Author Topic: Interesting digital reading, the best format  (Read 4232 times)

Offline stevenvalve

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Interesting digital reading, the best format
« on: September 28, 2013, 12:58:27 AM »
Have a read of this, the tape machine, is it up to it.  I have heard master tapes that where brilliant amazing real, you name it. I have heard others that sound crap. If the tape machine is not maintained properly, even great tapes sounded crap. What do you make of it
 http://www.realhd-audio.com/?p=629
« Last Edit: September 28, 2013, 01:19:24 AM by stevenvalve »

Offline stevenvalve

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Re: Interesting digital reading, the best format
« Reply #1 on: September 28, 2013, 01:00:17 AM »
More to read. What do you think. A quote

Yesterday, I lauded Cookie Marenco for the marvelous recordings that she produces. She prefers the sound of analog tape and DSD to PCM. She’s stated that when a group of audio professionals evaluated a recording made to analog tape, PCM and DSD, that the analog was chosen by 100% of them. I would have to get more information about that test because I’ve experienced just the opposite in a test we did at Snow Ghost Studios in Whitefish, Montana. Using state-of-the-art microphones, preamp, converters and recorders, Peter McGrath (a well-known recording engineer and representative for Wilson Speakers), myself and a group of about 6 other professionals rather quickly ruled out the playback from a new Studer A 820 24-track analog deck through an SSL Series 9000 console to VTL monoblock tube amplifiers to Wilson Alexandria speakers (total value of the signal chain…well over $500,000). The analog tape just didn’t have the sparkle and detail that the digital formats did. I wrote about the weekend at Snow Ghost some months ago.

http://www.realhd-audio.com/?p=1598
« Last Edit: September 28, 2013, 01:09:53 AM by stevenvalve »

Offline ozmillsy

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Re: Interesting digital reading, the best format
« Reply #2 on: September 28, 2013, 01:27:07 PM »
Steven, there's a problem.    From the first article,,,,,,,

Quote

there were different DACs involved but this was about good as one is likely to get when comparing these formats.


WTF?
It's all about the music,, not the equipment.

Offline gamve

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Re: Interesting digital reading, the best format
« Reply #3 on: October 03, 2013, 01:25:14 PM »
 The analog tape just didn’t have the sparkle and detail that the digital formats did. I wrote about the weekend at Snow Ghost some months ago.

Horsesh!t.......

Offline ozmillsy

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Re: Interesting digital reading, the best format
« Reply #4 on: October 03, 2013, 05:02:21 PM »
LOL, straight to the point Graham. :)

yeah, obviously a problem there somewhere.

Even good quality gear may not sound great, if it isnt properly maintained or setup.

I demo'd a new yarlung tape to my sister for the 1st time over the weekend, and she couldn't believe what she was hearing. 



It's all about the music,, not the equipment.

Offline gamve

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Re: Interesting digital reading, the best format
« Reply #5 on: October 03, 2013, 05:55:59 PM »
LOL, straight to the point Graham. :)

yeah, obviously a problem there somewhere.

Even good quality gear may not sound great, if it isnt properly maintained or setup.

I demo'd a new yarlung tape to my sister for the 1st time over the weekend, and she couldn't believe what she was hearing.  




Yeah the new Yarlungs are pretty spectacular.
« Last Edit: October 03, 2013, 06:26:21 PM by stevenvalve »

Offline stevenvalve

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Re: Interesting digital reading, the best format
« Reply #6 on: March 14, 2014, 01:11:15 AM »
Found this as a link on SNA, very interesting but is it true.


24bit vs 16bit, the myth exploded!

It seems to me that there is a lot of misunderstanding regarding what bit depth is and how it works in digital audio. This misunderstanding exists not only in the consumer and audiophile worlds but also in some education establishments and even some professionals. This misunderstanding comes from supposition of how digital audio works rather than how it actually works. It's easy to see in a photograph the difference between a low bit depth image and one with a higher bit depth, so it's logical to suppose that higher bit depths in audio also means better quality. This supposition is further enforced by the fact that the term 'resolution' is often applied to bit depth and obviously more resolution means higher quality. So 24bit is Hi-Rez audio and 24bit contains more data, therefore higher resolution and better quality. All completely logical supposition but I'm afraid this supposition is not entirely in line with the actual facts of how digital audio works. I'll try to explain:

When recording, an Analogue to Digital Converter (ADC) reads the incoming analogue waveform and measures it so many times a second (1*). In the case of CD there are 44,100 measurements made per second (the sampling frequency). These measurements are stored in the digital domain in the form of computer bits. The more bits we use, the more accurately we can measure the analogue waveform. This is because each bit can only store two values (0 or 1), to get more values we do the same with bits as we do in normal counting. IE. Once we get to 9, we have to add another column (the tens column) and we can keep adding columns add infinitum for 100s, 1000s, 10000s, etc. The exact same is true for bits but because we only have two values per bit (rather than 10) we need more columns, each column (or additional bit) doubles the number of vaules we have available. IE. 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024 .... If these numbers appear a little familiar it is because all computer technology is based on bits so these numbers crop up all over the place. In the case of 16bit we have roughly 65,000 different values available. The problem is that an analogue waveform is constantly varying. No matter how many times a second we measure the waveform or how many bits we use to store the measurement, there are always going to be errors. These errors in quantifying the value of a constantly changing waveform are called quantisation errors. Quantisation errors are bad, they cause distortion in the waveform when we convert back to analogue and listen to it.

