Does High Resolution Audio sound better

[The Computer Audiophile]

Here is an interesting PDF talking about the issue.

 

http://attachments.goldmund.com.s3.amazonaws.com/2015/01/23/15/49/42/359/goldmund_does_high_resolution_audio_sound_better_white_paper.pdf

[buffalobill]

Thanks for providing. Consistent with previous articles. I want the best sound from my audio system so I am staying with 16/44.1 (PCM).

[petaluma]

Seems to blow a big hole in the high-res revolution? Spend your money on better speakers, room acoustic treatment, and CD resolution music?

[esldude]

I do hate the repeated misinformation about digital timing resolution. Sorry folks, the timing resolution is not restricted to the sample rate. Why is this myth so hard to kill? This is not controversial, it is a fact. Even CD can resolve between the two channels a few orders of magnitude less than microseconds.

 

The paper is also incorrect about dynamic resolution not being better at 24 bit vs 16 bit. I don't think the difference is important, but it is better with 24 bit. It also potentially impacts timing resolution though again even at 16 bit that resolution if far more than adequate.

 

Keep making posts like this Chris and we might need a poll: Is Chris a troll?

[Tony Lauck]

Here are a few quotations from the paper, coupled with my comments. These are not intended to be complete.

 

Improved Timing Resolution:

 

Some of the proponents of high-resolution audio cite the timing resolution of the human ears. Sound almost always arrives at the left and right ears at slightly different times. Humans can detect timing differences between the right and left ears as small as 15 microseconds; to capture this information, a sampling frequency of 66.7 kHz is required. Omitting frequencies above 20 kHz eliminates these subtle timing differences, hich could, at least in theory, affect the perception of sound.

 

This is technically wrong. The timing resolution can be much less than the sample time. It's approximately 1/65536 the sample time for 16 bit audio.

 

Increased Distortion:

 

The main audible flaw of high-resolution audio involves intermodulation

distortion (IMD), the effect created when two audio tones interfere with each other. With IMD, “Perfection in an imperfect world” sum and difference tones are created, usually at frequencies that are not harmonically related to the two original tones. IMD occurs in all audio equipment to some degree, but decades of design evolution have reduced it to insignificance. However, IMD is a more common problem at ultrasonic frequencies. Equipment not designed to reproduce such high frequencies – including many amplifiers and most of the high-frequency drivers (tweeters) used in today’s speakers – may produce substantial IMD if forced to operate at frequencies they were not designed to handle. Unfortunately, the effects of IMD are not limited to high requencies.

 

I thought that Goldmund was a high-end manufacturer. Presumably they can design equipment that operates properly at ultrasonic frequencies or, at the least, filtering out frequencies they can not properly handle.

 

 

Oversampling to Reduce Filtering Demands:

 

The benefits of sampling at frequencies higher than 44.1 kHz can be and are achieved by using oversampling in standard-definition analogto-digital and digital-to-analog conversion. Almost all currently available analog-to-digital converter (ADC) and digital-to-analog converter (DAC) chips oversample at high rates, typically 96 kHz or higher. With oversampling, the anti-aliasing filter in the ADC and the reconstruction filter in the DAC can employ higher frequencies and/or more gradual slopes. If the audio is stored in standard resolution, the extra samples are simply discarded – yet the benefits of the higher filter frequency and/or more gradual filter slopes remain, while the problem of IMD at ultrasonic frequencies is eliminated.

 

 

This is FUD. It confuses mechanism with function. Oversampling is a technique to replace a difficult analog filtering mechanism with an easier digital filtering mechanism coupled with a simple analog filtering mechanism. Unfortunately, all filters have effects on waveforms that are related to the function they perform, namely the specific filtering, and these are limited by mathematical laws. The result is tradeoffs between high frequency bandwidth, aliasing and image distortion, and transient response.

 

Dynamic Range Beyond 96 dB:

 

While it is generally accepted that recording with greater bit depth allows quieter sounds to be captured, 16 bits is actually enough to capture any sound that can be reproduced through even the best audio equipment. The noise floor of a digital audio system is usually cited as minus 6 dB per bit – i.e., a 16-bit digital audio system has a noise floor 96 dB below the maximum recordable signal level.

 

This is technically wrong. The dynamic range of dithered 16 bit audio is 91 dB measured from the peak recording level, after allowing for a 7 dB increase in noise due to the use of TPDF dither. In addition, musical signals that have not been compressed typically have a peak to average ratio (crest factor) of 14 to 20 dB, and it can even be more. This means that uncompressed reproduction of music signals has a noise floor that ranges from about 70 to 80 dB below peak levels.

