In article ,
Mike Gilmour wrote:
Back in those olden days of quadraphonic you needed a cartridge with
an upper range of around 40-45kHz.

All together now.

OH NO YOU DIDN'T

OH YES YOU DID.. take CD-4 if you wish, much the same....The difference
signals are first modulated onto a 30kHz carrier then added to the
cutter L&R inputs respectively. This upper modulation is tailored to
fit the bandwidth from approx 20-45 kHz. Bog standard pickups don't
respond to these signals and will just reproduce L&R signals. For Quad
reproduction to happen you need cartridges with a consistent response
around 40-54 even to 50 kHz - only when this range is passed from the
cartridge to the demodulator will you recover your 4 channels.

CD-4 was one of the less popular quadraphonic setups - for the very reason
it needed a new and expensive pickup.
The other matixed setups were more popular - if that's the word, because
none of them worked well.

--
*You're just jealous because the voices only talk to me *

Dave Plowman London SW
To e-mail, change noise into sound.