Dual subwoofer placement question

Posted by: nickbuol

Dual subwoofer placement question - 06/19/13 12:00 PM

I am building my 2nd sub (turning into quite a monster, but should be nice when done - pictures to come later) and was wondering if I am going to gain much with the second sub. It seems like the "Best" locations for a two sub setup could be one up front and one in the back of the theater, or one along the middle of each side wall. That won't work for me. I need to keep things up front behind my false wall.

So I am wondering if I will get much benefit from this or if I am just doing this to sound cool that I built my own sub, blah blah blah...

I saw this on another vendor's website, but wanted to run it past some "experts" here. The diagram isn't mine either, but shows the sub placement idea to match the words.


Try positioning the subs along the front wall with the woofer cone centers at the 1/4 and 3/4 distances of the room width. Rooms that are sympathetic with subs at these locations will yield almost as much bass output as corner placement but with a smoother overall frequency response. Of course, this reduces overall output compared to full corner placement, but most quality subwoofers nowadays have more than enough headroom to compensate.



Time to go watch the Axiom Multiple Subwoofer videos maybe.
Posted by: GregLee

Re: Dual subwoofer placement question - 06/19/13 02:21 PM

Some of the older literature on sub placement is aimed at maximizing output (which would probably mean putting the subs together in a corner), but my impression from reading discussions on AVSforum is that there is a consensus these days for getting as smooth a bass in-room response as possible, for greatest fidelity, and that would probably mean keeping them apart, not both in a corner, and perhaps at different heights. The advice I have seen is to measure the response and do some experimenting with placement.

I have three subs in varying positions, one in the middle of a wall, one out near the middle of the room, and one in a closet. I haven't measured -- too much trouble. I listen to some jazz with a walking bass line, and if the notes don't fade in and out as they go up and down the scale, I figure I'm on the right track.
Posted by: nickbuol

Re: Dual subwoofer placement question - 06/19/13 03:09 PM

Right, old school of thought is to slap them in corners and get reinforced sound waves (perceived as louder), but I am hoping to smooth out the bass more than anything. Not that I have any (known) major problems. The room is about 14 feet wide, so using the 1/4 "rule" means 3.5 feet from the wall to the center of the woofer. I will have to do some measuring tonight when I get home to see how that fits with the bass traps and so forth behind the false wall.

I am pretty sure that my current single sub (SVS 20-39PCi) is at least 5 feet from the one side wall, maybe not.

I have one of my construction photos showing the sub between the left front speaker and the center (my memory had it out side of the left front speaker, but...):



It would seem that the subs should sit about where the M60s are currently at, bumping them inwards a little. Keep in mind that this picture is from BEFORE I built the stands to raise the M60s up a little and to get the VP180 up a lot off of the ground (in line with "ear height").
Posted by: tomtuttle

Re: Dual subwoofer placement question - 06/19/13 03:51 PM

I think Greg's "perhaps at different heights" comment is brilliant.

Since you can't move them around the room much, you might be able to get the effect of diversified, non-symmetrical placement using the third dimension (height).

Hang that sucker from the ceiling.

I was thinking you were doing a Rhythmik sealed build. Did I dream that?
Posted by: nickbuol

Re: Dual subwoofer placement question - 06/19/13 04:18 PM

Originally Posted By: tomtuttle


I was thinking you were doing a Rhythmik sealed build. Did I dream that?


I was trying to think of a great response, but I couldn't so I will just say yes. You were dreaming.
Posted by: tomtuttle

Re: Dual subwoofer placement question - 06/19/13 04:33 PM

Wishful thinking, apparently.

Harumph. Well, if I already had a perfectly nice amp laying around, I'd probably use that, too.

I hadn't yet seen the other thread before commenting here.