 

Dither – a small amount of noise – is added to the signal so that the

system does not exclude information below the theoretical minimum signal level. Typically, dither is limited to higher frequencies where it is not audible. The result can further be improved through noise-shaping techniques that shift the inherent noise of digital audio systems to ultrasonic frequencies. The result is that the noise floor of a 16-bit system within the audible frequency range can be as good as -110 dB or even -120 dB in practice.

 

Noise can be shifted around in frequency. Unfortunately, there are tradeoffs involved. Some recording engineers and audiophiles find that noise shaping can produce harshness and more fatiguing sound, particularly if noise shaping is not used in moderation.

 

Limited Dynamic Range of the Listening Environment:

Large, professionally installed home theater systems are calibrated to a reference sound pressure level (SPL) of 105 dB for each main channel. However, most people consider this level too loud for comfortable listening. (For reference, a jackhammer produces approximately 100 dB SPL at 1 meter.) Even most home theater enthusiasts listen at levels about -6 dB lower. Rarely are two-channel audio systems played at levels exceeding 100 dB. On the opposite end of the dynamic range, the best professional recording studios have a noise floor around 30 dB SPL. For a professionally installed, acoustically isolated and treated home theater, the noise floor might be about 40 dB SPL. For a living room, the noise floor is typically about 50 dB SPL – or even louder if the living room is open to other parts of the house. Thus, even when considering an extremely high listening level of 110 dB, in an acoustically isolated listening room with a 40 dB SPL noise floor, the dynamic range of the listening environment is only 70 dB. This is well within the commonly assumed 96 dB dynamic range of standard resolution digital audio.

 

This discussion of room noise levels is misleading, because it does not take into account frequency. Most room noise is in bass frequencies, because this is very difficult and expensive to isolate. It is not difficult to have quiet in the range where hearing is most sensitive.

[petaluma]

Dennis, Tony:

 

A little help here. I and I'm sure others are not engineers. You guys pointed out technical inaccuracies/discrepancies in the paper but is the ultimate conclusion of the paper incorrect? I would guess based on your statements you feel it is?

 

Thanks

 

David

 

Edit: And assuming the authors of the paper would have known their technical statements were inaccurate and going to be picked apart by other engineers what do you feel the motivation is for writing the paper? Are they incompetent engineers?

[Superdad]

Here are a few quotations from the paper, coupled with my comments. These are not intended to be complete.

….

 

Bravo Tony! Thanks for keeping it real.

 

What you state is all true, but I must say that these days really good SRC--and I don't mean by the typically resource-constrained DAC chip or FPGA--such as with HQ Player, can take Redbook to a VERY satisfying place. I'm much more concerned with mastering and recording quality than I am with bit depth and sampling rate. Not that I'll ever complain when good music is available in high res formats!

[esldude]

Dennis, Tony:

 

A little help here. I and I'm sure others are not engineers. You guys pointed out technical inaccuracies/discrepancies in the paper but is the ultimate conclusion of the paper incorrect? I would guess based on your statements you feel it is?

 

Thanks

 

David

 

I don't disagree with the ultimate conclusion of the paper. Tony can speak for himself.

 

It is simply unnecesary to have the obvious technical inaccuracies in the paper.

 

The one on timing is oft, oft repeated and has never been true. If you don't believe it, you can do a test of the idea yourself. I have done such a test and posted results. Most any pair of more or less current computers with soundcards will let you test out the idea.

[Tony Lauck]

Dennis, Tony:

 

A little help here. I and I'm sure others are not engineers. You guys pointed out technical inaccuracies/discrepancies in the paper but is the ultimate conclusion of the paper incorrect? I would guess based on your statements you feel it is?

 

Thanks

 

David

 

Edit: And assuming the authors of the paper would have known their technical statements were inaccurate and going to be picked apart by other engineers what do you feel the motivation is for writing the paper? Are they incompetent engineers?

 

I was trying to be polite and stick to facts. It is a marketing white paper. It is presented as technical truth. As far as I am concerned, if there is a single technical error (other than a typo) in a marketing white paper then the document should be trashed as marketing BS.

 

I can not fathom the motivations for Goldmund writing such a paper. I thought they were a hi-end company.

 

If you want an answer to the question of whether or not higher resolution formats are better you will have to listen and decide for yourself. No pseudo-technical arguments should make the slightest difference. There are hundreds of threads on numerous audio forums debating this question.

[mayhem13]

Here's my take......and it's based on the often misguided assumptions some make when they've heard or hear an improvement from HiRes over CD....

 

IT'S THE MASTER! In most cases when the material is purposely remastered with great care which is most often the case, yes, the hires version sounds better. When the content of both the Redbook and HiRes version is from the same mastering session, then NO....both sound the same.

 

I feel the pain of many here that have no idea of the provenance of so called HiRes content. Of course, one can do the homework and surfing in many cases to identifiy if in fact the title is worthy of Hi Res as opposed to upsampled.

