Here's my proposed layout (pic); should I do 1 or 2 subs?

The most inexpensive sub, that's generally acceptable is the BIC F12. There's just nothing cheaper that would be acceptable. At around $200, nothing can touch it. Two of these would easily fit into your $500 budget, and you could scale up and purchase 2 more when the situation permits. There are many outstanding reasons to go with multiple subs. Optimizing the sub/room interface is difficult at best. Multiple subs makes this endeavor much easier, and generally brings with it a higher quality experience.

Also, there are single offerings of more powerful subs that would be fine to. They may exhibit more peaks and nulls in the room response, but they would be powerful, and adding more of them as finances allowed is always an option. Your room looks like the front two corners would allow for decent response, and likely about the best LF loading possible.

The ED A7S-450, a sealed 18" 1.3kw powered is a strong performer, and under $1k. The HSU, VTF15H is vented, at around the same price. The Epik Empire is a sealed dual 15 in the same price range.

This paper will illustrate why multiple subs tend to be optimum. It is an industry standard reference.

This paper is by Toole, and also illustrates the manner in which to optimize one's LF in room.

Learning about the speaker/room interface is key. Your room is odd shaped but you'll be fine.



Good luck

Not that I know of.

Many of us are just aware of the commercial products availed to us, and can just rattle them off. Their are many unsuccessful one offs, that don't get much chatter, but anything that can exhibit a solid performance/dollar ratio gets the attention of enthusiasts quickly...and that news travel fast. There are cost no object approaches as well, but oddly many of these under-perform for HT.

JL for example, superior workmanship, remarkable linearity, however they don't plunge the depths that the LFE standards require for contemporary soundtrack releases. Their F113, a revolutionary product in it's own right, however it has a -3db point whereby much lower frequency content would elude the listener.

Their flagship Gotham, a dual 13", 300lb masterpiece, it costs around $8K, and would be great in any system. It excels at music because music doesn't have the ULF requirements that HT does. It is an excellent product, by any standard...but, for extreme low frequencies that exist these days, there are better options for HT. For around $2k, one could get a Seaton Submersive. Larger drivers, more powerful amplifier, and it plunges about as deep as the material requires. So one could get 3 Submersives, which offers 12,000 watts across 6 drivers in technically superior dual opposed cabinets....all this and money to spare.

Study the differences that vented and sealed offer, and how each alignment would be best for your room. Learn how optimization will enable you to get a lot more out of your system. Don't discount the need for additional headroom. Headroom, or the gap between the operational level, and the max potential of the system, is the most critical aspect in proper sub-woofing. Headroom cures nearly all non-linearity issues. Rarely is someone regretful about buying too much sub. Oftentimes however, they realize they should have pursued a more robust product. Buy something that you can buy more of later, to increase in scale. A multi-sub approach is the theoretical ideal. Keep in mind the power ratio of 3db for every doubling in power. So power reserves get gobbled up fast with EQing, which every system needs. Remember that for every halving of frequency, a driver must quadruple it's excursion to maintain the same volume level.

The dynamics in HT, the wildly swinging levels exceed music substantially. 30db swings are commonplace. These dynamics must be tended to produce a realistic experience. This takes a lot of air movement,..there is no substitute for displacement. Explore DIY, and the incredible high value encountered in that arena.

I'll stop..too much caffeine.

Good luck and no, I don't know of a list of subs

If you're open to spending $1000 later on, then I think I would wait and spend $1000. In that price range you start getting into some of the real heavy hitters. Hsu VTF-15H, Elemental Designs A5-350, Epik Empire...

OR

You could buy one ~$500 sub now, then add another $500 sub later. Dual Hsu VTF-2's, dual Elemental Designs A3-300's, dual Outlaw LFM-1 Pluses... All good choices.

I think the BIC sub is probably good for people that just want one cheap sub. But if there's a budget for buying a higher quality, higher power sub, I say skip the Bic and go for something better.

That is a pretty big, oddly shaped room, so I think I would go for dual subs personally.

Very good points, however, what's good, and available at ~$500 The Epik Legend is in that area, but, not available.

This is a very interesting situation. Would a BIC $200 scale out, and be contending with a more effective solo sub. Four BICs against a HSU vented 15"...interesting. Thread worthy.

recommended subs thread (more appropriate for low-end)

http://www.avsforum.com/avs-vb/showthread.php?t=1246684

The above advice that individuals have given you is excellent.


