LP with better dynamic range than digital

[Atmasphere]

^^ Ideally for LP, the 20db louder figure as the noise is broadband.

If I set up my sound pressure meter in my listening room, the quietest I have ever seen is 30-35db. Its rare that I see a room with less noise than that, I'd be very surprised to discover one that is 20db.

 

[Don Hills]

Sony Super Bit Mapping is not dither but a noise shaping solution ...

Who you gonna believe - Bruno or Sony? (Don't answer that. )
Actually, in a narrow sense, you're right. Sony don't use a classic dither process when bit reducing. They apply an error feedback process. For any given sample, the quantisation error is distributed into surrounding samples, similar to the error diffusion process used in image processing. Because the process uses a limited number of terms it results in slightly higher distortion but lower added noise (than using classic dither techniques). You get a similar effect when you use insufficient classic dither.

 

[Don Hills]

^^ Ideally for LP, the 20db louder figure as the noise is broadband.

If I set up my sound pressure meter in my listening room, the quietest I have ever seen is 30-35db. Its rare that I see a room with less noise than that, I'd be very surprised to discover one that is 20db.

What weighting? At these SPLs, it matters a lot. In my own limited experience, the noise characteristic is typically 1/f. A couple of years back I recorded my own room and then played it back at an elevated level via headphones. I don't know the absolute levels because I lacked a calibrated source, but the loudest audible sounds were the ticking of the wall clock and my own breathing. There was a surprising amount of LF noise showing on the spectrum analysis even though it was the early hours of the morning in my suburban location.

 

[Orb]

.....

Now if you used shaped dither some frequency bands in the noise will be increased, and some lowered. The total level of noise over the entire 20 khz band would be higher. Most likely in this totally quiet environment you would hear dead silence. In the 3-4 khz range you would therefore be able to hear a -120 db tone or just barely above that if your hearing is good.

Without putting exact numbers on it if you did this same thing with an LP in vinyl as you normally can buy records the noise level will be higher. In that 3-4 khz range you probably will need a tone 20 to 30 db louder to hear it amongst the noise.

Unfortunately you cannot used shaped dither for ADC or at the point of mixing (context for both being related to this thread and audio), which makes this a bit restricted, also part of this results more in perceived dynamic range increased rather than providing greater amplitude bit depth.

Cheers
Orb

 

[Orb]

Who you gonna believe - Bruno or Sony? (Don't answer that. )
Actually, in a narrow sense, you're right. Sony don't use a classic dither process when bit reducing. They apply an error feedback process. For any given sample, the quantisation error is distributed into surrounding samples, similar to the error diffusion process used in image processing. Because the process uses a limited number of terms it results in slightly higher distortion but lower added noise (than using classic dither techniques). You get a similar effect when you use insufficient classic dither.

Hehe yeah never trust Sony
I would need to check but I thought Sony SBM is based around the Gerzon & Craven theory, other solutions do require dithered quantizer.
In fact all this is reminding of old papers; need to dig through some of the works by Gerzon/Stuart/Hawksford/Verhelst/etc.
Ah well something to do if bored this week
Cheers
Orb

EDIT:
OK I think it is this paper that shows SBM and non-dithered quantization, Noise Shaping filter ;
Akune, M., Heddle, R.M., and Akagiri, K., ”Super Bit Mapping: Psychoacoustically Optimized Digital Recording”, AES preprint 3371, presented at the 93rd AES Convention, San Fransisco, October 1-4, 1992.

 

[Don Hills]

... I need to revisit that; the thread is moving too fast for me... can you provide links again? ...

Here:
http://www.whatsbestforum.com/showt...e-than-digital&p=292796&viewfull=1#post292796

...
1) having just said the CD's dynamic range is 93dB over 0-22kHz using TPDF dithering, do you believe THIS 16-bit system can still encode any signal in the [-100dB to -130dB] range, or if not that range, what range would you say? (I think you answered this upthread, but I am looking for a clear Yes/No answer again, if I may, along with a clear range)

2) Now assuming a "shaped dither is most commonly used for final distribution" as you said, can you provide a similar clear and complete answer to my original question relating to dynamic range and the follow-up question relating to ability to encode in the [-100db to -130dB] range, including the commonly used noise-shaping algorithm in the industry that would give you that? ...

