1 sub vs. Dual sub dilemma

DavidHuguet · 07-11-2007, 07:25 AM

Ok, I have a 25-31pci that’s a couple years old and working fine. We bought a house a couple years ago and I’m remodeling a room downstairs to be a home theater/media room. It’s approx 30’ x 13’ x 8’ high. I am going to do frequency analysis and room mode analysis to figure out where to place a subwoofer for optimum flatness, along with some bass absorption…but my question is this:

I’d like to go lower in the frequency range. Would I be better off getting 2 subs, like two 16-46 pci’s, or one larger sub like a pb12+2 to fill this room? Without price factoring in (I’d probably buy used if I could), would the performance be equivalent? I realize that the dual subs can be placed to eliminate modes and such, but do two subs not need to be quite as beefy, since there are two?

Thanks,
dave

SherardP · 07-11-2007, 10:14 AM

I went dual PB12+Plus 2's and the bass is surreal. If your room is big enough go for that. My room is the largest but that amount of bass is no joke guy. Im also using the Velodyne SMS-1 to get the best performance of them as well.

troy evans · 07-11-2007, 01:58 PM

I have 2 subs, Velodyne CHT-8 in the front left all the way to the wall with a 2"space between it and the wall.That sub is fired straight forward down that wall.Then, I have a far less impressive Yamaha YST-SW215 caddy-cornered behind Me on the left hand side.That sub is fired into the room at that angle. Even though it's cheaper and less powerful it compliments the Velodyne very nicely in My set-up.So I think it's more benificial if the subs are not equal in power but I do like the 2 subwoofer effect.For My space which is 20x15x9,It works very well.My subwoofers were not super expensive or the absolute best but I can't imagine tighter or more accurate bass even with higher end models.Just My Opinion.

Kevin C Brown · 07-11-2007, 07:26 PM

Two subs vs one won't get you any deeper extension. But you might get a smoother in-room response. I say "might", because if you're not careful, you can get interference between them and worse peaks and valleys than just one in the optimal spot. If you're going to do 2, I highly recommend ETF5 or something like TrueRTA to do this right. Or, plot your response with a Radio Shack meter and a discrete test tone CD. Regardless of how many people say that 2 subs sound better than one, it is simply not that easy to get the integration down. Not only does each sub have to be integrated with the main speakers in terms of level and phase, they have to be matched up to each other too. And then you have to worry about how everything is crossed over, and how flat that frequency response is.

douglas-b · 07-11-2007, 08:14 PM

2 subs do sound better than one and don't believe the hype the boys at SVS will give you a very easy way to set up 2 subs. It is NOT hard at all. I had one 20-39 NSD and came into some extra money and added a second one and all I've got to say is I thought I had bass before! I would get a second 25-31pci if I were you. You won't be sorry at all. My room is real close to the size you stated. With all that room you can run a pair "a little" hot and still have a bunch of head room to play it loud...

**HTF Ads**

troy evans · 07-11-2007, 10:45 PM

Most of Us with 2 subs started with one so We know how different the low end between one vs two subs is. A very important question I'd like to ask You is, Do You want Your bass to merely be an extension of Your 2 front speakers ? If so You'll only need one subwoofer right up front near them. Now, if You want bass You can feel without cranking the hell outta one subwoofer till the whole house shakes, or You don't want to spend $1000.00+ to get a super sub,Then, 2 subs even at modest prices will do a fantastic job. One of My favorite '"subtle" bass tests is the lightsabre battle between Darth Maul and Qui-gon,Obi-wan in Episode I.When I got My second sub for My system and set it up as a rear low end subwoofer I could feel the sound in My chest from those "sabres" humming. You're going to have to decide how low of a response You want. After that It'll be easier to decide what kind and how many subs You want.There is the possibility You don't need 2 subs. You won't know until You get everything calibrated.After You do that along with the other steps You mentioned it may be sweetin' nuff.

DavidHuguet · 07-12-2007, 11:17 AM

I'm thinking of 2 20-39pci's now, based on ed mullen's saying that the 16-46 is really only for pipe organ aficionados...I'm thinking of placing them as the attached pdf shows to tame some room nulls/modes.

now just need to find some...
dave

Kevin C Brown · 07-12-2007, 07:24 PM

Quote:

Most of Us with 2 subs started with one so We know how different the low end between one vs two subs is.

Wrong. If you have two subs that are -3 dB to 20 Hz, for example, how is that going to get you any deeper extension? Two subs are good for more output, and possibly smoother room response. Not lower extension.

David- If you go to Harman's site, there is a well known white paper that talks about the best location for multiple subs. In general, it's opposite each other, 1/2 way along the longest walls. It might look wierd, but the best place for the sub you now have on the right, might be near the left front speaker.

Bottom line, is somehow you're going to need to look at your room's response once you get both running. Be careful.

Peaky bass (which sounds "good" to most people) is not good bass!

I'd also try to move those side surrounds a little bit more forward into the room if you can. Your room looks very similar to mine: 1/2 for HT, 1/2 for something else (in my case, for the kitchen). (If I was going to do 2 subs, I'd place them where the tile meets the carpet, front and back of the room, for example. But I keep holding off because I have pretty good response now. I have a little help with a pre/pro that has room EQ.)

troy evans · 07-13-2007, 01:28 AM

Originally posted by Kevin C Brown:
(Wrong. If you have two subs that are -3 dB to 20 Hz, for example, how is that going to get you any deeper extension? Two subs are good for more output, and possibly smoother room response. Not lower extension.)
My Response: First let Me state that nowhere in My post that You qouted did I say that 2 subs created more lowend.Don't read things into what I post that are inaccurate.I was simply saying that there is indeed more bass presence in a room with 2 subs because of the extension of the bass.2 subwoofers is becoming more and more recommended as time goes by for that very reason.Second, You Do Not put 2 subwoofers directly opposite one another because they will cancel each other out.I can't believe anyone would recommend that and if that's on Harmon's site then that most assuredly is Wrong.You don't put your crossover to 80(THX)just because someone tells You that that is the best crossover.The same goes for subwoofer placement.Every room is different,some have carpet,some have bookshelves,some have furniture arranged differently,Etc. All these factors have an effect on sound.Dave, The best way to find out where to place a subwoofer is a process called "Crawling for Bass".What You do is put the sub where You intend to sit in the room.Then,You play DVDs or CDs with good heavy bass.While that's playing You crawl around the room listening for where the bass sounds tightest and most natural.Bingo! That's where You put the subwoofer.Like I said before,once You get the sub You have going right You may find It's enough.You won't know for sure about getting another sub till then.Why waste money or Time if You don't have to,Right.