Passive sub @ center

Posted by: brwsaw

Passive sub @ center - 03/16/13 11:48 AM

I've got a SB100 sitting around and I'm considering trying it in my current system.
I would need to rob one of the channels from my amp and stacked banana plugs at the amp and back of the center. The sub has 2 in 2 out.
I used to have a amp that I could control and it was a nice compliment to the sub. I had removed the cover to fit it in an old rack, lost the case, had a kid and decided it wasn't worth the risk.
I'll be using the reciever to controll it now.
Anyone care to comment on the idea before I rip my living room apart?
Posted by: JohnK

Re: Passive sub @ center - 03/16/13 10:13 PM

I'd comment, but I can't follow what you're proposing. To begin with, what's an SB100?
Posted by: brwsaw

Re: Passive sub @ center - 03/17/13 01:01 AM

Posted by: brwsaw

Re: Passive sub @ center - 03/18/13 04:09 AM

The SB-100 was a passive sub sold by Paradigm long ago.
I found this picture online a while back. The wiring diagram on mine can no longer be read.

I walk past it every day and wish I could put it to use again.

In the last two days I've watched a few good movies without my subs. The M80's really do sound nice on their own.
I am tempted to run the M80's through the SB100 just to see.
I'd think its pretty unlikely I'll put more than 100 watts through the sub to the M80's.
Not sure how the ADA would handle the impedance though.
Posted by: JohnK

Re: Passive sub @ center - 03/18/13 09:42 PM

Your latest post partially clarifies the situation. The SB-100 apparently has dual voice coils and if you connect two(not one)main channels to the M80s "through" the SB-100 this would create a parallel connection between the M80 and SB-100 voice coils. The net impedance, using the nominal 8 ohm and 4 ohm impedance ratings, would be 1/8+1/4=1/X, X=2.67 ohms.

It's unknown(unless you have the SB-100 manual or other info)if there would be a high-pass filter on the M80s if they're connected through the SB-100. For example, if there was a 100Hz high-pass on the SB-100 outputs, the 4 M80 bass drivers would be rolled off below 100Hz and the net effect with only the single SB-100 driver covering those frequencies would be less bass than with the M80s alone.
Posted by: brwsaw

Re: Passive sub @ center - 03/18/13 09:49 PM

I'm pretty sure I'm following what you're saying.
Only thing is everytime I've wired it it was in a similar manner with inferior equipment and it always made it sound better.
I am impressed with the M80s when used in true stereo.
Posted by: JohnK

Re: Passive sub @ center - 03/18/13 09:58 PM

Possibly there might not be a high-pass filter on the connected speakers. If not, all of the bass drivers would be working their full range and the added SB-100 driver would make a net improvement in the bass compared with the speaker bass drivers alone.
Posted by: brwsaw

Re: Passive sub @ center - 03/18/13 11:46 PM

Thanks, I'm thinking it can't hurt but then again I've ruined a good thing by tweaking more times than I care to admit.
I'm so lazy I may never know.