Help with my 1st sub design adventure

[Valorum]

Total newbie here trying to build his first sub. Did lots of reading here and on AVSForum, and got some questions answered there already and some suggestions for plans. I figured I'd come over here with my plans this far and see what you guys have to say about it before i start cutting.

The plan is to use the Dayton 15" DVC from PartsExpress. The sub size can be pretty big, it's going to be in a dedicated room (14'Wx29'Lx8'H) where looks don't matter too much.

Here's a pic of the front of the home theater:

Image not available

The front wall is about 14'Wx8'H with a 10.'5Wx4.5'H screen on it. I have about 24" from the floor up before picture blocking would take place, while on the sides i have about 16" max. The floor area in front of the screen where i can put stuff (the black area) extends to about 6' from the wall.

Since the pic i have moved the L & R speakers further into the room a good distance (and recalibrated). So i now have room for a rather large box to the left and right of the center channel. The mains can be moved around some if necessary, and i'm not married to the stands they're on. The center channel is the only one that really can't move much.

The plan as it stands now is either a box of ~350L tuned to ~17.7Hz or a box of ~470L tuned to ~15.5Hz. The box would be 24"Hx24"Dx~4.5'/~5.5'W. (The 470L box would fill almost the whole area from the side wall to the center channel.) I can see myself building another box just like it later on to put on the other side of the center channel and get more SPL that way :B

Here's what Unibox has to say about these 2 box designs. The 350L box would use about 240W while the 470L box would use about 180W before cone excursion becomes a problem.


Images not available


Here's the design of the 470L box this far. The wall thickness is 1" (2x0.5" MDF so i can do the rabbit joints easily) The 350L box would simply be about a foot shorter and have only 2 braces.

Image not available

So, what do you guys think? Am i on the right track here? What would you change? Is the 470L box overkill / not worth it? Is the way i'm planning on doing the 4 ports (4" ports) a good or bad idea? (I'm concerned about the distance to the brace, and the distance between the ports etc...) Where should i put the driver? Facing forward into the room i assume. In the middle of the box? Off-center towards the center of the room?

I'd really like to know if i can go ahead and start building the box, or if there's stuff i should really reconsider.

Thanks!

[ThomasW]

The logic behind this design escapes me.

What's the reason for the enormous box and why 4 ports?

Why a DVC15?

What's the budget?

The room is pretty big, I think you want more Vd

[---k---]

He posted on AVS http://avsforum.com/avs-vb/showthread.php?t=662098
that he choose the DVC15 based on cost.

I'm guessing the 4 ports are because SVS does it that way, and it is kewl.

[Newfiestang50]

Hey Valorum, what software are you using to draw that box, I need something like that aswell.

[Valorum]

Thanks for chiming in guys :T Let me give some background on how I got to this design:

My request was for a sub that'd give me the most extension for HT use. I want something that'll get me down into the high teens, as in 15-20Hz.

I was originally looking at a budget of about $500 max to buy retail (PB-ISD10), but was kindly informed that with such a large room I'd need something a lot bigger. After doing some more research, it looked like I'd have to spend $700-$900 if I wanted something that'd fill up that room adequately.

That's when I asked about DIY. I read all the time about how with DIY you can make something competitive, so I asked if I could make something that competes with what I'd buy for $700-$900 for less money, preferably staying close to my original budget.

Given my room, the size of the box is not as much an issue. As in - I don't really have a WAF to deal with here :B

The DVC 15" was suggested as a driver for my budget. It was suggested I make as big a box as I could fit in, and that that'd give me the most extension. Perhaps that's not fully correct, or perhaps there are other / better options. I'm certainly not married to these choices.

As for the 4 ports: When I model this in Unibox and WinISD, it seems to be telling me that I either need large diameter pipe (8") or several smaller diameter pipes to keep the air speed in check. Since I could buy 4" pipe readily at my local Home Depot, I modeled with 4" pipes, which results in needing 3 or 4 ports. 3 ports seems ok, and 4 ports would keep the air speed nice and low. Since I have the room in the box, I figured it can't hurt to go with 4 ports of the length Unibox and WInISD suggest.

So that's the story of how I got to where I am. I didn't think the size of the box was -that- ridiculous, since this thread is talking about a similar size sub

I already bought 3 sheets of MDF and some 4" PVC pipe. I was getting ready to give this a try, but figured I'd do a sanity check with you guys since I'm completely inexperienced with this.

