Can I mix my RT-12d with a SVS PB-13Ultra?

[thecutter]

My RT-12d just doesnt hit low enough for me. I want to get a SVS 13Ultra. I heard mixing subs is hard. I would put the SVS in the front field with my RF-63's and RC 64. I would put the RT-12d Behind the couch behind me. I would use the RT-12d as a near field sub.

ANY ideas ? The EAR?

[wuzzzer]

There are several problems with using two subs, especially two very different ones. One problem with putting one sub way up front and one directly behind you is the bass from the sub behind you will reach your ears first. If you want things to sound their best you have to artificially delay the signal going to the rear sub so that each sub's information reaches your ears at the same time. There are digital signal processors you can buy that will let you do this.

Phase cancellation is also a big issue with a setup like you're describing. Two subs playing the same bass information can sometimes cancel each other out, resulting in less bass at your listening position than if you stayed with one sub. Those subs do have phase control though so you should be able to take care of that without too much difficulty.

If you want to make it easier I would sell the RT-12d and buy two PB-13 Ultras and put them both up front next to your RF-63s.

[The Dude]

Well i guess this explains why the guy at the ht store around here gave me a funny look and didn't recomend that.

[Mic Stiffy]

Well, you never really know until you try. There are a lot of variables (room, reciever features, position, etc). Give it a try and let us know!

[thecutter]

I've seen smaller subs used as near field subs. I believe HSU markets the MSM? as such a product. So why won't the RT-12D work in that capacity?

[Mr. RF62]

I'm using two different subs, one behind the couch, and the other about 6ft in front of me to the left and only 2ft infront of the mains. It sounds fantastic, only thing is I've had to continuously tweek the phase, but I finally got what I've been looking for yesterday(benn at this phase issue for about 5months). I had to have the levels right as the front sub is playing more midbass than the one behind the couch. I put the bigger one behind the couch to give effect, x-over at 40Hz, and the front sub x-over is bypassed. I played with the phase on the rear sub for a long time before I set it where it is now so it don't sound "located" as the front one does, it may also be the fact that the front one is easy to locate that takes the attention off the rear sub.

[wuzzzer]

I've seen smaller subs used as near field subs. I believe HSU markets the MSM? as such a product. So why won't the RT-12D work in that capacity?

The Hsu MBM-12 is a mid-bass woofer. The MBM is designed to play frequencies from 50Hz on up to whatever the user selects as the top end crossover point. The other subwoofer used with an MBM is supposed to be crossed over at 50Hz at its highest bass output point and will then play bass information from 50Hz on down. That way the subwoofer's output frequencies don't overlap each other and cause phase cancellation issues.

Case in point: I have my subwoofers and Fortes crossed over at 80Hz. Now, my Fortes have pretty strong bass output below 80Hz but my subwoofers have even better output down there. If I lower my Forte crossover point too much below 80Hz guess what happens? I actually hear less bass output at my listening position compared to leaving it at 80Hz. You'd think that I'd have more since both Fortes and both subwoofers are ouputting low bass information, but phase cancellation rears its ugly head and again the end result is less bass output.

I'm not saying it wouldn't work, but I'm saying integrating two subwoofers, especially two from different brands and of totally different designs can be quite a headache.

[nola]

Wuzzer,

Can you elaborate on this:

If you want things to sound their best you have to artificially delay
the signal going to the rear sub so that each sub's information reaches
your ears at the same time. There are digital signal processors you
can buy that will let you do this.

Specifics on the processor names/types/models and approx prices might be nice )

This or next weekend, I can finally begin reclaiming my 17 x 40 ft main room, high sloped ceiling too. Current plan, subject to change:

K horns (trachorns arrived but waiting on Crites caps) up front w acad or LaScala center and Heresy I rears.

2 x 18" cab sub front rt center. Madison Amps brand-metal band cab

2 x 18" cab sub mid, behind couch a bit too, far lt wall

1 x 18" behringer rear center or rear right, in front of kitchen

intend to xover at 60-80 Hz from my Outlaw Audio 990 pre pro

Sub amps: 1000w rack type from parts express x 2 for the dualies and 500 w plate type for behringer. Phase can be modified on all 3 amps. But agrree, timing will pose an issue. Ok, 5 18" drivers are a bit much, "...but got a great deal on these....(frying pan in the air, aimed at head)."

Any suggestions most welcome.

[wuzzzer]

I believe Behringer makes a digital DSP module that allows you to select crossover points, speaker delay in milliseconds, etc. I think the rule of thumb is 1 millisecond per foot of distance.

Obviously you can try everything without something like that first and see how it sounds.

http://www.guitarcenter.com/Behringer-Shark-DSP110-182463-i1125202.gc

Something like the above-linked device lists features such as:

• Delay line with up to 2.5 seconds of delay, adjustable in meters, feet and msec.
• Subsonic filter with adjustable cutoff frequency
• High-resolution 24-bit A/D/A converters

[Jay481985]

Guys, he has a RT-12D which has another audio out for a subwoofer. Just get another coaxial cable and let the RT-12D room calculator do its work. Surprisingly it does it quite well from some non klipsch employee subwoofer experts.