Let us know how that PE 15" works for you.
Posted by: nickbuol

Re: Dual subwoofer placement question - 06/19/13 08:17 PM

It is actually a PE 12. Still going to be awesome... I hope...
Posted by: Socketman

Re: Dual subwoofer placement question - 06/19/13 09:09 PM

Nice setup nick, are there more pics in the gallery.
Posted by: JohnK

Re: Dual subwoofer placement question - 06/19/13 09:43 PM

Nick, as you say, for the best effect in minimizing room modes, placement at the midpoints of opposite walls(or in diagonally opposite corners)is best. If the subs must both be placed along the front wall, the 1/4 placing shown is correct. As discussed by Dr. Toole and others, that placement serves to minimize or cancel some modes related to the width of the room. It has no effect on the modes related to room length, and doesn't have all the benefits of the placements described above, but is worthwhile.
Posted by: nickbuol

Re: Dual subwoofer placement question - 06/19/13 11:46 PM

I do need to update the room photos now that I have the crown molding with color changing LEDs and the LED/fiber optic star ceiling. For now, I am going to go to my build thread and add some subwoofer build pictures.
Posted by: michael_d

Re: Dual subwoofer placement question - 06/21/13 01:41 PM

I have my two 500's placed on the front wall like the drawing. It was for aesthetics more than anything else, but they work well enough for me to now want to try anything different.
Posted by: nickbuol

Re: Dual subwoofer placement question - 06/21/13 02:03 PM

Originally Posted By: michael_d
I have my two 500's placed on the front wall like the drawing. It was for aesthetics more than anything else, but they work well enough for me to now want to try anything different.


Did you really mean "now" or did you mean "not"?

Also, did you go from a single sub to dual subs? Improvements?
Posted by: michael_d

Re: Dual subwoofer placement question - 06/21/13 02:36 PM

Fat fingers got me again.... Yes, I meant NOT.

I went from a single EP600 in this room to two 500's. I also had a third sub in the room (Outlaw LF1), but I removed it. It just did not blend well with the EP's. It was distracting.

LFE is smoother with the two 500's than it was with the single 600. I suppose there's a difference with regards to the lower frequencies the 500's do not reach that the 600 did, but I did not miss it. SPL level is higher running both by about 5 db than running one, but that doesn't really matter, as they are both dialed down to about 25%.

So yes, I prefer the two 500's over a single 600. My room is pretty small though. 12 X 18 X 8.5

Posted by: tomtuttle

Re: Dual subwoofer placement question - 06/21/13 03:40 PM

Look at all those speakers!
Posted by: SirQuack

Re: Dual subwoofer placement question - 06/22/13 09:31 AM

My 350's are up front, similar to how Michael has his and sound great alone, however, adding the 600 to the back wall makes a difference in overall smoothness across the room for all locations.
Posted by: J. B.

Re: Dual subwoofer placement question - 06/22/13 09:47 AM

they say the best is 6 subs.
Posted by: nickbuol

Re: Dual subwoofer placement question - 06/22/13 12:40 PM

Nice room, and that IS a lot of speakers. I image it sounds outstanding.

Randy, I will see about putting the sub in the back of the room, just as an experiment, however it will pretty much consume the whole walkway behind the 2nd row of seats and probably need a "pedestal" build to raise it up to at least be on the same "floor" level as the top of the riser.

Not sure how long that would "fly" with the wife, but maybe....

J.B., you are just silly. grin

I am sure that at some point someone will say that you need a sub in each corner and one in the middle of each wall (8 total) for the smoothest bass. We will all have Dolby Atmos in our homes by then I suspect.

I still say that laser actuated sound (laser beams actually focusing and creating sound waves right by people's ears will win over in speaker replacements some day for the home. The laser system can be so precise that the sounds aren't actually loud enough to be heard by people right around them, but just each individual, and based off of there position in the room. No more room acoustic issues for that. I will have to come up with some (crazy) idea about how to get the LFE delivered to the room so that subwoofers are a thing of the past too. crazy
Posted by: exlabdriver

Re: Dual subwoofer placement question - 06/22/13 01:16 PM

nick:

Will the lasers track my head/ears when I get horizontal on the couch?

TAM
Posted by: nickbuol

Re: Dual subwoofer placement question - 06/22/13 02:02 PM

Of course. Super sophisticated stuff. Granted it won't come out until we get a real Star Trek style Holodeck, but...
Posted by: Hansang

Re: Dual subwoofer placement question - 06/22/13 02:12 PM

And great for military/law enforcement use. You can talk to others w/o anyone knowing about it. Not to mention sending out 165 dB to your enemy! smile
Posted by: J. B.

Re: Dual subwoofer placement question - 06/22/13 02:39 PM

Nick: "J.B., you are just silly."

Thanks, i knew.
Posted by: SirQuack

Re: Dual subwoofer placement question - 06/23/13 10:38 AM

Nick, most likely you will find that the dual subs up front will be just fine...