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PHILIPS RED BOOK

amirm

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Sorry, I don't see how that's relevant. Peak SPL is Peak SPL.
It is relevant because people's impression of how loud something is, is based on slow averaging SPL meters, not peak. The notion that "120 db SPL" is too loud for your neighbor stems from that type of understanding, not peak.

At LA audio show someone asked Andrew Jones how loud he was playing. Instead of answering, he asked the audience. Numbers were thrown in 80 to 90 db range. He then answered to everyone's shock that peak SPL was likely in 110 to 115 db!

We should also remember that we are talking about momentary peaks here. That kind of sudden peak is not going to get anyone thrown out of the room let alone have the neighbours complaining.

There may be a few people, with scant regard for their hearing or the peace and tranquility of their neighbours who might want to make more noise, but should music companies pander to those?
None of the data for noise levels is based on peak SPL. They are all slow averaging SPL data. Here is OSHA safety standards way of measuring SPLs:

upload_2017-12-11_12-14-21.png


It is both a-weighted and slow averaged. Neither is in play when we are talking about peak values.

To that end, I think everyone's understanding SPL in this context is incorrect. Unless you have performed tests using peak reading SPL numbers, you don't have a good feeling and certainly no reference to know how loud that really is.

Peak SPL measurements are very rare. I know of three published studies and that is it. The best one is the one I have referenced here.

All of this aside, my theater is in my basement and with our large lots, I could play at any level and my neighbor would not even know I am home! :) We can't set standards for music transmission that disadvantage people who build such quiet spaces.

Regardless, all of this came about because we had to comply with a fixed format at 16/44.1. When distributing music online, there is no reason whatsoever to try to conform it to CD specs. Music should be released it its originally captured bit depth and sample rate. People can make their own conversion to 16/44.1 if necessary and so can the music distributor.
 

Thomas savage

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It is relevant because people's impression of how loud something is, is based on slow averaging SPL meters, not peak. The notion that "120 db SPL" is too loud for your neighbor stems from that type of understanding, not peak.

At LA audio show someone asked Andrew Jones how loud he was playing. Instead of answering, he asked the audience. Numbers were thrown in 80 to 90 db range. He then answered to everyone's shock that peak SPL was likely in 110 to 115 db!

We should also remember that we are talking about momentary peaks here. That kind of sudden peak is not going to get anyone thrown out of the room let alone have the neighbours complaining.


None of the data for noise levels is based on peak SPL. They are all slow averaging SPL data. Here is OSHA safety standards way of measuring SPLs:

View attachment 9742

It is both a-weighted and slow averaged. Neither is in play when we are talking about peak values.

To that end, I think everyone's understanding SPL in this context is incorrect. Unless you have performed tests using peak reading SPL numbers, you don't have a good feeling and certainly no reference to know how loud that really is.

Peak SPL measurements are very rare. I know of three published studies and that is it. The best one is the one I have referenced here.

All of this aside, my theater is in my basement and with our large lots, I could play at any level and my neighbor would not even know I am home! :) We can't set standards for music transmission that disadvantage people who build such quiet spaces.

Regardless, all of this came about because we had to comply with a fixed format at 16/44.1. When distributing music online, there is no reason whatsoever to try to conform it to CD specs. Music should be released it its originally captured bit depth and sample rate. People can make their own conversion to 16/44.1 if necessary and so can the music distributor.
I think you touch on a lasting factor at the end of this, there’s a academic advantage to high res we can argue about till the cows come home but really unrestrained by physical media the question is why not high res?

Can it do harm? Is it that important?

There’s a responsibility for us to not stoke the fear in the audiophile by claiming some huge actual advantage over Red book imo I spin cd’s with a consideration for all the mitigating circumstances involved in play back Im certain I’m not missing out on anything. The marketing of high res is cynical imo maybe that sticks into a few of the red book forever types ( like me).

Can you show the current implementation (available recordings ) of high res brings a advantage? Not some lovely lab sample for a experiment , the tracks available over streaming services or downloads? From what Iv seen these tracks are often not what they appear to be and certainly the potential advantage seems lost.
 

amirm

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So in summary: if I want to reproduce the sound of a 747 taking off (or whatever) in my living room at the absolute loudness it occurred, I need high res digital in order for my system not to contribute any perceptible noise when the sound stops - assuming it was recorded in a silent environment with the best microphones and pre-amps.

But if I only want to reproduce it at the level of a jackhammer (or whatever sound is 20-30dB lower down on the illustrated dB chart!) then CD will not be the limiting factor.
Again, all of those impressions are based on slow averaging SPL numbers. Most of us have heard pretty high peak SPLs without knowing it.

