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

[steve_1979]

Ah, the old 'no-one's forcing you to read it' argument, huh?

Yes, I'd love to discuss hi-fi on a hi-fi forum. Do you know of any I could try? ;-) The personal combat here is taking things further and further away from that.

Seriously, though, this isn't a discussion about hi-fi, just like the endless threads about cables, active/passive speakers and other topics have little to do with the music and how it's played. Like those threads, this one has far too much w1lly-waving, far too much backstory for that, and that's a bit sad.

This is a thread about digital audio formats, which believe it or not is a hifi related subject being discussed on a hifi forum. Several people have already commented that they've enjoyed reading it and found it educational.

 

[hone_u2]

I guess this thread has been, if not a revelation, something to make us think more and put things in perspective... A lot of what I believed was right and wrong, overall I learnt a lot from it. I think to discover or learn anything usually it involves an argument or a 'combat'... But doesn't take away how educational this thread has been!

 

[relocated]

I haven't read this topic, but it says something about the contributors and moderation that it has gone to this many posts and still not locked. Excellent.

 

[fr0g]

However, If you would like to discuss hi-fi on a hi-fi forum I don't think complaining about how boring and circular a thread may be is very constructive, it just exacerbates the issue , neither is belittling other forum members for posting information they may think is a genuinely new contribution to the discussion. If you find a thread dull, worthless or past it's sell by date then don't comment on it, simple as that.

Ah, the old 'no-one's forcing you to read it' argument, huh?

Yes, I'd love to discuss hi-fi on a hi-fi forum. Do you know of any I could try? ;-) The personal combat here is taking things further and further away from that.

Seriously, though, this isn't a discussion about hi-fi, just like the endless threads about cables, active/passive speakers and other topics have little to do with the music and how it's played. Like those threads, this one has far too much w1lly-waving, far too much backstory for that, and that's a bit sad.

The "personal combat" as you so eloquantly put it, is down to trolls. The original point was to get any science out in the open, not to go back to the cables, active v passive debate.

But then you seem to be a bit of a professional troll on this forum (albeit occaisionally quite funny).

Then there are the folk who miss the point entirely and say "use your ears".

Then there are the dimwits who can't be logical and throw in arguments that don't follow the logic of what is being discussed.

There are quite a few people who are interested in the science, and more importantly in this instance, the truth.

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.

-

This forum is proof that you can fool some of the people, some of the time, but not all of the people, all of the time...It's a shame that the balance is more in favour of the first half of that quote right now, but it does at least seem to be moving in the right direction...

 

[altruistic.lemon]

the gist of the thread is as follows:

approx 60% combatants believe Nyquist Shannon prooves hd music is unnessesary

approx 20% combatants believe in their ears

approx 20% combatants believe NS is correct, but cannot be accurately applied to audio due to variables I'm still trying to absorb.

Of which 80% of the 60% of combatants believing unconditionally in NQ are all members of a certain small manufacturer's speaker forum!

It's a troll thread.

 

[andyjm]

Hi,

I have not read all the posts, but from an engineering perspective, the higher number of bits and higher sampling rate will be a benefit.

As long as the engineering process to record and then replay is as accurate as possible - then higher bits and higher sampling rate will be a benefit.

So, a higher sample rate and greater number of bits per sample is always a benefit, but whether they have been implemented correctly is another issue.

Regards,

Shadders.

Er no. Not done much engineering then I guess, Shadders.

Hi,

Surely if you increase the number of bits it will reduce the quantisation noise ?? (which is a benefit)

If you increase the sample rate, you will ensure that the actual waveform output from the DAC approaches the original signal values and less reliant upon interpolation by the output filter - hence more accurate - therefore a benefit.

Please can you explain why these statements are incorrect or not a benefit ?

Thanks and regards,

Richard.

My hero, Colin Chapman used to say "an engineer can do for a shilling, what any fool can do for a pound"

You can design a washing machine to last 50 years, but it will be so expensive no one will buy it, or a plane with triple redundancy, but it will be too heavy to fly. The engineering solution is to balance cost, weight, performance, speed, power consumption, size - in fact all of the constraints and requirements placed upon the design.

I am speculating, but I would guess that the design team at Philips that came up with the red book standard were given a brief along the lines of "come up with something that exceeds human frequency response and has a higher dynamic range than can be experienced in a domestic setting" 16/44.1 does this.

This is engineering. A higher sample rate or greater bit depth is triple redundancy on a plane.

 

[BenLaw]

the gist of the thread is as follows:

approx 60% combatants believe Nyquist Shannon prooves hd music is unnessesary

approx 20% combatants believe in their ears

approx 20% combatants believe NS is correct, but cannot be accurately applied to audio due to variables I'm still trying to absorb.

