Phil Leigh;539680 Wrote: > > > NewBuyer;539658 Wrote: > > I'm wondering: Isn't cliveb right about this? Aren't there similar > > SNR/dynamic-range/distortion etc issues regarding the effect of analog > > attenuation as well?> > > analogue attenuation (in a preamp) lowers the noise from all > components prior to the pre-amp, along with the signal. This > maintains the SNR as constant (ignoring any noise from the power amp > itself - and they are usally -100dB these days) > digital attenuation ahead of the DAC lowers the signal but the noise > from the DAC output stage, preamp etc is untouched so the SNR > deteriorates. This is true: analogue attenuation after a DAC as opposed to digital attenuation before the DAC preserves more of the DAC's resolution. But the point I was trying to make was in the context of turning down the playback loudness when listening to music...
Let's say you're listening at a peak level of 96dB SPL. And to simplify the sums lets assume an ambient noise level in the listening room of 0dB. That means you're hearing a 96dB dynamic range, the equivalent of 16 bits. Now turn the loudness down so the peak level is 72db SPL (a reduction of 24dB). The maximum dynamic range you can now hear is 72dB, equivalent to 12 bits. Let's suppose you've used analogue attenuation to do this. You will have preserved the full 16 bits of resolution, which of course is fine. But the bottom 4 bits will now be below the threshold of audibility and you can't hear them anyway. But now let's suppose you've used digital attenuation: you'll have thrown away 4 bits of resolution. Sounds pretty dire, right? BUT THESE ARE THE FOUR BITS YOU CAN'T HEAR ANYMORE BECAUSE YOU'VE TURNED THE VOLUME DOWN. I don't understand why this basic simple fact is so hard to grasp for so many people (not you, Phil - I realise that you understand this). Bottom line: when you turn down the playback volume, the low level details drop below the bottom of the audibility envelope. Doesn't matter whether you use analogue or digital attenuation. Digital throws away the bits you can't hear anymore. Analogue preserves them, but you can't hear them anyway. -- cliveb Transporter -> ATC SCM100A ------------------------------------------------------------------------ cliveb's Profile: http://forums.slimdevices.com/member.php?userid=348 View this thread: http://forums.slimdevices.com/showthread.php?t=77725 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/audiophiles
