Well SM, The words do matter. In the last week you have confused a great many things. 1) You condemmed the Threshold amp when you "meant" a Bryston amp. 2) You confused 1 in 100,000,000 with 1 in 10,000, and 3) now you confuse F1 with F2.
Please tell us at what point we should beleive what you say? Or are all words 'trivialities"?
I am afraid you miss SM's role in this thread. He is the comedic relief.
There are 24 critical bands in the human hearing system, therefore, any distortion which creates harmonics in a separate band than the original sound will sound louder, but if all of the harmonics fall within existing bands that already have content then the effect will be less.
James D. Johnston was involved with Bell Labs, who have done some of the most extensive research on human psychoacoustics. I do not know whether specific research was done on vinyl, but rather that the loudness perception studies were combined with the knowledge than vinyl cutting and playback involves amplitude-dependent distortion. Thus vinyl produces a dynamic range expansion that doesn't appear on electronic meters, but instead is perceived in the human ear and brain system.
By the way, when I transfer an LP to CD, people can't tell the difference. In fact, many of them are already listening to their LP on a 24-bit digital system anyway. In these examples, I'm talking about modern electronic music DJs who are admitted vinyl snobs. The crux of the matter is: If they can't see the digital components, they think it sounds better.
Well, it "should" be pretty easy, but last time a conversation involving two software engineers discussed this, they couldn't even agree on the math. It's not trivial. I had to ask JJ for confirmation of the correct math. There are various logarithmic power curves involved, questions of where the critical bands lie, and the whole issue of how to map an FFT with its linear-spaced frequencies onto the 24 critical bands with their logarithmic spacing.
Not exactly. But some folks claim 32 or so. When I hear that I thank them for explaining why a piano only has 32 keys. I take it your keyboards only have 24! Critical bandwidth over time has had two similar definitions. The actual critical bandwidth varies with frequency.
Harvey Fletcher who first used the term meant it to be the electrical equivalent to the "Auditory Filter." The filter however can move it's center frequency.
Can you cite any references to "32 critical band" proponents?
Your comments about 24-key and 32-key pianos seem to indicate a lack of understanding of human hearing. Nobody has ever claimed that we can hear only 24 distinct frequencies. In fact, I once asked J.J. whether a 65536-point FFT would be enough resolution to capture "every" frequency that we can hear, and he said that there a millions of cilia in the inner ear, each tuned to a unique frequency (don't quote me on the millions, but it was certainly too large for an FFT, and possibly too large to even count). Where's the million-key piano, eh?
Also, can you clarify what you mean by bandwidth "varies" with frequency? Since each critical band is at a different frequency, I have no problem with each of them having a unique bandwidth. Evolution has given us quite an adaptation to hearing speech, perhaps at the expense of hearing other frequencies as well.
I wouldn't say it's 'specious' because loudness is always a factor. Even a fraction of a decibel 'louder' will tend to make people prefer the louder option. I will admit that matching is difficult, and perhaps impossible, but that does not mean loudness preference is not a factor to consider.
Your point about dynamic compression is interesting, because you seem to be thinking only of the compression that is applied knowingly. I assume you mean how pop CDs are compressed. For the purposes of my comparison, let's assume that the digital content is not compressed any more than the vinyl. Also, let's assume that we've gone beyond the frequency limitations of CD, because vinyl can actually reproduce frequencies that are completely missing from CD due to the brick wall filtering. I would disagree with your suggestion to use the same turntable preamp, because it would be really bad to apply RIAA decoding to CD, and also because some people do not use a phono preamp, per se, but rather listen to vinyl through a professional digital audio converter with digital RIAA decoding and 'preamplification.'
But all of that is just fine-tuning the matching of the A/B/X comparison. Difficult, but not to be ignored completely.
But my point - or I should say J.J. Johnston's - is that the cutting and playback processes themselves create new, amplitude-dependent distortions which are then perceived by the human ear plus brain system as increased dynamics. Thus, even if you were to match the purposeful dynamics processing of a given recording on vinyl versus CD, you'd still have the perceived dynamics changes of the vinyl output versus the input. In other words, the vinyl stage would increase the perceived volume of the louder passages, and thus make the vinyl preferred merely for the basic loudness-preference, and not due to any other quality of vinyl or digital. In that case, I suppose you'd have to compare A/B/C/X with an original master analog 1" tape, vinyl, and some form of digital media if you really want to know what is 'best.'
I looked for a link to Johnston's paper online, but he may not have published it. He basically gave a talk at a Pacific Northwest Audio Engineering Society meeting that was focused on the practical application of psychoacoustics to a more tangible question such as "Why vinyl sounds better." I don't know if he wrote anything besides a powerpoint slide set, but maybe he has released that somewhere.
Don Davis was well known for the 32 number that was his explanation for why a 1/3 octave equalizer was great for pro audio.
I don't think I miss-quoted you, please look up sarcasm to understand my reply.
The bandwidth of a critical band varies with the frequency at which you are measuring it.
There are lots of good references on the web. One of the interesting issues is how the term is used to described similar but different effects.
Okay, thanks for the explanation. However this is an extreme simplification of how we hear. We don't respond the same way to all distortion. You can have distortion that's just plain irritating and fatiguing. If I don't dial in a preamp just right (through listening) the distortion can be really bright sounding and unlistenable. It takes time to get it biased right.
Most power amplifiers out there that have increasing distortion with output voltage too, some more than others of course. I really like our Boulder 250AE amps (op-amp based amps) and I've owned gear with tubes as well where the distortion increases significantly with output. I like the low distortion Boulder amp.
