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ok...small room sub or subs...thoughts?

1537 Views 23 Replies 8 Participants Last post by  benareeno
After some deliberation on what I wanted to do...I have decided to start my DIY with a sub or subs.I am now running a pair of B&W 602's...no center. I will address this scenario in the future...but for now, sub or subs.


I am in a smallish room 18X10.5 or thereabouts...I would rarely listen at reference level...I want a sub or subs that are very hard to locate (this may be why I think I want 2 subs?)


I am now sitting off the back wall by at least 3 feet, so I am fairly close to the main speakers...I'm thinking a single sub in between the 2 speakers, and I'm thinking that I prefer a sealed sub, for sound and ease of building.


This kit is in my price range, and it's in Canada, any thoughts? Is it overkill or underkill?
http://www.creativesound.ca/details....el=Trio12APR15


In the past, I had always felt I could localize the sub..and from what I've read, 2 subs are really the way to go...is there any way I could build a pair of sealed subs in and around the 500 range? It looks like creative has a 10 inch kit that is 300..perhaps I should start with it and build another one should I feel the need?


Again...just guessing here. With the movies I watch and the things I enjoy in a soundtrack, I suspect I'd prefer the 2 10" subs. Am I out to lunch here?


One other concern is the size of a 20" cube on feet...might be too obtrusive in a small room. This is another factor which makes me think a single 10" is a better start. Or at least, the ability to build a more rectangular cabinet, which would fit into the room better.
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I would go with three subs using the principles made popular by Dr. Geddes.

Two in the front of the room and one in the rear of the room, near the ceiling (upside down sonotube can accomplish this).
http://www.avsforum.com/avs-vb/showthread.php?t=1124011
Multiple subs can help smoother the response and make the bass more consistent from seat to seat. If you do get two subs, I would place them on the midpoints of opposite walls (either front/back or left/right). If you get a single sub, I would try placing it behind the couch to take advantage of nearfield bass.
I would look at a pair of these Peerless S315SWR3908 12" woofers in a 3 ft3 sealed box, with something like a Behringer A500 to power them.
a 3ft cube?


both subs in the same enclosure?


What about 1 sub up front and one in the rear?


So, just to get this straight...I can just buy drivers if I'm going to use an outboard amp? And if my processor sets the crossover, then I need not worry about building in crossovers to the sub?


What about the phase adjustment?
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And I definitely like the economics of this suggestion...2 subs and an amp for 500 and that would likely include mdf and connectors etc...


What is the drawback to this sort of setup? Why wouldn't others simplify and do a similar setup?

Quote:
Originally Posted by benareeno /forum/post/20851523


a 3ft cube?


both subs in the same enclosure?


What about 1 sub up front and one in the rear?


So, just to get this straight...I can just buy drivers if I'm going to use an outboard amp? And if my processor sets the crossover, then I need not worry about building in crossovers to the sub?


What about the phase adjustment?

3 ft3 box for each woofer. You can adjust the dimensions to what suits your preference, for example a 18"h x 16"w x 25"d box made out of .75" material will get you roughly 3ft3 after bracing, and the drivers displacement are considered. You would simply give the subs standard binding posts, connect those to each channel of the amp, then run the L/R amp inputs to a Y adapter , and then to your receivers LFE output.

Quote:
Originally Posted by benareeno /forum/post/20851547


And I definitely like the economics of this suggestion...2 subs and an amp for 500 and that would likely include mdf and connectors etc...


What is the drawback to this sort of setup? Why wouldn't others simplify and do a similar setup?

The dual subs will smooth out issues with your room affecting the bass response. You're not going to get ridiculous output, just nice quality bass at a decent level. The people on this forum are very much HT enthusiasts.
I'm an enthusiast too... I suppose I could afford 4 18" subs and thousands of watts of amplification...but that would likely be more than I or this room require.


So far, the outboard amp with 2 passive enclosures seems like a winner to me...especially since I can do it for a reasonable price.


I guess I would fire these towards the listener(s) or downward? And how did you come up with a 3 ft enclosure? Would any bigger be better?

Quote:
Originally Posted by benareeno /forum/post/20851622


I'm an enthusiast too... I suppose I could afford 4 18" subs and thousands of watts of amplification...but that would likely be more than I or this room require.


So far, the outboard amp with 2 passive enclosures seems like a winner to me...especially since I can do it for a reasonable price.


I guess I would fire these towards the listener(s) or downward? And how did you come up with a 3 ft enclosure? Would any bigger be better?

The 3ft3 enclosure limits the drivers from being severely overdriven by the amount of amplification they will receive. A larger box would give a deeper, flatter response, with the risk of bottoming out the drivers during high level, low LFE scenes.


I would place each box along the front wall, near/in opposing corners to start. Front/down firing wont make that big of a difference below 100hz.
could I use the box as a speaker stand? Or does it rattle too much to bother?


If a larger box would be better...I suppose I would consider that.
I'd hunt around for a cheap pro amp used or something. Get 2 or 3 trio 12s and you'll be impressed I think.

Quote:
Originally Posted by benareeno /forum/post/20851718


could I use the box as a speaker stand? Or does it rattle too much to bother?


If a larger box would be better...I suppose I would consider that.

I wouldnt use a bigger box, the smaller size protects the driver.


You could use them as stands with something like foam or rubber in between, but then your bass response would be less then ideal.
I think the trio is designed to be used with a passive radiator...


my last B&W sub had a similar driver to the one proposed by Jay1, I think I'd be comfortable using that one in a dual config. It should be the ticket...I would think.
what about some small tapped horns...
trapped horns?


How would they differ in terms of cost, size, sound quality?
the tapped horn gives you somewhere around 6db additional sensitivity vs. ported but requires a large enclosure...


sound quality is going to be subjective...


cost is the same.


they perform like ported though, so have a lower cutoff frequency.


if you want the ultimate lfe, you have to go sealed or infinite baffle.
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Quote:
Originally Posted by benareeno /forum/post/20851547


And I definitely like the economics of this suggestion...2 subs and an amp for 500 and that would likely include mdf and connectors etc...


What is the drawback to this sort of setup? Why wouldn't others simplify and do a similar setup?

Great question. This is the recipe of many over the top designs that you will read about here. Simply multiply the drivers and enclosures and amplifiers.


I use 4 sealed subs, some guys have 8, and more.... But they are simply a sealed subwoofer design....


By multiplying the drivers and amps and such their combined ability is increased, kinda like one painter painting you house opposed to eight painters painting...


.....oh, then there is the $ issue...it gets pricey too
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could I use a 4 ohm car sub?? SOmeone is selling a couple of these locally for a very good price.

http://www.sonicelectronix.com/item_...-GTO1004D.html

Quote:
Originally Posted by benareeno /forum/post/20855990


could I use a 4 ohm car sub?? SOmeone is selling a couple of these locally for a very good price.

http://www.sonicelectronix.com/item_...-GTO1004D.html

Those woofers would work great in a small ported box. For example a 14"x14"x40" box with a pair of 4"x33" ports will give you very good output down to 25 hz. You will need a much more substantial amp with adjustable HPF options, like this Crown XTI1000 . Just make sure you wire the woofers voice coils in series for an 8 ohm load to each channel.


A sealed box could be tiny, with output being similar to the peerless
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