Skyfish:

The hiss is volume control dependent from the top +10 on down to about -15 or so, at which point the noise from the 950 itself measures about -90db (an absolute measurement - not signal to noise ratio), which is very quiet. The trims also effect noise, but throughout their whole range: they don't plateu off at the lowest setting. The 950 now has about 8db more gain too.

All this does add up to a 10-12db or so subjective reduction in hiss. On my own horns, I could hear hiss from 5 feet away, and now that same level of hiss is somewhat less than a foot away. Pretty blasted good.

As I posted earlier in this thread, to get the benefit of this noise reduction however, you must re-calibrate your system to take into account the 8db of extra gain, which essentially 'turns down your volume control', which lowers hiss which is now volume control dependent.

I don't know about how your calibration with the volume control at -15 and using 70db as a reference would work, given your speakers. I would recommend using the conventional "00" setting on the volume control and 75db, and lowering the trims to get the proper level. You will find that they will end up about 8db lower than before, which is essentially turning the volume, and noise down by that amount.

[This message has been edited by soundhound (edited January 05, 2003).]