Of which 80% of the 60% of combatants believing unconditionally in NQ are all members of a certain small manufacturer's speaker forum!

It's a troll thread.

It's not a troll thread, as I participated in the original thread to which fr0g referred. However, the person who claimed that there was science contradicting N-S hasn't posted (despite being active on other threads) and was clearly in fact a delusional conspiracy theorist. Nonetheless, there's been some occasional interesting scientific points made on both sides in amongst the normal lunacy.

I'm afraid Spiny's point is a bit rubbish as clearly there are people reading this thread who haven't heard all the arguments before. So it may not be worthwhile for him but it has been for some people. He should perhaps apply a little of his laissez faire attitude a little more broadly and let people get on with the discussions they want to get on with. Spend their money how they want to, as it were.

 

[spiny norman]

The original point was to get any science out in the open, not to go back to the cables, active v passive debate.

No argument at all with the original motivation of the thread, but it has rather turned into the same old people saying the same old things, which is my problem with it.

But then you seem to be a bit of a professional troll on this forum

Unfortunately I am neither professional nor a troll, but I recognise the stereotyping: 'does not agree with me = troll'

However, let's not get off-topic - there's science to be done...

 

[BigH]

The original point was to get any science out in the open, not to go back to the cables, active v passive debate.

No argument at all with the original motivation of the thread, but it has rather turned into the same old people saying the same old things, which is my problem with it.

But then you seem to be a bit of a professional troll on this forum

Unfortunately I am neither professional nor a troll, but I recognise the stereotyping: 'does not agree with me = troll'

However, let's not get off-topic - there's science to be done...

What do you expect its the WHF forum, you expected a load of new people with new ideas to suddenly appear, its the same with forums the world over, most getting boring after a while with the same old topics.

I have not really seen any strong arguements for 24 bit yet.

 

[pauln]

However, If you would like to discuss hi-fi on a hi-fi forum I don't think complaining about how boring and circular a thread may be is very constructive, it just exacerbates the issue , neither is belittling other forum members for posting information they may think is a genuinely new contribution to the discussion. If you find a thread dull, worthless or past it's sell by date then don't comment on it, simple as that.

Ah, the old 'no-one's forcing you to read it' argument, huh?

Yes, I'd love to discuss hi-fi on a hi-fi forum. Do you know of any I could try? ;-) The personal combat here is taking things further and further away from that.

Seriously, though, this isn't a discussion about hi-fi, just like the endless threads about cables, active/passive speakers and other topics have little to do with the music and how it's played. Like those threads, this one has far too much w1lly-waving, far too much backstory for that, and that's a bit sad.

The "personal combat" as you so eloquantly put it, is down to trolls. The original point was to get any science out in the open, not to go back to the cables, active v passive debate.

But then you seem to be a bit of a professional troll on this forum (albeit occaisionally quite funny).

Then there are the folk who miss the point entirely and say "use your ears".

Then there are the dimwits who can't be logical and throw in arguments that don't follow the logic of what is being discussed.

There are quite a few people who are interested in the science, and more importantly in this instance, the truth.

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.

-

This forum is proof that you can fool some of the people, some of the time, but not all of the people, all of the time...It's a shame that the balance is more in favour of the first half of that quote right now, but it does at least seem to be moving in the right direction...

:clap:

 

[spiny norman]

What do you expect its the WHF forum, you expected a load of new people with new ideas to suddenly appear, its the same with forums the world over, most getting boring after a while with the same old topics.

That's a rather depressing view: you'd hope, given the appeal of the magazine to newcomers to 'tech', there might be more new people with some fresh thinking, rather than us bunch of old gits who've been here for ages going round and round in circles.

 

[shadders]

Hi,

I have not read all the posts, but from an engineering perspective, the higher number of bits and higher sampling rate will be a benefit.

As long as the engineering process to record and then replay is as accurate as possible - then higher bits and higher sampling rate will be a benefit.

So, a higher sample rate and greater number of bits per sample is always a benefit, but whether they have been implemented correctly is another issue.

Regards,

Shadders.

Er no. Not done much engineering then I guess, Shadders.

Hi,

Surely if you increase the number of bits it will reduce the quantisation noise ?? (which is a benefit)

If you increase the sample rate, you will ensure that the actual waveform output from the DAC approaches the original signal values and less reliant upon interpolation by the output filter - hence more accurate - therefore a benefit.

Please can you explain why these statements are incorrect or not a benefit ?

Thanks and regards,

Richard.

