[tlarwa]

I'm looking for help/advice on an appropriate/optimal sub set-up for my listening room. I recently completed the build of a pair of Decware ZOB speakers (see them in this thread: http://www.audiocircle.com/index.php?topic=130284.0). I'm pretty happy with them so far (even though they have a ways to go before the TB W8-1808 drivers are broken in). That said, and as others have noted, they can use some help in the low end. I currently have them paired up with my Adire Audio Rava sealed sub, with some success. But I'm interested in building a pair of stereo subs, or at least a pair of subs run in mono. I have been looking at an H or U frame build, but a concerned about having enough space in my listening room to maximize their performance. The ones I've been considering would use the Eminence Alpha 15" woofers and plate amps. I started thinking about OB subs since they are OB speakers, but since the bass on the ZOB's is more similar to a traditional cabinet, I'm open to sealed subwoofers as well (which may be a better fit due to space constraints).

Here's the details of my room and equipment set-up (this is a dedicated listening room, by the way). The attachment shows the room in a previous iteration (a while ago) but it gives an idea of what I'm trying to describe:

Room dimensions are 12' x 17' with 7'6" ceiling
Equipment is on one of the short walls (audio rack and turntable stand)
Room is "live end/dead end" treated, with Superchunk corner traps in corners of wall where the equipment is , as well as absorptive panels on wall between the traps (behind equipment) and at the first reflection points on the side walls and ceiling. There is one absorptive panel on the back wall (behind my listening position) that I'm thinking about replacing with a diffuser.
The ZOB's are currently placed 40" from the front wall (to center front of the baffle) and 26" from the side walls to the center of the driver, with slight toe-in. The Rava sub is between the right speaker and my equipment racks (which are between the ZOB's on the front wall).

So, I don't have enough room for both subs to reside between the ZOB's and my equipment racks (only on one side is there enough space) at a similar distance from the front wall. I do have room to place subs 3' to 6' from the front wall, but only 0" to 12" from the side walls to the side of the cabinets. Any further out from the side walls and they'd be in the middle of my room and in front of my listening position, for the most part. I think the distance I could place H or U frames from the front wall would be okay, but I'm concerned they'd be too close to the side walls (from what I've read).

The first pic I attached hopefully gives some idea of the rooms layout (it's an old pic with old equipment).  The second pic shows the room fairly recently with the ZOBs in it.

Given my room dimensions, equipment location and the OB speakers I'd be using the with, what suggestions does anyone have for a set up that would be optimal for my situation? I look forward to reading any and all input!

Tom

[Tyson]

Side wall and rear corner would be a good place to start.  You already have 2 bass producers in the front of your room (your speakers), so best to spread things out a bit.

[Wayner]

I am farting around with finding a new sub location for my system as well. I have the REL T5 and they say to put it in the corner. But I can close my eyes and point right at it when the music is playing. So I don't think too much of the "bass is omni-directional" theory (unless the bass is really, really low). So, now I'm back to putting it in between the front mains, but I've always been told that is a bad idea, because the sub will build a "pressure ridge" between the mains and hose up the stereo imaging/sound stage. The one thing I have going for me is that the REL is a down-firing sub, so that may not be as much of an issue. Like Tyson suggested, start in the corner and go from their......

[*Scotty*]

Here is an approach that works assuming you have a rear wall in your room that you can place one or sub-woofers against.
See link to PDF DOC. http://vbn.aau.dk/files/12831869/AC-phd.pdf
Scotty

[JohnR]

@wayner, localization of sub can be caused by:

A. Crossover not steep enough. The common 12 db/octave in plate Amps is not steep enough, 24 is necessary.

B. Distortion generated in sub

C. Extraneous noises in sub - buzz, rattle

D. Nearby objects vibrating, or even the drywall/framing/floorboards

E. Sub level set too high, which exacerbates all of the above.

[JohnR]

Given my room dimensions, equipment location and the OB speakers I'd be using the with, what suggestions does anyone have for a set up that would be optimal for my situation? I look forward to reading any and all input!

Tom

Hi Tom, I would try right behind the sofa. It looks like it might be feasible in your situation. You will need a DSP crossover or an amp with DSP in it for best results. However this as all other suggestions would be a starting point only, measurement will be needed. I'd suggest drawing up a plan of the room, marking possible locations for subs, then measure all of them (or at least, likely candidates). Then you will know. Pick the best, and experiment with small position changes. In my room, front and rear wall centre work best (behind the chair not being feasible).

[Mudslide]

I'll second the measurements-required suggestion.  Or the "crawl technique" works but is hokey in my mind.  To avoid those things, I think you might want to look at the award winning DSPeaker AntiMode 2.0, which provides automatic room correction for multiple subs...and SO much more.  Check it out, here ... http://www.dspeaker.com/en/products/20-dual-core.shtml

If I had your room, I'd start with two subs...one where yours currently resides, and one opposing it on the back short wall.  If you have enough room to pull them out from corners a bit, then corner placement for each (in opposing corners) would be ideal.

