Digital, but not by the numbers

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Doing it this way would keep it all digital to the output filters, and thus make noise controll less of an issue, (I did propose a 1 box version myself earlier, one protective earth connection), and for the output you could use planar inductors or a planar transformer with capacitive screening to further stop any digital noise coupling to the analogue outputs (even if they are speaker level outputs, help with EMC when you add them long antennas). Seen a similar thing with an ADC input, to digital, transported, pulse width out with cap inductor to recreate the analogue signal, this was Bell Labs telephone bandwidth though, not high end audio.
 
Doing it this way would keep it all digital to the output filters

I guess it depends on your definition of "digital". I don't consider pulse width modulation or pulse density modulation "digital" as such, it is still an analog domain, albeit a switched one. To me "digital" really involves encoding the signal as discrete symbols and/or numerical values. A conversion from PCM to PWM/PDM is a digital-to-analog conversion.

Of course, that conversion can happen in one step that is powerful enough to drive a speaker, but that involves a feedback loop all the way back from the "amp" output to the pulse modulator in the DAC, and I am not sure that doing it in "one step" really buys you anything - is noise control really such an issue, and how do you prevent the noise from affecting the (analog) feedback loop?
 

TNT

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Class D needs a DAC, as it is an analogue architecture. Whether the A is a voltage which then gets converted to a pulse width (which then finally gets converted to a voltage), or A is just a pulse width, it is still analogue because the voltage or the pulse width are both analogues of the original sound pressure signal.

Roger that - it has to be de-quantizised but maybe not by the recreation stage as in sinx/x but exchanged for something else... is there some gains to be made here? The "filter point" could be a single one and moved to the edge of the system. I'm really out fishing here competence wise so please correct me if I'm wrong in my reasoning.

Also, I would like to use the ESS (32 bit) digi level control. No pots - it's so 19xx...

All inside is synchronous except for a USB / spdif input which should be protected by a fifo buffer which downstream side is clocked by the master clock(s) which in turn is located very close to the critical point where the payload (music) leaves the digital domain and going analogue.
 
TNT said:
Roger that - it has to be de-quantizised but maybe not by the recreation stage as in sinx/x but exchanged for something else... is there some gains to be made here? The "filter point" could be a single one and moved to the edge of the system. I'm really out fishing here competence wise so please correct me if I'm wrong in my reasoning.
Sorry, I can't comment because I don't understand what you are saying.
 

TNT

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Joined 2003
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I guess it depends on your definition of "digital". I don't consider pulse width modulation or pulse density modulation "digital" as such, it is still an analog domain, albeit a switched one. To me "digital" really involves encoding the signal as discrete symbols and/or numerical values. A conversion from PCM to PWM/PDM is a digital-to-analog conversion.

Of course, that conversion can happen in one step that is powerful enough to drive a speaker, but that involves a feedback loop all the way back from the "amp" output to the pulse modulator in the DAC, and I am not sure that doing it in "one step" really buys you anything - is noise control really such an issue, and how do you prevent the noise from affecting the (analog) feedback loop?

OK 48 bit. I did not mean anything else really than what Julf wrote previously.

Merry C!

/
 
Here's something one or two of you guys might be interested in - a passive filter designed for NOS DACs. I've read a few reports and agree that NOS sounds a bit rough at the top end - I've wondered if this is due to amps or tweeters creating intermod products with the ultrasonics. So here's a design which I'm currently building to test my hypothesis - a 50dB stop-band passive anti-imaging filter. Ignore the 0.001 resistors, they're just there to see the effects of lossy inductors in running the sim.

Hello

Any new developments on your 7th order filter ?