In theory, a properly dithered ADC-DAC process has infinite resolution. In practice, the answer is "it depends" on what you're trying to do. A 16-bit system can certainly capture a signal smaller than -130 dB, the hard part is detecting it in the noise afterwards. Techniques exist to do so, usually for scientific applications. It would be a waste of time for audio, our ears aren't that good at discrimination. And in practice, real ADCs / DACS simply aren't that good either. Their own internal errors and noise swamp the signal. Even the best 24 bit audio ADC-DAC chains don't get down to -130 dB noise level.

... But I think what you want to know is "how quiet an audio signal can you record on a 16 bit system using various dithers". The answer is, as usual, "it depends". How much noise can you tolerate? And what type of signal?

 

[BruceD]

There was a surprising amount of LF noise showing on the spectrum analysis even though it was the early hours of the morning in my suburban location.

Ha Don!--Are you sure it wasn't the rumble of a Straits Southerly blowing up the Island Bay Valley?--Just kidding!

Enjoy your banter by the way--but I still enjoy my LP over my CD--but can make room for both

Good Listening

BruceD

 

[esldude]

Unfortunately you cannot used shaped dither for ADC or at the point of mixing (context for both being related to this thread and audio), which makes this a bit restricted, also part of this results more in perceived dynamic range increased rather than providing greater amplitude bit depth.

Cheers
Orb

So what? You have a 24 bit ADC, and play it back as 16 bit to get the point across. That is how most recordings are done anyway. 24 bit recordings converted to redbook if needed. I also no of no reason you could not use shaped dither on the ADC. With 24 bit ADCs it is useless as your electronics aren't quiet enough for that to matter anyway. About the best any DAC will do upon playback is in the vicinity of 20 bit performance or noise floors of -120 db. And I don't know of any domestic rooms that are quiet enough to even do that if the rest of your system should manage it.

Yes, perceived dynamic range within the 16 bit restriction. Also could be described as resolution below the LSB.

Admittedly all of this is rather extreme and artificial.

 

[Orb]

So what? You have a 24 bit ADC, and play it back as 16 bit to get the point across. That is how most recordings are done anyway. 24 bit recordings converted to redbook if needed. I also no of no reason you could not use shaped dither on the ADC. With 24 bit ADCs it is useless as your electronics aren't quiet enough for that to matter anyway. About the best any DAC do upon playback is in the vicinity of 20 bit performance or noise floors of -120 db. And I don't know of any domestic rooms that are quiet enough to even do that if the rest of your system should manage it.

Yes, perceived dynamic range within the 16 bit restriction. Also could be described as resolution below the LSB.

Admittedly all of this is rather extreme and artificial.

And so you break the argument case around 16bits as you now talk about using 24bits to begin with (appreciate we agree probably need around 20bits).
What your proposing now is a 24bit solution using decimation/downsampling with right dither type and amount to reach a conclusion on what has been the discussion recently.
It may seem I am being pedantic but you would otherwise need to remove all CDs produced before 24bit recording was introduced in the studio.
That said emphasis does also improve dynamic range of CD.

BTW I am sure both myself and ack do agree with a lot said such as Don's recent post #288 and your comments, just the context and scope-limitations on how it applies to real world audio is where we have been a bit at odds I would say.
Late here so sorry if a bit garbled and yeah as I mentioned much earlier is full dynamic range really the primary factor in perceived quality differentiation between different formats from LP to CD/hirez PCM/DSD.
I tend to think not myself, and not something we should be losing sleep over..... but wait.... I freaking am losing sleep as its late bah...
Cheers
Orb

 

[esldude]

BTW I am sure both myself and ack do agree with a lot said such as Don's recent post #288 and your comments, just the context and scope-limitations on how it applies to real world audio is where we have been a bit at odds I would say.
Late here so sorry if a bit garbled and yeah as I mentioned much earlier is full dynamic range really the primary factor in perceived quality differentiation between different formats from LP to CD/hirez PCM/DSD.
I tend to think not myself, and not something we should be losing sleep over..... but wait.... I freaking am losing sleep as its late bah...
Cheers
Orb

A few factors are behind the sound differences in the formats.

