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Question regarding subwoofers

I have an RHLabs SB-1 that’s served me pretty well for many years and use with it with my Acoustat 1+1s. (Had it refoamed a couple years back.) As well as the 1+1s image, I’ve always been slightly annoyed by having a single subwoofer between the panels. When playing something with a large sonic image like orchestral music the setup works fine. However when playing something more intimate like Jazz it’s easy to "see" where the lower frequencies are coming from: The middle. As my listening has gotten more refined it’s getting to be less acceptable to me. So I’m looking possibly at a pair of smaller, powered subwoofers. Why powered? Simple: If I do this, I’d rather the ARC VS-110 just power the panels. So, my questions:

1) The SB-1 has a single 10 or 12" driver. I’ve seen subs anywhere from 8" to huge. What folks experiences been with a pair of 8-10" powered subwoofers? Too much? Not enough?
2) Did a pair of subs affect imaging much? IOW, could you discern enough left/right to make it worthwhile?
3) How tough was it to balance them?
4) Do I run another set of interconnects from my SP11? Or do I get a set of Y adapters to feed both subs and amp?

Let me close by saying that like with most things audio there’s going to be a lot of "it depends". I get it. But I’d still like to hear of folks’ experiences as I do see a lot of systems with subs.

As always, thank you much for your time and comments!

128x128musicfan2349
lalitk's avatar
lalitk
5,084 posts
 
“However I must disagree with your implication that bass is non-directional. I have moved the subwoofer in the past to different locations and please believe me when I say that I could tell you where it was (and wasn’t) in the soundstage.”

OP, It appears you missed the whole point. If your system is properly calibrated, you won’t be able to localize main speakers or subs in the room from your listen chair (sweet spot). Please read it again what @millercarbon and others are saying. And yes, two subs are always better than one (small or large) if you can’t accommodate 4 (DBA or Swarm setup).

“The one thing that really matters is the one thing you don’t mention: crossover frequency. It should be below 100Hz, and 80Hz is even better.

This is because bass this low in frequency, you cannot localize it. If a sub is putting out any energy above about 100Hz you will localize it and that is why your bass seems to be coming from one spot.

Below 80 you can’t tell where the sub is, you can only tell there’s more bass. Where the bass is coming from, your main speakers provide those location cues. Also since you can’t localize there is no L and no R.”


eganmedia's avatar
eganmedia
26 posts
 
I used to use a pair of Dynaudio BX30 subs time aligned and crossed over with my Dynaudio BM15as at around 80 hz as essentially a three way system.  If I sent full range to the BM15as and all the low end info to just one of the two subs I could absolutely tell where it was coming from.

Then I got a trio of JBL M2s (LCR) and a single JBL SUB18 located between the center and right M2 along the front wall.  The crossover is at 55Hz and there is no sense of directionality from the sub whatsoever.  If your mains are suitably full range to cross over that low you can't hear where the sub is located.
mijostyn's avatar
mijostyn
8,224 posts
 
Hi Musicfan, I used Acoustats with 2 SB-1's for years. The SB-1 has a downward firing 12 " woofer in what has been described as a Helmholtz resonating enclosure. It is a great subwoofer. It is bigger than most subwoofers now and it is passive. Your biggest problem is that you need at least two of them and finding a second one in good condition is going to be hard. 
Right now I use 2+2's with my own subwoofer system. Please visit my system page and have a look to get an idea. You have very much the same situation with your 1+1's. They are full range Line sources and require line source subwoofers to match them correctly. We can discuss this on the side if you like. 

Mike 
soix
8,770 posts
 
Below 80 you can’t tell where the sub is, you can only tell there’s more bass. Where the bass is coming from, your main speakers provide those location cues. Also since you can’t localize there is no L and no R.”
Totally agree, but one thing I’ve noticed — and I have no data or other knowledge to back this up — is that with one sub as compared to multiple I do notice what I’ll call a “pressure” difference coming from the direction of the single sub that doesn’t exist with two or more subs.  Everything “sounds” even, it just doesn’t “feel” as even, if that makes any sense.  Not sure if this was addressed at all above, but just a personal observation. 

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