Dual RL-p15 D2 LLT Sub Project...

**Sonnie** · **02-15-07, 02:27 AM**

True... I can take measurements first. Even with the SBS-01 system I use 80Hz... I may try 100Hz, but there could be localization issues with those rear subs, that's one reason I wanted to keep it at 60Hz back there.

**aceinc** · **02-15-07, 09:19 AM**

One last thought. This assumes side or front firing drivers.

If you need extra volume for this enclosure, look down. It appears that you are placing the sub(s) on a platform. I suspect that if you wanted to go hog wild you could get as much additional volume as you want/need by opening the bottom of the cabinet and put a hole in the platform, mounting the bottomless cabinet over the hole.

This might entail pulling the floor partially up to beef up the cavity, put in the appropriate cross pieces for volume, seal everything, etc. This should allow for a smaller box behind the recliners.

Paul

**Sonnie** · **02-15-07, 09:35 AM**

I think I'm good on volume and have some room to get more. There are some good cavities in that riser though, but I'm not sure how well sealed they are with wires going from one cavity to another, etc. It would definitely be a complicated case of having to remove the carpet and I know the floor is liquid nailed to the floor joist.

I would still like you guys opinion on using PVC for the port, the binding posts and do I need polyfill. Thanks!

**Sonnie** · **02-15-07, 09:44 AM**

I'm not sure what I was thinking, but I'm moving this to the SoundSplinter forum.

**aceinc** · **02-15-07, 09:50 AM**

Sonnie:

I understand, it would be a lot more work.

Should I ever have the opportunity to build a purpose built home theater I have always envisioned using the platform for my sub(s). Living in S. Florida, we don't have basements, and attics are very hot most of the year, so IB's are fairly impractical. SAF dictates unobtrusive, plus I hate to waste space.

It's a shame you weren't just building the room

Paul

**Sonnie** · **02-15-07, 09:58 AM**

Yeah, when I built that room I had never even heard of IB or LLT subs and would surely never have thought of doing anything with the riser. That is some really good space that could be put to use though.

**Rodny Alvarez** · **02-15-07, 08:43 PM**

Why you guys don't like slotted ports???
I don't used round ports any more when I build boxes, I build slotted ports or triangle ports, it's easier build the port when there is not enough depth for the round port.

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**Exocer** · **02-15-07, 09:44 PM**

Rodney, nice job on those ports. I don't see anything wrong with those

Sonnie, if you're set on an 8" port, why not 8" diameter sonotube for the ports? I've seen that done a few times.

Some food for thought...WillD uses a 6" precision port with his TC-2000 LLT and hasn't reported a single port chuffing issue.

**SteveCallas** · **02-17-07, 01:09 PM**

8" would be too large for a single RLp-15 sub with a low tune. Slot ports create more turbulence than a cylinder, especially when 90 degree angles are used, and one of the goals of a LLT is to eliminate all potential air movement issues with ports. Stick with cylindrical ports if at all possible.

**Sonnie** · **02-17-07, 02:35 PM**

I'm not sure what I can find in 6" tubing, but Montgomery is pretty big. Rodny may know somewhere where I can get something similar to Sonotube... but I'm thinkin' it's probably gonna be easier just to pick up some 6" PVC pipe.

**Sonnie** · **02-19-07, 01:56 PM**

I think we have our final dimensions:

I believe I'll go with one solid box and seal off each enclosure.

Figuring about 30 liters per box for the drivers and the bracing, that should give us about 265-270 effective liters per box/driver, which is what I believe we were shooting for.

Does this appear it will work okay?

Thanks!

**Sonnie** · **02-19-07, 02:03 PM**

If I've calculated correctly this will yield about a 14Hz tune with this net volume.

**Rodny Alvarez** · **02-19-07, 09:09 PM**

Do you guys think this will work ?

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**Chrisbee** · **02-20-07, 06:30 AM**

It's looking good. Now all you need is NASA to deliver it to the launch pad.

**SteveCallas** · **02-20-07, 01:54 PM**

If the goal is to treat them as two seperate enclosures, I would do just that, keep them as two seperate enclosures, otherwise, there really is no benefit to having a divider. Two seperate enclosures will be easier to move and allow some fine movement between the position of the two if need be. If you'd prefer to keep it as a single piece, I'd eliminate the dividing wall and just make it another brace, making it a single sub with two drivers.

Aside from that, I'd maybe position the port a bit higher so as not to obstruct the vent of the drivers and shave a bit more material off the braces around the port if possible. Ryan used what I believe were some 1"x1"s running the length of all 90 degree corners as further bracing, and since you have no horizontal bracing, I'd definitely recommend using some 1"x1"s from brace to brace horizontally at the top, bottom, and in the middle of the back wall. On the front angled wall, you could do the same though it wouldn't have to be in the corners. See attached.

**Sonnie** · **02-20-07, 02:33 PM**

Whether it's one unit or two... there's really not going to be room for movement.... not even fine movement. It has only one position with no options for even moving it one inch left, right, back or forward. This was one of the reasons I would rather have one unit, so that I wouldn't have to worry about keeping the two units separated or either have to connect the two together and having a seam.

The purpose of separating the tow inside via the divider is to allow two ports, one on each end to keep a port near each driver.

Is there any benefit to having the two in the single enclosure with one port vs. two separate enclosures with a port in each enclosure?

**SteveCallas** · **02-20-07, 03:15 PM**

You can have the interior space open, making it one sub, and still use the two ports. The drivers will couple with and "activate" both ports equally as long as they are the exact same length. That said, a single 9" port would still be better than two 6" ports in terms or corss sectional area.....but on the other hand, the two 6" ports will allow for a slightly lower tuning when keeping first resonance in mind.

**Rodny Alvarez** · **02-20-07, 05:08 PM**

Sonnie!! are you sure we can get the box inside the HT??:holycow:

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