PrestonTom Posted November 11, 2019 Share Posted November 11, 2019 I am not sure I agree Chris. Bit depth determines the quantization noise. It is still what was on the original CD (16 bits or a little less than 100 dB below the peak signal). The 24 bit encoding on the ADC will not increase that ratio (we both understand this). However when a preamp is before the ADC (which could be assigning 24 bits of voltage across close to 15-20 dB RMS), then the ADC and its 24 bits are not being "filled up". Depending on this or that, it could be well less than losing just a couple of bits. I do agree that that the real noise floor is probably not determined by the DAC (16 bits is plenty). There are so many other system and environmental considerations that come into play. Running a hot signal is a good idea and putting the pre-amp (attenuators) after the DAC is also a good idea. By-passing the analog input section (by sending a digital out from the CD player to the digital input of the DSP unit is also a good idea (at the same time, by passing the anti imaging filters from the CD player). My suggestion is just a good practice. No need to have an extra conversion. However, I do agree that ones's milage may vary as to the benefit. Quote Link to comment Share on other sites More sharing options...
Chris A Posted November 11, 2019 Share Posted November 11, 2019 I've never heard quantization noise off a fully digitally implemented CD before (i.e., recorded, mixed, and mastered digitally). My goodness--it would be really loud in the loudest passages if you could: 96 dBC of dynamic range in a listening room...on top of a nominal 30-40 dBA noise floor in the room in order to hear the quantization noise--assuming the recording has been mastered to a zero dBFS peak. That's getting close to the threshold of pain (130-140 dBSPL). Finding a set of loudspeakers to faithfully reproduce that SPL would be difficult to find, indeed. Quantization noise sounds just like tape hiss--which is probably what all of us have heard when cranking up CDs made from old analog tape masters (tape hiss, that is, generally from all recordings made 35+ years ago and older). What we're really hearing is tape hiss from an original analog tape recording performance (which is ~8-12 bits equivalent bit depth--at best), not digital quantization noise. Chris Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted November 11, 2019 Share Posted November 11, 2019 Correct. That is why I don't think it is quantization noise from the original 16bit CD. The actual "noise floor" when listening is established elsewhere. I don't want folks to get confused so I will iterate my original point. 1) Digital input to the DSP unit is preferred. 2) If analog is the only option then feed the ADC a hot signal (including putting the pre-amp after the DAC in the DSP box, if possible). Time to move on, -Tom Quote Link to comment Share on other sites More sharing options...
mark1101 Posted November 12, 2019 Share Posted November 12, 2019 You could just use preamps and amps compatible with Xilica's pro audio levels.............like McIntosh. I have a C220 preamp feeding my Xilicas (2) and it lights the Xilicas up baby..........no weak signal in Georgia. I do agree though it would be best to keep it all digital and do 1 conversion. That would probably be one good excuse to change some of what I have now. Quote Link to comment Share on other sites More sharing options...
MechEngVic Posted November 16, 2019 Share Posted November 16, 2019 I remembered one of the experiments we did in physics class in college where we found the resonant positions of a pair of speakers emitting the same signal. There are several positions, not just where the diaphragms align, where the drivers will be in-phase. Not happy with the reflections off the top of the speaker cabinet with the tweeter and horn aligned. I looked for a resonant position towards the front and found one about a half inch past the end of the motor-board. In-phase, resonant, and no reflections! It sounds awesome. Quote Link to comment Share on other sites More sharing options...
ClaudeJ1 Posted November 16, 2019 Share Posted November 16, 2019 On 11/4/2019 at 9:31 PM, Marvel said: Chief... It should, probably does make a difference. I sit just below the tops of the cabinets, tried different materials, foam, etc., I couldn't tell the difference. I could definitely hear the difference in alingment, though. I'm going to be going digital and adding delays soon. Whole new ballgame since I got some MWMs from JWC. Your new Heresy and Cornwall models look really good, though. Maybe I should sell what I have to get a pair of those. Bruce Trading one acceptable compromise for an unacceptable one. Good move. Quote Link to comment Share on other sites More sharing options...
ClaudeJ1 Posted November 16, 2019 Share Posted November 16, 2019 26 minutes ago, MechEngVic said: I looked for a resonant position towards the front and found one about a half inch past the end of the motor-board. In-phase, resonant, and no reflections! It sounds awesome. Spoken like a true Mechanical Engineer! Quote Link to comment Share on other sites More sharing options...
MechEngVic Posted November 16, 2019 Share Posted November 16, 2019 1 minute ago, ClaudeJ1 said: Spoken like a true Mechanical Engineer! I just knew those several years in school was gonna come in handy one day! 1 Quote Link to comment Share on other sites More sharing options...
Marvel Posted November 16, 2019 Share Posted November 16, 2019 2 hours ago, ClaudeJ1 said: Trading one acceptable compromise for an unacceptable one. Good move. What are you talking about? Having the mid and tweeter in alignment is good. I can hear the difference In my room I can't hear if reflections are causing a problem. Also good. Quote Link to comment Share on other sites More sharing options...
ClaudeJ1 Posted November 16, 2019 Share Posted November 16, 2019 3 hours ago, Marvel said: What are you talking about? Having the mid and tweeter in alignment is good. I can hear the difference In my room I can't hear if reflections are causing a problem. Also good. Precisely my point. Make your own compromises, as you hear improvements or not. 1 Quote Link to comment Share on other sites More sharing options...
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