4 15" Sealed Subs

[InPhase]

Hi everyone! I have been doing a lot of reading and have decided to take the DIY plunge. I'd like to get any recommedations on this idea. As a reference, I currently have a SVS PB12/2+ in a ~1000ft^3 sealed, dedicated and heavily treated HT room. The mains currently are Rocket RS750's, center RSC200, and the matching surrounds. I have the mains, as well as the center and sub under the screen (8' wide DIY).

I have heard an IB and have heard multiple sealed subs in other theaters vs. ported, and I definitely prefer the sealed sound. I am trying to keep costs around $1,500 for the whole project. This may not be possible, but ultimately I want a very high performance system (maybe a little overkill ), for a resonable amount of $$. After doing some modeling with WinISD, I am leaning towards 4 Titanic MkIII's or 4 RPL's in ~22" (~4ft^3)boxes, with 2 layers of 3/4" MDF on all walls and 2 or 3 window braces inside. Due to my budget I believe 2 of the Behringer EP2500's is my best bet for an amp. Is this enough power? Are there any deals to be had on 4 drivers, or 4 amps somewhere? Should I consider any other drivers? I currently have a BFD, but I think I'll sell it and get the DEQ2496 (I think this is right) in order to simulate an LT or at least to do the shelving filters. Will this work for 4 subs?

If you were building 4 sealed 15"s in Dec. what would you use for everything, given a budget constraint around $1500? Btw, I have a woodworking shop available to me, so I don't need to purchase tools.

TIA for the help! ;x(

[gitarretyp]

I'm not sure if you mean 4 ft^3 for each or a pair, but i'd look at the Datyon RS390 HF (4 ft^3 each) and HO (a pair would work in 4 ft^3). I just built a sealed sub using the 390HO in ~4 ft^3 and am very happy with the sound.

[Dennis H]

The RLP or the similar TC2000 are much better drivers than the Titanic. Better built and lower distortion. That's what I'd go with. The DEQ2496 and a pair of EP2500 should work just fine.

[kgveteran]

Now , this is a topic ! What size is your room ? I'm sure you have read about the 12db/oct. rolloff of the sealed enclosure.This usually gives you a F3 between 28hz and 35hz.This can be overcome be a LT type device to extend the frequency response at least to 20hz (if not into the midteens) . Doing this will do two things quick.One, eat up all your Xmax.Two, eat up all your power. If you have enough Xmax and enough power you are in business.These are the two big factors in a sealed system.You seem to have the cabinets all set.

I think you will want one of the guys here to spec out the drivers in the enclosures and give you an idea of the limits that design will have.

You can start with two behringers.That will get the ball rolling.You may end up bridging those depending on how much you juice the system with your LT type device.

I think this is the part where i say how much I love my quad sealed 15's !

[ThomasW]

I have heard an IB and have heard multiple sealed subs in other theaters vs. ported, and I definitely prefer the sealed sound.

No comment other than to say an IB is a sealed sub....

I am trying to keep costs around $1,500 for the whole project. This may not be possible, but ultimately I want a very high performance system (maybe a little overkill ), for a resonable amount of $$.

Not a problem.

After doing some modeling with WinISD, I am leaning towards 4 Titanic MkIII's or 4 RPL's in ~22" (~4ft^3)boxes, with 2 layers of 3/4" MDF on all walls and 2 or 3 window braces inside. Due to my budget I believe 2 of the Behringer EP2500's is my best bet for an amp. Is this enough power? Are there any deals to be had on 4 drivers, or 4 amps somewhere? Should I consider any other drivers? I currently have a BFD, but I think I'll sell it and get the DEQ2496 (I think this is right) in order to simulate an LT or at least to do the shelving filters. Will this work for 4 subs?

If you want a low cost LT and additional EQ functions the DEQ is the best bet.

If you were building 4 sealed 15"s in Dec. what would you use for everything, given a budget constraint around $1500? Btw, I have a woodworking shop available to me, so I don't need to purchase tools.

Look at the current crop of new drivers from TC-Sounds. And depending on your room and other variables, you might be fine with a pair of 18"s

[InPhase]

WOW! Thanks for all the quick responses. Just to clarify: this will be 1 15" driver per 4ft^3 box. The room is: ~8 x 15 x 8. (I know the modal problems with these dimensions, which is part of the reason I am planning for 4 subs.)

