[t-dog]

Danny was kind enough to send me 2 MFW-15's and 2 SA-1's. The plan was to either build 2 ported enclosures or 2 sealed enclosures. Based on my desire to keep this simple I'm leaning toward 2 sealed boxes. I also have size limitations since these will be sitting on top of my stage and below my screen. The max I can go height wise is 21". These are primarily for Home Theater. 

Looks like the recommendation is 3 cu ft. for sealed. My calculations show approx 18" cube I.D. (3.375 cu ft.) then figuring braces every 3" (127.6 cu in per brace with a 14" circular hole, 18x18". Total for 5 braces is about .37 cu ft. This takes me down to 3 cu ft but doesn't include the driver volume or the plate amp. Not sure how to calculate that volume for those 2 items. I'm also thinking of doing the sandbox design unless someone says this isn't a good idea or has a better suggestion. I can't imagine how heavy these will be when they are done. 


Thanks in advance for the help. I greatly appreciate it.

[nottaway]

I think generic 15" sub displacement is somewhere around .10ft^3.  The sand box design is one heck of a box, those components will be properly clothed if not a bit overdressed in that!   

[mcgsxr]

Danny will likely chime in with suggestions around the displacement specifics of the pieces in question.

In terms of accounting for them, I would worry more if you are going ported.  A sealed design is pretty tolerant of 10% volume changes, without dramatic changes in frequency response.  However, it will not dig as deep overall.

Ported will go deeper, but in my experience is much more sensitive to errors in tuning (displacement and port calculations).

With a pair of 15's, and a pair of amps, I have to ask - are you after the deepest possible extension, or outright slam?

If you can help us determine the trade offs you are willing to make, I am sure there are plenty of folks that can chime in with their own build experience, and how design vs reality was or was not close etc.

[t-dog]

After looking at my options for placement again I just don't see how I am going to get a ported design to work with such a limited height restriction. I'm sure a design could be made to accommodate the 20" height I'd like to stay within but maybe it's just best to stick with other designs.

As for what I'm looking for I'd have to say I am more in this for reproduction of movie soundtracks more than music quality. While I might occasionally listen to music in this room I can honestly say that the room will be 80% movies, 10% Gran Turismo 5  and the rest music and the occasional sports game on Direct TV.

Here is what is currently in the room if that helps give you some idea of what I am starting with.



I am not that concerned with shaking things off my walls nor do I want muddy bass. I would like the sub to play as low as needed to reproduce deep bass found on movie soundtracks but I don't need that feeling of having my chest crushed. I am actually content with the AV-3's I have but run into problems in action movies as they just cant pressurize a room of my size nor play deep enough.

I am more than willing to make 2 different designs if that is an option so that I might have the best of a few design options. OB and Sealed? I am really looking to you guys for advice. I am a pretty skilled woodworker so with a little direction I can pull off the design options.

Lastly as far as ported goes I also am reluctant to deal with this just based on sure weight. While the stage is acoustically as dead as I could make it (it's over the garage) I don't want to add more than 300 pounds of weight to it. Here is the stage.





Thanks in advance! I appreciate the comments so far.

Lastly. I am finding trouble picking up some 3/8" MDF for the inner box (Assuming I go with a sandbox design). 3/4" is available of course. Is standard particle board a NO NO for the inner box? I'm sure I can get the 3/8" MDF from a lumber store during the week and have problem waiting.

[corndog71]

A single sealed servo subwoofer should suffice.

[HT cOz]

Tdog,

That is a great looking project.  That stage looks very nice and those speakers look like a pro built them.  How big is your theater room? 

Do you have any areas that you could do an IB sub, perhaps in the middle of your ceiling at the front of your theater?  Then you would not have to build a box. 

The single greatest improvement that you can make for your project is to plan on some minimal room treatments.  Treat the corners for bass and contemplate absorbing the first reflection points.  My brothers HT is 3x larger than mine but has no treatments.  I think my smaller room with treatments might have an edge...

I can tell you that since my project has been completed my wife and I have enjoyed watching movies so much more.  Redbox Blurays are fantastic...  You are going to love your new room!

[t-dog]

That is a great looking project.

Been a lot of fun so far! 

That stage looks very nice and those speakers look like a pro built them.

Appreciate the compliment. I'm no pro but have some good woodworking skills.

How big is your theater room?

