What objectivists and subjectivists can learn from each other

[Ron Party]

Thus my confusion, rbbert. Has anyone (and, in particular, Ethan & Tim, since Tom just replied) posted perfect reproduction is attainable?

 

[fas42]

Again, this has nothing to do with the fidelity of the gear, and I wish people would stop inserting this red herring into a discussion of audible transparency and differences between audio devices. It's another issue entirely, having more to do with loudspeakers, room acoustics, and mic technique than audio fidelity.

I guess this is the passage of interest by Ethan. This comes to down to the difference in philosophy of the types of audio enthusiasts: the majority accept that audible and disturbing distortion emerges from the speaker cones -- because of deficiencies earlier in the chain -- so the job of making the sound appear credible then requires a great deal of manipulation of the listening environment to minimise the impact of those abberations; others, like themself, attempt to reduce those "distortions" exiting the driver to the lowest subjectively audible level.

So fidelity of the system is fixed, by its current status, its state of "tune". But the fidelity as heard by a listener is variable, depending upon the environment in which it is heard.

Frank

 

[Bruce B]

BTW, how does one measure a microphone, or a speaker? Does anyone else see a tautology here?

Microphones can be measured/calibrated by sending to NIST in the U.S. or to NPL in the U.K. and are calibrated either by Reciprocity, which is the standard, Comparison or Pistonphone.

 

[fas42]

Well yeah, but this had been resampled from 24/96 to 16/44.1, then back up again. So the two files were not bit-identical.

Edit: Once you do the resampling along with conversion from 24 to 16 bits, that resolution is lost forever.

What would be really interesting, is sending the digital through a "best" D/A -> A/D and comparing that using DiffMaker ...

Frank

 

[andy_c]

Yes, that would be interesting.

 

[fas42]

Microphones can be measured/calibrated by sending to NIST in the U.S. or to NPL in the U.K. and are calibrated either by Reciprocity, which is the standard, Comparison or Pistonphone.

But notice no mention is made of distortion: this is a hard one to crack, a whole lot of technique would have to go into getting something like valid measurements of this ...

Frank

 

[Bruce B]

What would be really interesting, is sending the digital through a "best" D/A -> A/D and comparing that using DiffMaker ...

Frank

What would you define "best"? I've never seen/heard a converter that had the best A/D AND D/A. The best A/D are the Grimm AD1 and the MSB Studio ADC and the best D/A is the MPS-5 or the dCS Scarlatti

 

[rbbert]

Thus my confusion, rbbert. Has anyone (and, in particular, Ethan & Tim, since Tom just replied) posted perfect reproduction is attainable?

NOBODY in the world has a two channel stereo system that replicates a live performance. About as clear as I can get since you asked again!

I am not implying nothing but whats in my signature space below and would be glad to debate anyone line by line

Tom

You say you are not implying it, but I (and probably others) certainly infer from your statement that multi-channel audio could replicate live music. My point is that the extra spatial reproduction accuracy from multi-channel compared to 2-channel doesn't address the main differences between live sound and recorded sound, so that is a red herring in this discussion. Nobody has a multi-channel system that replicates a live performance; you could simply say that "nobody in the world has an audio system that replicates a live performance" and leave the misleading "two channel stereo" part out.

And both Tim and Ethan have stated (see previous posts and quotes) that the A>D>A chain is perfect. Their arguments are unconvincing, to say the least, and I also haven't seen an answer to my question about Tim's self-contradictory post about "voicing" of DACs.

 

[rbbert]

Microphones can be measured/calibrated by sending to NIST in the U.S. or to NPL in the U.K. and are calibrated either by Reciprocity, which is the standard, Comparison or Pistonphone.

But what is the mechanism for the measurement, i.e. how are signals generated for the microphone to respond in order for its characteristics (frequency response, distortion, polar pattern, etc) to be measured? It appears that either (Reprocity) another (calibrated) microphone is used as a signal generator (i.e., essentially equivalent to a loudspeaker), or (Pistonphone) a specially built piston is used to generate a precise air pressure change, but obviously this latter only works at one frequency (probably fairly low).

So my point was that you have a transducer that is calibrated by comparing it to another transducer; then that newly calibrated transducer (microphone) is used to measure a third transducer (loudspeaker under test, for example), thus the tautology.

 

[fas42]

What would you define "best"? I've never seen/heard a converter that had the best A/D AND D/A. The best A/D are the Grimm AD1 and the MSB Studio ADC and the best D/A is the MPS-5 or the dCS Scarlatti

That's why I quoted the word: I would defer to your estimation of the very best combination of units, or single unit, that did the job when chained in an optimum configuration ...

Frank

 

[fas42]

But what is the mechanism for the measurement, i.e. how are signals generated for the microphone to respond in order for its characteristics (frequency response, distortion, polar pattern, etc) to be measured?

This gives you a pretty good rundown: http://en.wikipedia.org/wiki/Measurement_microphone_calibration

Frank

 

[Bruce B]

That's why I quoted the word: I would defer to your estimation of the very best combination of units, or single unit, that did the job when chained in an optimum configuration ...

Frank

Well the best all-in-one converter with AD/DA capabilities is the Digital Audio Denmark AX24. Give me a hi-rez file and I'll just make a loop out and in and capture the signal.

Now what cable should I use!!

 

[fas42]

Now what cable should I use!!

Aye, there's the rub!! Many a slip twixt ...

The best would be a unit that was capable of doing it all internally, to get rid of that nasty "compromise"! ...

Frank

 

[rbbert]

This gives you a pretty good rundown: http://en.wikipedia.org/wiki/Measurement_microphone_calibration

Frank

But the question that is unanswered (and critical, IMHO) is how is the original standard microphone itself calibrated?

 

[treitz3]

What a train wreck.

 

[Ron Party]

And both Tim and Ethan have stated (see previous posts and quotes) that the A>D>A chain is perfect. Their arguments are unconvincing, to say the least, and I also haven't seen an answer to my question about Tim's self-contradictory post about "voicing" of DACs.

Hi rbbert.

We'll have to let them speak for themselves. Perfect is such an absolute term. I'd be surprised if, when either of them return to this thread, either one states any DAC is perfect. Audibly indistinguishable from one another under a proper scientific test, probably.

 

[andy_c]

But the question that is unanswered (and critical, IMHO) is how is the original standard microphone itself calibrated?

Have a closer re-read of the reciprocity calibration section. I've repeated part of it below.

The technique provides a measurement of the sensitivity of a microphone without the need for comparison with another previously calibrated microphone, and is instead traceable to reference electrical quantities such as volts and ohms, as well as length, mass and time.

 

[andy_c]

What a train wreck.

Seems okay to me as these sorts of discussions go. Sure, it's going in many directions, but that's expected and part of the fun for some.

 

[NorthStar]

I agree.

 

[Keith_W]

What a train wreck.

I agree. I started off with the hope that at least some people would be open minded enough to see the merits in other people's approach. But no, we got the usual "we know everything and have no need to change" attitude from the same sector of the hobby. Given my 20+ years in this hobby I should have predicted it. I mean, people were saying the same things in rec.audio back in 1992 I suppose this thread has outlived its purpose, and if you think the community would be better served by closing it, I would support it.