So, if you have a better suggestion, I'm all ears. This is my first venture into this kind of thing, and i just ran with the suggestions that were given to me.

Thanks again for giving your feedback ;x(

[Valorum]

Hey Valorum, what software are you using to draw that box, I need something like that aswell.

I used 3D Studio Max. I've used it in the past for modelling & animating 3D graphics, so i just used that since i'm familiar with it.

[Newfiestang50]

Is it free to download, if so where?

[SteveCallas]

If your budget is $700, why wouldn't you go dual driver with the 15" DVC?

[Valorum]

Steve - I could do that i suppose. It'd give me +6db, right? My thought was i'll build a box with a single driver for now, and then i can build another box just like it to go on the other side if i like the first one. Kinda like you proposed originally.

What'd be better: 2 drivers in one (big?) box, or 2 boxes with a driver each? If i wanted to do 2 drivers in one box, wouldn't i also need to up the amp? I'm looking at a 250W plate amp now, like you suggested. That'd be good enough for 1 driver it seems, but for 2? ANd if i get a bigger amp (like the 500W maybe?) that'd up the cost even more.

I'm thinking with just a single 15" DVC and a 250W plate amp, the costs stay in check for my first project, and then if i like it, i can duplicate the whole setup into a 2nd box just like it. What do you think of that idea?

[Valorum]

Is it free to download, if so where?

No, not free to download unfortunately. It's commercial software made by discreet / AutoDesk

[ThomasW]

With that budget I recommend using the SoundSplinter RL-p15", it's a significantly better driver than the DVC15".

[Valorum]

Thomas - When i try to model the RL-p15 i can't seem to figure out a good solution. Could you suggest a box size and tune that'll accomplish what i'm looking for? Also, when i asked about this before, it was suggested that 2 DVC15s would be better than 1 RL-p15. What is your take on that?

[ThomasW]

When i try to model the RL-p15 i can't seem to figure out a good solution. Could you suggest a box size and tune that'll accomplish what i'm looking for?

Read through this thread.

https://www.htguide.com/forum/showthread.php?t=18713

it was suggested that 2 DVC15s would be better than 1 RL-p15. What is your take on that?

There's no comparison in build quality the RL-p is stunning, the DVC look cheap in comparison. A pair of DVC15" have a advantage in swept volume over a single RLp-15

[SteveCallas]

It'd give me +6db, right?

As well as less overall distortion for a given output level and possibly a more even FR in room.

My thought was i'll build a box with a single driver for now, and then i can build another box just like it to go on the other side if i like the first one. Kinda like you proposed originally.

Fair enough, but trying to go for a 470 liter box with a very low tune doesn't appear to suit a single DVC 15 design well.

If i wanted to do 2 drivers in one box, wouldn't i also need to up the amp? I'm looking at a 250W plate amp now, like you suggested. That'd be good enough for 1 driver it seems, but for 2? ANd if i get a bigger amp (like the 500W maybe?) that'd up the cost even more.

Two subs, each with its own 240 watt plate amp should be fine. You'd still be under $700.

[Valorum]

Thomas - I read the thread, thanks. Cool project As for the RL-p15's build quality being better than the DVC's, i do not doubt that at all! Can you explain how that better build quality effects the result though? Does it create a cleaner sound or something like that? What would i notice differently?

Steve - If i try to model 2 drivers in a single box, i get a FR that starts to drop off very early. In a 350L box @ 17.7Hz the -3dB is about 27Hz according to WinISD. What am i doing wrong?

[ThomasW]

3" dia voice coil, cast basket, copper shorting rings, dual spiders, tinsel leads woven into one spider, alu cone, rubber surround.

And if you're into the engineering

http://www.tcsounds.com/Images/15tc9_2570.pdf

Compare that to the DVC15"

http://www.partsexpress.com/pdf/295-190dx.pdf

[Valorum]

Thomas - I'm afraid those things, while they sound impressive, don't really mean anything to me I'm not an engineer, so i have no idea what all that means. I assume it all somehow translates into better sound, but i don't understand how and how much improvement we're talking about here. This is simply lack of knowledge and understanding on my part. I'm trying to learn though.

[SteveCallas]

Steve - If i try to model 2 drivers in a single box, i get a FR that starts to drop off very early. In a 350L box @ 17.7Hz the -3dB is about 27Hz according to WinISD. What am i doing wrong?