Aren't the HO subs geared toward >30Hz performance? I'd like these subs to dig deep. Will 2 EP2500's power all four subs sufficiently? And will one DEQ handle all 4 subs? Also, will any of the new TCSounds drivers be a better bang-for-the-buck than 4 RPL's? I'm willing to give up a little performance for a big savings. I'll look into the TCSounds 18"ers and see if that would be a good idea. Would two 18"s out perform 4 15"s? I'm concerned that the box for an 18" driver would need to weigh around 150lbs. In general, if I keep the box around 4ft^3 won't 4 15s play deeper with more authority than 2 18"s?

Does everyone concur that the RLP 15"s are worth the extra $$ over the Titanics?

Thanks for all the help.

[ssabripo]

I think this is the part where i say how much I love my quad sealed 15's !

I thought you were converting to the darkside, uhm, I mean, IB?! :rofl: :lol: :T

[ThomasW]

Aren't the HO subs geared toward >30Hz performance? I'd like these subs to dig deep.

They lack the high excursion of other drivers. Other than that yes they'll play low

Will 2 EP2500's power all four subs sufficiently?

Probably

And will one DEQ handle all 4 subs?

Yes, but only if you need two channels of EQ

Also, will any of the new TCSounds drivers be a better bang-for-the-buck than 4 RPL's?

Some model better, most are sold out

Would two 18"s out perform 4 15"s?

Not if they all had the same Xmax

In general, if I keep the box around 4ft^3 won't 4 15s play deeper with more authority than 2 18"s?

Same question as above. Depends in the Xmax.

Does everyone concur that the RLP 15"s are worth the extra $$ over the Titanics?

The RL-p15" will play louder and take more abuse.

[---k---]

I have built two RL-p15 sealed subs and used one EP2500 and one DEQ with them. I was pretty happy.

I think the RL-p15 is the best value at the moment. If you can afford 4, I would definetly do that, but I think that blows your budget with amps and a DEQ. SS is supposedly going to come out with an RL-p18 in January. Depending on how it is priced, I think it would be worth waiting for or at least asking Mike @ SS about. (We also really love guiney pigs!)

If placement is an option, I would HIGHLY suggest building two subs. Each sub having two drivers, mounted opposing. Thomas tried to get me to do this, but my original room placement wouldn't allow it.

For box size, 100L per driver will give you a Qtc of roughly 0.5 - which is our ideal target. 100L is approximately a 20" cube. But, putting two drivers in one box doubles this, and I don't think this is needed, especially with four drivers. 150L would probably work well.

Double layer 3/4" MDF is typically recommended, with a third layer on the front baffle. Lots of bracing of course.

I think you will definetly want two amps. One EP2500 is plenty for a pair of drivers.

You will also want a Behringer DEQ2500. It will add the desired thump in the rump. One will be plenty. You will be able to run one channel of the DEQ for each amp.


Be sure to check out the previous sealed RL-P15 threads, such as mine and SteveNN's. I think, even though we are both now running ported, that our builds were successes. (I only run ported now because I can't afford 4 rl-p15 drivers.)

[dyazdani]

I'm concerned that the box for an 18" driver would need to weigh around 150lbs.

A 22" cube will weigh out in that ballpark anyway. I built mine a bit smaller, maybe 19-20" or so and it weighed around 110 lbs (empty and raw).

[engr_dave]

Hi InPhase

I'm just getting started on almost exactly what you are talking about. :T

I considered the following criteria...

1. Multiple subs provide more positioning opportunities.
2. Stereo front subs may have "imaging" advantages (and my prepro supports this)
3. My theater/listening room can more easily accommodate two small boxes rather than one large one
4. Two boxes are easier to move around
5. Two drivers per box in opposite-firing configuration cancel forces on the enclosure - minimizing wasted energy and and preventing "walking".

... so I converged on two 4 cu ft subs with two 390HO's each, LT'd with the Bob Ellis boards and/or a DEQ2496, and Crown K2 for power (1250 w/chan). The LT/EQ will easily get them flat to below 20Hz, especially with room gain.

The four HO's actually model a little better than two RL-p's or TC2000's. Of course I considered four RL-p's or TC2000's :E, but those perform best in slightly larger boxes, and they strain the budget, and I'd probably need even more power to take full advantage of them.

Considering that I'm going from a single vented-equalized JBL 15" 2235H (only 7mm xmax :nonod: ), I figured nearly 8x the Vd and 8x the power should be a noticeable improvement :blink:

I have all of the parts except the DEQ. I'll start making MDF dust this weekend and post some pics.

