RLP-18" LLT box

**mi. bill** · **06-03-08, 09:25 PM**

hello everyone I'm building a subwoofer box.it is about 698 liters before subtracting for the port. driver. bracing. etc. it will be my fist sub build. I got it from ss around last November while i was waiting for an sr-71 speaker kit. now I'm ready for a sub. I never tested the rlp-18 when I got it because I didnt want to hurt it. how should I test it to make sure it works? also what to line the box with premium carpet pad. ridged foam insulation. mattress foam. rigid fiberglass. fiberboard. acoustic ceiling tiles. and how thick? it would be nice to use something I could buy in a store here in town. the box or enclosure is in a perminit location boarded by a closet, wall back of fireplace,wall on the side front firing. port in side wall. rear projection TV on top. 8"port 28"long. I have wire terminals but I'm thinking of just ruining wire Thur the box it would be one less connection whatdaya think. I have very much enjoyed reading these threads and building, then reading, then building. then hearing some good sounding music. I will try to put some pics on here. I,m not so good on my computer yet. something about pic to large. anyway thanks very much to all of you . bill

**Blaser** · **06-04-08, 02:22 AM**

Welcome Bill,

Box sounds big for a rl-p18. What's the tune?

**Mike P.** · **06-04-08, 03:55 AM**

The net volume would be around 645 liters, depending on how much bracing you used. Tuning would be 13.5 hz. For lining the cabinet, I use mattress foam, just make sure it's the open cell type. It's cheap and easy to install. If you have the wire terminals, use them. It's easier to connect and disconnect if the sub would ever need to be serviced. If your pics are to big to upload you'll have to make them smaller. If you're using Windows XP, you can download a program to resize them.

http://www.microsoft.com/windowsxp/u...schelman2.mspx

**Blaser** · **06-04-08, 02:52 PM**

I used 625 L net and tuned 13.5. Very nice!

**mi. bill** · **06-04-08, 06:34 PM**

yes the box is big. I can always put. a log in it. or a balloon. just kiding. I put resize on my computor. lets see if it works.

**mi. bill** · **06-04-08, 06:48 PM**

hey Mikey! I like it. that hole in the wall is for the port. here is more.

**mi. bill** · **06-04-08, 06:55 PM**

if I put more bracing in it will the tune go up a little. whats good 14.5?

**mi. bill** · **06-04-08, 06:59 PM**

port.

**mi. bill** · **06-04-08, 07:05 PM**

tv will go on top.

**Mike P.** · **06-04-08, 10:03 PM**

Quote:

if I put more bracing in it will the tune go up a little. whats good 14.5?

Your box is so big that adding a cubic foot of bracing to what you already have would barely affect the tuning. To find out what the tuning really is, you'll need to add up all the bracing, the sub and the volume of the port and subtract that from the internal dimensions of the box. Gotta tape measure?

If you will be placing a TV on the sub, I strongly suggest you add some shelf bracing to your box. You don't vibrations transfered to your TV.

**mi. bill** · **06-04-08, 10:54 PM**

that's as far as I got so far. more bracing to come. I can subtract the driver and port volume and 1cubic ft of bracing that maybe close to 650L. is bigger than that bad?. 26.5 h 29.D 54.5w.

**eyekode** · **06-04-08, 11:08 PM**

Woah that is a box. But I would not put a TV on it. I built a sub that fits into my entertainment cabinet (measly ported 12" driver) and even at less then half volume it causes sympathetic vibration in the TV cabinet. I am in the process of trying to isolate/dampen the cabinet now.

**Mike P.** · **06-04-08, 11:28 PM**

The setup is in a good location. A shelf just above the sub should work.

Quote:

I can subtract the driver and port volume and 1cubic ft of bracing that maybe close to 650L. is bigger than that bad?.

Not at all. There are bigger builds then yours in the Database.

http://www.hometheatershack.com/foru...-database.html

**mi. bill** · **06-05-08, 03:07 AM**

holly smokes! you guys. I never thought about the poor TV. if the vibretions killed my wifes big old tv I might have to get a front projector. hey mike, what would the shelf sit on? maybe I could put a matress between the box top and the tv. its very big and heavy. it will take a forklift to get it up there. I think I'l look inside that monster and see if I can take some stuff out. like the speakers. ect. I'll wait till the wife leaves.

**Mike P.** · **06-05-08, 06:35 AM**

Post the make and model of your TV so we know what we're dealing with.

**mi. bill** · **06-05-08, 10:23 AM**

it,s a toshiba 53ax61.

**Mike P.** · **06-05-08, 03:18 PM**

Well that changes things a bit! I was not expecting it to weigh 240 pounds! I'm not sure what to suggest here. Hopefully someone will join in with an idea on how to isolate the TV from the subwoofer.

**hot grits** · **06-05-08, 08:56 PM**

How bout building a heavy duty shelf above the sub. You have 3 sides so it should be pretty easy to support the shelf. Use 2x4s on edge, sort of like a sub floor. Attach a sheet of plywood on top.Cover the front of the 2x4 with a nice piece of 1x6 ripped down to 5 inches or so, for aesthetics. You can try putting 2 auralex subdudes on the shelf under the TV. That might help a little.

**mi. bill** · **06-05-08, 09:53 PM**

those are neat. MR HOT G. never seen um before. I,ll keep them in mind. first I,ll try some home made stuff.

**mi. bill** · **06-09-08, 11:09 PM**

say. has anyone used spray-on foam for the inside walls.

**mi. bill** · **06-09-08, 11:13 PM**

more bracing on the way.

**eyekode** · **06-09-08, 11:14 PM**

Do they make a spray-on open cell foam? I don't think a closed cell foam would have the desired effect. I think it would mostly just eat volume.

**mi. bill** · **06-09-08, 11:42 PM**

I,m not sure they make a kit for open cell foam. when retro foam came out an sprayed the inside of my garage roof it was open cell. what about the canned foam called great stuff. it dose not say opened or closed. no one at manards knew what I was talking about. but if its going to be bad to use closed cell foam wont use it. I sent for a greenfoam kit already I,ll use it for something else. it would be nice to spray on something. thanks for the heads up. MIKE P. also said make sure its open cell foam so that makes it unanimous.

**Owen Bartley** · **06-10-08, 10:19 AM**

Hi Bill, you definitely want open cell foam, otherwise you aren't giving the air any room to move. You can use fiberglass, polyfill (I think it's used for crafts and available at WalMart), or anything similar, but for a ported sub, you shouldn't need much. Maybe just a thin layer to line the inside of the sub. Usually sealed subs get stuffed to fool the driver into thinking it is in a bigger enclosure (or something like that).

**mi. bill** · **06-10-08, 10:57 AM**

thanks -OJ- I.m headed to walmart. can I glue it over the ribs or cut it and glue it only to the walls.

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