So far so good, what I've said until now would agree with the supposition of how digital audio works. I seem to have agreed that more bits = higher resolution. True, however, where the facts start to diverge from the supposition is in understanding the result of this higher resolution. Going back to what I said above, each time we increase the bit depth by one bit, we double the number of values we have available (EG. 4bit = 16 values, 5bit = 32 values). If we double the number of values, we halve the amount of quantisation errors. Still with me? Because now we come to the whole nub of the matter. There is in fact a perfect solution to quantisation errors which completely (100%) eliminates quantisation distortion, the process is called 'Dither' and is built into every ADC on the market.

Dither: Essentially during the conversion process a very small amount of white noise is added to the signal, this has the effect of completely randomising the quantisation errors. Randomisation in digital audio, once converted back to analogue is heard as pure white (un-correlated) noise. The result is that we have an absolutely perfect measurement of the waveform (2*) plus some noise. In other words, by dithering, all the measurement errors have been converted to noise. (3*).

Hopefully you're still with me, because we can now go on to precisely what happens with bit depth. Going back to the above, when we add a 'bit' of data we double the number of values available and therefore halve the number of quantisation errors. If we halve the number of quantisation errors, the result (after dithering) is a perfect waveform with halve the amount of noise. To phrase this using audio terminology, each extra bit of data moves the noise floor down by 6dB (half). We can turn this around and say that each bit of data provides 6dB of dynamic range (*4). Therefore 16bit x 6db = 96dB. This 96dB figure defines the dynamic range of CD. (24bit x 6dB = 144dB).

So, 24bit does add more 'resolution' compared to 16bit but this added resolution doesn't mean higher quality, it just means we can encode a larger dynamic range. This is the misunderstanding made by many. There are no extra magical properties, nothing which the science does not understand or cannot measure. The only difference between 16bit and 24bit is 48dB of dynamic range (8bits x 6dB = 48dB) and nothing else. This is not a question for interpretation or opinion, it is the provable, undisputed logical mathematics which underpins the very existence of digital audio.

So, can you actually hear any benefits of the larger (48dB) dynamic range offered by 24bit? Unfortunately, no you can't. The entire dynamic range of some types of music is sometimes less than 12dB. The recordings with the largest dynamic range tend to be symphony orchestra recordings but even these virtually never have a dynamic range greater than about 60dB. All of these are well inside the 96dB range of the humble CD. What is more, modern dithering techniques (see 3 below), perceptually enhance the dynamic range of CD by moving the quantisation noise out of the frequency band where our hearing is most sensitive. This gives a percievable dynamic range for CD up to 120dB (150dB in certain frequency bands).

You have to realise that when playing back a CD, the amplifier is usually set so that the quietest sounds on the CD can just be heard above the noise floor of the listening environment (sitting room or cans). So if the average noise floor for a sitting room is say 50dB (or 30dB for cans) then the dynamic range of the CD starts at this point and is capable of 96dB (at least) above the room noise floor. If the full dynamic range of a CD was actually used (on top of the noise floor), the home listener (if they had the equipment) would almost certainly cause themselves severe pain and permanent hearing damage. If this is the case with CD, what about 24bit Hi-Rez. If we were to use the full dynamic range of 24bit and a listener had the equipment to reproduce it all, there is a fair chance, depending on age and general health, that the listener would die instantly. The most fit would probably just go into coma for a few weeks and wake up totally deaf. I'm not joking or exaggerating here, think about it, 144dB + say 50dB for the room's noise floor. But 180dB is the figure often quoted for sound pressure levels powerful enough to kill and some people have been killed by 160dB. However, this is unlikely to happen in the real world as no DACs on the market can output the 144dB dynamic range of 24bit (so they are not true 24bit converters), almost no one has a speaker system capable of 144dB dynamic range and as said before, around 60dB is the most dynamic range you will find on a commercial recording.

So, if you accept the facts, why does 24bit audio even exist, what's the point of it? There are some useful application for 24bit when recording and mixing music. In fact, when mixing it's pretty much the norm now to use 48bit resolution. The reason it's useful is due to summing artefacts, multiple processing in series and mainly headroom. In other words, 24bit is very useful when recording and mixing but pointless for playback. Remember, even a recording with 60dB dynamic range is only using 10bits of data, the other 6bits on a CD are just noise. So, the difference in the real world between 16bit and 24bit is an extra 8bits of noise.

