High resolution audio. The science, or lack of...?

[andyjm]

All very well, it's just a suggestion. I would fight for your right to post your pointless drivel on this thread... But unless you are simply trying to troll, then wouldn't it be better to go and enjoy a thread that suits you?

You are the equivalent of a spawn-camper in a FPS (That's a synonym by the way)

I'm not the one trolling pal. I'll post where I like, as I said before. Your veiled and frankly pathetic insults are tiresome now.

Hmmn. I see you are back (again).

On this thread you have a) demanded it be locked, b) said that you have had enough and wouldn't be back.

Rather than childish retorts, do you have anything to add to the hires / standard res discussion?

 

[Anonymous]

Here's a link to some high res files http://www.audiocheck.net/testtones_highdefinitionaudio.php There's also a section where you can blind test files of different resolutions.

As I've said before. For it to be fair and scientifically valid test you need to convert the high res files to 16/44.1 yourself before doing blind comparisons otherwise there could be other factors such as the mastering which could cause them to sound different.

But he is trying to help and this is a halfway house test. So, thanks for that lemon.

 

[Anonymous]

Hmmn. I see you are back (again).

On this thread you have a) demanded it be locked, b) said that you have had enough and wouldn't be back.

Rather than childish retorts, do you have anything to add to the hires / standard res discussion?

I object to your comment of 'childish retorts'. I have contributed in the interim. I said I had retired on that particular day.

 

[shadders]

. . . those were 4 bit files, true. but it shows what would happen to SQ if you tried to use too much of available dynamic range from 16 bits format. if you recorded down to 4 bits you'd get exactly that kind of SQ for the quiet parts as you got in those examples on TNT website. if you still don't get it then I'm afraid even another 30 pages of this thread won't help you understd it either.

Oldric, your premise is not valid.

This is a well known and accepted explanation which might help you understand. It's a few years old, but concise and accurate.

In particular this bit addresses the points you raise.

The concept of the perfect measurement or of recreating a waveform perfectly may seem like marketing hype. However, in this case it is not. It is in fact the fundamental tenet of the Nyquist-Shannon Sampling Theorem on which the very existence and invention of digital audio is based. From WIKI: “In essence the theorem shows that an analog signal that has been sampled can beperfectly[/b] reconstructed from the samples”. I know there will be some who will disagree with this idea, unfortunately, disagreement is NOT an option. This theorem hasn't been invented to explain how digital audio works, it's the other way around. Digital Audio was invented from the theorem, if you don't believe the theorem then you can't believe in digital audio either!!

JC

Hi ,

Agreed, the theorem does state that the waveform can be perfectly reconstructed - but the filter required is not possible in the analogue domain.

In the digital domain it is possible with a very long delay - using a filter with a Sinc envelope for the impulse response - up to infinity.

This is not practical - so we approximate with analogue filters - hence an error will be introduced.

If we sample at a higher sampling rate - the interpolation of the analogue filter error is reduced.

If we use more bits - then yes - the dynamic range possible cannot be used - but the accuracy of the waveform is increased for the same full scale deflection as a 16bit quantised waveform.

If we can implement this correctly - 24bit 96kHz sampling or higher - then why not - have the best source possible.

Regards,

Shadders.

Shadders,

We had this discussion some pages back. The challenge as an engineer is often where to draw the line - when is enough, enough. 'Lets sample at higher rate, lets have a few more bits' is all well and good, but why? and where do you stop?

Link below is to a 1.5 Giga samples per second, 16 bit DAC. Want to use that? Of course not. But according to you more is better?

http://www.idt.com/products/data-converters/digital-analog-converters-dac/high-speed-jesd204b-serial-interface-dac/dac1658q-high-performance-16-bit-quad-dac-high-common-mode

If you could explain what signal to noise ratio you think is necessary and what maximum frequency you want in your baseband, then we could have a sensible discussion about changing sample rate and bit depth, but until you can explain why 96dB and 20KHz doesn't do it for you, I am afraid it is all just pie in the sky.

Hi,

Our discussion was based on your proposal that engineering is the requirement to design and implement a system based on cost, requirements, specification and reliability, where these aspects are in contention, so the engineer has to make decisions to meet the specification at the lowest cost whilst still meeting the reliability critera etc.

My response was that in the early 1980's the technical capability limited our decisions and the current standard for CD was based on the capbility as per 1980's technology. Therefore, we have advanced with regards to the density of capability and performance in IC's to the point where we can readily implement 24bit words at 192kHz sampling frequency in a single IC. Ths your engineering proposal was not valid.

One question you have posed is that why not take it to the extreme and use your DAC which you have referenced.