Fielder measured a ton of live concerts from actual seating position and found countless ones above 100 db SPLs:

upload_2017-12-11_12-43-5.png


Pretty sure people sitting where he was were not liking the levels to jackhammer or jet taking off. :)
 

RayDunzl

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An enthusiastic hand-clap somewhat near my theoretically calibrated microphone registers a peak SPL in the 120dB range.

(old image from another thread)

index.php
index.php
 

sergeauckland

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It is relevant because people's impression of how loud something is, is based on slow averaging SPL meters, not peak. The notion that "120 db SPL" is too loud for your neighbor stems from that type of understanding, not peak.

At LA audio show someone asked Andrew Jones how loud he was playing. Instead of answering, he asked the audience. Numbers were thrown in 80 to 90 db range. He then answered to everyone's shock that peak SPL was likely in 110 to 115 db!

We should also remember that we are talking about momentary peaks here. That kind of sudden peak is not going to get anyone thrown out of the room let alone have the neighbours complaining.


None of the data for noise levels is based on peak SPL. They are all slow averaging SPL data. Here is OSHA safety standards way of measuring SPLs:

View attachment 9742

It is both a-weighted and slow averaged. Neither is in play when we are talking about peak values.

To that end, I think everyone's understanding SPL in this context is incorrect. Unless you have performed tests using peak reading SPL numbers, you don't have a good feeling and certainly no reference to know how loud that really is.

Peak SPL measurements are very rare. I know of three published studies and that is it. The best one is the one I have referenced here.

All of this aside, my theater is in my basement and with our large lots, I could play at any level and my neighbor would not even know I am home! :) We can't set standards for music transmission that disadvantage people who build such quiet spaces.

Regardless, all of this came about because we had to comply with a fixed format at 16/44.1. When distributing music online, there is no reason whatsoever to try to conform it to CD specs. Music should be released it its originally captured bit depth and sample rate. People can make their own conversion to 16/44.1 if necessary and so can the music distributor.
I think that part highlighted is relevant. A few people, especially in North America, may be able to enjoy such dynamics, but for others, it's just not possible. Consequently should the record companies put effort into HiRes releases when most can't even get to the dynamic range of a cassette.
If HiRes releases are available on-line, for those who want them, then fine, but as a mass-market distribution, I still fail to see where CDs are lacking.

S
 

Cosmik

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Peak SPL is an interesting concept. I guess it is statistically unlikely, but it would be possible for *all* the violins' waveforms to momentarily sum at their peaks as they reach the listener's ear, just at the moment the leading edge of the tympany strike arrives, at the same time as all ten 10 piano notes hit their peaks, etc. I wonder what the theoretical peak SPL from an orchestra is at the front row of the concert hall?
 

RayDunzl

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I wonder what the theoretical peak SPL from an orchestra is at the front row of the concert hall?

30 incoherent sources with the same amplitude yield a gain of 14.7dB

Sum three groups of them (90 players) and get +19.5dB instead.

(I haven't found a quickie coherent calculator for the big numbers of sources)

All being coherent wouldn't happen, and it would only add 3dB (?) anyway.
 
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fas42

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Are the limits of Red Book CDs AUDIBLY surpassed by other formats? Subjective responses backed up by objective measurements, please.
No. Just doing some analysis at the moment of 'pro' DA/AD loop circuits functioning in the real world of music tracks, and some of them show artifacts at only 20dB below the waveform level - so, first of all make sure implementations work properly when processing Red Book data, before passing judgement on formats.
 

oivavoi

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Interesting discussion. My brain tells me to agree with the “CD quality is more than enough for real life” crowd, but my heart tells me to side with Amir on this! Reason: I’ve always felt that one of the things which separates real acoustic music from reproduced music is the effortless dynamics of acoustic music, which hifi systems very rarely are able to mimic.

But I do think that format is probably not the limiting factor in this regard for 99 percent of the audiophile population.

For, what would actually be required to have a dynamic range of 120 dB? First, a very quiet listening space. There’s a reason BBC’s “guide to acoustic practice” from 1990 starts with a very long section on sound isolation. In most cases, this will require either a house in the woods or a dedicated music basement. Listening in the living room, with all kinds of noisy electronics all over, will usually not be an option.

Second, an amp/speaker combo which easily can reach peaks of 120 dB in all of the frequency range. This would in all probability require a dedicated bass system, and possibly horns? (or super duper monitors from Geithain for example)

Only then would there be any point for me in complaining about the limitations of redbook. Furthermore, the recordings would have to preserve this dynamic range - and how common is that in the age of MP3? Which means that I would be able to enjoy the theoretical advantage of hi-rez on a very small amount of music.

Still, in principle I’m very much for as much dynamics as possible.
 

