"Iain Churches" wrote in message
i.fi
"Arny Krueger" wrote in message
. ..
"John Phillips" wrote
in message

I have sometimes pondered (without real cause, I admit)
about whether the "usual" IMD tests are good enough as a
predictor of audible IMD effects.

Not really.

Agreed. They must be better than nothing, but probably
have little bearing on what might be happening in a
complex musical signal.

Do you think the normal two-tone IMD tests (from SMPTE,
DIN, IEC, etc.) provide an adequate basis for testing
something where (I postulate) more complex IMDs may be
the more audible effect?

Not really.

There seem to be several opinions regarding the
frequencies of the fundamentals used in such tests.
Is there any standard?
I have seen 70Hz and 6kHz mentioned, and
also 19kHz and 20kHz.

Swept 2-tone tests are more to the point.

Much more like music.

Multitone-based tests can also work well.

Much more like music.

Multitone is indeed interesting:-)

http://www.nti-audio.com/Portals/0/P...nual_v332e.pdf

http://wireless.agilent.com/rfcomms/...audio_desc.php

http://www.tti.co.uk/products-resale/ap/ap-ats2-1.htm

http://www.pcavtech.com/play-rec/ra10436/index.htm

Are there any recommendation for centre frequencies?

Depends... ;-)