My hero, Colin Chapman used to say "an engineer can do for a shilling, what any fool can do for a pound"

You can design a washing machine to last 50 years, but it will be so expensive no one will buy it, or a plane with triple redundancy, but it will be too heavy to fly. The engineering solution is to balance cost, weight, performance, speed, power consumption, size - in fact all of the constraints and requirements placed upon the design.

I am speculating, but I would guess that the design team at Philips that came up with the red book standard were given a brief along the lines of "come up with something that exceeds human frequency response and has a higher dynamic range than can be experienced in a domestic setting" 16/44.1 does this.

This is engineering. A higher sample rate or greater bit depth is triple redundancy on a plane.

Hi,

Philips and Sony would have been limited by the technology available - the design of CD was based on possible technology at the time.

Using the DSP books i have - specifically the Sampling and Reconstruction of Signals, if the Nyquist rate is implemented correctly for a sampled signal, then the "ideal" interpolation function is a Sinc response in the time domain.

A Sinc function in the time domain is not realisable in this context, as such, a low pass filter (analogue) is used to approximate the output - that is, reconstruct the signal.

This introduces errors based on the non-ideal interpolation of the filter.

Increasing the sample rate and sample bit depth will reduce these errors, and hence any increase in the sample word length or sample frequency will reduce the errors and be of a benefit to the reconstruction of the original signal - that is, more accurate.

Regards,

Shadders.

 

[andyjm]

Hi,

I have not read all the posts, but from an engineering perspective, the higher number of bits and higher sampling rate will be a benefit.

As long as the engineering process to record and then replay is as accurate as possible - then higher bits and higher sampling rate will be a benefit.

So, a higher sample rate and greater number of bits per sample is always a benefit, but whether they have been implemented correctly is another issue.

Regards,

Shadders.

Er no. Not done much engineering then I guess, Shadders.

Hi,

Surely if you increase the number of bits it will reduce the quantisation noise ?? (which is a benefit)

If you increase the sample rate, you will ensure that the actual waveform output from the DAC approaches the original signal values and less reliant upon interpolation by the output filter - hence more accurate - therefore a benefit.

Please can you explain why these statements are incorrect or not a benefit ?

Thanks and regards,

Richard.

My hero, Colin Chapman used to say "an engineer can do for a shilling, what any fool can do for a pound"

You can design a washing machine to last 50 years, but it will be so expensive no one will buy it, or a plane with triple redundancy, but it will be too heavy to fly. The engineering solution is to balance cost, weight, performance, speed, power consumption, size - in fact all of the constraints and requirements placed upon the design.

I am speculating, but I would guess that the design team at Philips that came up with the red book standard were given a brief along the lines of "come up with something that exceeds human frequency response and has a higher dynamic range than can be experienced in a domestic setting" 16/44.1 does this.

This is engineering. A higher sample rate or greater bit depth is triple redundancy on a plane.

Hi,

Philips and Sony would have been limited by the technology available - the design of CD was based on possible technology at the time.

Using the DSP books i have - specifically the Sampling and Reconstruction of Signals, if the Nyquist rate is implemented correctly for a sampled signal, then the "ideal" interpolation function is a Sinc response in the time domain.

A Sinc function in the time domain is not realisable in this context, as such, a low pass filter (analogue) is used to approximate the output - that is, reconstruct the signal.

This introduces errors based on the non-ideal interpolation of the filter.

Increasing the sample rate and sample bit depth will reduce these errors, and hence any increase in the sample word length or sample frequency will reduce the errors and be of a benefit to the reconstruction of the original signal - that is, more accurate.

Regards,

Shadders.

I agree 100% that more bits will increase the dynamic range, and a higher sampling frequency will make life easier for the anti ailiasing and reconstruction filters. Where I disagree is whether this will be audible, and whether therefore it is good engineering.

 

[SpursGator]

Then there are the folk who miss the point entirely and say "use your ears".

Then there are the dimwits who can't be logical and throw in arguments that don't follow the logic of what is being discussed.

There are quite a few people who are interested in the science, and more importantly in this instance, the truth.

So 'using your ears' misses the point of hifi entirely? With this kind of doubletalk, it isn't surprising that even a non-dimwit might get a little confused by your logic.

Of course, your 'logic' includes statements like this:

What do you think large 3-way speakers are - essentially 2-ways, each sitting on a sub...

except they are subs that are stuck in a fixed position and non-configurable. A good single sub can be configured to integrate perfectly.

Since this illustrates your complete non-understanding of even the most basic concept of how speakers work, maybe you ought not to be calling anyone a dimwit (you know, the kettle black and all that). And perhaps, you ought to master the basics of hifi before wading with such marked arrogance into a debate about the complexities of digital reproduction and the nature of human hearing. Since you don't even know what a three-way speaker is.