Agreed - why not - I believe the Metrum DAC implements either this device or similar, and has very good reviews.

My further statements are since we have the technological capability, we can increase the sample rate, increase the word length for each sample, such that the output filter introduces less error. The reduced error means a more accurate replay of the signal.

I never claimed that 20kHz and 16bits were insufficient.

I will state that the closer to the original waveform that can be achieved, then the better our source is for replay of the music.

Regards,

Shadders.

 

[steve_1979]

Here's a link to some high res files http://www.audiocheck.net/testtones_highdefinitionaudio.php There's also a section where you can blind test files of different resolutions.

As I've said before. For it to be fair and scientifically valid test you need to convert the high res files to 16/44.1 yourself before doing blind comparisons otherwise there could be other factors such as the mastering which could cause them to sound different.

But he is trying to help and this is a halfway house test. So, thanks for that lemon.

We've already been over this one at the start of the thread. The test tones in AL's link are invalid because they are deliberately designed to have anti aliasing distortion from frequencies above 22kHz.

Remember: 16/44.1 is only accurate up to 22.05kHz (which is higher than humans can hear). To convert the high res files to 16/44.1 properly (without introducing anti-alising distortion) you should filter out the frequencies above 22kHz first before converting the high res files to 16/44.1. I've done this myself before and they sound identical when converted to 16/44.1 using this method.

 

[jcbrum]

My further statements are since we have the technological capability, we can increase the sample rate, increase the word length for each sample, such that the output filter introduces less error. The reduced error means a more accurate replay of the signal.

I never claimed that 20kHz and 16bits were insufficient.

I will state that the closer to the original waveform that can be achieved, then the better our source is for replay of the music.

Regards,

Shadders.

I think you are a bit out of date with your filter technology info and assumptions, Shadders.

For some years now digital filter systems have been been incorporated into DAC chips and systems. They are cheap, readily available, and work to the required specification.

No-one depends on analogue style filters, as used a few years ago, anymore.

Have a read-up on delta-sigma systems, as being just one example of digital filter technology as used commonly today.

JC

 

[busb]

Here's a link to some high res files http://www.audiocheck.net/testtones_highdefinitionaudio.php There's also a section where you can blind test files of different resolutions.

As I've said before. For it to be fair and scientifically valid test you need to convert the high res files to 16/44.1 yourself before doing blind comparisons otherwise there could be other factors such as the mastering which could cause them to sound different.

The only point of down-sampling at home is too remove any doubt that downloaded files maybe not quite cosher. It also requires the DAC used is not inherently better at 24/96k than at 16/44.1!

Given contemporary DAC technology, this thread (or some of the links posted in it) has restored my faith in 16/44.1 being perfectly adequate for the music we buy (unless we want to remix it ourselves which most of us don't).

What this thread has highlighted to me is just how dishonest parts of the music/audio industry is. The concept of producing better quality recordings under the guise of higher bit rates when these recordings could be sold as 44.1k grealy perturbs me. Why not just sell CD quality at a premium price to reflect the effort & time taken for better mastering? It would more honest than spreading the myth that 24/96 is better. This thread highlights the most important issue with music is the recording quality & not the medium!!

Science, technology & engineering moves so quickly that understanding even a small part of it can be very scary. An example was all the fuss regarding mobile phone aerials damaging health. Groups of individuals were using their mobile phones to organise themselves! What's worse - a bonfire 50m away or a sparkler held against one's ear? If you believe that phone masks are an issue, you'd better understand that holding a phone to your ear would be far worse! People generally resent those folk more cleaver than they are - some get very touchy about their own lack of understanding of stuff so invent all sorts of strategies to disguise this. When I read up on a lot of scientific stuff, I soon hit the buffers of my understanding. I either persevere if for work or my interest is sufficient (which takes effort) or go straight to the conclusions as being correct as far as I can tell. I am personally grateful that there are many, many people far more intelligent than I am. One issue with a modern technological society is less with folk being "too damn clever" (jealousy) than the level of specialism required in any one subject or technology. Much technology might as well be magic!

 

[jcbrum]

You have reached some interesting conclusions, busb.

I think the answer to the OP might go something like this . . .

16/44 which was decided upon thirty years ago is entirely adequate for domestic replay purposes, still today.

For reasons un-connected with replay, 24/96 is the preferred format for recording purposes, bearing in mind the practical requirements for mastering and production.

The over-riding factor governing the perceived replay sound quality, is the quality of the recording and mastering and production processes, not the format.