Good luck with your quest.

[tlarwa]

I have room to leave one in the current location, and another on the back wall (more or less centered).  I can't do opposing corners though, since I have the bass traps on the front wall and a fireplace and door occupying the corners of the back wall.  I'll check out the DSP that was recommended.  I've also been considering the minidsp unit, which has gotten good reviews. 

What about the subs themselves?  I have 2 available to me now; the Klipch SW-10 that is shown in the picture, and an Adire Audio Rava sealed sub (she's a beast), which I recently hauled into the room (it's typically my HT sub).  I'm thinking about building a couple small sealed subs.  Or, I could look for another matching SW-10 (it's a forward firing driver/passive radiator design).  I was originally thinking OB bass to go with the speakers, but I don't have nearly enough room to move them out from the walls.

[Mudslide]

I have room to leave one in the current location, and another on the back wall (more or less centered).  I can't do opposing corners though, since I have the bass traps on the front wall and a fireplace and door occupying the corners of the back wall.  I'll check out the DSP that was recommended.  I've also been considering the minidsp unit, which has gotten good reviews. 

What about the subs themselves?  I have 2 available to me now; the Klipch SW-10 that is shown in the picture, and an Adire Audio Rava sealed sub (she's a beast), which I recently hauled into the room (it's typically my HT sub).  I'm thinking about building a couple small sealed subs.  Or, I could look for another matching SW-10 (it's a forward firing driver/passive radiator design).  I was originally thinking OB bass to go with the speakers, but I don't have nearly enough room to move them out from the walls.

You are wise to use two subs, as they will tend to cancel peak and null modes...somewhat.  That's why the Anti-Mode is so cool.  It'll flatten your room bass response fairly precisely. 

Since you already have an SW10, I'd try another one.  They are affordable (but aren't the best for music).  Your budget should make the call on subs.  If you can afford them, a pair of Rythmyk sealed subs would offer musical bliss.  If you have the DIY bug, you can build some decent subs with the right drivers and amps, or use kits from the likes of GR Research.

[rollo]

   You can use two as suggested . One as is one behind sofa. For now as an experiment run the rear sub out of phase and the front in phase. I would meld the mains and the front sub first. Meaning getting a linear sound with neither the sub or mains standing out.
     Once you get that to your satisfaction dial in the rear. Just enough volume to fill the room without taking over. A start and learning experience. Your room is small. Two subs may be to much. Experiment and by all means have fun doing so.


charles

[Mudslide]

   You can use two as suggested . One as is one behind sofa. For now as an experiment run the rear sub out of phase and the front in phase. I would meld the mains and the front sub first. Meaning getting a linear sound with neither the sub or mains standing out.
     Once you get that to your satisfaction dial in the rear. Just enough volume to fill the room without taking over. A start and learning experience. Your room is small. Two subs may be to much. Experiment and by all means have fun doing so.


charles

Good call on the 180 phase settings, Charles.  And I agree, two subs may overwhelm that room.  BUT...two subs also would tame some peaks and nulls.  One sub with the Anti-Mode would work well, but be more expensive than a second SW10.  A single sub also makes localizing more likely.

Working with subwoofers is such a fun yet goofy project.   

[rollo]

    One night I decided to use the crawl method. Unaware my Wife walked down the stairs as I was crawling and listening for the sweet spot. So she says let me help you look for ??? Nah honey did not drop anything checking for bass output.
    Running back up the stairs yelling "that's it he's gone" Audiophile insanity" and me saying "I got It" " I got it" "Yeah you got it alright". The result ? Less boom in da room.

charles

[tlarwa]

I've been watching for another SW-10 to come up for sale locally for a while now,but haven't ha any luck.  Because of my space constraints, I'm leaning towards building a pair of small sealed subs, using an 8" or 10" driver.  Any suggestions, or can anyone point me to a good box/driver pairing? 

[Wayner]

I'm wondering if my room is too large for the sub to be in the corner (28 X 32), I'm on the long wall...

[Mudslide]

I'm wondering if my room is too large for the sub to be in the corner (28 X 32), I'm on the long wall...

Short answer...no, it's not.  First, corner placement, if moved a bit away from the actual corner, will not generate boominess in the bass.  OTOH, if your subs are a bit weak, you'll want the sub(s) deep IN the corner which will generate corner loading of the bass frequencies (but have a bit of bass bloom).  If you have two powerful subs, perhaps like SVS Ultra(s), you can keep them a little away from the corner(s).  My room is the size of yours with a vaulted ceiling.  I have placement restrictions (WAF  ) and have mine in the opposing corners...but one behind the corner placed video/audio setup, and one kitty-corner in the back.  Lovely bass from my brace of SVS PB12 Plusses.

