[OldSchool1]

I would like some expert opinions to adding more subwoofers to my system.  My room is somewhat of a challenge acoustically but what I have sounds pretty darn good so far.  What I am trying to accomplish is filling the room with better/more bass.  See my room layout.  Scale is 1 square = 1 foot.  Front speakers are Paradigm Signature S2's, center channel is Paradigm CC-490, surrounds are Paradigm Studio 20 V5 and sub is REL T-9.  To further describe the room, behind the sofa is all mirror, to the left of the sofa is floor to ceiling wall to wall glass covered with vinyl vertical blinds closed anytime music or movies are playing, behind the TV is flat wall, fireplace is covered with textured rock and to the right of the sofa is open to the rest of the room.  Ceiling height in the living room is 10 ft and rest of the condo 8 ft.

The speaker placement is pretty good working around the rooms characteristics but the sub is what I'm working on.  The REL T-9 is in the corner behind the television  and front left speaker provides some really nice bass.  It fills the room nicely.  What I want to accomplish is more even bass throughout the room.  My thought is to add another REL T-9 and locate them on either side next to the sofa and add another higher output sub behind the television and left front speaker to output lower frequency information.  Using the high level connection on the REL for L&R channels will provide the musical blend for sure and low level for LFE gives the extra for HT. With the aid of a higher output sub behind the television and left front speaker it would be the icing on the cake I believe.  Thought about using a REL R-528 for this since it could be connected the same way using the high level and LFE connections.  I really love the musicality of the T-9 and for HT it does a nice job so I think complimenting it with a twin, moving them either side of the sofa and something higher output opposite behind the left front speaker would be complete.  My thinking is using the same manufacturers product things would blend easier and better than mixing and matching.  Otherwise I would only use a different brand for the behind the television (higher output) sub.

I have read hundreds of reviews and toyed with ideas like the Paradigm Seismic 110 which I have auditioned and wow does it put out some punch!  Another to consider are the Rythmik F15HP.  They really make a beautiful piece of furniture and they spec out impressively!  I am favoring the REL....

I need some opinions since this decision is an expensive one and I'd rather do it rite the first time cause selling and rebuying gets expensive!!!

 

Comments please???

[medium jim]

Hi Oldschool1:

Welcome to the Audio Circle and the Bass Place!  I'm sure that you will get some answers soon.  Please check out the Useful Link Thread as it contains many good links that will help. 

Thanks,
Jim

[JohnR]

I suspect that one on either side of the sofa would work pretty well... you could move the one you have there to get an idea. As long as there's no extraneous sound from the sub or anything nearby.

Possibly not what you want to hear but my suggestion would be to measure the sub that you have in all possible locations to get a better idea of how your room behaves, before making further purchases.

[JLM]

Three ideas:

One

Yes, play around with location as JohnR mentions.  The standard advice is to move the sub to where you listen, then move around the room.  Where ever the best sound is, is where the sub should be located.  I'd also play around with the location of the couch itself (pulling it away from the back wall) as you're bound to have a high pressure node there.

Two

As you have a square room (never a good thing for bass reproduction), consider room treatments.  The blinds won't help with bass.  I'd look to the acoustics circle for help (bass is really hard to deal with due to high energy levels and large waveforms).  I might suggest trying to make the room acoustically appear longer (especially behind the couch). 

Three

Try to read Floyd E. Toole's "Sound Reproduction".  Toole worked for the Canadian National Research Council for 25 years (that did tons of basic research to help audio companies in their country, like Paradigm, develop better product).  He then directed research at Harmon International.  In his book he really pushes the concept that bass frequencies behave like waves and that any room, especially residentially sized, have massive standing bass waves.  Think of pushing shallow water back and forth in a bathtub.  Depending on frequency and position the waves coming off the ends of the tub add to or cancel each other out.  The solution is a swarm of subwoofers (search this circle).  An easier solution for existing systems like yours might be this:

http://www.spatialcomputer.com/page6/page6.html

This is a freestanding sub that goes on the back/far wall that senses the bass and emits a 180 degree out of phase cancelling signal (eliminating the far end of the tub so that the waves can't return to add to or cancel each other out).  Frankly I said "might" because this is a fairly squarish room, the whole bath tub analogy may have limited application (but the swarm concept would still makes lots of sense).

[poseidonsvoice]

Both John and JLM are really on the mark here. I would strongly agree with JohnR's comments and would first do a nearfield measurement of the sub, i.e. place the mic about 1 inch from the cone of the woofer and take a measurement sweep from say 15 Hz up to 200 Hz, without smoothing. That tells you what the sub would be like (or at least as close as you can get) without the room involved. Then place the mic at your listening position, at the level of your ear and take another measurement (again without smoothing). Suddenly you see how badly the room affects the response. Now you know what the ideal measurement is, versus what your ear is hearing. Start moving the sub around, as people have advised, just a few inches here and there, can make massive differences.

It's a very educational experience. It's like you said...a quest. Read the articles on HIfiZine as well - they are indispensable! Use a microphone to capture what is really going on in your room!

Good luck to you,

Anand.

http://www.hifizine.com/issues/bass-integration-guide/

[roscoeiii]

Yes, find out where the room is causing dips in the bass response, and position your sub to minimize or cancel these spots out (or move them away from the listening position). Room treatments is another option, depending on how much decorating flexibility you have.

The main thing I would add is the possibility of DSP (Digital Signal Processing). Some subs seem to have this built in, or you can use devices such as the DSPeaker products. I use a DSPeaker Dual Core 2.0 as my DAC and for DSP. It automatically adjusts the bass (up to 500Hz), and then you can manually adjust other frequencies, and do some other fun tweaking. They also have sub-specific units, though I am not sure if those can be used with the REL's high level inputs (the real design strength of the REL, if you aren't using those I don't thing you are getting the best out of those subs).

[OldSchool1]

Thank you gentlemen for all the info.  Since its my living room, room treatments would be difficult to deal with.  I have considered getting the software, mic etc. to perform a frequency sweep but have not yet.  I think its about time I start collecting the pieces to see what I'm dealing with before going further.  Yes Mr. Roscoe I am using the high level connections as well as the LFE and set up my AVR to crossover the LFE at 100 Hz.  The LFE is defeated in 2 channel made so when I listen to a CD the only subwoofer information is from the main speakers as full range.  The Paradigm Signature S2's with the REL T-9 using the high level connection are very nice sounding.