Having accepted that the recording studios and record producers are going to produce (typically) a 24/96 audio file, then they may decide to release that for distribution, or a 16/44bit version. The main consideration here (imo) should be file size requirement, and thereby consumption of bandwidth for electronic distribution and storeage. An hour of stereo 16/44 consumes about 635Mb, and a 24/96 file is four times bigger than that at around 2.5Gb.

So, the big question is, since both formats are readily available (for recent recordings), and equally satisfactory in terms of sound quality, - Should a 24/96 file (as a download) cost any more than a 16/44 version.

That. IMO, is the real question.

JC

 

[fr0g]

You have reached some interesting conclusions, busb.

I think the answer to the OP might go something like this . . .

16/44 which was decided upon thirty years ago is entirely adequate for domestic replay purposes, still today.

For reasons un-connected with replay, 24/96 is the preferred format for recording purposes, bearing in mind the practical requirements for mastering and production.

The over-riding factor governing the perceived replay sound quality, is the quality of the recording and mastering and production processes, not the format.

Having accepted that the recording studios and record producers are going to produce (typically) a 24/96 audio file, then they may decide to release that for distribution, or a 16/44bit version. The main consideration here (imo) should be file size requirement, and thereby consumption of bandwidth for electronic distribution and storeage. An hour of stereo 16/44 consumes about 635Mb, and a 24/96 file is four times bigger than that at around 2.5Gb.

So, the big question is, since both formats are readily available (for recent recordings), and equally satisfactory in terms of sound quality, - Should a 24/96 file (as a download) cost any more than a 16/44 version.

That. IMO, is the real question.

JC

Without the 24/96 version of course, they can't resell to people who already own the album.

As for the question, Yes, they can honestly charge more for the larger version, as bandwidth costs money.

What I object to is where the 24/96 version uses a better mastering, and is not available in a 16/44.1 format to the same standard.

As I have mentioned before, I would gladly pay a bit more for an "audiophile" release on CD or FLAC 16/44.1 format, but at the moment, Linn for example will charge 11 Euros for a CD standard quality, and 21 Euros for a 24/96 download...That is taking the mickey. Especially when you download the 24/96 version, resample to 16/44.1 and realise that both sound identical.

And what's more for my own purposes I am more than happy that a 256 Kbps MP3 or AAC file is indistinguishable from the original 16/44.1 or indeed the 24/96 file...

 

[jcbrum]

As for the question, Yes, they can honestly charge more for the larger version, as bandwidth costs money.

Hmmm, I don't think the proportional cost of bandwidth is significant, to the producers, when considering the total cost of production and release.

I take the rest of your points.

Possibly, a distribution format such as 'Mastered for iTunes', which is a very high quality AAC compressed format, will turn out to be the best, and most preferred format for domestic HiFi, by discerning listeners, with high quality equipment.

JC

 

[jcbrum]

Mastered for iTunes, (clicky)

JC

 

[shadders]

My further statements are since we have the technological capability, we can increase the sample rate, increase the word length for each sample, such that the output filter introduces less error. The reduced error means a more accurate replay of the signal.

I never claimed that 20kHz and 16bits were insufficient.

I will state that the closer to the original waveform that can be achieved, then the better our source is for replay of the music.

Regards,

Shadders.

I think you are a bit out of date with your filter technology info and assumptions, Shadders.

For some years now digital filter systems have been been incorporated into DAC chips and systems. They are cheap, readily available, and work to the required specification.

No-one depends on analogue style filters, as used a few years ago, anymore.

Have a read-up on delta-sigma systems, as being just one example of digital filter technology as used commonly today.

JC

Hi,

I am aware of current technology - i implemented the PCM1792 TI DAC in the DAC i built. I understand that this implements oversampling and digital filters - which you can select from two different digital filters provided by the device. You can also implement an external digital filter.

I also implemented a sample rate converter (SRC4392) in the same design.

By implementing 24bit words at a high sample rate - the internal DAC IC filters may not be a requirement - depending on how the DAC IC is designed.

The proposal is to achieve an accurate as possible source data, which does not rely upon interpolation filters (digital or analogue) to attempt to reproduce as accurate as possible the original wavefrom.

Regards,

Shadders.

 

[busb]

You have reached some interesting conclusions, busb.

I think the answer to the OP might go something like this . . .

16/44 which was decided upon thirty years ago is entirely adequate for domestic replay purposes, still today.

For reasons un-connected with replay, 24/96 is the preferred format for recording purposes, bearing in mind the practical requirements for mastering and production.

The over-riding factor governing the perceived replay sound quality, is the quality of the recording and mastering and production processes, not the format.

