Is VHS Hi-Fi sound perfect? Is Beta Hi-Fi sound perfect?
> The HiFi recording format is subject to two different problems: > Head-switching noise and compression errors. > > To get perfect reproduction, the FM subcarrier waveform being > played back by one audio head must perfectly match the waveform > from the other head at the point of head switching if a glitch > is to be avoided. If you record and then play the tape on the > same VCR under exactly the same conditions, you have a > reasonable chance of this working. But if the tape stretches > just a bit, or you play it on another VCR whose heads are not in > exactly the same position, or the tracking is off, the waveforms > will no longer match exactly, and you will get a glitch in the > recovered waveform every time the heads switch. This sounds > like a 60 Hz buzz in the audio, which is often audible through > headphones even if not through speakers.
The HiFi recording format is subject to two different problems: Head-switching noise and compression errors. To get perfect reproduction, the FM subcarrier waveform being played back by one audio head must perfectly match the waveform from the other head at the point of head switching if a glitch is to be avoided. If you record and then play the tape on the same VCR under exactly the same conditions, you have a reasonable chance of this working. But if the tape stretches just a bit, or you play it on another VCR whose heads are not in exactly the same position, or the tracking is off, the waveforms will no longer match exactly, and you will get a glitch in the recovered waveform every time the heads switch. This sounds like a 60 Hz buzz in the audio, which is often audible through headphones even if not through speakers. The same glitch will occur in the video waveform too, but since head switching always happens during vertical retrace, you won’t see it.
