or Connect
AVS › AVS Forum › Audio › DIY Speakers and Subs › 2x 18" LMS Ultra 5400 in 27 cubic foot 15hz vented enclosure build thread
New Posts  All Forums:Forum Nav:

2x 18" LMS Ultra 5400 in 27 cubic foot 15hz vented enclosure build thread  

post #1 of 46
Thread Starter 
This is a continuation of this thread. Most of you are familiar with my current setup which is pretty over the top and think I'm crazy for wanting more. Regardless of that, I do want more. I feel the sealed enclosures I built left a lot on the table between 10-35hz that I can pick up by going with a vented alignment. I'm going to try to pickup a few sheets of ply tomorrow and get this build going. I'm starting with one enclosure to test and tune with, then will build three more.

The outer dimensions of this measure 48" long, 46" high, and 30" deep. Ports will be oriented on the sides as I will be stacking these.

Since there is some debate on the vent length, I'm starting it out at 40". I will test and add more as necessary, with the end goal being a 15hz tune. Do not try to build this until this is complete. I will update the dimensions/cutlist with the proper sized inner vent piece when complete.

I will not be adding any damping. The enclosure will be braced by 1" dowels and/or scrap ply. It will be a challenge getting bracing in while having the port in a position where I can add more length to it, but I'll figure it out when I get there. I'll be using some kind of 3/4" ply for the build. These are going to be heavy.

Sketchup file: download

Visual stimuli below.

Modeled at 6200w with 14hz 3rd order butterworth highpass.

SPL:


Excursion:


Port Velocity:


Comparison to my current setup once all 8 are built.


Enclosure:




Cut List:


Cut Sheets:




Edited by notnyt - 12/8/13 at 4:35am

Gear mentioned in this thread:

post #2 of 46
Thread Starter 
Gonna nap for a little bit now, but if the weather holds I'm off to lowes first thing to grab the rest of the material I need.

I'm thinking of trying this with titebond instead of PL. That stuff works good, but its so nasty. Thoughts?
post #3 of 46
The new tightbond isn't bad but can be runny as hell. Use screws too IMO; that beast will try to push itself apart. GoodLuck!!!! biggrin.gif
post #4 of 46
Thread Starter 
I'll be using my brad nailer, much faster that way. I just worry about the seal with titebond.... so not sure if that or PL is on the agenda frown.gif
post #5 of 46
Either way if your cuts are perfect. For cleanliness and less headache - titebond your joints and a bead of pl or silicon free caulk on the inside corners you can hit for insurance. Pl on your final side panel and the dowels.

Also, I really like using the brad nailer for smaller panels, but the Kreg system is your friend with big panels.
post #6 of 46
cool.

while not in the picture, I assume the braces will be longer than the initial port, so that you have the option of adding just one panel to increase length?
post #7 of 46
Cool Notnyt, I'll be eager to see how this plays out.
post #8 of 46
I'd use PL just cause it works GREAT!
Sure it's messy but I've learned to work with it and it works great!

I now NEVER wipe any joints, I wait 2-3 hours and cut them off as it's nice and soft still but not gluey anymore.

I love the stuff!

Anyways...looking forward to this myself too!!!!!
Thanks for all the updates you'll be doing

Sub'd!
post #9 of 46
Sub'd....watching this might help in the decision on box type for my build. Plus I know it's gonna be bada$$
post #10 of 46
^ ^ ^ bada$$ is right cool.gif

Well best of luck with the project, I hope it's exactly what you want and more.

Also, regarding this exercise, and knowing full well your astute observations, measuring chops, and best of all the willingness to document and share your findings here, ... will benefit the community in a big way. This will be very, very cool for sure.

I'm guessing it's been brought up already, but considering the size of the gen 2 vented cabs, I'm curious what impact, ... if any, you might encounter as a by product of the huge physical elements being up in the front of the room (additional acoustic interactions, SBIR/diffraction, etc). A bit down on the order of importance, but if consistent with experimentation performed in my room, ultimately the playback may benefit from some additional considerations.

I followed the development thread, much good discussion there. I did follow, but as I've got nothing to offer wrt resonant systems, I kept quiet and paid attention. Your idea to adjust vent length via driver openings will be pretty neat. Good luck on the tune.

Curious, somewhat OT, but certainly could tie into integrating these monsters once their built. Have you given any thought to employing a screen-wall or baffle-wall? As I'm sure you realize the wave-launch benefits are significant, as are the many positive by-products. You're to a evolution and development point in your system whereby much of the low hanging fruit may have been picked clean, and further tangible performance advantages become tougher and tougher.

Baffle-walls/screen-walls, they're certainly not for everyone or every room. You're really locked down wrt other room considerations. Also, they really magnify the rear wall acoustic needs and importance as well. It's just a thought, you've got a lot going on already, thought I'd throw it out there.


Anyway, good luck, and thanks for sharing all the details. I plan on watching this one closely.
post #11 of 46
I'd use PL. It's extra insurance. I also use a nailer but also use screws as no matter how you do it, a nailer will never be tight enough in the size of box you are doing. 100+ sub boxes built and these are things you learn. Unless you have 50 clamps, a few 1 1/2 screws on the joints is well worth the extra 10 seconds of work.
post #12 of 46
I'm making some slight alterations in SketchUp that could possibly shed some light on bracing. Will post when complete.
post #13 of 46
Awesome man!