Two things probably make LP sound more dynamic for the most part in my opinion.

One is that to improve playback without tracking issues I believe the majority of LP's have some compression. Some compression in rather moderate amounts will make most music sound more dynamic even though you just reduced the actual dynamic range. Go too far like most modern recordings and it just sounds loud and awful.

Another is the cartridges on peaks generally generate a few percent distortion. One of the ways our hearing decides how loud something is happens by how many of its multiple frequency bands are activated. So some music with content at 500 hz with some peaks periodically will go up in level the distortion near the top will become significant briefly. The harmonics above that 500 hz which aren't supposed to be there activate additional bands in our hearing which makes our perception of it louder than the energy in the signal really is. So we perceive really loud for a moment and then it goes away as the level drops and the distortion harmonics with it. Seems like a really dynamic sound. It will be too brief to sound like the nasty distortion it really is. It will just sound dynamic and exciting. The effect will be absent in clean digital. So the same exact recorded signal would sound more dynamic in one format vs the other in one sense.

So digital recordings could be compressed only moderately if record companies would go for that. There no doubt could be plug ins to copy the effect of a cartridge on the signal. That should get you most of the way there.

Now I would prefer the clean version myself.

So the idea I have which obviously many won't agree with, is the LP has a pleasing sound due to its lack of transparency while digital is pretty close to transparent. The LP coloration is liked by many. Certainly music on well done LP can sound quite wonderful. There are well done CDs that sound wonderful too. Most CDs are pretty horrid, but I think it is forgotten that when LP was the dominant format most LPs were horrid as well.

 

[Don Hills]

Ha Don!--Are you sure it wasn't the rumble of a Straits Southerly blowing up the Island Bay Valley?--Just kidding!

It was a rare dead calm and clear night, which was why I did it. It can be quite instructive, especially the amount of LF noise that you don't normally notice because of the ear's low sensitivity in the low bass.

 

[Orb]

Hmm not sure I fully agree with that assessment of LP myself and discussing compressed/compression I find can be equally bad/good for any depending upon the studio/mastering trends (IMO worst for digital in general).
Agree both can be horrid or good though, and as I mentioned much earlier CD will be more consistent (caused technically and from business-logistic model approach) than the LP process-production.
Just coming back to the subject I should clarify my context.
For me dynamic range in digital is the defined word length/bit depth describing the available range in a digital notation system critical to recording-editing-mixing (such as dbfs,headroom-footroom-usable dynamics,associated studio digital processes-functions affecting lsb,etc), while subjective/effective dynamic range is as discussed very recently.
Hence why I would say a lot of what has been discussed recently should be put into the context of differentiating between audio recording-to-mastering stages and that of mastering-playback for recent discussions on digital (where specifically CD must be 16bit AND 44.1khz).
I also notice Xiph is very careful to differentiate between this when discussing 16bit and subjective-effective dynamic range below -96db.
Just one last technical point, while we have been discussing increasing dynamic range and noise shaping, we forgot to mention the required sampling rate to achieve equivalent of extending the bits (hence why 1-bit systems require 2.8mhz for high quality audio - crude/basic example I know ).

Cheers
Orb

 

[Atmasphere]

One is that to improve playback without tracking issues I believe the majority of LP's have some compression. Some compression in rather moderate amounts will make most music sound more dynamic even though you just reduced the actual dynamic range. Go too far like most modern recordings and it just sounds loud and awful.

This is actually incorrect. They have compression solely because its easier to master. Something that many here are failing to realize is how profound a 1 or 2 db change in cutting level can have on the resulting groove. 3 db is twice the excursion!! To make the difference between something that is untraceable and something that works might only be 1 db. But if you have to make several goes at it, well each lacquer is done the moment something gets screwed up. To avoid engineering time and the cost of lacquers, compression is employed, but IME you never need it if you are just careful.

