Dual sub/pr combo...need a design

Blaine_M · « **on:** 8 Mar 2006, 03:24 pm »

Does anyone have a design that I can 'borrow' for a dual sub/pr box for Danny's combo? I'd like a tower type design that would have as much of a footprint and I'm not creative enough, nor do I have the know how to design such a box. Also can something like that run on one larger plate amp?

trekker · « **Reply #1 on:** 9 Mar 2006, 12:25 am »

Check this post http://www.audiocircle.com/index.php?topic=20592&postdays=0&postorder=asc&start=10 Look towards the bottom of the page. Here's a tower with (4) of Danny's subs.

Blaine_M · « **Reply #2 on:** 9 Mar 2006, 01:25 pm »

That's kind of what I'm looking for, only 1/2 that. Problem is I need dimensions and some type of plan.

Danny Richie · « **Reply #3 on:** 9 Mar 2006, 02:21 pm »

I built a 2 woofer/2 PR sized box using the box plans shown on our web site. It was like building a pair of those boxes side by side, but one side was used as a common wall dividing the two air spaces. Top and bottom panels then went the full length of both side.

Blaine_M · « **Reply #4 on:** 9 Mar 2006, 02:32 pm »

I see, so if I wanted to I could stack one right on top of the other and build it that way. I guess for that matter I could literally build two boxes and bolt/glue/screw them together couldn't I? How do you wire the subs then using one amp? Do you run wire from the amp to the each sub individually, or do you wire them together some how?

Danny Richie · « **Reply #5 on:** 9 Mar 2006, 02:51 pm »

Quote

I see, so if I wanted to I could stack one right on top of the other and build it that way. I guess for that matter I could literally build two boxes and bolt/glue/screw them together couldn't I?

You could, but I would join them as building them and not after building them. When I veneer them it will look like one box (as it is) and not like two.

Quote

How do you wire the subs then using one amp? Do you run wire from the amp to the each sub individually, or do you wire them together some how?

That's a good question with an easy answer. The subs are 8 ohms each. Just parallel them onto one sub woofer amp. Amp positive output to positive woofer terminal and to second positive woofer terminal. Amp negative output to woofer negative terminal and then to the other woofer negative terminal.

Blaine_M · « **Reply #6 on:** 9 Mar 2006, 03:07 pm »

Ok, I understand, sort of. So I run for example on the possitive side one wire out from the amp to the woofer possitve terminal, then from that woofer's possitive terminal to the other woofer's possitve terminal? Same thing on the negative side?

Brian71 · « **Reply #7 on:** 9 Mar 2006, 04:09 pm »

Yes.
When you have 2 8ohm woofers and you wire them like that, it's called "parallel" and results in a 4ohm load on the amp, which is fine. Wiring in parallel results in the impedance being cut in half.

Danny Richie · « **Reply #8 on:** 9 Mar 2006, 04:11 pm »

Blaine,

It was just like when you wired your A/V-3's. You wired the two M-130-16 woofers in parallel.

Blaine_M · « **Reply #9 on:** 9 Mar 2006, 04:17 pm »

Ok, that makes sense. We are working on my friends sub/pr this weekend, I'm curious to see how it will sound. Is that amp you have linked on the GR site enough to two subs?

justinc2 · « **Reply #10 on:** 9 Mar 2006, 04:18 pm »

I am almost finished with a design that might be what you are looking for. It uses 2 subwoofers with 4 of the passives, and a rythmic a350 amplifier in a large enclosure.

I added 500grams of weight to each PR to get the tuning down around 14hz. This provides a response that is -4db at 16hz and -6db at 12hz. If you use the boost/rumble filter on the amplifier set to 14hz you will get a -2db point near 14hz!

I decided to break it up into 2 seperate enclosures to make them easier to move( each one weights well over 100lbs. Each enclosure measures 14"x24"x48" or 5cuft net.

The front and rear baffle is 2.25" thick using 2 layers of mdf and 1 layer of birch ply. The front baffle holds the subwoofer and 1 PR, while the rear baffle holds the 2nd PR directly opposite the PR on the front, and the amplifier. The amplifier was sealed of from the rest of the enclosure by building a 5" deep by 14" long chamber. This chamber also needs to be built into the box without the amplifier so they contain the same internal volume.

Braces were put every 6" The inside was then sprayed with a rubberized sound deadening spray, and the walls were lined with acoustic foam. I placed a small bit fiberglass insulation behind the woofer.

I'm in the process of staining them now so hopefully should have them done within a week.

Danny Richie · « **Reply #11 on:** 9 Mar 2006, 04:26 pm »

Quote

Is that amp you have linked on the GR site enough to two subs?

Yea, that amp will actually output 400 watts into 4 ohms. It will driver them just fine.

Blaine_M · « **Reply #12 on:** 9 Mar 2006, 05:14 pm »

My wife is going to kill me when I tell her I want to build this thing.....! You should have seen the reaction I got when I told her I was doing the AV 3's!