amping Passive Sub

[mikeh1960]

Hi All

I have a Paradigm SB-100 Subwoofer, it's a passive sub. dual voice coil.
My AV receiver has a SUB pre out, so the sub not being powered is less effective.

So here's my question, can I unplug the crossover inside the sub and run a feed from a poweramp, in mono mode(Bridged) to the sub, and use this from my Sub pre out of the AV receiver?

Or even better yet, just run from the SUB pre out on the AV receiver to the poweramp pre IN and then both L/R speakers into the L/R on the Sub?

Cheers Mikeh

[Cal Weldon]

Hi Mike,

Option 2 sounds good to me, just don't unhook the passive XO right away. Listen to it first and make sure your line out for the sub isn't full range like my HK receiver is.

EDIT: Do you have a gain control on your power amp?

[hep]

Mike, did you experiment the AV pre sub out functionality?

I have a similar kind of a situation. Some time ago, I made DIY 6ch UcD180 amp for my home theater. Only 5 of 6 channels will be used for the main, center and surround speakers. Since I have one un-used amplifier channel and AV preprocessor (NAD T163) with subwoofer line-out with 4th order low pass filtering (crossover point adjustable between 20Hz and 200Hz in 20Hz increments).

Hence, I have been considering the following subwoofer set-up:
- built passive subwoofer (without amplifier; just an appropriate vented box with an appropriate element)
- UcD180 (180W to 4ohm) amplifier
- AV preamp subwoofer settings to control the low pass to sub
- AV preamp delay settings to control the subwoofer phase
- AV preamp sub gain control the subwoofer level

What would I be missing to do it this way instead of building active subwoofer with a subwoofer amplifier?

For the background info, my home theater room (= the living room) is relatively small, and I rarely need hundreds of watts of subwoofer SPL. Other speakers (will be) 3x DIY Zaph ZD5 + 2x undetermined surround speakers, or, 5x something from Jordan JX92S (2 main speakers probably in ML-TL construction)