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What is behind a "warm" or "vinyl"sound?

I found an interesting article in The Saturday Toronto Star's entertainment section on the resurgence of vinyl.

What I found most interesting in this article was a description of why people describe vinyl as "warm". Peter J Moore, the famous producer/mastering engineer of the legendary one microphone recording of the Cowboy Junkies' Trinity Sessions recording says it all comes down to the fact that humans do not like square waves - ie. when you go from super quiet to super loud at no time at all. He gives the example that if someone was to slap two pieces of wood together right beside your ear would be about the only time one would feel a square wave - and that would make you jump right out of your skin! He says digital, particularly MP3s reproduce square waves like crazy, which triggers fear which also produces fatigue. He says if those same two pieces of wood were slapped together across the room, the square wave would be rounded off by the time the sound reached our ears. Turntables cannot reproduce square waves due to through time it takes for sound to get though the length of wire and the magnet that the wire is wrapped around in the cartridge. By the time the signal gets through that the sharpness, he ugliness, has been rounded and that, he says, is what people are talking about when they describe vinyl as "warm" sounding. Interesting!

I find there are a bunch of digital manufacturers, like Lumin, that are striving for a vinyl sound. I wonder if they are somehow rounding off the square waves in the digital signal to do so? If this is the case, "perfect" reproduction may NOT actually be beneficial to the sound...at least for someone who really wants a vinyl sound experience. Better may not actually be better when it comes to digital sound reproduction!
camb
mapman's avatar
mapman
22,178 posts
 
Czar,

CD is based on principles of Nyquist sampling theory.

I have a lot of experience applying that in digital image processing and resampling. It works quite well in digital imaging. I ran a lot of test cases over the years on various forms of digital imagery that convinces me of that.

Granted, it leaves little room for error, but it works pretty well when done right, even if not 100% perfectly in all cases.

That jives with what my ears tell me these days. It's a fine line between good digital and poor, but luckily the technology used with the format has improved immensely over the years and most of the problems resolved. CDs still being as relevant as they are 30 years later and the lack of traction on any scale for high res audio formats these days despite the technology to enable it existing testifies to that.

It is true that CD redbook spec has a fixed limit for dynamic range and more there is clearly possible with more bits, but the dynamic range possible already well exceeds what most consider safe levels for listening, and I have heard good CD format playback sound indistinguishable from good vinyl to me even with massed orchestral violins(though not as often as I'd like), so there you go.
audioengr
3,282 posts
 
"It's almost like carrying frequency in radio transmission only it's carried internally through the digital processors to be decoded at the end just like in radio receiver. "

Not a good analogy. RF is always a modulated carrier frequency. Digital is encoded, not a modulated carrier. Most RF is really analog. Digital is discrete states and levels, not handled like analog.

Steve N. EE since 1976
Empirical Audio
audioengr
3,282 posts
 
Most of the SQ issues associated with digital have to do with poor digital filtering in the DAC, (whether in the CD player or other separate DAC), jitter and the sample-rate. For accurate dynamic playback at high-frequency 44.1kHz is insufficient. 88.2kHz and 96 kHz are sufficient. Poor digital filtering abounds unfortunately.

Even 44.1 can sound wonderful however, depending on how much HF information is in the track.

Steve N
Empirical Audio
almarg's avatar
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almarg
9,670 posts
 
I agree with the comments by Steve (Audioengr) and Mapman just above. One further point:
02-05-14: Czarivey
With vertical axis not everything is perfect either. For red book CD we have 16-bits resolution. It tells you that maximum amplitude is 16 bits and the whole dynamic range is divided by 16 portions of the vertical axis.
As you may realize, the vertical (amplitude) axis is divided into 65,535 portions (increments), not 16. For 16 bit data, there are 65,536 possible amplitude values (corresponding to 2 raised to the 16th power), which means that there are 65,536 - 1 = 65,535 increments.

To put things in perspective, it's perhaps worth noting that each of those increments is small enough to represent 0.0015 percent of the maximum possible ("full scale") amplitude.

Regards,
-- Al
czarivey
5,946 posts
 
Steve,

It's not only modulated carrier frequency, but also could be modulated phase or amplitude (AM signal is Amplitude Modulated)
Most RF is really analog
Why most? Square waves cannot propagate through the air unless there's again carrying frequency and in case of digital encoding phase modulation is used to define 1 or 0 in the air.
In all of the cases mentioned above and even more than above of this post we deal and deal and deal with carying frequency
Digital is discrete states and levels
It's not what Al said or even books. It will never be discrete or sudden. Before it forms "square wave" there's a process and certainly components that build it step by step so nothing is discrete for sure.

Mapman,

My objective was not to critisize digital playback vs. an analogue, but to express points where digital playback is inferior to analogue. There are bunch of points where analogue playback is inferior to digital as well...
Technology grows and there are far better formats than red book CD as well and post Y2K CDs in vast cases sound substantially better, but taken that and consumed, still I can spin records whole day while even after 2...3 perfectly mastered and recorded CDs I have to dial 'Analogue' function on my recently purchased DAC-preamp(hoped to boost my poor digital collection, but it's huh still poor). I'm also glad that my record shop visit more and more of teens and students who may or maynot have the idea why analogue is so cool, but they certainly hit on great past music of our analogue 60's, 70's and 80's :-).
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