Running two subs

What kind of receiver do you have? That is a great option I wish I had. I would run them left and right, then you are getting stereo bass from your subs. I would love to hear how that would sound and if it would make much of a difference that running them in a mono setting.

I'd run mono unless you cross over very high. Our ears cannot tell direction of lower frequencies, so stereo won't do anything for audible spaciousness, while mono should maximize the ability of the 2 subs to compensate for room effects.

I would think along the same line as he his. I'm not sure if the left and right setting accomplishes the same thing as setting your sub's phase to 0 and 180 when you're running dual subs? Anybody could clarify on this?

Cheers

I run dual subs up at the front of my theater and a single sub in the rear. I get the best response having them all set at 0 phase. You are correct about the low frequencies not being directional so now that I think about it that way, running them in stereo will probably have no benefit.

The other thing is that deep bass is not recorded in stereo hardly ever. The people who mix the sound for recordings know the vast majority of end users do not have a system that can maintain stereo from beginning to end. They also know that at frequencies under 80 Hz or higher, it is about output and not L vs. R, so you are dealing with a mono bass signal.

There may be some esoteric recordings with true stereo bass but I couldn't even begin to figure out which ones are fully stereo bass.

The other thing is that the goal with subwoofers is to avoid localization. You would have to go in the opposite direction for stereo deep bass to be perceptible.

You don't say where the locations will be. All rooms are going to be different, but, I have found having dual subs setup so they are symmetrical to the centerline running front/back, and thus to the center seat works best.
Then try them with L/R setup and then mono. And go with which ever sounds better to you.

I agree, that would be a fantastic option to have!! I want to know what type of AV he/she has too??

curious if anyone has a 2 sub setup with different subs? I read that if you go with a multiple sub setu you should use the same type of subs, but I'm running a front/rear setup with a Sunfire True Sub EQ as my front and an Outlaw LFM-1 EX as my rear and I wondering if there are issues with that that I'm not aware of. The bass sounds fine to me.

I have run a 2 sub setup with different subs in the past with excellent results. While different, both subs were very good performers. I never found that one sub was limiting the other, which is the biggest problem with running 2 different subs.

If your current subs sound fine to you, I think you are golden.

Heck NO... the snow can stay away!! LOL.. anyhow, good to see another S. Dakota friend around here Sounds like you have quite the receiver... I'm Jelious! I live in Sioux falls so you can hit me up sometime.... maybe a beer or two

The ideal setup with two subs is to place them exactly where your two fronts are. But since that's impossible, the suggestion is to place them slightly behind and outside the two fronts and let the receiver use a slight delay to the fronts. The reason is to prevent them from cancelling out the bass coming from the fronts. Particlarly at frequencies near the crossover for the subs.

It's not a good idea to have one sub in front of you and one behind you because they may cancel each other out at certain frequencies.

I'm glad you said that. I would have thought at the outset that some phase control would be required, especially given 3 subs.

I actually have my subs next and to the inside of my mains, which are just slightly behind the sub. With the time delays, which are set by the distances to the seating position, and auto phase on, cancellation is not an issue with my set up.


Ian

Actually, that is not impossible, depending on your mains. I've had two different sets of speakers (3-way, 24" tall) mounted to the tops of my subs. In the room I built in '97, besides the corners, the hot spots for the subs were where the mains were located. So in effect, I created full range main speakers.
L212 mounted


PT800 mounted


And at times, I've had both mounted, back~back, using a ball bearing between the sub box and removable top.

When I first set them up, I did what seemed an obvious thing to do. The two Klipsch subs up front were set at 0 and I set the Velodyne in the rear at 180. I run all three thru a Velodyne SMS-1 and when I checked out the response, I was getting a big dip between 40 and 60 HZ. When I flipped the switch on the Velodyne from 180 to 0 the dip leveled right out.

I thought THX recommends if you use 2 subs to position them in the middle of the wall. One directly in the center of the front wall and the other in the center of the back wall. I have tried this and it sound fine with some phase adjustment. I set the front at 0 and the rear at 180 but there was a big void of bass at the front row of seats. I changed the rear subs phase to 90 and it balanced out.

Don't use THX as the be all to end all. If you want to know about sub placement, read through the "Harman White Papers" concerning subs.

http://www.google.com/url?sa=t&rct=j...Lcfi3f9vh-4sYg

Or better yet, get some measuring gear so you can truly optimize sub positions, crossovers and phase using RTA. It's the only method that will guarantee an optimal setup. And it's a small cost, imo, compared to the cost of other gear and has the greatest SQ/cost advantage as well.

I don't think THX is the end all be all, I was simply making a statement concerning sub placement. Depending on your room layout placing your subs at the mid point along the front and back can work. I have done it and it did work for me. I simply like how two subs look at the front of a set up. I makes it look more balanced.

I believe the placement capricorn kid is using is listed as one of the preferred placements in the "white papers", also middle of 2 opposing side walls.

There are so many variables that factor into sub positioning and in properly dialing them in that any advise is almost pointless. Harman's research assumed a rectangular shaped room with all subwoofers being identical. So if your subs are differenent and/or your room isn't a sealed rectangular shape, then all bets are off. In my case I have a sealed rectangular room and positioning the subs at the mid-point of each side wall (I have two Rythmi F15 subs) was not the ideal location but instead they needed to be slid back so that they are just behind me location but still on each side wall. So why didn't their recommendation work - because of the presence of doors, windows and that only 3 of the four walls are exterior concrete blocks.

You will ultimately need a measurement device and test tones etc to find the best location and even then you may find that each sub has a slightly differenct phase, volume and even cross-over point. All this to say that no one can really help you (inclding me) because we don't know your room's layout, peculiarities, treatments, furnishings etc. So, get yourself a Dayton Audio OmniMic or XYZ acoustical measurement system to begin what will be an iterative process of placement->measurement->alternative placement->measurement etc.

good luck, and have fun learning in the process. Talking of reading, have you read Dr Floyd Toole's book? Might be a good starting point.