Another is the cartridges on peaks generally generate a few percent distortion. One of the ways our hearing decides how loud something is happens by how many of its multiple frequency bands are activated. So some music with content at 500 hz with some peaks periodically will go up in level the distortion near the top will become significant briefly. The harmonics above that 500 hz which aren't supposed to be there activate additional bands in our hearing which makes our perception of it louder than the energy in the signal really is. So we perceive really loud for a moment and then it goes away as the level drops and the distortion harmonics with it. Seems like a really dynamic sound. It will be too brief to sound like the nasty distortion it really is. It will just sound dynamic and exciting. The effect will be absent in clean digital. So the same exact recorded signal would sound more dynamic in one format vs the other in one sense.

This is exactly the same reason SETs can sound so dynamic despite their low power output. This may well be the best argument provided by either side about why LPs sound more dynamic. IME, whenever audiophiles are in a casual conversation, when the term 'dynamics' is used, about 90% of the time the word 'distortion' can be substituted without changing the meaning of the sentence. So what seems to be needed here is actual measurements to see how much distortion is actually involved.

So digital recordings could be compressed only moderately if record companies would go for that. There no doubt could be plug ins to copy the effect of a cartridge on the signal. That should get you most of the way there.

Now I would prefer the clean version myself.

So the idea I have which obviously many won't agree with, is the LP has a pleasing sound due to its lack of transparency while digital is pretty close to transparent. The LP coloration is liked by many. Certainly music on well done LP can sound quite wonderful. There are well done CDs that sound wonderful too. Most CDs are pretty horrid, but I think it is forgotten that when LP was the dominant format most LPs were horrid as well.

The only problem I have with this is why do LPs usually (not always) sound more detailed than CDs? If I do a comparison as a demonstration, anyone that I do it for (especially non-audiophiles) are pretty stunned by the difference. But I imagine that is a whole 'nuther conversation

 

[jkeny]

..... So what seems to be needed here is actual measurements to see how much distortion is actually involved.

Yes, that would be of great interest.

 

[Robh3606]

Most CDs are pretty horrid, but I think it is forgotten that when LP was the dominant format most LPs were horrid as well.

Hello esldude

Yes and the original Half Speeds and direct to disks were real eye openers. Seemed like they really got it right just as they moved over to CD. I was a late CD adopter, just loved those Telarcs and Mobile Fidelity LP's. My first CD's were a big disappointment.

Rob

 

[Atmasphere]

Generally there seems to be one thing we can all count on... the record industry is going to find a way to mess it up.

 

[Don Hills]

Yes, that would be of great interest.

We know that the auditory system considers signals in different bands to be louder than when the signals are in the same band.
For example, equal level 400 Hz and 800 Hz signals will be perceived as louder than equal level 400 Hz and 410 Hz signals. And we know this because someone(s) did the research and measured it. We could start by finding the results of this research. I think we might have to look back quite a few years...
I'll take a look in the Bell Labs archives. Someone with AES access might care to look there.
From there, we can probably come up with a testing routine. For example, A/B the 400/410 and 400/800 Hz tone pairs above and adjust the levels until they sound as loud as each other. The difference in dB tells us how much "dynamic gain" the "distortion" adds.
Or take various well-recorded and dynamic sources. Add harmonic distortion to the peaks until they start to become audibly distorted, then back off a bit. Now compare the clean against the distorted and again adjust the levels until they sound the same level, once more arriving at a "dynamic gain" figure.

 

[esldude]

Yes, that would be of great interest.

Distortion measurements of cartridges.

http://www.hi-fiworld.co.uk/vinyl-lp/70-tests/103-cartridge-tests.html?start=4

Lots of very good info on cartridges in this seminar. You will have to look about a 1/4 of the way down the page to see distortion measurements. Be sure to look at the latter part of the article too. It goes into what kind of signals are on an LP.

http://shure.custhelp.com/app/answe...lity-phonograph-cartridge---technical-seminar

More distortion measurements.

http://www.audioasylum.com/cgi/vt.mpl?f=vinyl&m=1044263&VT=T

Some measurements here though only a little about distortion scattered within this page.

http://www.resfreq.com/phonomusings/phonomeasurements.html

 

[Atmasphere]