I think you spoke of being able to localize the sub in your room.  For certain you need to either move the unit, or better yet...buy another.  Your REL is undersized for pressurizing that large room of yours.  And I would also suggest that you crossover to the sub at 60 Hz at the highest...the lower the better (of course depending upon your mains).  Below that, the bass source is less distinguishable. 

Subwoofer placement is more art than science I sometimes think.  But gear like the Anti-Mode make it idiot-proof for decrepit old geezers like me.

[Wayner]

I have Martin Logan reQuests as the main fronts. I almost never use the system for movies and the REL is certainly not underpowered. I use the sub to extend the bottom end of the MLs, which it does do very well. It's the localization of it that is the problem. I have since moved it to a position in between the mains and the directionality of the sub is gone, but I'm not sure of it's effects on the mains' imaging. My old sub sat the outside of the left speaker and integrated perfectly. I will listen to this configuration this weekend and see what happens. I do agree that sub placement is more art (or luck) then science. BTW, my room is irregular shaped on the left side and I'm sure that is throwing a monkey wrench into the whole equations.

I really don't like bringing in new stuff.......

[JohnR]

Because of my space constraints, I'm leaning towards building a pair of small sealed subs, using an 8" or 10" driver.  Any suggestions, or can anyone point me to a good box/driver pairing?

Hi again, FWIW, instead of building two subs I would use two drivers in the one box, like this: http://www.audiocircle.com/index.php?topic=123611.0

With regard to specific drivers, this PE 10" driver looks like a good candidate:

http://www.parts-express.com/dayton-audio-rss265hf-4-10-reference-hf-subwoofer-4-ohm--295-460

I've not used it but it's what I'd try if I were building another 10" sub. There's also an 8 ohm version (choice depends on your amp configuration):

http://www.parts-express.com/dayton-audio-rss265hf-8-10-reference-hf-subwoofer-8-ohm--295-442

To calculate box size, download Unibox.

[Mudslide]

I have Martin Logan reQuests as the main fronts. I almost never use the system for movies and the REL is certainly not underpowered. I use the sub to extend the bottom end of the MLs, which it does do very well. It's the localization of it that is the problem. I have since moved it to a position in between the mains and the directionality of the sub is gone, but I'm not sure of it's effects on the mains' imaging. My old sub sat the outside of the left speaker and integrated perfectly. I will listen to this configuration this weekend and see what happens. I do agree that sub placement is more art (or luck) then science. BTW, my room is irregular shaped on the left side and I'm sure that is throwing a monkey wrench into the whole equations.

I really don't like bringing in new stuff.......

Wayner, I didn't mean to disparage your REL.  It's a fine sub.  It's just that NO 8" subwoofer is going to pressurize that huge room of yours.

[JLM]

Search Audio Circle for "swarm".  There's good science behind the need for multiple subs to provide the only possible means for flat in-room bass response.

End of story, everything else is pointless.

[Wayner]

Wayner, I didn't mean to disparage your REL.  It's a fine sub.  It's just that NO 8" subwoofer is going to pressurize that huge room of yours.

No offense taken' there, Mudslide. My comment was more to the "bass seems adequate" side. The room size helps to develop wave lengths on the long order. My T5 is supposed to go down to 23 cycles. The Martin Logans are supposed to go down to 30 cycles so, I'm not asking the sub to do that much, just re-enforce that tiny little bit at the bottom, to give the MLs some feel. I have the cross-over at about 40 and the volume at 1/4 of the range, so there actually seems to be plenty of power for its mission.

I listen to digital music in this room, in a 4.1 system controlled by my soon to be vintage Sony TA-e9000 ES preamp. The power amp is the Sunfire series II, 2 channel w/300wrms per channel. The REL is wired according to the preferred method by REL with the signal coming from the amplifier via a special Speak-on connector to the sub's high input section. The main and rear speakers are put to large on the preamp, and I have a "phantom" center channel, generated by the Sony preamp, in case I want to watch some 5.1 DVDs, TV (via antenna) or BR.

My old sub was an AR sub with a 300 watt Sunfire plate driving a down-firing 12 woofer in a ported enclosure. That sub integrated well into the system. It sat about 18" from the rear wall and a couple of feet from the left speaker. When I replaced it with the T5, It went into the same location, but I felt very edgy about the performance, so I moved it to the recommend corner. Unfortunately, the left corner does not have a nearby outlet and due to WAF, did not want to run an extension cord over there, so I moved it to the right corner. There is a small couch over there and I think the subwoofer was kind of "boxed" in there and that is why I heard localization of it. I appreciate JohnR's points, and I don't think I had any issues that he brought up except for point one, being a steep cross-over point.

The compromise position (in between the mains) seems to have solve the localiztion problem, but perhaps I do not have quite the depth that I wanted. I do not understand the technique of crawling around on the floor.......