44.1K was chosen because the math worked out for both NTSC and PAL video systems. Digital audio was recorded to 3/4" video machines and could be edited like video.

In 60 Hz video, there are 525 lines of which 35 are blanked, which leaves 490 lines per frame or 245 lines per field, the sampling rate works out to:

60 fields X 245 lines X 3 samples per line = 44.1 KHz

In 50 Hz video, there are 625 line of which 37 lines are blanked, which leaves 588 active lines per frame or 294 per field, the sample rate works out to:

50 fields per second X 294 lines X 3 samples per line = 44.1 Khz.

The Sony PCM-1600 series of PCM processors were initially used to convert analog master tapes to PCM for CD mastering. They were used for all CD mastering. The bad rap that CDs got originally as sounding cold and harsh was due to the "quality" of the A/D converters in the 1600 PCM processors. In the mid-1980s, the audiophile consumer division of Sony came out with the F1 which was part of their high-end "ES" audio line and recorded to Betamax tape and could also be used with VHS machines although Betamax was preferred because you could defeat the video dropout compensator which messed with the PCM error correction. The Sony pro audio division got more than a little upset with the portable, battery-operated F1 and the 501, 601 and 701 PCM processors because they sounded considerably better than the hugely expensive PCM-1600 processors. I bought several PCM-601ES processors in 1985 and used them extensively for CD mastering. The 601 had S/PDIF I/O for computer editing or use with external A/D and D/A converters. I have hundreds of hours of PCM recordings from that era that sound great. DAT machines eventually killed the PCM processors.

One thing about the 1600 series in NTSC countries was that it used 30 FPS, not 29.97, so its sample rate was exactly 44.1k. Since the "prosumer" Sony ES processors used Betamax (and VHS) their sample rate was 44.056k to conform to 29.97 fps video. They operated at 44.1k in PAL countries. They operated at 16 bits or you could record at 14 bits with an extra 2 bits of error correction.

Both VHS HiFi and Betamax HiFi audio were analog.

Betamax was first with HiFi audio because there was some unused space in the video bandwidth to place a pair of FM modulated audio channels. The Betamax camp was convinced that VHS would never have HiFi audio because VHS did not have the unused space in the video signal so VHS's implementation of AFM relied on a clever form of magnetic recording called depth multiplexing. The modulated audio carrier pair was placed under the luminance carrier (below 1.6 MHz), and recorded first. After that the video head erases and re-records the video signal over the same tape surface, but video signal's higher center frequency results in a physically shallower magnetization of the tape, allowing both the video and residual AFM audio signal to coexist on tape. (PAL versions of Beta Hi-Fi use this technique). During playback, VHS Hi-Fi recovers the depth-recorded AFM signal by subtracting the audio head's signal (which contains the AFM signal along with a weak image of the video signal) from the video head's signal (which contains only the video signal), then demodulates the left and right audio channels from their respective frequency carriers.

The frequency response was 20hz to 20Khz, 70 dB signal-to-noise ratio (second only to the compact disc), dynamic range of 90 dB, and channel separation of more than 70dB.

I recall those times when I was a teen. Once again, a lot of valuable information here.

Yet another example why I like this forum very much.

@farss: "Well the common answer has to do with fitting a certain piece of music onto the first commercial CD."

According to this BBC article http://news.bbc.co.uk/2/hi/technology/6950933.stm
...Philips ended up adding 0.5 cm to the diameter of the disc (11.5 --> 12.0 cm) because of Sony's insistence that the CD should be able to hold a recording of Beethoven's 9th (74 minutes).

Based on what I remember from Dr. Stockham, you're both right. Sample rate and bitdepth were due to tape, and disc size was because of Bolero.....
That's sure going back in time...