19'8" x 17'3" x 9'

Do you have any areas that you could do an IB sub

I have considered this option as there is attic space over the room and to the left of the stage. Here are the issues with IB. It is nearly impossible for me to get to the space over the room. While there is a few feet (maybe 3') I cant really crawl up there due to the blown in insulation. I'm sure I could push it off to the side to make a nice crawl-way but then I have to deal with that and reinsulating it when finished. Also now that I already have 2 SA-1 amps what would I do with them? I know Danny is a nice guy and would allow me to return the amps but I don't like sending stuff back and possibly taking a restocking fee. Could you use these amps to drive an IB setup? From my reading on Cult of the IB website it looks like 2 15" drivers is not enough. There is a possibility I could do a manifold over the front stage and not really ever need to go into the attic. I have a lot of wiggle room with wiring in the room since I'm building everything myself and hiding wiring isn't an issue. I could mount the manifold then fish the wire to the nearest wall (only a few feet away) and run it to the equipment rack, which is on the front wall. Here is a very messy picture of what I have done on the front wall so far. Keep in mind all of this will be covered with black cloth and there will be fabric covered doors covering the cabinets. I really regretted putting the cabinets on the front wall but was really limited on locations in this room and needed an equipment rack somewhere. I worry about controlling the sound on the stage since corner traps aren't really conducive to the way the stage is.

As far as sound control goes in the room. I have Linacoustic RC on the front wall already and plan to have it from the ground up 4 ft. around the perimeter of the room. Above that there will be cotton batting up to the soffit which I still need to construct. I was planning to stuff the soffit as well to add more bass trapping. The room has double sheetrock with Green Glue between it.





You are making me feel IB might be a better option now but I was really shying away from this due to the possible cost of so many drivers and the amp. Maybe the cost isn't all that different. At this point I'm into it $460 bucks or so with the 2 15"s and the 2 amps. Are these drivers good for IB setups? Are 4 MFW-15’s enough for an IB? Could you use the 2 SA-1's to drive an IB setup? Sorry for being all over the place on this project.

[Ron]

T-dog,

 Your speakers look great as well as your new stage area!  Beautiful cabinet work. I have a pair of AV-3's and they do sound great with movie sound tracks. The AV-3's in my opinion are a little more lively sounding without sounding overbright compared to the N3. The N3's have a smoother, more detailed sound quality.

[t-dog]

Thanks Ron.

Assuming IB even becomes an option this seems like the most likely manifold I would need to use.

[HT cOz]

Very nice setup.  I like the racing wheel and pedals  I'm not sure if the MFW 15 are appropriate for IB, but I'm sure the SA-1 amp would work as it is built to run OB subs.  Do you know if the MFW driver is 4 or 8 ohm?

On the other hand messing around with that blown in insulation is a major pain.  I was fishing through it for my cables and it sucked.  I would think in building a sealed sub is best as long as you get the volume correct, and brace the heck out of it, I wouldnt worry about not having the exact MDF available.  You could glue two sheets together if needed in some areas and use either Baltic Birch or MDF for interior braces.  What about building a box shapped like this /_| to go under the screen?  Surely you can work around the height issue?  Is there room above your cabinets for the subs? 

Again great looking project.  Thanks for posting some pics.  Be sure to come back and post finished pictures.

[Danny Richie]

A sealed box will be the easiest to do, and making it rock solid (like a sand box) will give you great sound. And mcgsxr is correct.

A sealed design is pretty tolerant of 10% volume changes, without dramatic changes in frequency response.

You also don't have to use 3/8" thick panels for the inner box. You can use 1/2" thick wood if you like, or even 3/4" if you really want to make them solid.

If you go IB then the SA-1 will be ideal as it not only adds a transform circuit but a 20Hz rumble filter to keep the really low frequency stuff from bottoming them out. Just keep in mind that it puts as much low frequency information in your attic as in the room. So if your attic is vented then you might easily hear the rumblings down the street and around the block. 

[HT cOz]

Check out Voncarlos gallery for some great ideas on room treatments.  I would have loved to see these ideas before I got so far along in my own build.  http://www.audiocircle.com/index.php?action=gallery;area=browse;album=4012

[t-dog]

Went sandbox sealed route. Here is where I'm at on 1 of them. The other is half way to this point.

Weight of the box in it's current state completely void of a driver and amp, 115 Pounds.




Getting ready to paint them soon. Goin truck bed spray route. Never gonna see these so I'm going the easy route. 

[jeffh]

Getting ready to paint them soon. Goin truck bed spray route. Never gonna see these so I'm going the easy route. 

I've thought about that.  I think it will look good and help make the box dead. Are you going to DIY or take it to Rhino Linings, Line X or some place like that?

[hayden]

I would suggest this product:

http://www.acrytech.com/catalog.asp?prodid=547778

Many people, including me, have had good luck with it.

Jim

[t-dog]

I would suggest this product:

http://www.acrytech.com/catalog.asp?prodid=547778

Many people, including me, have had good luck with it.

Anyne have a link to a finished product that uses this finish?

[Danny Richie]

Went sandbox sealed route. Here is where I'm at on 1 of them. The other is half way to this point.

Weight of the box in it's current state completely void of a driver and amp, 115 Pounds.

Getting ready to paint them soon. Goin truck bed spray route. Never gonna see these so I'm going the easy route. 

Nicely made. 

[jeffh]

Anyne have a link to a finished product that uses this finish?

Here you go:  http://www.lonesaguaro.com/speakers/Buyout2/Potables.html

[chip]

I used that on my GR Subs -

[Downer]

Did this ever get completed and/or how does it sound?