3 subs not worth it?

bigbassdave

bigbassdave

Full Audioholic
So a couple years ago I replaced a sub in my main theater room with a SVS PB-2000 and it blew my freaking mind. A couple weeks later, I added a second 2000. Again, mind blown. A few days ago I added a third and honestly, I can’t really tell a difference over two.

No worries as I’ll probably add it to my kid’s theater/arcade room at this point, but is this normal? Am I just into diminishing returns at this point?
 
S

shadyJ

Speaker of the House
Staff member
So a couple years ago I replaced a sub in my main theater room with a SVS PB-2000 and it blew my freaking mind. A couple weeks later, I added a second 2000. Again, mind blown. A few days ago I added a third and honestly, I can’t really tell a difference over two.

No worries as I’ll probably add it to my kid’s theater/arcade room at this point, but is this normal? Am I just into diminishing returns at this point?
The returns of multiple subs largely depends on optimal placement. You need to measure the responses and place it in a spot that best helps to flatten out the overall response.
 
bigbassdave

bigbassdave

Full Audioholic
Admittedly, I just stacked it on one of the others and set the dials to match as I had calibrated the two previous. Not a lot of placement options with these beasts in a living room. I’m sure you’re right though.
 
William Lemmerhirt

William Lemmerhirt

Audioholic Warlord
Well by stacking, it’s just like making one really big subwoofer taking away the benefit of smoothing the FR that multiples provide. It will add up to 6db output though.
 
Verdinut

Verdinut

Audioholic Ninja
Well by stacking, it’s just like making one really big subwoofer taking away the benefit of smoothing the FR that multiples provide. It will add up to 6db output though.
Adding one speaker only increases SPL by 3 dB. However, if both drivers are powered by the same amplifier and if they are connected in parallel, the impedance is halved and the overall volume could be increased by up to 6 dB then for same input power.
 
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William Lemmerhirt

William Lemmerhirt

Audioholic Warlord
Adding one speaker only increases SPL by 3 dB. However, if both drivers are powered by the same amplifier and if they are connected in parallel, the impedance is halved and the overall volume could be increased by up to 6 dB then for same input power.
Well correct me if I’m wrong. But putting a subwoofer in a corner is 1/4 space, netting +3db for each boundary interaction. I didn’t see how to account for that in the calculator you linked. I think in actuality the gains usually are between 4 and 6 db but like everything, it’s usually not that simple.
 
lovinthehd

lovinthehd

Audioholic Jedi
I'd find another place in the room to place the third sub, as it doesn't seem to offer any particular advantage as placed now. If you find a better spot in terms of improved performance (smoothing room modes more than spl is the usual advantage of another sub) then great, but if not then using it in another room could be a good solution.
 
Verdinut

Verdinut

Audioholic Ninja
Well correct me if I’m wrong. But putting a subwoofer in a corner is 1/4 space, netting +3db for each boundary interaction.
If a woofer is in a corner, the overall output is increased by 3 dB, but adding a second sub cabinet on top won't add another 3 dB because it's in the same corner.
 
William Lemmerhirt

William Lemmerhirt

Audioholic Warlord
A theoretical rule is not necessarily what happens in practical purposes.
That’s true. But Ime it’s pretty much a rule of thumb, and I believe that’s the case and seems to be supported by Genes recommendation above. I also believe the literature in the article to be correct and reflects what I said.
 
bigbassdave

bigbassdave

Full Audioholic
I'd find another place in the room to place the third sub, as it doesn't seem to offer any particular advantage as placed now. If you find a better spot in terms of improved performance (smoothing room modes more than spl is the usual advantage of another sub) then great, but if not then using it in another room could be a good solution.
You’re right and will likely go that route. I found this third one on OfferUp and jumped on it. I figured I’d find a spot for it either in the main room, kid’s arcade/theater or the bedroom. Tried it in the bedroom and my mother in law came running over asking why her pictures were falling off the wall. Switched over to a sealed Triad in there and it’s great. If I can’t find a spot in the main room that makes sense, it’s going to the 10 year old. He’s desperately hoping that’s the case.
 
Verdinut

Verdinut

Audioholic Ninja
That’s true. But Ime it’s pretty much a rule of thumb, and I believe that’s the case and seems to be supported by Genes recommendation above. I also believe the literature in the article to be correct and reflects what I said.
IMO, you will not gain 9 dB because you put a subwoofer in a corner with a second one. The gain with the corner placement cannot be more than 3 dB, no matter how many drivers you have in the corner. That is independent from the gain which occurs with the addition of drivers. My reasoning concurs with Gene's opinion as he referred to a 6 dB gain, not a 9 dB gain, no?
 
William Lemmerhirt

William Lemmerhirt

Audioholic Warlord
IMO, you will not gain 9 dB because you put a subwoofer in a corner with a second one. The gain with the corner placement cannot be more than 3 dB, no matter how many drivers you have in the corner. That is independent from the gain which occurs with the addition of drivers. My reasoning concurs with Gene's opinion as he referred to a 6 dB gain, not a 9 dB gain, no?
Well then we agree. I also said 6db and unless you can show me where I said 9, then we’re good.
 
3db

3db

Audioholic Overlord
To the OP, you need REW, a USB measurement mic to measure in room response. This CANNOT be done by ear. With 3 subs, you will also need something like a MiniDSP 2x4HD to integrate the subs into the system and room.

Room geometry, layout and location of the seating position relative to sub placement will dictate how much gain one will get with multiple subs.
 
Verdinut

Verdinut

Audioholic Ninja
Well then we agree. I also said 6db and unless you can show me where I said 9, then we’re good.
You put one subwoofer in a corner and that gives you a 3 dB gain. Adding a second sub on top of it will give an additional 3 dB, but no further SPL increase of 3 dB because it's added to the corner. That's the way I understand it.
 
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