Having accepted that the recording studios and record producers are going to produce (typically) a 24/96 audio file, then they may decide to release that for distribution, or a 16/44bit version. The main consideration here (imo) should be file size requirement, and thereby consumption of bandwidth for electronic distribution and storeage. An hour of stereo 16/44 consumes about 635Mb, and a 24/96 file is four times bigger than that at around 2.5Gb.

So, the big question is, since both formats are readily available (for recent recordings), and equally satisfactory in terms of sound quality, - Should a 24/96 file (as a download) cost any more than a 16/44 version.

That. IMO, is the real question.

JC

To answer your question: no, IMO. However, I'd expect some labels to charge a premium due to the time & effort taken in mastering as I mentioned earlier.

As for Fr0g's original question, I doubt any scientifically valid arguments exist to prove that going greater than 16/44.1k is worthwhile for final output. Dealing with people's own perceived experience is equally important to this whole question. I'm reluctant to dimiss every subjective observation being down to Expectation Bias as being a little too convenient. However, you can only inform (educate is a term I'd personally refrain from using on this forum as it smacks of superiority) those willing to listen & be open-minded as they accuse their opposites of not being! I can remember more than one thread where posters have reacted extremely strongly against the concept that our brains can be so easily "tricked" - it's a very powerful argument to say "listen for yourself!"

 

[chebby]

And what's more for my own purposes I am more than happy that a 256 Kbps MP3 or AAC file is indistinguishable from the original 16/44.1 or indeed the 24/96 file...

I am broadly in agreement but have, personally, drawn the line at 320k AAC for my own rips from CD.

When I originally tested and compared 256k / 320k AAC I was finding audible distortion on - just a few - loud/sudden vocal shouts or screams (or other such moments) when listening to audio drama. Although it only happened occasionally, it would be enough to break my concentration and be a minor irritant.

Ripping everything in 320k AAC VBR instead cured this totally.

I should stress this only applies to rips from speech based CD content but, as I listen to so much of it, that matters to me and I won't be persuaded that - just in this context - 256k is indistinguishable from 320k or ALAC.

 

[altruistic.lemon]

As for Fr0g's original question, I doubt any scientifically valid arguments exist to prove that going greater than 16/44.1k is worthwhile for final output. Dealing with people's own perceived experience is equally important to this whole question. I'm reluctant to dimiss every subjective observation being down to Expectation Bias as being a little too convenient. However, you can only inform (educate is a term I'd personally refrain from using on this forum as it smacks of superiority) those willing to listen & be open-minded as they accuse their opposites of not being! I can remember more than one thread where posters have reacted extremely strongly against the concept that our brains can be so easily "tricked" - it's a very powerful argument to say "listen for yourself!"

Thing is, I doubt the protagonists have a sufficiently high-end system to be able to tell the difference anyway, irrespective of the "science". I can certainly tell the difference between high res blue ray and remastered CD, mostly because the remasters tend to be cr*p. Is it the high definition? Frankly, couldn't give a sh*t.

 

[busb]

And what's more for my own purposes I am more than happy that a 256 Kbps MP3 or AAC file is indistinguishable from the original 16/44.1 or indeed the 24/96 file...

I am broadly in agreement but have, personally, drawn the line at 320k AAC for my own rips from CD.

When I originally tested and compared 256k / 320k AAC I was finding audible distortion on - just a few - loud/sudden vocal shouts or screams (or other such moments) when listening to audio drama. Although it only happened occasionally, it would be enough to break my concentration and be a minor irritant.

Ripping everything in 320k AAC VBR instead cured this totally.

I should stress this only applies to rips from speech based CD content but, as I listen to so much of it, that matters to me and I won't be persuaded that - just in this context - 256k is indistinguishable from 320k or ALAC.

Although I have ripped lossless in iTunes, I generally use 320k VBR. I do go lower for audiobooks. I've been unable to detect any appreciable differences between 256 & 320 AAC VBR but allow for a little headroom - I'm hedging my bets a little! I find iTunes 256k downloads fine as I do Spotify Premium listening.

 

[altruistic.lemon]

So despite all the fuss, the major players are't even using CD quality? Makes you wonder why the hell Philips and Sony bothered.

 

[jcbrum]

Thing is, I doubt the protagonists have a sufficiently high-end system to be able to tell the difference anyway,

HaHa, that's sour grapes, bitter lemon.

Frankly, couldn't give a sh*t.

Neither could I, atm, the Six Nations Rugby is about to start on BBC1

JC

 

[fr0g]

And what's more for my own purposes I am more than happy that a 256 Kbps MP3 or AAC file is indistinguishable from the original 16/44.1 or indeed the 24/96 file...