QUOTE=rsdio said:
So, you did a blind test? What kind? Conducting a good blind test is not an easy thing to do, and takes time. Thing is we learn sounds - we all have increased gain for different sounds - and how we respond to sounds is based on beliefs formed from past experience. It's no surprise that the DJ's liked what they thought was analog better. It's very easy to trick people.
If they think the digital sounds better blinded, how does that show that the distortion is perceived as making the sound louder/better?
The only way to do proper blind test is to give a person time to learn the sounds under the same conditions that the test is performed and then see if they can identify the difference between the sounds. This could take weeks.
A 24 bit digital system can sound very good. I prefer quality SACD and Bluray sound to my analog setup anyway. This depends a lot on recording quality of course.
Well, I don't discount James D. Johnston work, as I haven't seen it. There may be something to what he's talking about. I would like to know what harmonics he used in his distortion test, an how the test was performed.
The brain naturally turns up the gain for some sounds and this can be a pleasant or unpleasant experience. Some sounds give you goose bumps and others drive you from the room. So, sure, changing the harmonic content of a sound will cause you to respond differently to it and this could be perceived as louder. But, I kind of doubt all kinds of distortion will do that. I think some may do just the opposite.
John
Let's be clear here: I did not recount J.J.'s entire presentation in one posting of this thread. The extreme simplification that you're noticing should not be directed at him. He went into elaborate detail as to the frequencies of the harmonic distortion and how they fell into various critical bands, along with formulae to describe the perceived loudness as a result. I can't help but simplify this to the extreme without getting into some serious math, and I won't do that here, because I'm not even sure what's legal.
Sorry for mixing up the topics here. J.J. made an analysis of why vinyl sounds better, I was merely commented on your personal claims that people don't like vinyl when converted to CD. My response was that your results are due entirely to your level of experience in digitizing the vinyl and producing the CD. When I convert vinyl to CD, people can't tell the difference - well, unless they listen on their computer speakers. In other words, I'm saying that digitizing vinyl does nothing to alter the sound. That's entirely unrelated to J.J.'s claims that cutting vinyl distorts the sound in a way that is euphonically preferred. It's almost the opposite claim, in fact. At the very least, it's not an apples to apples comparison.
I should be clear that the research performed at Bell Labs was not focused on vinyl at all, but rather on human perception of sound. They built serious anechoic chambers, tested all manner of frequencies, distortions, etc. J.J.'s comments about vinyl are more of a distillation of a much larger body of research as applied to a particularly interesting topic: vinyl. I wish I had a reference to cite, because his presentation was certainly a lot clearer than my summaries.
Well, J.J. didn't say that all kinds of distortion produce the same effect. Instead, he outlined a very complex set of mathematical analysis formulae which would allow calculation of the exact perceived change in loudness, based upon the exact frequency and amplitude of each component. So, you could theoretically measure any flavor of distortion and see how it would be perceived differently.
But most of the comments in your closing paragraph are subjective, and yet you seem mysteriously doubtful of the objective research, or at least unaware.
Yes, I think we're at risk of convoluting multiple concepts. At the very least, I think that the 1/3 8va EQ doesn't entirely map onto critical bands, although is almost fits.
The important fact is that J.J.'s talk explained how harmonics added by distortion will increase the perceived volume, provided that the harmonics are sufficiently outside the critical band containing the original frequency or frequencies. Whether critical bands exist as exactly 24 fixed ranges that never change, or as some other number of ranges that shift around according to the frequencies of the actual sounds - it doesn't really matter. What's important is whether the added harmonics fall into a higher critical band that is otherwise lower in energy in the original content. Secondarily, the fact that the distortion produced by vinyl is level-dependent leads to its perceived enhancement of dynamic range.
rsdio said:
Okay, but you've provided no objective evidence to support that claim.
rsdio said:
My comments were based on the neurophysiological model for hearing. This model was developed by Dr. Jastreboff as an explanation for problem tinnitus (ringing ears) and hyperacusis (increased sensitivity to sounds). It's a theory, but one that works well for treating people with hyperacusis, tinnitus, and phonophobia (fear of sounds). There is a ton of clinical evidence supporting the Jastreboff as well as 3 placebo controlled studies showing the effectiveness of TRT. ( Tinnitus Retraining Therapy (TRT). The definitive site for )
I can also say it's the only thing that has helped me with overcoming my hyperacusis and sound sensitivities.
The only thing I know about the objective research is what you said about it. But I appreciate you more thorough explanation.
Here is some objective evidence showing spectrum analysis dynamic range of LP. According to this it looks like the CD loses in dynamic range in the higher frequencies.
"We can see why statistics often "mislead". LP's noise floor is actually quite low over most of the spectrum, ranging from -84dB around 1kHz to -96dB for frequencies above 10kHz . In other words, the LP recording has a lower noise floor than the CD recording for the majority of the spectrum (frequencies above 2kHz )."
Dynamic Comparison of LPs vs CDs - Part 4 - page 2 — Reviews and News from Audioholics
In analog recordings there is also significant recorded information below the noise, according to Ken C. Pohlmann in his book Principles of Digital Audio. Our ears are really good noise filters and we can hear below the noise.
So, there are also other explanations for the subjective perception of increased dynamic range in LPs, besides the work by J.J. you mention.
Guys, you really should post this on the LP Vs CD thread http://www.diyaudio.com/forums/anal...er-turntable-compared-cd-158.html#post2552368
It would also be good to add your Psychoacoustic insights into this thread http://www.diyaudio.com/forums/ever...uman-auditory-system-its-relevance-audio.html
It would also be good to add your Psychoacoustic insights into this thread http://www.diyaudio.com/forums/ever...uman-auditory-system-its-relevance-audio.html
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