We know that the auditory system considers signals in different bands to be louder than when the signals are in the same band.
For example, equal level 400 Hz and 800 Hz signals will be perceived as louder than equal level 400 Hz and 410 Hz signals. And we know this because someone(s) did the research and measured it. We could start by finding the results of this research. I think we might have to look back quite a few years...
I'll take a look in the Bell Labs archives. Someone with AES access might care to look there.
From there, we can probably come up with a testing routine. For example, A/B the 400/410 and 400/800 Hz tone pairs above and adjust the levels until they sound as loud as each other. The difference in dB tells us how much "dynamic gain" the "distortion" adds.
Or take various well-recorded and dynamic sources. Add harmonic distortion to the peaks until they start to become audibly distorted, then back off a bit. Now compare the clean against the distorted and again adjust the levels until they sound the same level, once more arriving at a "dynamic gain" figure.

Its the content or spectrum of distortion that makes a difference. If you get lower orders (2nd-4th) they just affect tonality. So you have to know what distortion exists, and then create a correlation. That's not been done properly yet in the case of cartridges, as we see below:

Distortion measurements of cartridges.

http://www.hi-fiworld.co.uk/vinyl-lp/70-tests/103-cartridge-tests.html?start=4

Lots of very good info on cartridges in this seminar. You will have to look about a 1/4 of the way down the page to see distortion measurements. Be sure to look at the latter part of the article too. It goes into what kind of signals are on an LP.

http://shure.custhelp.com/app/answe...lity-phonograph-cartridge---technical-seminar

More distortion measurements.

http://www.audioasylum.com/cgi/vt.mpl?f=vinyl&m=1044263&VT=T

Some measurements here though only a little about distortion scattered within this page.

http://www.resfreq.com/phonomusings/phonomeasurements.html

You can't take those distortion measurements seriously. Go through the articles/posts and look for what the setup is. Its not there. So we have no clue about how well or poorly the cartridge was set up in the arm or even what tone arm, and that stuff can have huge effects!! In a nutshell, its not scientific. If a poor arm is used, it can't be used to claim that is what this cartridge does, its only good for what that cartridge did in that arm with that setup. I'm surprised lawsuits didn't emerge from this junk.

A proper anaylisis will show the kind of arm used as well as the equalizer and the equalizer's distortions will be subtracted from the total... Then if the arm is a radial tracker we have to measure at the null points such that we get the actual distortion of the device, and then measure at the worst points to find our range; then we can state what the distortion is for that cartridge in that arm with that geometry.

 

[esldude]

Its the content or spectrum of distortion that makes a difference. If you get lower orders (2nd-4th) they just affect tonality. So you have to know what distortion exists, and then create a correlation. That's not been done properly yet in the case of cartridges, as we see below:



You can't take those distortion measurements seriously. Go through the articles/posts and look for what the setup is. Its not there. So we have no clue about how well or poorly the cartridge was set up in the arm or even what tone arm, and that stuff can have huge effects!! In a nutshell, its not scientific. If a poor arm is used, it can't be used to claim that is what this cartridge does, its only good for what that cartridge did in that arm with that setup. I'm surprised lawsuits didn't emerge from this junk.

A proper anaylisis will show the kind of arm used as well as the equalizer and the equalizer's distortions will be subtracted from the total... Then if the arm is a radial tracker we have to measure at the null points such that we get the actual distortion of the device, and then measure at the worst points to find our range; then we can state what the distortion is for that cartridge in that arm with that geometry.

I believe the HiFi World tests are done by Miller Research. They usually do a good and thorough job. You can go to Miller research for more detailed information if you register there. The info by Shure is likely reliable as it was written by their cartridge designers. They do specify an SME 3009 II arm for some tests. You think the average audiophile sets up for playback better than these guys did for their testing? The other two links would appear to be less thorough, but all share showing that with higher level signals distortion is into the several percent range. Some show the various harmonic levels though you wouldn't trust them I suppose.

Lower level distortion doesn't merely effect tone though it does this. It also effects perceived loudness. Of course the higher the level and more extended the harmonics the more audible the effect will be.

And contrast these tests with digital. Clip it and you get plenty of distortion. Anything short of clipping no real significant distortion to speak of at any time.

One of these formats is clean and transparent with high fidelity. Another is less than clean, less transparent and of moderately good fidelity.