Dual RL-p15 D2 LLT Sub Project...

[Sonnie]

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]

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]

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]

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

[aceinc]

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]

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]

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.

[Exocer]

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]

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]

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]

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]

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

[Rodny Alvarez]

Do you guys think this will work ?

[Chrisbee]

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

[SteveCallas]

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]

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]

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]

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

[Sonnie]

SteveCallas wrote:

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.

Just to clarify... it's okay to stay with the same size volume and ports that we have now, but open up the center divider making the interior all combined volume with no sealed divider?

Rodny Alvarez wrote:

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

"we"... ??? I am excited that you are willing to come to the house and help me install it... It will fit, but we'll have to move the recliners out of the way. No doubt it will be extremely heavy, but you are all muscle...

[Rodny Alvarez]

Like I said before... a possum or deer sandwich will be good.
Are you bringing the camera tomorrow?
Somebody is coming thursday to see the TV and the speakers!!!, if they buy something I will have money for the Toshiba XA2

[Sonnie]

Yes... I'll bring my camera and be there at the shop at 7:30am. That means I gotta get up around 6am you know... that's gonna cost you extra...

Maybe you'll sell them both. My XA2 is already sitting at the office.

[SteveCallas]

Sonnie wrote:

Just to clarify... it's okay to stay with the same size volume and ports that we have now, but open up the center divider making the interior all combined volume with no sealed divider?

Yep. I wouldn't brush off the 1x1s though, and I'd position the ports a bit higher up. It's much easier to spend some time do a few things to try and overbuild now than it is when it's all built and closed up and you notice a resonance or something like that

[Sonnie]

We'll move the ports on up higher and include the 1x1's as well...

[Sonnie]

Rodny and I got started pretty early this morning and worked on it for a few hours. We mainly got it all laid out and most everything cut with a couple of pieces together, but nothing worth taking any pics of yet.

I spent some time, more than expected, finding the 6" PVC. Had I been in Troy where I work, it would have been no problem, but in Montgomery it was a challenge. The plumbing supply store wanted 80 bucks for a 20' piece. I was in my car and needed the pieces cut to the 35" lengths. The guy says, "I'll give ya a saw to go cut it with." HA-HA! Yeah, I could see me paying 80 bucks and spending an hour cutting that stuff with a hack saw... I don't think so.... I went around the corner and found a plumbing company that had a piece left over and the guy there cut both pieces for me and 10 bucks later I was out the door on my way back to the shop.


Btw Rodny, the drivers came in today.... I'll bring them with me Saturday.

[Sonnie]

I never got an answer on the polyfil from anyone... is it necessary for this sub?

Thanks!