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In Reply to: RE: Yo, Goob ! posted by E-Stat on January 26, 2015 at 14:11:08
Sure several files recorded at 2 different sample rates - not 2 files one converted from the other (as you seem to believe I am suggesting - the decimated file being the other, third, case). From figure 2 I see two different converters, 2 different clocks and two different recorders recording at different rates. Everything from the placement to the connectors in this set up should be suspect. Additionally from the verbiage we know a single converter operating at 2 different rates is applied at playback - we are supposed to assume identical performance at both rates during recording and playback.
The fact the results agree with your expectations is enough for you to accept the assumptions. It's too much for me.
From first hand experience - good luck with that 2 identical component idea and further had no differences or the wrong differences been heard in with this setup the first thing that would have happened is the setup would have been assumed to be wrong. Changes would then have been made until the desired results were achieved. Usually this is an honest attempt to get at the truth as flawed as it is - and it actually kind of works when the results are already known in advance and expected. Not so good when trying to present a proof of something.
And even if I did accept the veracity of these test results, it hardly matters when we are talking about mass marketed recordings to be played back on a portable player now does it?
Give me rhythm or give me death!
Follow Ups:
Sure several files recorded at 2 different sample rates - not 2 files one converted from the other
That's the whole point. Get it?
From figure 2 I see two different converters...
It's the same model converter running at a different sample rate.
2 different clocks
At the expense of stating the obvious, one needs a different clock to operate at 44.1 vs 88.2.
and two different recorders
Once again, it is the same model recorder running at the rate of the two sources.
It's too much for me
Obviously, Goob.
it hardly matters when we are talking about mass marketed recordings to be played back on a portable player now does it?
Once again, you've introduced not one, but two straw men - not all recordings found in high resolution are "mass marketed" nor do the vast majority of folks who listen to high resolution recordings use a "portable player".
"At the expense of stating the obvious, one needs a different clock to operate at 44.1 vs 88.2."
Most likely the converter used the exact same A/D circuitry running at the exact same master clock rate, and used different DSP algorithms to downsample the original data stream to either 44.1 or 88.2. In the playback, your DAC will most likely upsample whichever format back to its master clock rate and play that back. You are hearing ae the differences caused by software, as dictated by the mathematical limitations of the low-res format.
For this reason, the easiest and best way to compare formats is to use the best available software converters to convert a high res format to a lower resolution format and then back up to the original format. Any problems that you hear will be due to the limitations of the converter software or the format. If you use the best available algorithms you will discover, as I have, that the limitations come from the filters. One can try various filter settings and none of them will be transparent. One will lose something, according to the filter settings, e.g. tonality, air, transients, imaging, soundstage. Most of the filter tradeoffs hit in the downsampling process. If these are done right, then the playback filters don't matter much. If these are down wrong there will be aliasing distortion that can not be separated from the music.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
the value of upsampling and downsampling to determine whether or not a higher resolution format has merit over Redbook. If memory serves, you find Redbook severely lacking with your recording.
Why not do as this test did and simply record a single event in multiple native resolutions?
If it's a live event then it would involve running multiple converters in parallel. If it's a master tape transfer, then one could play the tape twice, and presumably there wouldn't be any tape wear involved. But if someone else did this, you have no idea what they did. There is a lot of secret sauce involved in mastering, no matter what people may claim to do or not do.
My comments were directed to people who want to KNOW what the differences are with regards to format conversions. The only way to know this is to do the format conversions oneself starting with the same recording and then playback with the identical playback chain. This has the further advantage that by experimenting with different formats and different filter parameters one can train oneself to hear all of the various artifacts involved. This training will make the various "tests" that others come up with relatively easy. I spent the better part of 100 hours doing these experiments some years ago. In the end, I concluded that it was all a waste of time. The lower resolution formats were lower resolution no matter what I did.
The 44.1 kHz format could not transparently reproduce the output of my cassette player.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
it will answer all your questions and eliminate the need for speculation.
Thanks. This answered my questions. I note that they used live acoustic music with decent venues, so it is not surprising that they got positive results, even though listeners had not been specifically trained to discriminate sample rates. However, they did not fully comply with the ITU recommendation for blind tests. [ITU-R BS.1116-1, ITU-R BS.1534-1, ITU-R BS.775-2] Had they used specifically trained listeners or used a preliminary stage to select the best scoring listeners they would likely have gotten much greater statistical significance.
The paper didn't give a specific model number for the RME ADC that was used, so I could not investigate further as to the specific ADC chips used. In all likelihood, they used a multi-bit sigma delta modulator that sampled at around 5 Mhz. The converters therefore downsampled to whatever PCM formats were chosen. As far as I know, all modern audio ADCs that output PCM downsample internally. The differences between downsampling in hardware and software will be small and will depend on details of the DSP involved. There is nothing lost in principle in following a two step process downsampling over a one step process except loss of 1 bit of resolution from the original output format. Given that the RME outputs 24 bits, this would mean restricting the precision to 23 bits, which if reduced to 44/16 would be irrelevant. In the case of reducing to 44/24 it might possibly be relevant, however the 88/24 format already has more resolution in the range 0-20 kHz because of the higher sampling rate.
One might have made the 44 kHz playbacks sound better by using different filtering in playback. Apparently, the experimenters just used the filters provided by the RME Fireface DAC.
IMO this was a good paper, great in comparison to horrible examples such as Meyer - Moran. It could have been better. One thing that I did not like is the use of second tier converters. Better results could have been achieved by taking the converters out of the picture and using file level conversions. This would allow extensive experimentation on how the different possible filter designs affect sound. It would also ensure that all of the analog equipment operated identically in all cases and the only differences being the DSP processing. Furthermore, when doing DSP processing file to file it is possible to capture that impulse response of the filters very precisely, providing much better documentation of the experimental procedure.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
All in all, I found it used a far more plausible setup than any number of contrived ones you find (like the M&M).
"That's the whole point. Get it?"
Laugh - all along."It's the same model converter running at a different sample rate."
Sure but what guarantee is there that they, the ADCs, sound/work the same? It's not unusual for professional test equipment to give different results. In fact it's not unusual to find a single piece of test equipment that gives different results when used in different locations using the same test interconnects/leads - and even easier to find when using different interconnect/cables or leads of the same manufacturers model.And the DAC, ie. the playback device, is the same unit operating at different rates. What guarantee do we have that it sounds the same at both rates? In fact the test/evidence/results would equally well prove that the DAC, sounds different at different rates - if one wanted to assume the both samples (of the dual conversion) sounded the same. No different than assuming the DAC sounds the same at two different rates - which is what we have do in order to support the printed conclusion of this test. Or that the decimation and several other factors play no part in the differences heard. We believe what we want to believe.
"At the expense of stating the obvious, one needs a different clock to operate at 44.1 vs 88.2. "
Yea but again you assume the device(s) functions equally as well at both rates.
"Once again, it is the same model recorder running at the rate of the two sources."
And again you assume the recorders are equal and that they operate equally well at both rates.
Obviously, Goob."
Sorry you need to resort to misquoting my comment in order to try to score a point!"Once again, you've introduced not one, but two straw men - not all recordings found in high resolution are "mass marketed" nor do the vast majority of folks who listen to high resolution recordings use a "portable player"."
It wasn't my intention to introduce a straw man - it was you who opened the topic on this test in this thread about a portable player.
Give me rhythm or give me death!
Edits: 01/26/15
and yet you scored twice!
"and yet you scored twice!"
LOL - but surely you've called me names many more than 2 times. How about you declare yourself the winner and move on?
Give me rhythm or give me death!
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