350 liters is for one driver - 700 would be for two. Deja vu?

[JonMarsh]

/RANT-ON

One of the things I'm amazed at with all of these sub threads is that NO ONE ever seems to talk about distortion of the drivers, just theoretical Xmax as if these parts all perform the same and they're nice and clean until you run up to the wall and "clip" the speaker at max Xmax.


As Dr. Phil would say, "How's that workin' for ya?"

I guess if you're just reproducing explosions 20% HD and IMD doesn't matter, but I get the impression most of you guys are using these systems for music, too, right?

I've measured sub drivers with claimed low distortion that frankly stink even at levels like 4 VRMS. There's more than just ugly or pretty baskets to differentiate build quality.

I'm wondering when you guys are going to look at these drivers in a qualitative mode, not just quantitative. Hmmm? :rant:



OK, /RANT-OFF


~Jon

[---k---]

Also see this thread on AVS for a ported RL-p15: http://www.avsforum.com/avs-vb/showthread.php?t=657394

I'm sure there are more. Several people are building subs with this driver right now.

And besides, 2 DVC is about the same price as the RL-p15, so I would go for the better driver.

[Valorum]

350 liters is for one driver - 700 would be for two. Deja vu?

Yes! ;x( So i guess i made a long 360 to get back to where you pointed me originally :lol: Well, i learned a thing or two along the way at least.

I think 700L in a single box is too big for my room to be able to practically place it, so i'll stick with a single 350L box with a single driver, and build another later on when this one works out.

Now i gotta figure out if i want the DVC or the RL-p15... :unsure: When i model 'm both, i don't see a whole lot that the RL-p15 gives me over the DVC besides output. But i'm certain that FR graphs don't tell the whole story. It's obvious that the build quality is better on the RL-p15, but i'm not sure how that translates into performance.

[Valorum]

One of the things I'm amazed at with all of these sub threads is that NO ONE ever seems to talk about distortion of the drivers, just theoretical Xmax as if these parts all perform the same and they're nice and clean until you run up to the wall and "clip" the speaker at max Xmax.[

Certainly a valid point. I'm just a n00b, so i don't even know how to evaluate this ops: What would you recommend i do to factor this into the equation / design? Would you recommend a particular driver or box size or both to address the distortion concerns?

[---k---]

Hey Jon,
I understand your rant. You as longtime DIYer probably have more than a firm grasp on all things speaker building and long ago moved beyond pure output capacity. However, those of us that are new to this, it is a lot more difficult. Output is easy. More Xmax, More Sd the more output. We can also plug the t/s numbers they give us, without knowing much about them, into Unibox and get output and extension. Works!

As far as I know, there is no way to get information about the quality of a driver or design out of a simple tool like Unibox. And, most of the DIY webpages I've spent time on focus on either construction or simple design for output and extension. To me, it is just output is easy to understand. Quality is something I rely on You, Thomas & crew to determine.

I would love to learn more about what makes a good driver, ect. I started to read through your Testing thread the other day, but I wasn't able to corrolate what you were showing in the graphs to anything in the specs that would indicate that they would do that. I beleive that I'm going to be getting Speaker Building 101 this month as a gift, so I'm trying. But, if you had time to start a thread and educate us all, it would be greatly appreciated.

[Valorum]

And besides, 2 DVC is about the same price as the RL-p15, so I would go for the better driver.

I think it was Steve who, when i asked him, thought that 2 DVCs wouldbe better than a single RL-p15 for my situation. Also, i was desiging for a single DVC. 2 DVCs would mean 2 boxes. So a single DVC vs a single RL-p15 is what i'm weighing really. And then i'm wondering if the RL-p15 (which i do not doubt is a better driver) is worth the extra money and if i would notice or not. I'd like to know how the better quality of the driver translates into better performance. If in the end they sound pretty much the same in my situation, i'd rather save the money and build a second box with a DVC or get a Buttkicker. See my dilemma?

[Valorum]

Hey Jon,
...
To me, it is just output is easy to understand. Quality is something I rely on You, Thomas & crew to determine.
...
But, if you had time to start a thread and educate us all, it would be greatly appreciated.

Second all that wholeheartedly! :agree:

[ThomasW]

When i model 'm both, i don't see a whole lot that the RL-p15 gives me over the DVC besides output.

Box models don't tell you anything about the sound quality of the driver.