Thank

Bye

Gaetan
 
The thread got beseiged by trolls of objectivist persuasion (people who take measurements as primary guarantees of audio quality) and then when it was subequently cleaned up by a mod the overall balance had clearly shifted in favour of the trolls in that some trolling posts were left behind but my rebuttals to those were deleted. Hence I've decided to continue the saga in the more conducive environment over here at WBF
That is the opening spiel to the other thread, I have to strongly disagree with this statement, it was not trolls or trolling it was engineers presenting engineering based facts, that quite often go against the Audiophile fantasy world of design.
Marc
 
That is the opening spiel to the other thread, I have to strongly disagree with this statement, it was not trolls or trolling it was engineers presenting engineering based facts, that quite often go against the Audiophile fantasy world of design.
Marc

I have to disagree a bit with your disagreement. Abraxalito is certainly capable of defending his own statements, however (and, without regards to any particular post or person in this thread), I must say that there are some around who fancy themselves a bit too much as what I call, knights-of-objectivism. They often don't just seek to educate others on the objective technology of audio, they go on to suppress the subjective perceptions expressed by others. If someone reports subjective observations which appear to conflict with some device's technical specification, those observations are too often dismissed out of hand as faulty. Such knights are, in effect, defenders of the realm of orthodoxy. Yes, of course, I agree that there is real physical science and engineering underpinning the creation and behavior and mechanical and electronic audio devices. It's just that some seem to lose sight that the science and technology are in service of and informed by human perception, not the reverse.

Most objectivists (I'm generalizing here) seem to take the attitude that, if you cannot produce or cite a technical analysis to support what you claim to hear then you, in fact, do not hear anything and are merely fooling yourself. Ridicule often follows. It seems to me that the proper attitude would be to treat what we perceive from out systems as an observation in search of an objective explanation, not the other way around. A touch of humility - the simple recognition that just possibly, one doesn't know everything there is to know - would not hurt here.

I suppose, that part of the problem is the witch doctoring and basic misinformation which does sometimes accompany the marketing of high end audio products. Even so, I feel that we must attempt to keep disciplined, yet open minds regarding questions of human music perception. After all, objectively, CD is pretty much as sold, perfect sound forever. Subjectively, however, that seems far from true for many. The analytical search should be for why there is that perception, not for the many ways CD's technical specs. necessarily prove that such perceptions amount to some kind of delusion, or neurosis, or dishonesty.
 
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Most objectivists (I'm generalizing here) seem to take the attitude that, if you cannot produce or cite a technical analysis to support what you claim to hear then you, in fact, do not hear anything and are merely fooling yourself. Ridicule often follows. It seems to me that the proper attitude would be to treat what we perceive from out systems as an observation in search of an objective explanation, not the other way around. A touch of humility - the simple recognition that just possibly, one doesn't know everything there is to know - would not hurt here.

+1,000
 
I have to disagree a bit with your disagreement. Abraxalito is certainly capable of defending his own statements, however (and, without regards to any particular post or person in this thread), I must say that there are some around who fancy themselves a bit too much as what I call, knights-of-objectivism. They often don't just seek to educate others on the objective technology of audio, they go on to suppress the subjective perceptions expressed by others. If someone reports subjective observations which appear to conflict with some device's technical specification, those observations are too often dismissed out of hand as faulty. Such knights are, in effect, defenders of the realm of orthodoxy. Yes, of course, I agree that there is real physical science and engineering underpinning the creation and behavior and mechanical and electronic audio devices. It's just that some seem to lose sight that the science and technology are in service of and informed by human perception, not the reverse.

Most objectivists (I'm generalizing here) seem to take the attitude that, if you cannot produce or cite a technical analysis to support what you claim to hear then you, in fact, do not hear anything and are merely fooling yourself. Ridicule often follows. It seems to me that the proper attitude would be to treat what we perceive from out systems as an observation in search of an objective explanation, not the other way around. A touch of humility - the simple recognition that just possibly, one doesn't know everything there is to know - would not hurt here.

I suppose, that part of the problem is the witch doctoring and basic misinformation which does sometimes accompany the marketing of high end audio products. Even so, I feel that we must attempt to keep disciplined, yet open minds regarding questions of human music perception. After all, objectively, CD is pretty much as sold, perfect sound forever. Subjectively, however, that seems far from true for many. The analytical search should be for why there is that perception, not for the many ways CD's technical specs. necessarily prove that such perceptions amount to some kind of delusion, or neurosis, or dishonesty.

