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Topic: "The CD is limited to 22,000 cycles, whereas the LP is able to re (Read 6766 times) previous topic - next topic
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"The CD is limited to 22,000 cycles, whereas the LP is able to re

hi , I found this interview of bob ludwig :

http://mixonline.com/mag/audio_bob_ludwig/


He says that "It is customary to believe that the CD is superior to the LP in terms of bandwidth, but this is not the case. The CD is limited to 22,000 cycles, whereas the LP is able to reproduce frequencies up to 50,000 cycles, which in the PCM world equals a sampling rate at 100 kHz. The bottom line is that LPs mastered with DMM still sound really good."

What do you think ?

If it's true vinyle may be far superior to CD ?

"The CD is limited to 22,000 cycles, whereas the LP is able to re

Reply #1 –
Quote from: abducted on
hi , I found this interview of bob ludwig :

http://mixonline.com/mag/audio_bob_ludwig/


He says that "It is customary to believe that the CD is superior to the LP in terms of bandwidth, but this is not the case. The CD is limited to 22,000 cycles, whereas the LP is able to reproduce frequencies up to 50,000 cycles, which in the PCM world equals a sampling rate at 100 kHz.


Theoretically, the LP might be able to store frequencies up to 50 kHz but:

- I believe that given surface roughness of mass production vinyl material (this can be measured) is huge enough to mask all signal frequency content above - let's say - 30 kHz due to the linear-speed-induced "roughness frequency" a.k.a. noise or ground clutter

- in music, frequency content of 30 kHz+ is surely present through instrument overtones/harmonics ... this could be perceived via interference with the base frequencies. Since the human ear is rather insensitive towards these extremely high frequencies and since the corresponding amplitudes in music are really low, the chances of losing these frequencies in background noise of a mechanical playback system are far too great to be ignored.

- a mechanical pickup stylus (like the ones used with record players) has a given mass (which results in corresponding inertia) and a pickup-specific stylus compliance which limit the useable frequency range way below 30 kHz

- music reproduction is way more than just an extended frequency range (that no one can hear anyway) ... think possible dynamics or robustness against defective media (the LP is very pooor at these when being compared to CD), impulse response (if tonearm weigt and stylus compliance do not match, impulse response will suffer, too) or frequency response linearity (which is often way off the ideal 0dB-Line with non-matched input capacities of cartridge and phono amp or improperly-applied RIAA-equalization). Additionally, the cartridge will pickup sound from your speakers at higher listening volume levels ... this kind of acoustical-electrical feedback isn't really what you want when enjoying music.

- LP's do wear off by simply playing them ... I really doubt an LP will make 22000 playback cycles

Quote from: abducted on
The bottom line is that LPs mastered with DMM still sound really good.


Absolutely, DMM-recorded LP's of properly-mastered music material do indeed sound good on a proper playback system. But think of the limited dynamic range ... pianissimo-passages in e.g. classical music will always suffer from typical vinyl hiss and rumble.

To me, digital music storage is far superior in every technical aspect ...
The name was Plex The Ripper, not Jack The Ripper

"The CD is limited to 22,000 cycles, whereas the LP is able to re

Reply #2 –
It doesnt matter because humans cannot hear it.
I am arrogant and I can afford it because I deliver.

"The CD is limited to 22,000 cycles, whereas the LP is able to re

Reply #3 –
It is possible for vinyl to reproduce frequencies higher than the maximum a CD can put out, but that's meaningless. Humans can't hear above around 20 kHz anyway, and that's an ideal situation. Even relatively young people might not be able to hear above 18 or even 16 kHz, depending on genetics or hearing damage from concerts and whatnot.

These supersonic vinyl frequencies are likely destroyed after a few plays, anyway.

Vinyl can sound very nice if you're willing to drop a grand or more on equipment to play it, but it will never be more robust than a CD.

"The CD is limited to 22,000 cycles, whereas the LP is able to re

Reply #4 –
Quote from: Lyx on
It doesnt matter because humans cannot hear it.