Comparing these two drivers is like comparing pickup truck to a Corvette. Yes they both have 2 doors, 4 wheels, a drivertrain, etc, etc., but which one do you want to drive?

What would you recommend i do to factor this into the equation / design? Would you recommend a particular driver or box size or both to address the distortion concerns?

Jon being a purest would recommend using multiple Aura Sound 12", PE RS315 or 12" Oaudio TC2+ since they have the lowest overall distortion.

The problem using multiple 12"s is that it's going to break the bank if you buy enough to equal the output of a pair of 15"s. However you can get pretty close to those drivers by using the RL-p 15.

But, if you had time to start a thread and educate us all, it would be greatly appreciated.

Not likely to happen.

Read the driver testing threads and see the testing data. The commentary about the testing is a pretty good place learning what's important. Problem being people aren't testing 15" subwoofer drivers.

[Valorum]

Ok, so i should consider the RL-p15. I would go with a box of similar volume and tune as described in the thread you pointed me to (300L @ 18Hz). What kind of amp should i mate with that design? The design seems to use a 500W amp. Would the PE 500W one be a good one? Or should i get an even bigger amp then?

[ThomasW]

If you read the DIY sub threads here you'll see discussion about the Nady or Behringer fan cooled prosounds amps. If you can live with the fan noise you'll have a better long term investment with one of those compared to a plate amp.

[SteveCallas]

I guess if you're just reproducing explosions 20% HD and IMD doesn't matter, but I get the impression most of you guys are using these systems for music, too, right?

Here is the OP's first post on the matter at AVS:

My wishes...

I use my dedicated theater room pretty much exclusively for movie viewing. If i'm going to do this, i want to get something that lets me experience the bass down into the teens. I've read about the "Irene" stuff (@18Hz?) and want to feel that, and i want to experience WotW with that even lower bass. Same with the Darla scene and any other real bass movies. So in that regard i'm like most of you i guess

Now the limiting factors which make this a balancing act...

First of all, my budget is limited. I started out thinking around $400-$500 maybe. I will consider spending more, but with all the other stuff i want (BFD being one) i don't want to go too far over this budget if at all possible. $699 would be a stretch but doable if really necessary.

The room.... My room is about 14'Wx30'Lx8'H, or 3,360cuft. See attached pics of the front stage of the room. (Man, it looks so small in the pics!) The screen is ~10.5ft wide (not counting the frame) on an almost 14ft wide wall. It leaves a little over a foot of wall space on each side (~14"). The screen's bottom is about 2 feet from the floor. I have about 14ft x 6ft of floor space in front of the screen where i can potentially put the subwoofer. My main L-C-R speakers are in that space, with the L&R sitting on stands. I have quite a bit of space in the back of the room where i could put the subwoofer instead, but it seems that most people recommend you put the sub in the front.

So, now what?

Based on that, yeah, I'd still go with dual DVC 15s over a single RLp15 for about the same price. It's easy to say the RLp is a better driver than the DVC, but will a single RLP fulfill his wants in a 3,360 cubic foot room? Probably not.

[JonMarsh]

The TC Sounds motors are reasonably linear, so that RL-p15 is the safest bet based on past performance, in all likelihood. Look at the results for the TC2+ - this will give you some idea.

When you stray out into the weeds with bargain 15" woofers, I'm afraid you only get what you pay for, if even that.

My testing has concentrated on 12's because I've been looking for drivers that can work up to several hundred Hz, and cone behavior is a major issue. Still, LE affects the distortion products even at 70 Hz, due to inductivity modulation.

I hope that Darren does get a 15" RS woofer out later this year, as he says in in the works. For just below 60 Hz you may still prefer something like the RL-p15 with higher Xmax in one driver, but if you want to run up to a 100 Hz crossover, then you have to start paying attention to the upper bass distortion performance.

Didn't mean to thread jack, but if you go with the RL-p15 instead, it will have served it's purpose.

[---k---]

Not likely to happen.

Read the driver testing threads and see the testing data. The commentary about the testing is a pretty good place learning what's important. Problem being people aren't testing 15" subwoofer drivers.

Yeah, understood.

Like I said, I'm trying. It is just going to take some time. I just wanted to express where a lot of us are, and why we don't discuss quality first. Wasn't trying to argue, or say Jon was wrong or anything like that. His rant is very understandable, and I didn't take offense by it. I am so very greatful to the time that you and Jon give to this forum.



Anyway, back to the OP.