[ThomasW]

No doubt the HO's model better than the others you mentioned. That would be apparent just looking at the T/S parameters (the Le in particular). And using 4-HO's is going to give you a very nice high sound quality setup.... :T

But the OP would need 8 drivers and boxes to equal the output of 4 TC-Sounds drivers.

[engr_dave]

But the OP would need...

Er, Thomas you mean "InPhase would need..."?

Regardless, you're right. I guess I was making the heretical implication that 4 HO's in a 960 cu ft room might be enough :blink:. PE still has them on sale, and as Ryan pointed out, 4 Rl-p's, two amps, a DEQ, a pile of MDF, and miscellany will be closer to $2500 than $1500.

And to think just a few short months ago, I considered 4 HO's in a theater three times that size excessive. Clearly I need further recalibration as to my understanding of the term overkill! I am just a noob. ;x(

[ThomasW]

Er, Thomas you mean "InPhase would need..."?

OP as in original poster

[Dennis H]

Yeah, at current sale prices and free shipping, you could buy 8 of the RSS390 for about the same price as 4 RLP15. Tough choice, i guess it depends on how you want to deploy them. If you do like KG and have all 4 boxes in the front of the room firing forward, the 4 RLPs will probably be better. If you want to use them as end tables, etc, having two drivers on opposite sides cancelling vibrations would be better. 4 boxes, the same size, 1 RLP or 2 RSS per box. Hmmmm......

[Brian Bunge]

I have 8 HO's on order! I'm building 2 of my quad 15HO subs for a couple of guys. I'll build my box at the same time and buy drivers for my sub when they pay me the balance! I could have bought mine too if I hadn't chosen to buy my new wife a Nikon digital SLR for Christmas (oh yeah...and an 80G iPod for myself!)

[InPhase]

I considered going with two opposing 15"s per box (just like Mark Seaton's new SUBMersive), but thought that it might be a bit advanced for a DIY n00b. It may be as simple as putting the two in the same box and getting the wiring right. Additionally, I thought that having the placement options of four smaller subs would be beneficial in my current small theater with its nasty dimensions.

If you guys think that the advantages of the distortion improvement with the opposing drivers far outweigh the advantages of smaller, easier to place boxes that might play a bit deeper (due too more volume per driver), then I might go that route.

Looking at PE website, it lists the RSS390HO as having only 12mm of Xmax vs. 20.5mm for the Titanic. I haven't modeled them both, but doesn't this mean that in the lowest frequencies that I'll be running out of headroom very quickly with the HOs as compared to the Titanics or the RLP15s? I like the price for the HOs ( ), but don't understand how they can model anywhere near the others at the lowest freqs. Btw, I'm trying to future proof (at least couple years) my LFE, so these subs may end up in a different location and I want to have quality bass even in a much larger room.

As far as the budget, this is what I have right now:
$1100 $250 x 4 RLP15 + shipping?
$500 $250 x 2 EP2500 (hopefully from ebay)
$225 3/4 MDF
$100 Misc. (Glue, posts, spikes?)
$250 Behringer DEQ2496
_____
$2175 Total



Am I missing something? This is more than I'd like to spend, but if I'm going to do it, it has to be right. Has anyone gotten a discount for buying 4 of the RLP's?

[InPhase]

---k---,
I'll ask Mike at SS tomorrow about the RLP18 and report back.

Thomas,
I'm confused about this statement: "But the OP would need 8 drivers and boxes to equal the output of 4 TC-Sounds drivers." So are you saying that the HO models better (flatter?) but only has half the output? If this is true, then other than price, why would I want the HO? Thanks.

Brian,
Are you putting 4 HO's per sub? How big will that be and what kind of output are you modeling at 20Hz? Off-Topic: I grew up in Palm Bay. Went to Palm Bay High and now live in Sacramento,CA. How's the weather?

[InPhase]

---k---,
You said, "If placement is an option, I would HIGHLY suggest building two subs." Why would you do it this way? Did you have problems with the single driver subs moving around? I figure that at ~125lbs? apiece this should not be an issue. If I built the larger enclosure for 2 15s, could I forgo using 1.5" sides, top and bottom and triple up on the baffles?

[kgveteran]

Inphase,
I got (4) RLp15 for about 1130.00 shipped.Get a quote from Mike at SS.

[ThomasW]

You wouldn't want the HO unless you could use 8 of them given their low Xmax. They have a lower Le, and less distortion than the RL-p15". But they aren't going to stand up to the pounding that the RL-p15"s take given since the RL-p15"s have a heavier surround, double spiders and high Pmax.