 

[MakkaPakka]

..but that aside, Spursgator really valued your contribution

 

[cheeseboy]

So 'using your ears' misses the point of hifi entirely?

he wasn't referring to hifi though from what I can tell, it was about the hd music and testing with downsampling and comparing. (unless I missed something which is entirely possible)

As has been said many times before, human senses can be fooled many times over and made to hear and see things which are not there, and the point of this thread was to talk about the scientific points about high resolution audio. since that usually means talking about things which are not perceptable by the human ear, then using the human ear is surely not the best way to do this is it? Ideally you need some kind of repeatable tests, not just "use your ears".

Sure, we all listen to music through our ears, but If I wanted to prove to you track a was the same as track b for example, showing you the two waveforms in overlaying them to show there are (or are not) differences is a damn sight more scientific, repeatable and better way than subjectively listening to the same track again and again is it not. Bearing in mind it's science and doing things like that that gave us the hifi systems in the first place, I find it a wee bit odd that people are so quick to pick and choose which bits they want to believe all of a sudden.

Just my 2p's worth.

 

[shadders]

Hi,

I have not read all the posts, but from an engineering perspective, the higher number of bits and higher sampling rate will be a benefit.

As long as the engineering process to record and then replay is as accurate as possible - then higher bits and higher sampling rate will be a benefit.

So, a higher sample rate and greater number of bits per sample is always a benefit, but whether they have been implemented correctly is another issue.

Regards,

Shadders.

Er no. Not done much engineering then I guess, Shadders.

Hi,

Surely if you increase the number of bits it will reduce the quantisation noise ?? (which is a benefit)

If you increase the sample rate, you will ensure that the actual waveform output from the DAC approaches the original signal values and less reliant upon interpolation by the output filter - hence more accurate - therefore a benefit.

Please can you explain why these statements are incorrect or not a benefit ?

Thanks and regards,

Richard.

My hero, Colin Chapman used to say "an engineer can do for a shilling, what any fool can do for a pound"

You can design a washing machine to last 50 years, but it will be so expensive no one will buy it, or a plane with triple redundancy, but it will be too heavy to fly. The engineering solution is to balance cost, weight, performance, speed, power consumption, size - in fact all of the constraints and requirements placed upon the design.

I am speculating, but I would guess that the design team at Philips that came up with the red book standard were given a brief along the lines of "come up with something that exceeds human frequency response and has a higher dynamic range than can be experienced in a domestic setting" 16/44.1 does this.

This is engineering. A higher sample rate or greater bit depth is triple redundancy on a plane.

Hi,

Philips and Sony would have been limited by the technology available - the design of CD was based on possible technology at the time.

Using the DSP books i have - specifically the Sampling and Reconstruction of Signals, if the Nyquist rate is implemented correctly for a sampled signal, then the "ideal" interpolation function is a Sinc response in the time domain.

A Sinc function in the time domain is not realisable in this context, as such, a low pass filter (analogue) is used to approximate the output - that is, reconstruct the signal.

This introduces errors based on the non-ideal interpolation of the filter.

Increasing the sample rate and sample bit depth will reduce these errors, and hence any increase in the sample word length or sample frequency will reduce the errors and be of a benefit to the reconstruction of the original signal - that is, more accurate.

Regards,

Shadders.

I agree 100% that more bits will increase the dynamic range, and a higher sampling frequency will make life easier for the anti ailiasing and reconstruction filters. Where I disagree is whether this will be audible, and whether therefore it is good engineering.

Hi,

The people posting on this forum have stated that there is a difference - their experience has been better. Others may not experience an improved performance.

As you have stated "The engineering solution is to balance cost, weight, performance, speed, power consumption, size - in fact all of the constraints and requirements placed upon the design."

The capability of technology in producing 24bit recordings and mastering them is common place, since this is (please correct me if i am wrong) the industry standard. For the sample rate - not sure - but lets assume 192kHz. as standard (a £50 soundcard from PC World has 24bit 96kHz capability).

The cost of blu-ray duplication is very low - as per CD/DVD.

The current chipsets from semiconductor industries are either 24bit 192kHz capable, or 32bit 192kHz capable as standard.

Hence - from an engineering perspective, given that standard technology is 24bit 192kHz, the engineering argument is not valid.

If the discussion is whether a person can hear the difference - then we would required DBT to scientifically prove the difference.

Regards,

Shadders.

 

[Alec]

All of a sudden?!