This project will definitely reinforce the lower octaves. Looking forward to the results!


So few ported LMS builds out there. Cool!

.
Edited by jpmst3 - 12/8/13 at 2:39pm
post #14 of 46
Thread Starter 
Quote:
Originally Posted by LTD02 View Post

cool.

while not in the picture, I assume the braces will be longer than the initial port, so that you have the option of adding just one panel to increase length?

Extending the bracing will technically increase the port length, since you're essentially continuing the port on 3 sides, being the outer wall and the braces, instead of just 1 with the outer wall. I'll just add more bracing for it when i add pieces, not a big deal.

There's snow on the ground and it's set to rain for the next few days. This doesn't help me get the wood to my house, so this might get delayed a couple of days. Not too happy about that, but nothing to be done.
post #15 of 46
So, what I added was window bracing throughout, with the exception of the back wall where your port is. I used separate pieces in the model, but this could be fabricated from a single piece for increased rigidity and strength, if you have the leftover wood.

I doubled the width of the middle port divider. This gives you a nice wide landing point for two shorter pieces to meet instead of one long piece, so that as you're tuning, you're not trying to fit a long piece in there.

I also made some cosmetic changes just to add some flare. I have no idea what direction you're gonna go with them in that regard.

Let me know what you think.
Jim

Click me!

p.s. I agree that there aren't enough of these builds out there. I'm about to start my own LMS-U build once work slows down.
post #16 of 46
On a side note, if it were me, I'd increase the depth and cut down on the height, or orient the drivers vertically and slim it down. The "Monkey Coffin" look is just rough, even if it's twin Ultras.
post #17 of 46
"Extending the bracing will technically increase the port length..."

not sure about that. it would seem at first, but on second thought, where would the air go without extended bracing? just into the air from the other side of the port, so the net air flow in either scenario would end up being the same. then again. doesn't matter since you are going to measure and modify anyway.

as far as monkey coffins, i'm not really sure what that means. in quad sets, different driver arrangements can give rise to different effects though...







seems more like a personal preference than anything...
post #18 of 46
Thread Starter 
I put the drivers that way to keep them closer together. Didn't want the far ones ~7 feet apart.

LTD02, I was just going by what JL says re: effective port length http://www.jlaudio.com/header/Support/Tutorials/Enclosure+Ports/Tutorial%3A+Enclosure+Ports/287541


Jim, I don't have the depth to spare, so I'm going tall instead. It will not be the prettiest, but *shrug* it sure as **** will be loud.
post #19 of 46
anything new Not?
Tks
post #20 of 46
Thread Starter 
Weather is clear but cold today. Been snowing and raining since I started this thread. Going to get some lumber today when off work.
post #21 of 46
Thread Starter 
post #22 of 46
Here we go! Sub'd
post #23 of 46
Going with Arauco again?
post #24 of 46
Thread Starter 
they didn't have any. I went to a home depot and two Lowe's. ended up paying ridiculous price of 53 per board for some real nice 3/4 hardwood ply. unfortunately it's only five ply, but it should do fine. I just wanted t get the lumber situation sorted so I could get it built as soon as I had some free time
post #25 of 46
Double check all your boards. I did some of that stuff for my RE build, and while it looked great, there was a couple voids that I discovered WAY too late in the process that ran straight through an inner ply from one side of my baffle to the other. Any other side of the box would have been fine, but it took some serious measures to get it sealed up well enough...
post #26 of 46
Quote:
Originally Posted by d_c View Post

Either way if your cuts are perfect. For cleanliness and less headache - titebond your joints and a bead of pl or silicon free caulk on the inside corners you can hit for insurance. Pl on your final side panel and the dowels.

Also, I really like using the brad nailer for smaller panels, but the Kreg system is your friend with big panels.

dc...why silicone-free?
post #27 of 46
Thread Starter 
Silicon vapors can eat surrounds.
post #28 of 46
Quote:
Originally Posted by notnyt View Post

Silicon vapors can eat surrounds.

You could also use standard silicone and let it out gas for a week before installing the driver. But who has that kind of patience?? biggrin.gif
post #29 of 46
not, how far away from the center (between the subs) is the termination of the port?

This is something I have noticed over the years, all car audio related, that one of the drivers would unload sooner than the other and seemed to have a greater variance as the port terminated farther away from the center. In some of the larger ported enclosures I helped build, the drivers closest to the port were always the first to let go of the magic smoke when being driven to their limits. None of the drivers I used were of the caliber of the 5400, I just wanted to start the discussion, if there is any possible issue with mounting them side by side with the vertical port.
post #30 of 46
This is very interesting.
Wouldn't mounting the drivers one on top of each other eliminate this problem?
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: DIY Speakers and Subs
This thread is locked  

Gear mentioned in this thread:

AVS › AVS Forum › Audio › DIY Speakers and Subs › 2x 18" LMS Ultra 5400 in 27 cubic foot 15hz vented enclosure build thread