I know that some people are going to say this is all rubbish, and that “I can easily hear the difference between a 16bit commercial recording and a 24bit Hi-Rez version”. Unfortunately, you can't, it's not that you don't have the equipment or the ears, it is not humanly possible in theory or in practice under any conditions!! Not unless you can tell the difference between white noise and white noise that is well below the noise floor of your listening environment!! If you play a 24bit recording and then the same recording in 16bit and notice a difference, it is either because something has been 'done' to the 16bit recording, some inappropriate processing used or you are hearing a difference because you expect a difference.

G

1 = Actually these days the process of AD conversion is a little more complex, using oversampling (very high sampling frequencies) and only a handful of bits. Later in the conversion process this initial sampling is 'decimated' back to the required bit depth and sample rate.

2 = 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 be perfectly 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!!

3 = In actual fact these days there are a number of different types of dither used during the creation of a music product. Most are still based on the original TPDFs (triangular probability density function) but some are a little more 'intelligent' and re-distribute the resulting noise to less noticeable areas of the hearing spectrum. This is called noise-shaped dither.

4 = Dynamic range, is the range of volume between the noise floor and the maximum volume.           http://www.head-fi.org/t/415361/24bit-vs-16bit-the-myth-exploded
« Last Edit: March 14, 2014, 01:14:57 AM by stevenvalve »

Offline ozmillsy

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Re: Interesting digital reading, the best format
« Reply #7 on: March 14, 2014, 06:58:00 AM »
The poster contradicts himself, in a few areas.   He also only speaks of half of the equation.

Audio resolution = bit depth x sample rate

Or a better way to put it.
Bit rate(bps) = bit depth  x sample rate x # channels

He doesn't speak of sample rate, and the brick wall filtering of upper frequencies associated with 16bit.
It's all about the music,, not the equipment.

Offline YoungSC

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Re: Interesting digital reading, the best format
« Reply #8 on: March 14, 2014, 11:10:56 AM »
Yeah, I've always considered the sampling rate to be the main factor which takes the waveform closer to the original analogue.

I read this article years ago and it was quite informative.

http://www.mother-of-tone.com/cd.htm

Offline vitavoxdude

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Re: Interesting digital reading, the best format
« Reply #9 on: March 14, 2014, 12:53:47 PM »
Hmmmm

Quote
Bit rate(bps) = bit depth  x sample rate x # channels
x sh!t music = sh!t music :-X

I'll take an excellently recorded 16bit 44.1kHz CD and enjoy it if it has great music on it. ;D

I am more concerned that the bloke twiddling the buttons or mouse clicks via pro tools does not rip out all the goodness in the music chain, damned what the bit rate or KHz encoding is.   In these days of ultimate recording technology you still need a jockey at the controls to be able to do a really good job of capturing it all, without that its gum flapping and marketing.

I don't think anyone would argue that digital done right is the best recording medium, but it's when the studio boys hand it over to the format fiddlers of down sampling, different bit rates etc etc to sound good on am radio or mp3 players that the heart and soul is lost with the bath water.  For that to be avoided the likes of Kostas Metaxus recorded live with simple processes but who supported him.  I can remember him selling off master tapes on eBay and he has now gone to Germany I think to try and make a go selling them on a web site via downloads.  PC audio is where the marketing boys are pushing us all to and its getting there but when you hear an all analogue all valve HE system with Horns you just know that the digital stuff resembles a hamburger more than a steak. YMMV here.

HD, 4K, 8K, it will never stop the process of getting you to buy the music over and over again when most of the time they take old music and just up-sample it and dump it in an ever larger bit bucket.  True HD recordings are relatively rare IMO and do not get enough coverage to make a sizable impression in the market.  It looks like the market has already decided that the only way to buy new music is via downloads and you choose and pay for the quality that you desire.  Not quite the same as looking at Album covers and sleeve notes in your favorite record store :'([/font]
We all like different things so lets all agree to disagree and if any common ground is found then worship it.  Mine is the KD hence being present on this forum.

Offline vitavoxdude

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Re: Interesting digital reading, the best format
« Reply #10 on: August 18, 2014, 02:37:13 PM »
This is a telling statement from the manufacturer of the Benchmark Dac.

Quote
"24-bit word lengths provide a very efficient method of improving the noise performance of digital systems. When dither is properly applied, there is no advantage to long word lengths other than noise. All quantization errors in a properly dithered digital system produce a random noise signal. Properly dithered digital systems have infinite amplitude resolution. Long word lengths do not improve the "resolution" of digital systems, they only improve the noise performance."

