showthread.php?t=103842 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles
