I did a search and there were multiple links to products that in fact are audio delay units, but I am wondering which ones you HAVE USED, and trust. I need to spec one for a client.

One unit, the SESCOM unit, has a delay of up to 300 ms. Is this sufficient for most delay issues between zone one and zone two?

I can only add to the second question. The new Yamaha receivers (RX-A1050 and up) have a delay option for zone 2 (and 3, I guess). I was able to get the family room (surround) and the dining room synced-up at around 85ms.

I would think that 300ms is plenty, as long as the Yamaha values are accurate.

We had a thread about delays a few years ago and the one that seemed to be most interesting was from Hall Research. 1ms increments and it goes to about .5 seconds of total delay.

[Link: markertek.com]

Ive used the Sescom twice and both times it did the trick. I only needed a 50 ms delay. The adjustments are in set increments, so not sure if there would ever be a scenario where you would need to be in between two settings.

I also found this, but never have used it:

[Link: motron.com]

Thank you!