 

[SpursGator]

..but that aside, Spursgator really valued your contribution

Well, it isn't really HIS contribution, since he's just parroting misinformation from the AVI website:

'It is important to understand that ADM9RSs and the AVI 10" Subwoofers have been designed as a system and best results will be achieved if they are used together. The ADM9RSs plus AVI 10" Sub are, in effect, a three way floor standing system with the option of infinitely adjustable bass.'

 

[oldric_naubhoff]

..but that aside, Spursgator really valued your contribution

Well, it isn't really HIS contribution, since he's just parroting misinformation from the AVI website:

'It is important to understand that ADM9RSs and the AVI 10" Subwoofers have been designed as a system and best results will be achieved if they are used together. The ADM9RSs plus AVI 10" Sub are, in effect, a three way floor standing system with the option of infinitely adjustable bass.'

fair enough, but why don't you keep such comments to their respective threads. this has no purpose nor use here.

 

[oldric_naubhoff]

Using the DSP books i have - specifically the Sampling and Reconstruction of Signals

what books that may be? I'm no engineer but keenly interested in all things audio and why is that it all works. I think reading through articles available on the net brought me to a point where I won't learn anything new and I know I still know very little. I guess a comprehensive book on DSP woul likely quench my thirst for knowledge on the matter.

 

[oldric_naubhoff]

I have not really seen any strong arguements for 24 bit yet.

I believe, other more knowledgable than me may confirm or deny, that you can't get away with lower bit depth than 24 if you're seriously thinking about fiddling with DSP... have you ever seen a DSP engine working on anything less than 24 bits? with 16 bits you just have too low noise floor and you might hit the bottom accidentaly. but I agree that 16 bits may be just OK for replay, meaning differences between 16 and 24 bits could be inaudible.

since DSP is slowly becoming a common place in any digital audio stream (most of legacy hi-fi is propably the last bastion of analog sound processing) then it surely makes sense to use audio format that is compatible with the hardware, rather covert one format into another and then back again, ad infinitum?

 

[oldric_naubhoff]

there's one thing that sprang to my mind with relation to the topic. if 16/44.1 format is the be all and end all of digital audio formats then why 99.9% (my estimate ) of commercialy available DACs are using some form of sample rate conversion before D2A conversion? in some cases as extreme as up to 1.5MHz :?

it appears, as per Shadder's comments in this thread, that N-S theorem is one thing and its practical implementation is another. maybe DACs work better (ie. approximate to analog waveform better) if presented with higher resolution and higher sampling rate digital input signal.

 

[BigH]

I have not really seen any strong arguements for 24 bit yet.

I believe, other more knowledgable than me may confirm or deny, that you can't get away with lower bit depth than 24 if you're seriously thinking about fiddling with DSP... have you ever seen a DSP engine working on anything less than 24 bits? with 16 bits you just have too low noise floor and you might hit the bottom accidentaly. but I agree that 16 bits may be just OK for replay, meaning differences between 16 and 24 bits could be inaudible.

since DSP is slowly becoming a common place in any digital audio stream (most of legacy hi-fi is propably the last bastion of analog sound processing) then it surely makes sense to use audio format that is compatible with the hardware, rather covert one format into another and then back again, ad infinitum?

Yes but we are talking about playback. CD are still the most common form of music buying and have many advantages such as availbilty and cost. 24 bit download have very limited availbility and cost considerably more. CDs also have a huge used market where you can buy them for around £1 and you can resell them, not sure about selling downloads. CD can be ripped and streamed if you want, many people do this rather than using a cdp.

 

[andyjm]

I have not really seen any strong arguements for 24 bit yet.

I believe, other more knowledgable than me may confirm or deny, that you can't get away with lower bit depth than 24 if you're seriously thinking about fiddling with DSP... have you ever seen a DSP engine working on anything less than 24 bits? with 16 bits you just have too low noise floor and you might hit the bottom accidentaly. but I agree that 16 bits may be just OK for replay, meaning differences between 16 and 24 bits could be inaudible.

since DSP is slowly becoming a common place in any digital audio stream (most of legacy hi-fi is propably the last bastion of analog sound processing) then it surely makes sense to use audio format that is compatible with the hardware, rather covert one format into another and then back again, ad infinitum?

Yes but we are talking about playback. CD are still the most common form of music buying and have many advantages such as availbilty and cost. 24 bit download have very limited availbility and cost considerably more. CDs also have a huge used market where you can buy them for around £1 and you can resell them, not sure about selling downloads. CD can be ripped and streamed if you want, many people do this rather than using a cdp.

DSP engines run at higher bit depths to allow the calculations to take place without truncation. It is perfectly reasonable to have a DSP engine with 16 bit input and output, but to perform calculations in 24 (or higher) bits.