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View Full Version : Custom Sub built into floor joists, any thoughts?



The8thst
01-31-2005, 09:48 PM
I have a client that NEEDED to have all the equipment in the family room on the main level of the house (resulted in 2 middle atlantic srs4 racks 15spaces tall on each side of the fireplace.... real fun) and used up all the possible locations for an inroom sub, so we need to put it in the floor joists.

We found out too late that the house (built in the mid 40's) had Wirsbo heat added a few years ago, so we cannot safely put any big holes in the floor. Now we have a vented toe kick in the custom cabinets and only a 3" hole down into the floor joists which we were lucky to have a pre-existing hole.

Have any of you had to deal with this? do you have any pointers?

Best to solidly attach the sub box to the floor structure of the house, or to isolate it (hang it from 4 cables that are screwed into the joists)?

Work out a box with a port design where the port itself goes through the 3" hole and use that to move air in the main room?

Make an aesperiodic vent by making a sealed enclosure with the sub firing into a second air space that is sealed except for the 3" hole and restrict the airflow through that hole?


Just tell the client that there is no way to get decent bass response through a 3" hole and FORCE them to find a place to set an in-room sub?


The rest of the speakers are Paradigm Studio 20's, matching center channel, and the clients existing monitor audio speakers as rears. The amplification is done via a B&K AVR507.


Thanks for the help,
Pete

PHSJason
01-31-2005, 09:53 PM
Funny you should ask. I have a picture (http://www.integrationpros.com/modules.php?name=coppermine&file=displayimagepopup&pid=49&fullsize=1) on this site of a sub we just installed into the floor of a theater:
. The sub fires up into the floor through a standard floor register. The port was dual 3" ports that are 9.75" long. I can get you specs if you like, but the end result was a five cubic foot box tuned to 32hz, with a 3db down point at 25hz on the low side and 3db down at 67 on the high side. Very smooth with no port noise. We ran some test tones from DVE through it during pre-wire to make sure all was well and the low frequency transfer below 30hz was VERY impressive. We do a lot of in-floor subs and have yet to not have a happy client.

As for mounting it, we like to couple it directly to the floor, but we install a membrane to keep the box from buzzing against the floor.

If you are looking for a pre-built answer, James has one that will fit the bill:
Snuffleufugus (http://www.jamesloudspeaker.com/powerpipe.cfm)


Jason

mr2channel
02-01-2005, 05:52 AM
everything Jason suggested is right on and should work for you, minus one small issue, instead of two 3 inch ports you will only have one, and going back to speaker building 101, to tune that port properly, with a three inch port dia. you will either have a long ass port, if it is a larger driver, or a smaller driver that tunes with a shorter 3" dia. port. I like the in floor sub option based on what you are trying to do, but if that does not work out, you may want to consider an in wall sub. Truaudio makes a decent dual 8" inwall that requires an enclosure, so it is not as bad as you would expect, if the client is hardcore on astetics, then stealth acoustics makes an inwall sub that you mud up to the corners, sand and paint or wallpaper right over, they will never even know its there, as long as the finish on the mud work is good.

let us know what you end up doing, these are the fun projects that usually bring about good definitions of "custom installation".

LarryFine
02-01-2005, 07:40 AM
Also, take a look in the Cult of the Infinitely Baffled site:
http://f20.parsimony.net/forum36475/

PHSJason
02-01-2005, 08:44 AM
everything Jason suggested is right on and should work for you, minus one small issue, instead of two 3 inch ports you will only have one, and going back to speaker building 101, to tune that port properly, with a three inch port dia. you will either have a long ass port, if it is a larger driver, or a smaller driver that tunes with a shorter 3" dia. port.

Not entirely true. The port length is a product of woofer specs and enclusure volume. In car audio were space is limited, a 3 cubic foot bandpass enclosure for one woofer is almost uneard of. In most of the enclosures we do, we have unlimited space. The last one we built was 14" X 11.75" X 68" which is just under 5 cubic feet for one 12" woofer. The dual 3" ports were correct for this enclusure, or we could have used dual 4" ports at 10.25" long.
We have built smaller boxes for in-cabinet applications and then you are correct in that in order to properly tune them the port length gets very long with a single port. I had to build a 10" enclosure a year or so ago that had a 2"x 10" vent that was 28" long to properly tune it.
Just to be sure the enclosure was designed and modeled in term-pro to make sure the curve was what we were looking for based on the room requirements.
As with all aspects of our business each application is unique.

Jason

install1
02-03-2005, 06:40 PM
James Loudspeakers actually has the product you need. We just put one in and it works great.

Caffeinated
05-11-2005, 01:04 PM
The James powerpipe has a toe kick adapter plate - designed to mount in toekicks. and it truly is a killer sub. Plays very deep and tight. External amp also ,, so you dont need an outlet where you'll mount the sub.

http://jamesloudspeaker.com/speakerdetail.cfm?id=47

Matt
05-14-2005, 01:40 AM
James is the only speaker line I have been excited about in some time. The power pipe is awsome just dont alter the pipe or toe kick piece or you'll get port noise.

Woody
05-25-2005, 05:10 PM
We just installed a powerpipe and toe kick and it ROCKS!!!
Mike