"Eiron" wrote in message
...
On 19/01/2017 14:54, Iain Churches wrote:
"Eiron" wrote in message
...

Many years ago I built a gadget to do the same thing with an op-amp, 3
resistors and a capacitor.
Constant amplitude with a delay at higher frequencies on one channel.

Interesting. Was this totally mono compatible with the original?
That was the main part of the brief.

No but that wasn't necessary as my gadget was part of the replay chain
and could have been fitted into an amp (instead of a tobacco tin) with
a defeat switch and a pot for 'image width'.

I didn't think of using my tape deck as a delay.

Tape decks we had plenty of:-)

The Studer with external capstan control, was running
well in excess of 30 ips.

At one stage we tried, in addition to the main antiphase
pair, three pairs lightly EQ'd. These were added sparingly,
as one might add condiments in cooking! Once again in
mono, these pairs too cancelled out, just leaving a track
indistinguishable from the mono original.

Generally speaking the reprocessed material that I was
involved with was jazz and classical.

Iain