My new 'toy' !!!

[kexodusc]

My doubtful understanding is that the sensitivity, (actually the output), with two identical drivers is +6 dB, but only if they are identical and are positioned within 1/8 of a wavelength of each other. Your two Advent Tweeters would not meet the proximity condition, (hence you get interference, i.e. Dopler effects, depending on the listening position). Your woofers would meet the proximity definition only towards the bottom in their range, not up close to the tweater crossover point. (This is why I'm doubtful of the Dual Advent concept, though a lot of people think it's great -- the corresponding drivers are not close enough together to ensure blending, and that aspect is exacerbated by the fact that the tweaters aren't aligned vertically.)

I'm with you on this - all depends how they're wired, of course, but I assume it was parallel? When you wire an identical driver in parallel you get the +6dB boost, in series you get 0 dB effectively.

[E-Stat]

I'm with you on this - all depends how they're wired, of course, but I assume it was parallel? When you wire an identical driver in parallel you get the +6dB boost, in series you get 0 dB effectively.

The best way for doubling Advents is to run them parallel where most SS amps also put out more power at the nominal 4 ohm load (which falls to 2.3 in two ranges - so not all amps are happy here) and to use separate speaker cable runs. You definitely get +6db when run that way. All Advents take a bit of space between them and the listener for the drivers to blend optimally, but stacking them in a quasi D'Apolito arrangement noticeably improves their apparent image size.

I run a Threshold Stasis 3 amp (400 watts/4 ohms) with my double New Advents and find that I rarely run higher than -20 db (about 4 watts) which is LOUD. Because of their Scream Machine Roller Coaster impedance curve, they really need a bit more DF than the 6400's 40 to sound their best IMHO.

rw