Adding a second sub

[jeberhart]

I'm already running a Polk 450 sub out from a Denon AVR 3801, and tonight I decided to take advantage of Polk's offer to buy a PSW250 at a closeout price (it's being discontinued). My plan is to run the 250 in conjunction with the 450 -- I'm a bass freak anyway, and I think it'll help beef up movie soundtrack listening in particular. But a few questions for you wizards before the new sub arrives:

1. I was thinking of just setting the 250 atop the 450 to conserve space in the room, but is that a bad idea? If not, why not? These things are made to shake anyway, right? Could it hurt to mount the smaller 250 on top of the larger 450? And should I put a slab of something between them? If I don't mount them one atop the other, what's a better solution from an acoustic standpoint? On different walls? Same wal, firing same direction? My 450 now fires out at me, same direction as my front LRs.

2. I'm going to have to split the LFE out between the two subs. I know some of you are doing this. What kind of splitter are you using, and where did you get it?

3. Speaking of splitting the signal, in your experiences, has their been any signal degradation from doing that? Anything to keep in mind while running two subs?

I guess that's about it. Thanks in advance for your input.

[Dr. Spec]

Plop it right on top - it will add several dB and there will be no phase issues.

Use a Monster Y Splitter for $15.

There is no signal degradation.

Recalibrate and remember the 250 can't take the power that the 450 can so I'd run the 250 on the cooler side.

Doc

[trubluluc]

A second sub is a good idea, unless you're running a monster sub.
I'm runniing 2 psw450's, one in front, one in the rear.

I would think stacking them would be less effective acousticly than having one front and one rear, but no damage to do it that way.

I use a Y splitter, works fine, no loss of LFE signal.

-Luc

[Dr. Spec]

Stacking the subs is the most efficient means - it will add 6 dB of volume. No other config comes close to this - typically 3-4 dB, sometimes even less if phase hasn't been sorted out.

Doc

[jeberhart]

Y'all are terrific, as usual. Many thanks. I'll stack them up. I'm assuming phase switch on both subs should be set the same. The 450 is at 0 now; planning on setting the 250 the same way unless it truly sounds louder at 180. Can't imagine why it would if firing same direction as 450 and front LRs, though.

And yes, I'm planning on running the 250 cooler. The 450 ticks along just fine with volume knob set at 1 o'clock. I'll probably set the 250 at 11:30.

[mantis]

I agree with the good Doctor,
stacking them really works well.The last time I tried that was with 2 B&W asw1000 sub's and man it reallt worked out well.The phasing thing happens....but this method it will not.

[RBreak]

I used to run a PSW650 along with a PSW450. I had the 650 up front, and I tried putting the 450 just about everywhere else in the room--front, back, sides, and finally stacked on top of the 650.
Room acoustics of course make a difference, so others may vary, but having the 450 stacked on top of the 650 definitely sounded the best. No phasing problems and alot more volume. Good luck.

[jeberhart]

The new 250 came and I put it right on top of the 450. Works really well. In fact, this isn't a bad combo at all. Of course the 250 doesn't have a range as low as the 450, but that seems to be all right. What happens is that I actually hear low musical stuff like bass guitar and synths, along with low drums, through the 450. Interestingly enough, the 250 seems to add a presence with things such as the kick drum on a trap set, or floor toms, which is really what I wanted anyway -- more thump, more percussive snap. And it's really tight bass, too. Whether that's a function of its smaller size, power and range, or sitting up off the floor on the 450, I don't know, but the short answer is that the suggestion for stacking it was the right one. Thanks again to all.