[petaluma]

I don't disagree with the ultimate conclusion of the paper. Tony can speak for himself.

 

It is simply unnecesary to have the obvious technical inaccuracies in the paper.

 

The one on timing is oft, oft repeated and has never been true. If you don't believe it, you can do a test of the idea yourself. I have done such a test and posted results. Most any pair of more or less current computers with soundcards will let you test out the idea.

 

Dennis,

 

Thanks for the feedback. Learn a little bit more all the time from the discussions. But will never get to the level of you guy so I'm going to keep asking questions...

[petaluma]

I was trying to be polite and stick to facts. It is a marketing white paper. It is presented as technical truth. As far as I am concerned, if there is a single technical error (other than a typo) in a marketing white paper then the document should be trashed as marketing BS.

 

I can not fathom the motivations for Goldmund writing such a paper. I thought they were a hi-end company.

 

If you want an answer to the question of whether or not higher resolution formats are better you will have to listen and decide for yourself. No pseudo-technical arguments should make the slightest difference. There are hundreds of threads on numerous audio forums debating this question.

 

Tony, thanks for the info. Agreed on listening as the most important factor. If I like it who cares what others think. Just hoping I can make better buying decisions based on trying to understand the technical aspects of the hobby. One thing I seem to be learning is all the technical arguments around this hobby really don't lead to much of anything so maybe I'm misguided on my previous statement....Like you said listen...

[The Computer Audiophile]

.

 

Keep making posts like this Chris and we might need a poll: Is Chris a troll?

Ha!

[alfe]

I don't disagree with the ultimate conclusion of the paper. Tony can speak for himself.

 

It is simply unnecesary to have the obvious technical inaccuracies in the paper.

 

The one on timing is oft, oft repeated and has never been true. If you don't believe it, you can do a test of the idea yourself. I have done such a test and posted results. Most any pair of more or less current computers with soundcards will let you test out the idea.

 

 

Do you believe one second that an engineer wrote this white paper?

[astrotoy]

Years ago, I remember (perhaps not completely correctly) that one issue with CD's was that the chips that were used did linear quantization, rather than logarithmic, like the human ear hears (like the decibel scale). So most of the divisions of loudness occur at the loudest sound levels, leaving relatively few intervals at the lowest sound levels. This meant that fine gradations in sound levels at the lowest levels were being missed. (Was this the reason for dithering?). Anyway, I haven't heard much about this issue recently, and whether 24 bit quantization ameliorated or solves this problem. FIrst, do I remember this correctly and second, any enlightenment here?

 

Thanks, Larry

[alfe]

Tony, thanks for the info. Agreed on listening as the most important factor. If I like it who cares what others think. Just hoping I can make better buying decisions based on trying to understand the technical aspects of the hobby. One thing I seem to be learning is all the technical arguments around this hobby really don't lead to much of anything so maybe I'm misguided on my previous statement....Like you said listen...

 

no benefit for hi-res but when they compare PCM to DSD they use hi-res for comparison, it's quiet logic approach:)

[petaluma]

Went out to the Goldmund site. The Mimesis 20H DAC they sell does do hi-res. They have a product that does hi-res but the white paper states its not worth it. I find that a bit strange.....

[gmgraves]

Years ago, I remember (perhaps not completely correctly) that one issue with CD's was that the chips that were used did linear quantization, rather than logarithmic, like the human ear hears (like the decibel scale). So most of the divisions of loudness occur at the loudest sound levels, leaving relatively few intervals at the lowest sound levels. This meant that fine gradations in sound levels at the lowest levels were being missed. (Was this the reason for dithering?). Anyway, I haven't heard much about this issue recently, and whether 24 bit quantization ameliorated or solves this problem. FIrst, do I remember this correctly and second, any enlightenment here?

 

Thanks, Larry

 

 

All Audio PCM is linear rather than logarithmic quantization - regardless of the number of bits. Like you , I once thought that this might be a problem, but it turns out that once one understands how digital works, it's pretty irrelevant.

 

Dither, OTOH, is adding noise at the lowest level to randomize quantization where only one or two of the Least Significant Bits in a 16-bit system would be toggled without it. The noise reduces distortion at very low levels by working more than just the LSBs in very quiet passages. Many say that this makes digital sound better than just truncating the signal at the LSB.

[Jud]

Almost all currently available analog-to-digital converter (ADC) and digital-to-analog converter (DAC) chips oversample at high rates, typically 96 kHz or higher.

 

96 kHz? When was this written? The vast majority of DACs for a couple of decades now, with just a handful of exceptions, first interpolate to 352.8 or 384kHz, then the output is sigma-delta modulated to mHz rates.

