cliveb Wrote: > I don't read it as actually *advocating* it. What he actually says is: > "for those of you who want to use the built-in 40-step volume control > (performed digitally before the internal DAC), this reduction in > voltage allows for a more usable range in the volume control". To me, > that isn't saying that you should use it, but that if you do then > you'll be able to use a greater range of adjustments due to the lowered > output voltage. > > But your comment brings up an interesting question: what's wrong with > using the digital volume control? Many audiophiles here seem to just > take it as read that you shouldn't, but it's by no means clear-cut. The > digital data (both internally and as delivered out the SPDIF port) is 24 > bit. With the volume control at VC=40, you get a theoretical 144dB of > dynamic range. How loud do you want to listen? Let's say you want to > listen at a maximum of 120dB. Setting things up so that VC=40 gives > 120dB, the theoretical noise floor is 24dB below 0dB (ie. definitely, > without a shadow of doubt, inaudible). Now say you want to turn it down > a bit, let's say down to 96dB (ie. 24dB down). To achieve this, you'll > need to sacrifice 4 bits of resolution, which brings the dynamic range > down to 120dB. And where is the noise floor now? It's *still* 24dB > below 0dB. And this holds for *all* volume settings - the theoretical > noise floor remains at the same inaudible level, regardless of the > setting. > > This is the beauty of digital level control: distortion and noise > increase as the level goes down. This is exactly what you want: at > lower volumes, distortion+noise can be allowed to increase, because it > remains below the threshold of audibility. Contrast this to a > traditional analogue potentiometer, where the tracking gets decidedly > vague at very low settings, resulting in undesirable image shifts as > you turn things down very low. > > *If* you have 24 bit signals to play with, then level adjustment is > best done digitally (provided it's done properly, of course, which I'm > sure is the case with the SB2). Those of you with high-end 24 bit DACs > fed from a fixed SB2 digital output and subsequently feeding an > analogue preamp should experiment with connecting the DAC directly to > the power amps and using the SB2's digital volume control. The results > may surprise you. (Hint: my preamp is currently for sale on eBay as a > result).
Hi cliveb, -- Vinnie R. Vinnie Rossi Red Wine Audio, Inc. www.redwineaudio.com _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/audiophiles
