[Iraj]

I have the large subwoofer, installed and set up 30 years ago by Brian, rip. I no longer have any documentation, and am moving it to a single L/R channel power source. How do I connect it? Input to the bottom two of the lower posts and bridge to the lower of the upper set? Thanks for any help. Iraj.

[GeorgeAb]

Iraj,

I too have the Large Subwoofer.  I have two sets of bindings.  One set is going to 15" 8 ohm driver and other set is going to 12" 8 ohm driver.  If you bridge them it is a 4 ohm load.  You may want to measure resistance first just to make sure.  In my case I am only using the 15" driver as it more balanced with the 215 Subwoofer (uses a 15") used for the opposite channel. 

[Iraj]

Thanks George, and sorry for the delayed response, but I may have confused things with the title of my question. I have the Large subwoofer, with only one active (12") driver.  The 15" is passive.  I've got two sets of input posts and two sets of output posts, totaling 8 posts.  If I remember correctly, a two-channel stereo amplifier is to be connected to the subwoofer as follows: Left to one set of inputs and Right to the other, with the corresponding outputs going to the Left and Right speakers, respectively. My dilemma arises from my use of a 3-channel amp, only one channel of which is going to the subwoofer.  I don't know (1) if I will damage anything by bridging the two sets of input posts, and (2) if it makes a difference which of the two input sets I use if I don't bridge.



   

[Jstower]

Iran, I believe the driver is a dual voice coil. Yes you can use jumpers between the two inputs. I have the same subwoofer, that’s the way I run mine. Good luck

[Iraj]

Great, Jstower. That’s what I thought. Good to have confirmation.

Thank you. Ira.

PS: I looked at the passive cone for the first time in >30 years, and see the foam surround is deteriorating. Have you tried to re-foam?  I’ve done smaller speakers, and the process is simple, but getting to that beast seems a chore. Any thoughts on that task?

[Jstower]

You need to remove the base, hopefully it’s screwed on, this will give access to the 15” passive radiator.
I replaced mine with a rubber surround, it will last much longer. Also I will give you a link to vitrify your passive radiator, just scroll down to the instructions. Good luck

https://www.audiocircle.com/index.php?topic=47927.0

[Iraj]

Thanks again. I saw that thread yesterday, but didn’t read it fully. I will now. Cheers.