Since you were thinking about a SVS orginally, I'm guessing that you have spent time on a SVS-lovefest-forum, so maybe it would help you if I told you that the RL-P15 is based on the same driver as the SVS Plus driver is based on. So probably similar in sound quality, except the 15" will have a more output. I don't know what the DVC is based on (I'm sure Thomas does), but I would guess that the DVC is closer to the regular SVS PB12 ISD in terms of sound quality. So I'm going out on a limb here, and more or less making stuff about the ISD up, but I'm guessing that stepping up from a 12" DVC to a 12" RL-P would be similar to stepping up from a PB12 to a PB12+. and then going to a 15" on top of that, lookout!

Thomas, or anyone else, would you like to correct me?

[ThomasW]

The PE DVC15" is almost a clone of the first Tempest. The original Tempest and the DVC15 are made by Eminence. The build quality of the DVC15"s I've seen don't inspire confidence. Several were out of box failures or needed to be replaced after a few months. Now PE is very good handling it's warranty service, but why run the risk if the budget is there for a better driver?

I don't pay close attention to SVS or any other retail subs. So I can't comment how using a RL-p would equate to some upgrade.

No harm, no foul about the driver testing threads. Jon's a purest, so he would use only the lowest distortion drivers regardless of cost or practicality. Most people aren't in that head space but do understand build quality. That's a major resaon for recommending the RL-p15" over a pair of DVC15"s, even though the 2-DVC would have an output advantage

[Jack Gilvey]

I've measured sub drivers with claimed low distortion that frankly stink even at levels like 4 VRMS. There's more than just ugly or pretty baskets to differentiate build quality.

I'm wondering when you guys are going to look at these drivers in a qualitative mode, not just quantitative. Hmmm?

You are one of the very few sources for such information, most don't look past perfect freeware graphs. At least some of the programs model Le, though. And, of course, you'll see far more clamoring for photos of drivers than test results.
I've given to recommending the RS315, or multiples thereof, over almost anything. I'm a bit one-track that way...

[ThomasW]

The RS315 is certainly a VERY good driver. They just get a bit $pendy when one is looking for a relatively high Vd.

[JonMarsh]

You are one of the very few sources for such information, most don't look past perfect freeware graphs. At least some of the programs model Le, though. And, of course, you'll see far more clamoring for photos of drivers than test results.
I've given to recommending the RS315, or multiples thereof, over almost anything. I'm a bit one-track that way...

I'm with you on this one, Jack. But I am a little one track, also.

OTOH, I'm also the guy that did a lot of amplifier mods in the 70's so that the low bass with conventional full range speakers would have as much definition, clarity, and naturalness as possible- that mostly meant going from a total of 20K uFD to 100 k uFD in the power supply, using some film bypass if it was a full range amp, and sometimes doubling up on the power transistors. Inexpensive general purpose pro amps will give you watts for cheap, but don't expect them to be the best quality watts.

Before buying a new pro amp, I'd also consider the possibility of a good used amp on Audiogon. No fans, often better power supplies. I know that may not fit the budget at times, but when it does, it should be considered.

Then, there's the Crown K series.

[ThomasW]

People should just ignore Jon when he posts about subwoofers. He doesn't even own an operational subwoofer, and he hasn't owned one for probably 20yrs.

Step right up, get your satisfaction-guaranteed DIY sub support from tried and true 'bass-heads', not some 'want-to-be', who's 20yrs late to the party........ :heh:

[---k---]

Thomas,
If you hadn't locked the "Archive of Reference threads........." I would have added that one!

[JonMarsh]

People should just ignore Jon when he posts about subwoofers. He doesn't even own an operational subwoofer, and he hasn't owned one for probably 20yrs.

Step right up, get your satisfaction-guaranteed DIY sub support from tried and true 'bass-heads', not some 'want-to-be', who's 20yrs late to the party........ :heh:

Hey, Who's your moma, boy? Who designed the 15" slot loaded subs back in the 70's you used for years and amazed folks wid? I gots more subwoofer drivers than most folks own in a lifetime, STILL sitting in my closet, 'cause I'm looking for the one that will REALLY rock my world. :yeah:

Who built sub cabinets back in the 70's so stiff you could hang them on a string and tap them and the "ding" frequency (before veneer) really was a "ding" it was up so high? :frypan:

We ALL know the reason I don't build no sub out here is that those silly folks would start a panic becuase they're be sure it was the quake of '06 all over again. But lessee, it is 100 hundred years since the last one, so maybe that's a good idea for a project later this year- tuned to 6 or 7 Hz, with a three tone test cluster ought to do a good simulation of ground rumble!