Brad

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Still a long way from the dynamic range needed to record the Mt. Krakatoa eruption:
The Krakatoa explosion registered 172 decibels at 100 miles from the source.Sep 29, 2014

Regarding music, the plots of white noise that Amir posted should also be appreciated. Most of us don't want hiss in the recording, and even if the noise floor of your listening space is 40-50dB, you can still hear hiss at much lower levels (0-10dB).
If you listen carefully you can still hear hiss while music is playing, since its so wideband that not all the noise is masked (probably doesn't apply to pop/rock music)
 

Blumlein 88

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I posted some music excerpts with noise added at various levels in a thread once. I asked everyone to listen at their normal volume settings and say when the noise wasn't heard anymore. Mostly noise at -7o to -80 db with listening levels around 80 db were reported. So in general where our ear is most sensitive we likely can hear within 10 db of our hearing threshold in many of our listening rooms. This fits with things like Ray has shown which is in the 3-5 khz range noise levels are down pretty low even if lower frequencies intrude to raise the measured overall SPL.

So is 96 db enough using 16 bit? Or using dither maybe 90 db dynamic range and tack on another 15 db since we can hear into noise around that much in some frequency ranges? The answer is ultimately for the quietest rooms, finest recordings and keenest hearing 16 bit might fall just short by a couple bits worth. But only sometimes, and only rarely and only in a tiny number of recordings. The full 120 db range is a worthy target for full fidelity. 16 bit might be 90% of all that could be required and maybe only .1% of the time do systems, listeners and recording exceed its limits. So Redbook may fall just short of full possible transparency, but it rarely, very rarely is unmasked as such. Very difficult it is to get a recording and playback that exceeds its limits, and it will do so only fleetingly.
 
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Wombat

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I posted some music excerpts with noise added at various levels in a thread once. I asked everyone to listen at their normal volume settings and say when the noise wasn't heard anymore. Mostly noise at -7o to -80 db with listening levels around 80 db were reported. So in general where our ear is most sensitive we likely can hear within 10 db of our hearing threshold in many of our listening rooms. This fits with things like Ray has shown which is in the 3-5 khz range noise levels are down pretty low even if lower frequencies intrude to raise the measured overall SPL.

So is 96 db enough using 16 bit? Or using dither maybe 90 db dynamic range and tack on another 15 db since we can hear into noise around that much in some frequency ranges? The answer is ultimately for the quietest rooms, finest recordings and keenest hearing 16 bit might fall just short by a couple bits worth. But only sometimes, and only rarely and only in a tiny number of recordings. The full 120 db range is a worthy target for full fidelity. 16 bit might be 90% of all that could be required and maybe only .1% of the time do systems, listeners and recording exceed its limits. So Redbook may fall just short of full possible transparency, but it rarely, very rarely is unmasked as such. Very difficult it is to get a recording and playback that exceeds its limits, and it will do so only fleetingly.


This sounds like a reasonable summary to me. I als0 think that we seldom experience recordings that do justice to the capability of the CD format.
 
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Fitzcaraldo215

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I think you touch on a lasting factor at the end of this, there’s a academic advantage to high res we can argue about till the cows come home but really unrestrained by physical media the question is why not high res?

Can it do harm? Is it that important?

There’s a responsibility for us to not stoke the fear in the audiophile by claiming some huge actual advantage over Red book imo I spin cd’s with a consideration for all the mitigating circumstances involved in play back Im certain I’m not missing out on anything. The marketing of high res is cynical imo maybe that sticks into a few of the red book forever types ( like me).

Can you show the current implementation (available recordings ) of high res brings a advantage? Not some lovely lab sample for a experiment , the tracks available over streaming services or downloads? From what Iv seen these tracks are often not what they appear to be and certainly the potential advantage seems lost.

A meager attempt to answer some of your questions above.

Why not hirez? I think a lot has to do with music genres. There is a fair bit of legitimate, well engineered,
natively recorded hirez in the classical music genre I prefer, though much more is available at RBCD resolution. For pop, rock, jazz, etc. there is not much. For me and my interest in Mch, it is all hirez. So, why not indeed?

Can it do harm? I have never heard anyone say that it does.

Is it that important? Depends on who you ask. Again, refer back to the genre question. But, also, there is the question of whether it makes a worthwhile difference you can hear. I generally hear it in recordings natively done in hirez vs. their downsampled RBCD versions from the same master. I do not hear much of an improvement in remasters from analog, though a newer remaster from analog to hirez might sound better than an older remaster to RBCD just because of the better mastering, not the hirez. But, at best, is hirez a huge difference? No, but it seems usually to offer a small but noticeable and worthwhile improvement to my ears with native hirez recordings. The very best recordings

I personally have not seen much "cynical marketing" for hirez from industry sources in awhile. Sony did hype SACD starting 15-20 years ago, but not today. Yes, it is offered through a variety of media, but I am not seeing a lot of hype, except by some audiophile fan-boys. But, it is such a niche market, that I cannot believe there is soooo much of it you need to get hot and bothered about. There is way less hype for hirez than there is for vinyl, tubes, etc., and hirez hype is not the same as MQA hype. So, other than some obvious bias and prejudice, what is your problem?