[InPhase]

OK. So the drivers are set at the RLP 15"ers (4 Ohm). I got a great deal on some used ones. $800 for the set. :E Btw, I hope the 4 Ohm version is correct for the wiring. Time to do some modeling.

[---k---]

Positioning would have been a problem for me, because I originally wanted to put the sub in the corner. If I did this with drivers on each side of the box, one would likely fire into a sofa or have to be really close to the wall. Then I liked the idea of using them as speaker stands. Then....

Like Dave said, placing the drivers on opposite sides of the box will cancel out vibration and stuff. Take a look at Mark Seaton's new Submersive sub. There is a thread on it at AVS. I think you will want to build something very similar, and if you do it will be special. Take special note that Mark says that he used 3/4" BB ply for the sides, 1 1/2" for the front and back and only two brace. When I saw an early demo of his box, it was vibration free. So, you can build a slightly lighter box this way. Btw, my sealed boxes came in at around 80lbs.

[Brian Bunge]

Yes, 4 HO's per cabinet. Based on cabinet size (around 170L) the 4HO's worked better for me and model better than 2 RL-p15's (also couldn't stand the thought of having a logo on the drivers looking at me, no matter how unobtrusive they may be).

I went back and forth with Mark Seaton on this design and he gave it his recommendation. He said even with a bridged EP2500 that he felt I'd be fine on just about any program material. Test tones, of course, would be another matter altogether.

I do have room for a second quad setup in my living room should the need arise! Don't tell the wifey!

BTW, I love it down here in Palm Bay! My dad grew up in Melbourne/Brevard County and I grew up going to Ron Jon's every year. It was a dream of mine to move down here some day and finally made it to Brevard County in March of this year. I'm a beach bum at heart and WILL learn to surf (or die trying). Right now the weather is still warm, mid 70's-low 80's, and a bit rainy lately.

[---k---]

Yeah, I can see some advantages of 8 HOs over 4 RL-p15. But, I can also see a much more difficult build. I think the small improvement of the HOs over the RL-P in a sealed box may only be realized by the best ears, in the best of rooms???

[Brian Bunge]

Well, you know if it doesn't weigh over 200 lbs. Thomas won't touch it!

[WillyD]

Funny that you're building such a sub Brian, because last night I thought to myself "Man, building a 4-driver sealed cube sure sounds like it'd fun".

And these drivers are such a good value...hmm...I don't need to build anything right now, but a 4x15HO sub sounds mighty intriguing.

[InPhase]

Modeling

Can I get the experts to verify the model I put into Unibox? I put in 1050W just as a reference. Considering the impedence curve, will I end up with much less output using a single channel on the Behringer EP2500 per sub than shown here?

Does the shape of the box matter? If I go from a 22" cube to making it a couple of inches taller while decreasing the other dimensions is there anything I should be aware of?
Here is the RP-L15's website numbers: http://www.soundsplinter.com/rlp15_premium_series_15_inch_DIY_subwoofer_informa tion.html
Thanks again for all the help!

Images not available

[---k---]

That looks like you modeled the RL-p15 4ohm. Most here use the RL-p15 2 ohm driver. It has a slightly lower Fs. And, when you wire the 2 voice coils together, you get a nice 4 ohm load. With the driver you modeled, you either end up with a 2 ohm or 8ohm load.

I don't think box shape matters until you get really elongated. My sealed subs were like 19"x24.5"x20". I liked the 24.5" width, because that is half the width of the MDF sheet, so one less cut.

Attached is what I use.

So, are you going with 2 drivers in a box and 4 drivers total still?

[InPhase]

OK. Decision time. I'm supposed to buy the 4 Ohm 4 RP-l15's off someone this afternoon for $800. Can I use these? I'd really like to make this work, as it will save me $$$.

[ThomasW]

If the drivers are in good shape $800/4 is a good deal

If you're going with 4-4 ohm DVC drivers, each pair of drivers can be wired as a 4 ohm load. Most amps are very happy with a 4 ohm load

The model itself is somewhat irrelevant. Simply build the largest box you want to live with.

Cube shapes are fine.

[InPhase]

Cool. Thanks Thomas! I was getting worried there for a minute. Looks like I'll pick them up then. They are in good shape. I have seen them and they have barely been used.

[---k---]

Sorry, didn't mean to worry you. I didn't know that you had a line on some used ones. That is an great price for four of them, go get them.

You're going to have fun with these.

[InPhase]

Ryan,
No problem. Something came up today so I'll be picking them up tomorrow. Now I'm looking for deals on the EP2500 amps (or something comparable) and a DEQ2496. Anyone have any ideas?