So good for increasing signal to noise ratios but does nothing for audio quality?
V
We all like different things so lets all agree to disagree and if any common ground is found then worship it.  Mine is the KD hence being present on this forum.

Offline hedalfa

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Re: Interesting digital reading, the best format
« Reply #11 on: October 05, 2014, 07:14:43 AM »
<a href="http://www.youtube.com/watch?v=4eC6L3_k_48" target="_blank">http://www.youtube.com/watch?v=4eC6L3_k_48</a>

Vitavox I thought this was relevant to your thread. I had heard this position stated before interesting to have an investigation of the claim LP being
superior to CD.

Note the response of the old record, well my ears seemed to being hearing the same thing and I had written that here on Kdac a number of times. As the guy says its not a reason to trash CD, though lps despite the hassles associated with them can be rewarding.
« Last Edit: October 05, 2014, 07:22:19 AM by hedalfa »

Offline vitavoxdude

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Re: Interesting digital reading, the best format
« Reply #12 on: October 05, 2014, 02:08:05 PM »
Yes all interesting information.  Thanks for the post.  I would be surprised if most people above the age of 30 can even hear freq above 20Khz but acknowledge that having an extended HF brings more air to the proceedings.  As you say down sampling audio to fit red book CD cuts the hf off at half the sampling freq.  I can still enjoy a well mastered CD but also acknowledge that SACD can sound more natural with its higher HF cutoff on the right player.

Two audio mates have SACD players, well one sold his Sony CD1 and the sound is not too bad, opamps kill off most of the goodness though IMO and lots of them too.  Open reel tapes do not extend to 44Khz flat, they are quite a few dB down even at 30 ips so where the HF came from on that set up which looked like an el cheapo turntable / cartridge combination with a cheap ext sound card who knows.  Maybe vinyl roar and cartridge resonances played a part.  HF is one of the first things to go in vinyl replay through wear.

I do enjoy some of the black stuff, but like most consumers struggle with all the static precautions, dust, surface noise, high cost, warps, and having to lift the arm at the end of one side.  To get vinyl right costs around 3 times the cost of a CD source taking into account a MC step-up or phono stage, the arm, cartridge and turntable and have you seen how much they are charging for albums these days! Yikes :o

I have attached two files, the first showing the FR of instruments plus their harmonics and a second showing the FR of some of the best R2R recorders known.  I am not ignoring previous posts regarding HF extension but post a case for much above 20 Khz is harmonics only and only perceived in close confines of the original instrument.  By the time the mic feed has passed through the myriad of processors, gain stages, cables and tape eq it's amazing that the HF is there at all.
We all like different things so lets all agree to disagree and if any common ground is found then worship it.  Mine is the KD hence being present on this forum.

Offline hedalfa

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Re: Interesting digital reading, the best format
« Reply #13 on: October 06, 2014, 07:38:11 AM »
Vitatavox

Code: [Select]
I would be surprised if most people above the age of 30 can even hear freq above 20Khz but acknowledge that having an extended HF brings more air to the proceedings. 
Agreed, though this raises a point a read somewhere that I found very interesting indeed. What we may not hear or indeed register via our ears we are still effected by it as the sound is being felt by our body.  The gross easy example is low bass that is felt.  Yet sound is a vibration and as such I suspect the idea that we are still effected by what we cant strictly hear may be correct.

« Last Edit: October 06, 2014, 12:07:12 PM by hedalfa »

Offline zenelectro

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Re: Interesting digital reading, the best format
« Reply #14 on: October 06, 2014, 11:30:26 AM »
<a href="http://www.youtube.com/watch?v=4eC6L3_k_48" target="_blank">http://www.youtube.com/watch?v=4eC6L3_k_48</a>

Vitavox I thought this was relevant to your thread. I had heard this position stated before interesting to have an investigation of the claim LP being
superior to CD.

Note the response of the old record, well my ears seemed to being hearing the same thing and I had written that here on Kdac a number of times. As the guy says its not a reason to trash CD, though lps despite the hassles associated with them can be rewarding.

He says the highest sample rate he was able to work the EMU 0202 USB at was 120kHz?

I was not aware that the EMU 0202 supported non audio / variable sample rates. 

Z




Offline vitavoxdude

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Re: Interesting digital reading, the best format
« Reply #15 on: October 06, 2014, 12:11:43 PM »
 :)
Quote
I suspect the idea that we are still effected by what we cant strictly hear may be correct.

Yes agreed, it is not just the ossicles that are effected but the resonant size of the eardrum, having an extended high range from so called super tweeters can bring more ease when done well IMV.  Some are effected more than others in this regards.  The Western electric millionaires would say it's not required and again IMV if you do 50Hz to 15Khz well enough it become more of a mute point. :-X
We all like different things so lets all agree to disagree and if any common ground is found then worship it.  Mine is the KD hence being present on this forum.