I am broadly in agreement but have, personally, drawn the line at 320k AAC for my own rips from CD.

When I originally tested and compared 256k / 320k AAC I was finding audible distortion on - just a few - loud/sudden vocal shouts or screams (or other such moments) when listening to audio drama. Although it only happened occasionally, it would be enough to break my concentration and be a minor irritant.

Ripping everything in 320k AAC VBR instead cured this totally.

I should stress this only applies to rips from speech based CD content but, as I listen to so much of it, that matters to me and I won't be persuaded that - just in this context - 256k is indistinguishable from 320k or ALAC.

I have tended to go 320 now, Just in case. But an interesting test you can do with foobar and the ABX plugin...

Download the test track from Linn. The 24/96 one.

Resample all the way down to 128 Kbps...Try and ABX it...It's difficult. In this case I can see why. It's a very slow piece of simple classical...A 128 Kbps MP3 is probably enough.

 

[chebby]

I have tended to go 320 now, Just in case. But an interesting test you can do with foobar and the ABX plugin...

Download the test track from Linn. The 24/96 one.

Resample all the way down to 128 Kbps...Try and ABX it...It's difficult. In this case I can see why. It's a very slow piece of simple classical...A 128 Kbps MP3 is probably enough.

Thanks. I don't really have an iron in this fire so testing is unnecessary.

Even if I did discover that SACD quality (or higher) downloads sounded superior it wouldn't make any difference because so little of what I enjoy will ever be made available. in so-called HD digital formats. (Apart from a few classical and jazz titles.)

Some of the best classical music performances i've heard (apart from when actually there myself) were live performances on Radio 3. Far from being analogue, these were all distributed digitally between venue - Broadcasting House and digitally between Broadcasting House to all the transmitters.

From the early 1970s onwards this would have been 13 bit 32khz PCM and then, from 1993 onwards, 14 bit NICAM 3 companded to 10 bits. In both cases it was all filtered off at 15kHz for broadcast.

 

[busb]

So despite all the fuss, the major players are't even using CD quality? Makes you wonder why the hell Philips and Sony bothered.

If you mean software players such as iTunes, Foobar etc then many of us are not using CD quality which is a lossless format in favour of a good lossy one such as AAC; you would be correct. Myself & others have concluded that there is too little difference to worry about. If someone could demonstrate otherwise to my satisfaction, I'd curse then re-rip my better recordings! I am not saying that lossless formats are always as good but no obvious shortfalls have been heard by me so far. Many don't trust lossy formats, so use flac, or Apple lossless instead.

My now retired Rotel CDP decoded the few HDCD discs I own. The format (a rare one now owned by Microsoft), supposedly was to add to the SQ from compatible players but be completely transparent on normal ones. Jim L has found otherwise:

http://www.audiomisc.co.uk/HFN/HDCD/Enigma.html

At least 24/96 playback doesn't go backwards! As for remasters, many sound worse. I have vinyl thats sounds much better than the CD version.

 

[Alec]

If you mean software players...[/quote]

I don't think he did, but who cares.

 

[fr0g]

If anyone is interested, I did the test I mentioned earlier.

I used the free test file from Linn (a 24/192 track) and opened it in Audacity.

I resampled to 16 bits and 44.1 and saved another track.

I opened both and inverted one of them. I then combined them to a new 192 Khz flac file.

I then analyzed what was left...

There is a bit of noise at -84dB and some very high frequency at around -70 dB.

I played the file through the speakers...absolute silence...

 

[CJSF]

If it is possible (which I believe it is) to produce music of equal quality on a CD, then I want it, on a CD, and I don't want to be forced into paying double for the studio master or SACD for highly dubious reasons.

. . . :? I find most of what is in this thread pointless, a personal view of course, probably because 'I dont have the scientific understanding?'. However, I do believe what my ears and much modified system tells me in terms of 'musical pleasure' . . . I have just listened to 'Dark Side of the Moon' on CD and vinyl, both are 'Original Master Recordings', both I have owned from new.

Frankly the vinyl knocks spots of the CD . . . I suppose it might be my Rega Apollo CDp, then again, it may be the highly modified TT, arm, cartridge combination, I dont know, what I do know is, I enjoyed listening to the music, takes me back a lot of years . . . when trusting what you heard was the way to do it. Taking no notice of the hype trundled out to the gullible . . . have we come full circle?

Ho-hum, back to enjoying music . . .
CJSF

 

[Anonymous]

I find most of what is in this thread pointless

Careful, some on here will tell you not to bother posting and buzz off somewhere else.