BigDee2003 --
<< 44100 is more than your ear needs. 48000 is just a nice round number. >>
Ummm....
NO! Bad answer, both mathmatically and musically. I end up posting about this about every six months. I hope you're in the mood for a read.
Anyone who has seen my previous posts knows I think CD's suck compared to original sounds for two reasons -- 16 bits just aren't enough, and the sampling rate (44 KHz) is way too low.
16 Bit Quantization
The encoding scheme is
linear PCM (Pulse Code Modulation) which quantizes levels as a linear function (bits per volt) while your ear perceives sound as a log function (decibels = dB). As the signal level gets lower, you have fewer bits to resolve the details of the sonic image, so the distortion rises as the level goes down. Meanwhile, human beings tend to tolerate more distortion at higher levels and to be more sensitive to distortion at lower levels, because that is what happens with both your own ears and most real world sound generators like instruments, speakers and amps. In other words, when it's full bore blowing your own ears into distortion, it's as clean as it's going to get. In a moderately soft passage, where your ears are more sensitive to distortion, CD's are glad to give you lots more distortion.
It's like dot matrix lithography without enough dots per square inch (the equivalent of frequency response) or a good enough grey scale (the equivalent of dynamic range). A young man can get off single handed if the image is up to Playboy centerfold standards
, but IMHO, 16 bits x 44 KHz is the equivalent of crude newsprint.
If the system encoded the signal as bits per dB, the distortion would be constant. However, that is a
much more difficult system to build. Furthermore, the current system is already in place, and it would still require more bits to achieve acceptable results.
44 KHz Sampling Rate
44 KHz is an inadequate sample rate. This sampling rate was chosen based on Nyquist's theorem, which states that, to recover a given frequency, you must sample the information slightly more than twice the highest frequency. The problem is that Nyquist wasn't a musician. As you get closer to the high end of the audio spectrum, this theorem is only valid for a single, steady state tone. If you change the conditions to allow for a second tone, or to modulate the amplitude (volume) of the sine wave while it is being sampled, you have created a condition where there are literally an infinite number of possible outputs for a given sample.
As a designer of analog gear, when people ask me how many bits I want, I always answer,
All of them! No matter how many they have, I have more.
More Problems
Another problem is, the inherant distortion in CD's is
non-harmonic. That means, unlike harmonic distortion (THD), the distortion products are
out of tune with the music, which, in turn, means that human beings are far more sensitive to this kind of distortion. That is why I said that, to some extent, the inherent distortion of most analog systems is more tolerable than typical distortion found in PCM systems.
As I said, I used to be a professional musician, too. Music (and any art form, for that matter) transcends the medium. It isn't just counting to four and getting the notes in the right place. The subtle undertextures of a musical performance are part of the "magic" that moves your soul. When I turn off the scopes and meters and just kick back to play or listen, CD's don't cut it. I have CDR's in my machines, but I don't own a CD player.
If you want to hear the difference, get ahold of an old LP in good condition of something that was recorded analog, and a CD re-issue of the same thing. Cue them up so they are in sync, and switch between them. LP's win every time. Good examples would be Eagles, James Taylor, older Steely Dan and anything else with good air space in the recording.
It could be worse. MP3's suck even more than CD's. :Q MP3 is an example of a "lossy" system that discards information some machine "thinks" you can't hear. PKZIP is an example of a
lossless system. The data storage footprint is compressed, but you get all the data back when it is decompressed. The information lost in lossy compression is usually subtle stuff, but I have participated in experiments that prove you definitely can hear the difference.
There is hope on the horizon. The highest standard for the new audio only DVD is two channels of 24 bit data @ 192 KHz with only lossless compression. At that sampling rate, it will once again matter if the analog electronics I design can do a good job of reproducing the signal.
Don't worry. It's a multi-format standard that is compatible back to current CD's, so you'll still be able to play them. Of course, once you hear the new stuff on a good system, you may not want to, anymore. We may finally be about to come out of the Audio Dark Ages[/b].
Facebook
Twitter