I think the premise of the original post is that difference frequencies or other interactions between high frequencies produce results at audible frequencies.  E.g., two instruments that produce signals say, at 32KHz and 32.5KHz could produce some sort of difference tone at 500 Hz that would materially affect the perceived timbre of the instrument(s).

I think this is highly unlikely because it's unclear where in the signal pipeline this would occur in any system designed to minimize IMD.  Not to mention the fact that the RIAA equaliztion curve rolls off way below those frequencies (it's already -20 dB at 20 KHz) and the questionable premise that the mechanical limits of the cartridge could even pick up those frequencies, or that vinyl could that fine a surface geometry past the first few playings.

"The CD is limited to 22,000 cycles, whereas the LP is able to re

Reply #5 –
I saw some LP player parameters from 70's years. A regular player with crystal pickup was able to get frequencies up to 13 kHz, the better ones with magnetic pickups were able to play frequencies up to 16 kHz. Of course these were a consumer class players. A Hi-Fi gramophone might be able to reproduce higher frequencies, but there are another two problems:
1) Most LPs won't contain high frequencies
2) A human can't hear them anyway, like many already wrote

So the conclusion is that an average gramophone will sound far worse then an average CD player. A high-end gramophone might sound better then a CD player, but it will be indistinguishable for a human.

"The CD is limited to 22,000 cycles, whereas the LP is able to re

Reply #6 –
Not as an entry in the LP vs CD controversy, of which I care not a fig, but as a matter of fact on LP high frequencies: I have one LP with a test tone that sweeps to 30kHz. I can quite readily record it to computer. I have a couple of others, found in thrift shops, both very old and worn, that have test tones clearly going to  25kHz.

Recording at a sample rate of 88.2kHz, I see strong harmonics of these tones that remain quite distinct to the Nyquist limit of 44kHz. Whether these harmonics exist on the LP, as a result of generating the original tones, or as a result of cutting them into the master disk, or are a product of the playback system, not on the LPs at all, is unknown. The fundamentals, however, are there and are easy to read with my phono cartridge.

"The CD is limited to 22,000 cycles, whereas the LP is able to re

Reply #8 –
Quote from: kjoonlee on
Let's say DVDs can carry infrared information as well as visible light. Would that be useful? No.


Ultra Violet would be good though - you could get a tan while you watch your favourite beach movie  .

"The CD is limited to 22,000 cycles, whereas the LP is able to re

Reply #9 –
Just a few comments:

1. Bob Ludwig knows his stuff. Most things he says are worth taking notice of.

2. The quote was taken out of context. Mr Ludwig was referring to just one, isolated, theoretical parameter in which vinyl LPs *can* be superior to CDs. He wasn't saying that because of this, LPs sound better than CDs.

3. In practice, the vast majority of vinyl LPs contain only noise and distortion above about 18kHz. The reason for this is quite straightforward: most LP cutting lathes have low pass filters with turnover frequencies around 16-18kHz to prevent problems in the cutter head. Only highly specialised lathes for things like CD4 quadraphonic LPs, test discs, and "audiophile" pressings attempt to cut higher frequencies.

Perhaps the DMM lathes that Bob Ludwig has used also cut those higher frequencies? I don't know. What I can say is that the DMM LPs I own tend to have a clean yet somehow sterile sound. They seem to have no "oomph"; none of that organic vinyl warmth that can be so alluring.

"The CD is limited to 22,000 cycles, whereas the LP is able to re

Reply #10 –
Sure, LPs carry more frequency information, but what good is that frequency information with the disgusting levels of surface noise?

"The CD is limited to 22,000 cycles, whereas the LP is able to re

Reply #11 –
Again, this isn’t to promote one media over the other, but perhaps you have an extra noisy phono peramp. LP surface noise is certainly higher than any intrinsic CD noise, but with much music it isn’t audible, unless you want to consider the clicks and pops, -- unlike surface noise, not at all constant -- as part of your complaint.