cliveb;539812 Wrote: > 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.
I think you'll be surprized how many bits you can hear and it will be fairly close to the limit of the DAC. You're also assuming the DAC is perfect and that every bit peforms identically. It doesn't. I have plenty of 20bit (HDCD), DTS (24 bit), SACD 24/88 2-Channel, DVDA 24/96 2-Channel Music on my transporter. You will lose audible resolution with these. With 16bit you do have some elbow room but it isn't much. You may get 18bits in normal sitting position with (no Preamp) or Preamp at max volume (which also typically is not operating at it's best). So you have about 2bits of room (12db). Assuming a perfect 18bits of DAC and a Perfect Preamp at Max. I can't hear the difference between 24/48 and 24/96. But I certainly hear the difference between 16/44 and 20/44bit at normal volumes. So you saying you only actually hear 12bits at "normal" volumes is wrong. Also keep in mind many CD's are not full scale and may be down 6-10db. So now your saying we'd be down to 10bits. No way. You argument is flawed. Sounded good though :) -- 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
