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

Phus.

I haven't spun a CD in a couple years on my system. Music server + Squeezebox + DACs have replaced that.

But I use CD players as a reference in that they are typically associated with the format as well. Its more about the format and the technology options than CD players categorically.

Mapman,
Digital audio is very similar to the radio transmission where you have to have a frequency generator of waves that propagate through the air.
Same thing you do with digital audio. You divide your signal using a sample generator, the generator of so long discussed "square waves" that also someone clames to listening to them too much to the point of fatigue. So called "square waves" can be analogued to the carying frequency that will be decoded with appropriate device and brought as an analogue audio signal.

These square waves divide an input analogue signal and cary digital information about our original analogue signal that had been transfered from microphones and instrument sound pickups.

The red book CD sampling frequency is 44.1kHz and it does not change. It's almost like carying frequency in radio transmission only it's carried internally through the digital processors to be decoded at the end just like in radio receiver.

It clearly means that 1kHz frequency will have roughly 22 samples in positive half-wave and 22 samples in negative half-wave of the sin function totalling roughly 44 samples. In analogy, if the radio carying frequency 2mHz, than 200Hz signal will have 20,000 waves of the carying frequency...

2 kHz will have only roughly with 11 in positive and negative half-waves respective totally roughly 22 samples. etc...etc...etc...

The above two paragraphs give the horizontal axis picture.
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.

When the signal is loud, we get maximum resolution and when the signal is quiet we may only use 1...2 bits, so mastering of the digital CDs does involve great deal of compression in order to be able to hear quiet pieces with minimal distortion.

On the 'receiving' end we have DAC that reads either each bit or reads whole digital word which is in case of red book CD 16bit. Each bit will cary a very simple information in terms of either 1's or 0's. DAC determines the absolute value of each bit and reads it either as 1 or zero and so generates an analogue bit-portion of the signal of certain fixed magnitude.

"This is true for the vast majority of digital equipment, but not all. With very low jitter and noise, it can sound smooth and silky, just like analog."

Can you recommend a stand-alone CD player with these capabilities? I have over 1000 CD's in my music library and switching over to a different digital format won't help me get better sound from my CD's.

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.

"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