You be nice, or I'll sic Evil Twin on you... he doesn't play fair or nice.

~Jon

[SE-Raider]

Now there's an interesting concept,

A sub project by Evil Twin... RS315 clone droids... ruthless intolerance for distortion... crush the xmax and bl fanatics... vintage 70's cabinet concepts... could be very interesting

[SE-Raider]

Thanks for the previous rant, Jon

I think the emphasis on xmas and bl, etc. as ends in themselves comes from the marketing department, where mine-is-bigger-than-yours mentalities prevail. But because there are so many equally important and interrelated variables that apply to subwoofer design, opinions like yours, ThomasW's, and others here are invaluable in making design decisions. There is no substitute for experience, because the fundamental physics don't change.
I've always been facinated that most every speaker design and enclosure design existant is a variation of a design that dates back to the early days of movies. Many of the best designs were a result of the low power that was available in tube amps at the time. What has changed is the impact of cheap and available computing power, cheap amplifier power, and the impact of Moore's law and CAD/CAM/CNC on both the design and manufacture of loudspeakers. This computing power affords the ability to accelerate the design of speakers and enclosures. The sheer number of independent variables involved with both the speaker itself, and also the interrelated enclosure design, still depends to a large degree on good old-fashioned old-school experience for best results. Experience can also intuitively judge suitability for an intended use or application much better than the deductive computer.
I appreciate your willingness to afford the speaker community the opportunity to take advantage of the experience you have. :T So its refreshing to hear you step back and demand perspective on the situation.

In the end for most of us it's all about the music. It is truly magical when you attain a sub design that is more musical than the last, when the veil of distortion is lifted, and you hear those harmonics, ambience, and clarity on music you've heard a hundred times before. If it can be done and preserve the visceral feel of live performances, well, that's your next sub project. :lol:

[Valorum]

I had planned on starting cutting this weekend, but now i'm not so sure i'm ready. Gotta decide which driver i want to go with before i know how big a box to build.

I think i understand the argument for the RL-p15. I may decide to go with that one, but i'm not sure yet.

As for an amp - i don't think i'll like fan noise. I read in the other thread about a Samsung S700 amp, and i believe that one doesn't have fans? I can't find it online anywhere though. There's a Samsung S700 cell phone, so all search results are about that. Do you know where i could find one?

Thanks for all the feedback this far. I'm thinking a night of sleep will help me decide perhaps

[dyazdani]

As for an amp - i don't think i'll like fan noise. I read in the other thread about a Samsung S700 amp, and i believe that one doesn't have fans? I can't find it online anywhere though. There's a Samsung S700 cell phone, so all search results are about that. Do you know where i could find one?

It's Samson S700 not Samsung like the cell phone/TV/etc company :T

[Valorum]

It's Samson S700 not Samsung like the cell phone/TV/etc company :T

DOH! ops: Thanks

[Valorum]

I played around with box sizes etc some more, and it seems that if i make a box in the range of 300L to ~350L the required port lengths for the DVC and the RL-p15 to get 'm in a good tune (around 18Hz) are pretty close. That means that the same box size and port lengths would work for either driver. And that means that if i'm really cut-happy when i get up tomorrow, i could build a box.

I'm assuming here that a liter more or less or an inch more or less or a Hz more or less isn't something to agonize over. Is that a safe assumption to make? I mean, in the end the box size i predict when modeling isn't necessarily going to be the exact same size of the real box anyway, so this isn't a 100% exact science to begin with, right?

Also, if given the choice between

a) 15" DVC + Buttkicker
b) RL-p15 (and no Buttkicker)

Which option would you choose? I know it's not going to work out to the same amound of money, but the RL-p15 + Buttkicker is really pushing me out of my budget, while the 15" DVC + Buttkicker is something i could possibly stomach. (EDIT: I should note that the theater room is over a large crawl space and that the floor is wood with joists, and that i'd attach the BK to the floor / joist. And no, i can't do an IB setup, unfortunately. The wife, being cool with just about anything else, drew the line at cutting a hole in the floor... :cry: )

[ThomasW]

There's basically a 10% 'fudge' factor with ported boxes. Also you can play around with damping materials. So no don't worry about a liter here or there...