My own embrace of hirez dates back a decade using the hybrid SACD medium with natively recorded hirez classical music. Those discs made it easy to compare the CD layer to the stereo DSD hirez layer. Sure there is pleasant music either way that can be enjoyed. But, most people I know who carefully compared found the hirez slightly but noticeably better sounding. YMMV.

But, if you wish to experiment with downloads, try the free tracks in the Test Workbench at the 2L site. You can get RBCD and different hirez versions up to 352k Hz PCM, even MQA, from the same master. You might not like the music, and you might not hear a benefit. But, maybe you will.
 

Cosmik

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All being coherent wouldn't happen, and it would only add 3dB (?) anyway.
I guess that's right, but I'm thinking along the lines of supposing I took 100 people and asked them to repeatedly burst balloons simultaneously (something very sudden at any rate). Maybe it's outdoors so there's not many reflections. If I looked at a sample of it, I might find that I usually saw 100 separate 'impulses'. Sometimes maybe two or three of them would overlap, but I would never get 100 overlapping. I might, from this, conclude that the dynamic range I needed was a certain number of dB. Theoretically, though, under some fluke circumstance maybe my system might be overloaded if all 100 overlapped..? Is there some freak theoretical circumstance where the orchestra percussion and everything else just happen to align perfectly that gives more than the 120dB? Can this be worked out some other way other than just measuring the SPL of the orchestra?
 

RayDunzl

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Theoretically, though, under some fluke circumstance maybe my system might be overloaded if all 100 overlapped..?

That would be addition of coherent sources.

For each doubling of coherent (aligned) sources, add 6dB. Doesn't matter what the individual source levels are, using 100dB source for convenience.

1 = 100
2 = 106
4 = 112
8 = 118
16 = 124
32 = 130
64 = 136
128 = 142
256 = 148

Doubling of incoherent sources adds 3dB

upload_2017-12-11_20-15-3.png
 
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Cosmik

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That would be addition of coherent sources.

For each doubling of coherent (aligned) sources, add 6dB. Doesn't matter what the individual source levels are, using 100dB source for convenience.

1 = 100
2 = 106
4 = 112
8 = 118
16 = 124
32 = 130
64 = 136
128 = 142
256 = 148

Doubling of incoherent sources adds 3dB

View attachment 9749
Indeed. So if I go from a maximum overlap of three percussive impulses, say, up to 100, that's approximately six doublings, equalling an extra 36dB above what I thought my maximum was - in some freak circumstance that happens every million years.

Not going to happen, obviously, and not the nature of most of the instruments in the orchestra. Just a thought experiment.
 

Sal1950

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I don't understand why the continued debate on this subject.
Currently nearly every single contributor to Stereophile now agrees that the LP is the Gold Standard for High Fidelity music reproduction. :eek::p
 

bennetng

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I made some demo files.
https://drive.google.com/open?id=1kodOlklHbIAUD3k4ISalRz_Ma4BvqgPu

original.flac: original 16/44 file with very close to 0dBFS peak
[low peak float]: peak normalized original.flac from -90 to -120dB and saved as 32-bit float
[low peak 16bit]: convert files in [low peak float] to 16-bit
[+60]: add 60dB gain to files in [low peak 16bit]

So, after trying the files, find some CDDA rips or hi-res files with meaningful (music, voice, or anything you regard as "details") and unprocessed (e.g. digital fade) contents as loud as original.flac and as quiet as -110 16bit.flac within the same track.

Also, listen to original.flac and -110 16bit.flac alternately without touching the volume knob.

These are not blind tests, but I just hope people can actually listen, before digging too much into numbers.
 
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Wombat

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It seems like a lot of hurdles need to be cleared before an audible improvement over CDs can be claimed.

In addition to the test method:

1. same definitive source master,
2. same accurate playback system,
3. well developed, consistent and accurate listening skills, Hmmm.
4. neutral listening environment,
5. control of individual subjective preferences, Hmmm.
6. etc.,
Then there are the loudspeakers.

It is probably time to remove human hearing variables and biases and just use signal comparison and analysis to do comprehensive A minus B difference detection as the first cut to look for what may or may not be audible. No matter how good double blind testing is, participants can hear what is not there.
 

Cosmik

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It is probably time to remove human hearing variables and biases and just use signal comparison and analysis to do comprehensive A minus B difference detection
You don't need to physically do that: simply do it in software; this is a purely mathematical, software-simulatable issue.

You could even play back the difference in isolation i.e. without the masking of the original signal. And you could progressively amplify it until it becomes audible, etc.

The trouble is, audiophiles seem to believe that something that is 'silence' in isolation may become audible when against the main signal. Or at least that is the only explanation I can think of as to why they wouldn't do the experiment above.
 
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