Crossover point from sub to Heresy

[GWK]

I've got a pair of Heresies on their way (bought them on ebay a couple of days ago), and I'm trying to get the rest of the system ready.

I've got a Marchand electronic crossover, which has symmetrical 24dB/octave Linkwitz-Riley filters. I've got a sub consisting of 4 long-throw 15" woofers mounted on a baffle in my ceiling with the backs open to the attic. Currently, the sub is crossed in at 100Hz, because I wanted to have the dynamic output capability that my mains lack.

I'd like to cross lower to minimize integration issues. The speakers that I've got coming are Heresy I's, but I'm not sure from what year. I'm guessing that they probably start rolling off around 70Hz or so. Should I cross them there? Can I get away with a lower crossover point? Where do the low-xmax woofers of the Heresy start to be the bottleneck for high output?

Any detailed info on the actual rolloff of the Heresy or on others' experiments with sub integration would be most appreciatively received.

Thanks,

Grant W. Kahn

[JohnA]

I think 70 Hz sounds like an ideal crossover point for Heresies. The first prototypes were said to be solid as a brick outhoust down to 75 Hz and the production models went deeper.

John

[Malcolm]

Best advice I can give on this is try it and see what sounds best to you. Tuning by ear seems to work best for subwoofer crossover.

Input to my sub currently goes through a 50 Hz filter with a 6 dB slope. No filter on Heresys. This seems to work pretty well with the natural rolloff of the Heresy's woofer.

With a 24 dB filter, I would expect you would have to cross higher to avoid the woofer's natural rolloff.