I want to turn my garage into a subwoofer cabinet (1 Viewer)

[Michael Merrell]

Hi, my name is Mike, and I want to turn my garage into a subwoofer cabinet.

I moved, about a year ago, and I'm not sure that I'm satisfied with the bass output of my SVS PCi 16-46 in my new room. The old room was 1800 ft^3, and the new room is about 4800 ft^3.

Most of my fun projects are on hold while we work on installing new flooring, kitchen cabinets, and a few structural modifications. One of the things on my list for when some time frees up is building a new sub for our theater room.

I had been focusing my attention on either a big box or sonotube design when I found the IB projects.

The room is built over my garage, and I'm considering cutting a hole between the joists beneath the center channel and screen, and mounting the speaker enclosure below. The room has a vaulted ceiling, so there is no attic, an the only closet is in a rear corner. I'd use the bathroom (heh!), but it's next to the closet.

Some questions:

1) How well sealed would the garage have to be?

2) If I wanted to mount four drivers, initially or at some point down the road, one of them would back up to a wall. Does this matter on the IB side of the driver?

3) What kind of drivers am I looking at for HT usage at reference levels (max) in a 4800 ft^3 space?

4) How do I hide this from my wife?

Thanks,

--Mike

 

[Mark gas]

Do a IB setup so there will be no need to seal the garage.
Do a search on IB in this forum and you will get a ton of info.

 

[Chris Brock]

yup, there is a ton of info out there. the best information about IB is available at http://f20.parsimony.net/forum36475/

You will find basically everything you need to know about IB there. I just got through setting up my IB and I will tell you this, I will never have any other type of sub from now on. You would definitly want to check out the gallery at that site. It has a ton of different installs and you should see several that might be a possibility for you. I would post pics of my IB but we just moved and I still do not internet access from my home PC.

 

[Bryan Michael]

ps also the wall to the gurage is a fore wall and has to be rated at least for a 1 hour so if you sell the house you will ned to remove the sub and replace the drywall and if you have a fire the insurance might be a little tricky to

 

[Michael Merrell]

Yeah, I'm doing some construction in the garage, right now, and will be getting it inspected when I'm done. So, any work on the IB side will have to occur afterwards. Honestly, I'd like to rig up a way of covering and sealing the drivers and manifold on the garage side so that the assembly doesn't get sawdust in it when I'm doing any kind of wood working in the garage. Now, whether that cover is fire-rated, or just some plastic is another question. But, undoubtedly, I would pull out the manifold and patch the floor and ceiling to bring things back up to code before selling.

Is the insurance/code equation any different when the attic is involved?

Thanks,

--Mike

 

[Michael Merrell]

I did a little thinking. Perhaps it would be easier to use an inverted manifold, which would give me the option of making a trap door on the ceiling below for easy closure when it's time to make sawdust...

I'm going to start searching the forums for the benefits and drawbacks of an inverted setup, but I'd be glad to hear what people have to say about these options here, too.

Thanks,

--Mike

edit: reading this link, now.

http://f20.parsimony.net/forum36475/messages/3007.htm

 

[John E Janowitz]

Michael,

there really shouldn't be any drawback to the inverted setup other than appearance. You are now stuck with seeing the woofers in the room as opposed to having a small opening that can be hidden pretty well. In either case you need to make sure your plenum is not restricting the airflow at all.

The only other issue i see with the opening to the garage is that gas fumes and exhaust will be more likely to enter the room. Whether this is an issue or not, you would have to decide.

Another option that can work well is to build a stepped stage at the front of the room under your screen and use this as the subwoofer enclosure. You could also come down into the garage with a large vented enclosure. I've done a few stealth subs where a pair of 15" drivers fire into a slot 6" tall x 18" wide and 40" long and then out through the 6 x 18 opening in the wall. In these I ran the vent into the same slot. All that was seen in the room were a pair of 6" x 18" openings covered with a grill to match the room trim.

Although infinite baffle's are nice, there are many other ways to get as much or more output and still have a hidden enclosure. You can often gain even more output with a very large vented enclosure. The same amount of displacement and power input can give you 6dB or so more output on the low end if you do it properly. IB is typically the easiest way to get good results though.

John

 

[Michael Merrell]

I guess my focus is less on stealth and SPL, and more on quality. From what I have been reading, the IB configuration provides excellent bass if you have the structure available to construct one.

While I don't have any really good spots for corner placement, there's plenty of room on the right wall where my SVS is placed now. As I mentioned in my original plan was to build an uber sub for that wall, but an IB sub looks like an easier way to get results that are as good or better.

I'm not too worried about exhaust, given the sealed nature of the manifold, which I would make sure to extend all the way through to the garage, taking care not to allow air movement into the intra-joist space.

The stage idea is a good one. I do want to construct a proper frame for my screen (which is currently spring-clamped to the stair railing), with adjustable masking. IB or not, I could make a deeper (than the screen) portion down low that could hold the woofers, whether centered or out towards the mains.

Thanks,

--Mike

 

[Cam McFarland]

Mike,
I had this same idea a while back & it was mentioned that
the garage doors and all might rattle & be loud "outside" the house as this was my concern at the time.......

 

[Michael Merrell]

Cam, you said "at the time." Did you go a different route, or have a different result?

I think I've nailed down the "outie" or inverted option.

I'm also considering a different, more standard (under-floor) option. If instead of focusing on a single, centered manifold with four (possible) drivers, what if I made two manifolds, one by each main speaker, with two drivers each?

If I extended the two sides, and bottom, of the manifold box that do not hold the drivers to the same depth as the driver, I could cover that opening with acoustically transparent cloth (as hase been suggested for the ceiling opening if I do an outie) to keep out the dust.

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Top view, could also be a side view, sorta, with the .s representing cloth. That would allow free flow of air, but more easily allow for the opening to be closed off, or filtered, if necessary.

I hope I'm driving people crazy with questions about different approaches. I think I have as much fun figuring stuff out as I do completing the task.

Thanks,

--Mike

 

[Cam McFarland]

Sorry Mike, I guess just a poor choice of words. I have not
done an IB "yet", but probably will in the near future. I knew that it was just as loud on either side of the baffle, & was just curious how loud it would be outside the garage
when it was closed up as i didnt want to impose "too" much
on the neighbors....:wink:

 

[Michael Merrell]

I'll be running a table saw, and other assorted tools, plus dust collection in the garage. I'm not sure which will be louder...

--Mike