Consider two Hsu VTF2.3s or two Hsu VTF3.3s. You have a very large area.

I don't personally have any experience with the 2x$500 vs 1x$1000 question, but I do know that it has been discussed here more than a few times.

From what I can glean from the threads I've read, it's a trade off that depends on your room. If you have an "easy" room with some good room gain and no big nulls, one big sub would give you more output and probably lower freq response. BUT, if you have a "difficult" room, dual subs would give you a more even response over the listening area.

There's also some math that I don't understand about co-locating subs (stacking them) vs having them in different areas of the room. I guess co-locating the subs gives you more of an output gain than two separated subs would, but I don't understand the theory on that... Maybe someone better informed than me can chime in on that.

Rule of Thumb: Two identical subs not co-located +3 db, tend to smooth out room effects. Two identical subs co-located +6 db.

This is frequency dependant. If two subs are less than 1/4 the wavelegth, cone center to center, they too enjoy the benefits of mutual coupling.

Interesting..... So if the subs are 6 ft apart, they would see a +6dB gain from 1Hz to about 47Hz, then +3dB gain from 47Hz on up?

The benefits gained for theoretical co-location aren't an all or nothing proposition. The manner in which these spl gains occur don't baseline at zero (given the 3db gain inherent to a second, like powered source), and jump to 6db at full co-location. It's a gradual process whereby the two distinct sources operate entirely separate from one another, and slowly sum to the total +6db due to constructive superimposition at the LP.

When two sources, sub-woofers in this case, are positioned relatively close to one another, whereby their acoustical centers are approximately within 1/4 wavelength, mutual coupling is the consequence. This mutual coupling sums their acoustic outputs over the frequency range involved (within 1/4 wavelength) and will couple combine and propagate as one unified waveform. The incremental nature of the constructive superimposition is due to the sources being increasingly in phase at the LP, then the two drivers essentially act as one larger, more capable driver.


In live sound at an outdoor event, we know two sources producing the same signal, regardless of spacing relative to one another, will mutually couple on axis and will result in a 6 dB increase in level. However, as the LP begins to move off axis, the coupling decreases as the distances from each sub to the listener increasingly change. Now the higher the frequencies involved, these changes occur much quicker.

Clearly, we see that the degree of the mutual coupling at any point off-axis is dependent on the sub spacing, and the frequency the sub is producing. This creates what we term "power alley". The on axis shotgun area whereby the LF is the strongest perpendicular to the stage. The are many methods to alleviate this, if one chooses to do so. To start with, one could utilize a single point source sub system. That method would alleviate any lobing and inconsistencies, however, those individuals close to the system would be experiencing much greater levels than any other seat Even nicely directional cardioid sub-woofer coverage patterns are easily achievable in which high levels of LF can be directed into the audience area, and off the stage where it is highly problematic. There are off the shelf cardioid subs, or one constructs an array on site via delay and proper box spacing.


Interesting topic.



Good luck

That's pretty cool. It's certainly another argument for multiple subs vs a single. Especially if the duals were close enough that they had the coupling effect in the the lower frequencies where lots of cheaper subs struggle. But it also highlights the need for at least a rudimentary EQ for multiple subs, lest the coupling effect get out of hand and lead to a big hump down low in the frequency response.

Regardless of coupling, every sub system can benefit from EQ. You've got to knock the boom down to the point whereby you can hear the textural qualities of the LF. More head bob, more air bass

My home theater is very similar to yours as far as size of the room and size of the home theater area. I was planning on getting 2 Hsu VTF 2.3's, one at a time. Well, I got the first one and see no reason to add a second. Very, very impressed with this sub. I would recommend getting one of these and trying it in several different places and see if you would need another. I tried mine in 3 places and each one was very different. The difference of a few inches can completely change the geometry.


Edit:
Oh yeah, thought I should mention, my room is all hardwood, so that does effect quite a bit.

Properly executed, Audyssey's multi sub time and freq EQing (and products similar) should have huge impact on quality LF in the home. I've never had the pleasure, however it takes a very complex issue, and addresses the major issues in sub-woofing.

In a room that size I would definitely go ported with whatever brand you decide. I have a sealed sub, so I have no bias. Buying sealed can get expensive when trying to fill such large rooms.