 

Nothing I see in the quotes above from the paper (I haven't read it) talks about high res eliminating decimation filtering steps on the A/D end and possibly interpolation filtering steps on the D/A end, which strikes me as its biggest potential advantage. (That's with all else being equal, which it seldom is. mayhem's comment about mastering trumping all certainly fits my experience.)

[petaluma]

Jud,

 

Not sure when it was written but the paper is in Goldmund's Feb 2015 newsletter on their site.

[alfe]

96 kHz? When was this written? The vast majority of DACs for a couple of decades now, with just a handful of exceptions, first interpolate to 352.8 or 384kHz, then the output is sigma-delta modulated to mHz rates.

 

Nothing I see in the quotes above from the paper (I haven't read it) talks about high res eliminating decimation filtering steps on the A/D end and possibly interpolation filtering steps on the D/A end, which strikes me as its biggest potential advantage. (That's with all else being equal, which it seldom is. mayhem's comment about mastering trumping all certainly fits my experience.)

 

Oversampling started in '80s 2x at the beginning and very quickly after 8x

Up sampling in '90s.

[semente]

Oversampling started in '80s 2x at the beginning and very quickly after 8x

Up sampling in '90s.

 

What's the real world difference between one and the other?

[goldsdad]

Went out to the Goldmund site. The Mimesis 20H DAC they sell does do hi-res. They have a product that does hi-res but the white paper states its not worth it. I find that a bit strange.....

 

I'm sure they realise that almost no potential customer today would consider buying a DAC without support for higher than CD resolution.

[bdiament]

Here is an interesting PDF talking about the issue.

 

http://attachments.goldmund.com.s3.amazonaws.com/2015/01/23/15/49/42/359/goldmund_does_high_resolution_audio_sound_better_white_paper.pdf

 

Hi Chris,

 

What a surprising paper from a company I'd always thought was high end.

 

Two things stand out for me, aside from (what I deem) the obvious, which is their not hearing (or not having a system good enough to reveal) how much better high res is than Redbook:

 

1. I've noted before that I've heard some DACs that actually sound *worse* at 4x rates (like 176.4k and 192k) than they do at lower, easier rates like 2x (88.2k or 96k) or even Redbook. I attribute this to the significantly increased demands on clocking accuracy at the higher rates and on the requirement for performance at the wider bandwidths. Clearly, it is a lot easier to run a clock at 192k and put that number on a spec sheet, than it is to actually realize the potential of the format.

 

2. They continue the all too widespread confusion of signal-to-noise ratio with dynamic range. While these are *theroetically* the same -- or should be -- in reality they are two very different things. That is to say that low level signals might be well above CD's noise floor but they get increasingly raggedy as the level goes down and the signals are effectively represented by fewer than 16-bits of resolution. This is why cues in well made recordings, such as the size of the room the players are in, are relatively "out of focus" in Redbook when they are plain as day in a high res version created at the same mastering session. It is why instrumental harmonics don't reveal the same complexity in Redbook as they clearly do in the high res version.

 

Clearly, based on the paper, I would conclude that Goldmund does not see any benefit in high res and in fact, sees problems with the idea. To me, this sounds like they are saying folks who might be interested in high res should look to equipment other than that from Goldmund. At least that is how I would interpret their putting this on their website.

 

I've reported not too long ago about mastering the latest release for Soundkeeper, which was recorded and mastered at 24/192 (the first format I've ever heard, which when done right, can truly get out of the way). After listening to the 24/192 version all day with the artist at my side, we switched to check out the Redbook version. I immediately stood up to check the speakers and the rest of the system because it sounded to both of us like something broke. It was much harder to hear the characteristic sound of each of Art's many guitars, the acoustic of the church was much less in evidence, the soundstage dimensions seemed smaller, and it was as though the lights had been turned off and the air sucked out of the room. Going back to the 24/192 restored the sense of the recording and system getting out of the way, letting us hear things as they sounded when I stood at the position of the mic array in the church.

 

I want to go back to that aspect of the format getting out of the way. Over the years, I've used all sorts of recording devices, from Scully, Ampex, MCI, and Studer analog machines to all sorts of digital recording devices and formats. To my ears, each has a "color", some very nice but a color nonetheless. It was only when I heard 4x PCM done properly that I experienced, for the first time during any recording session, a recording I was unable to distinguish from the direct mic feed. So, when I see these "white papers" not only missing what I've waited decades to hear but calling it *worse*, I read it the same way I'd read a paper saying there are no colors in a rainbow.

 

In the end, I think folks who prefer Redbook, or hear no benefit to higher resolution, should enjoy their music in their format of choice. I never argue with whatever brings anyone their listening pleasure.

 

Best regards,

Barry

Soundkeeper Recordings

http://www.soundkeeperrecordings.wordpress.com

Barry Diament Audio

[esldude]

Do you believe one second that an engineer wrote this white paper?

 

No.