How come the same dude thinks it's ok to do an active crossover using numbers and dsp's or does he just pick and choose based on some arbitrary decision which is not based on any rational explanation ?
 
Most objectivists (I'm generalizing here) seem to take the attitude that, if you cannot produce or cite a technical analysis to support what you claim to hear then you, in fact, do not hear anything and are merely fooling yourself.

No, I think most objectivists (and I am generalizing, too) claim that it is a *possibility* that your brain is fooling yourself (and I would not use the word "merely" there). That possibility should be taken into account.

the simple recognition that just possibly, one doesn't know everything there is to know - would not hurt here.

Absolutely. But at the same time, it would not hurt for the subjectivists to acknowledge that the human brain is rather good at fooling itself, and that there really is no way to know if you are hearing what you think you are hearing without some objective references.

Even so, I feel that we must attempt to keep disciplined, yet open minds regarding questions of human music perception.

Indeed. That works both ways.

After all, objectively, CD is pretty much as sold, perfect sound forever. Subjectively, however, that seems far from true for many. The analytical search should be for why there is that perception, not for the many ways CD's technical specs. necessarily prove that such perceptions amount to some kind of delusion, or neurosis, or dishonesty.

I think modern research has shown that the perceptual issues are totally normal and results of the way the brain adapts to it's environment, and have nothing to do with delusions or dishonesty.
 
Absolutely. But at the same time, it would not hurt for the subjectivists to acknowledge that the human brain is rather good at fooling itself, and that there really is no way to know if you are hearing what you think you are hearing without some objective references.
Indeed it is, I've experienced this often. I was doing some experimenting with repairing compression artifacts on a track I barely knew, and at first it was easy, and obvious, to distinguish which was the original, and which the altered. But it steadily got harder to separate the two on continued listening -- what the hell was going on?? Then I realised, my brain was "learning" the music, the track; knew it better each time I listened, and was overriding what I heard "wrong" with one version vs. the other ...
 
Indeed it is, I've experienced this often. I was doing some experimenting with repairing compression artifacts on a track I barely knew, and at first it was easy, and obvious, to distinguish which was the original, and which the altered. But it steadily got harder to separate the two on continued listening -- what the hell was going on?? Then I realised, my brain was "learning" the music, the track; knew it better each time I listened, and was overriding what I heard "wrong" with one version vs. the other ...

And I guess we have a lot of examples of spending a lot of time tweaking the setting of an adjusting knob to find the perfect setting - only to find out that the adjustment device wasn't plugged in. But we definitely heard a difference (probably described as "night and day" by an audiophile journalist :) ) between the settings...

In that situation, we could either "keep an open mind" and start looking for some equivalent of audiophile homeopathy, where the device affects the sound remotely by just being in the room, or we could admit that our expectations affected the way we heard things.
 
Disagree, we were discussing digital and how to do that, sorry but you hear all folks is wrong.
Perceptions can be fooled, all the time....
But digital, well I'm sorry but if you do digital design and want to do it right you have to do it by the numbers, as with any electronics design, you have to use numbers physics and maths, to think otherwise is total ignorance of the design cycle. Now you'll all start waving you hands and shout at me, but it isn't gonna change the fact that electronic design is a NUMBERS based game, and digital more so than analogue design.
And before you shout and scream I am not dismissing listening tests from the design cycle, they are also an important part, but you still need to do the maths.
Funny, my response got exactly the reply I thought it would. If you read the thread you would realise we were discussing digital design and various points regarding such design to get the best results. As it did not fit the audiophile view of the world we were trolling, being dismissive etc, I do not agree, and have been party to many threads where we have discussed things from both sides of the equation to sometimes reach the same conclusion.
Of course all you subjective people often forget, and this may come as a surprise, that objectionist on this site probably listen to music....
Anyway bye bye for now.:)
 
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