[kmeisthax]

Audiotape is - or at least, Phillips compact cassettes are - recorded linearly. The recording method you're talking about for videotape is called helical scan, because the heads trace out a helix pattern. You might be confusing that with the head azimuth, which does alternate between fields on VHS to reduce cross-talk or something.

Some other bits of jank in the VHS spec:

- Because the tape is moving while it's being written, it stretches the signal out on the tape. This is perfectly fine for normal playback. But when the tape is not moving, the signal's now too wide for the playback head, and you can only read about half the picture. That's why your VCR had bars of static whenever you paused (unless you sprung for the four-head model)

- Audio is still recorded linearly, and you can't exactly chuck a linear head in an angled, spinning drum. So you have to put the audio head further away from the tape. And that distance is fixed; changing it means your machine is now playing audio out of sync with the video.

Also, there is an extension to VHS that lets you record audio along the video in the helical area, it's called VHS Hi-Fi and it improves the audio dramatically with the trade-off that any minor video glitches will add pops to the audio. Humans are way more sensitive to gaps in audio than video, after all.

[ddingus]

I dumped a bunch of albums, and a few CD's, to Hi-Fi VHS. A while back, I stumbled onto a compatible VCR at a yard sale for a couple bucks.

Yes, those gaps are annoying as all get out. Tracking has to be dialed right in to recover the sound properly.

But, once you do that?

It's really great! Frequency response goes almost to zero, and up to 22Khz, and it's flat for most of that range.

One of the albums I recorded had a warp in it. When the actual vinyl was played on a good stereo system it was possible to see the speaker cones actually move in time with the warp. It's essentially a very low frequency signal.

Cassette does not reproduce that. I bet a good reel-to-reel system would.

Hi-Fi VHS reproduced it pretty much bang on perfect!

The best part was being able to add index marks! While recording, one could press a button and get one of those written to the tape. I had several tapes made with music I really like and could access pretty much anything on it quickly.

Fun stuff!!