[InPhase]

Also, can someone explain what the "SPL produced by leaks" means on my Unibox model? I don't plan on having any leaks. Is this something inherent in the driver? TIA!

[kgveteran]

I thought you were converting to the darkside, uhm, I mean, IB?! :rofl: :lol: :T

Naw. I like Aarons IB I did, but I think I'll keep things as they are. I'm working on my rear surrounds.Mark's MT 225/28a's.Selling off the B&K's for Outlaw M-200's.

[---k---]

I got my EP2500 from MusiciansFriend.com. Either them or Parts Express (a forum sponsor, click through the link above), usually have a pretty good price with free shipping. Careful watching of EBay can get you maybe $50 savings on a new one. I did get my DEQ off Ebay.

Some people have had good luck getting used amp from local Musician's stores like Guitar Center or pawn shops.

I wouldn't worry about the SPL produced by leaks. I guess they always expect a little leakage around the driver and terminals. Build it right, and it isn't worth worrying about.

[InPhase]

4 RP-L15s are here

Some of the rubber parts are a little dirty, but all the important parts seem ok:

Image not available

That's a 96" 2.35:1 screen for reference:

Image not available

[ThomasW]

Looks good.... :T

Most often leaks aren't literal 'air-leaks' due to poor construction, they're referring to the losses from the box itself flexing or other such things...

The only person we know to build a no leak box is RandyMidd... :B

[InPhase]

I'd like to get some feedback on this box design. Did I do this right? This is NOT to scale, but the dimensions are there for a reference. Is this just too excessive for bracing? All six sides are double layers of 3/4" MDF, and the front baffle will be three layers. The two internal braces will be just 1 layer. Thanks for the help!


Images not available

[crackyflipside]

Looks good.... :T

Most often leaks aren't literal 'air-leaks' due to poor construction, they're referring to the losses from the box itself flexing or other such things...

The only person we know to build a no leak box is RandyMidd... :B

It seems RandyMidd is my polar opposite. :lol:

ThomasW perhaps you should add this link to how to not build a sealed subwoofer:The Portable Sub

[InPhase]

LMAO! :rofl: :rofl:

[InPhase]

I have sold the SVS, and bought 2 EP2500's and the DEQ. I plan on making sawdust this weekend. Thomas, you mentioned that I should make the boxes as large as I'm comfortable with. I was pretty much set on something very close to the above design, but then I saw a thread at AVS where they mentioned that you should make the box volume just slightly less than that which would allow the driver to bottom, in order to protect it. Should I be concerned about making my box volume exact? What volume would you recommend to protect the driver for a single RP-L15(4 ohm) and for 2 opposing drivers per box idea? I still haven't decided which to build. TIA!!

Thread at AVS:
AVS Forum Thread

[InPhase]

I have built two RL-p15 sealed subs and used one EP2500 and one DEQ with them. I was pretty happy.

I think the RL-p15 is the best value at the moment. If you can afford 4, I would definetly do that, but I think that blows your budget with amps and a DEQ. SS is supposedly going to come out with an RL-p18 in January. Depending on how it is priced, I think it would be worth waiting for or at least asking Mike @ SS about. (We also really love guiney pigs!)

If placement is an option, I would HIGHLY suggest building two subs. Each sub having two drivers, mounted opposing. Thomas tried to get me to do this, but my original room placement wouldn't allow it.

For box size, 100L per driver will give you a Qtc of roughly 0.5 - which is our ideal target. 100L is approximately a 20" cube. But, putting two drivers in one box doubles this, and I don't think this is needed, especially with four drivers. 150L would probably work well.

Double layer 3/4" MDF is typically recommended, with a third layer on the front baffle. Lots of bracing of course.

I think you will definetly want two amps. One EP2500 is plenty for a pair of drivers.

You will also want a Behringer DEQ2500. It will add the desired thump in the rump. One will be plenty. You will be able to run one channel of the DEQ for each amp.


Be sure to check out the previous sealed RL-P15 threads, such as mine and SteveNN's. I think, even though we are both now running ported, that our builds were successes. (I only run ported now because I can't afford 4 rl-p15 drivers.)

I am considering putting opposing 15's in each box, but when I put look at Unibox, it tells me that for a Q=.5 I need 913l of volume! I will be using the DEQ for a LT, so should I be targeting a different Q? Thanks!

[Brian Bunge]

I'd shoot for a Q around .6-.65 and then add the LT to get it lower if you wish.