(4) 2x 18" LMS Ultra 5400 in 15hz 27cube slot ported enclosure

[bkeane1259]

Re: (4) 2x 18" LMS Ultra 5400 in 15hz 27cube slot ported enclosure

It won't but it ain't impossible. Duratex is tough. It will take much longer time to dry and cure but you can speed up the process with a heat gun or blow dryer. Don't get too close with your heat source.

I wonder how my duratex is gonna like the cold :(

[wtr] Mastic Beach, NY (Clear/11.9|2F) H:50% W:6.0/20.0WSW

[johnnyrichards]

Re: (4) 2x 18" LMS Ultra 5400 in 15hz 27cube slot ported enclosure

I had very good luck this fall/early winter in the cool (not frigid) temperature range of 30-45 degrees using a heat gun. I heated the surface first, and rolled a coat on. Repeat.

[bkeane1259]

Re: (4) 2x 18" LMS Ultra 5400 in 15hz 27cube slot ported enclosure

Loved the video - thanks for sharing. Here's sort of an OT question since I also have a GoPro (hero3 black) How did you manipulate the frame rate of the video? That was done post production yes? What product do you use to edit? Thanks!!

Here's a vid I need to find a good way to share, it's FLV, so you'll need something that can play that. I may just re-encode to 30fps and deal with youtube I recorded at 120fps and slowed it down while I was pushing the sub at 10hz. Pretty neat. VId shows cone movement and port air velocity at and around tuning freq down to 10hz.

https://drive.google.com/uc?export=d...EFwaWhJMTFkVEk

[nyt]

Re: (4) 2x 18" LMS Ultra 5400 in 15hz 27cube slot ported enclosure

Loved the video - thanks for sharing. Here's sort of an OT question since I also have a GoPro (hero3 black) How did you manipulate the frame rate of the video? That was done post production yes? What product do you use to edit? Thanks!!

Premiere and after effects

[bkeane1259]

Re: (4) 2x 18" LMS Ultra 5400 in 15hz 27cube slot ported enclosure

Thanks. Here's another noobish question. With all that amplifier power how exactly do you manage to turn the equipment on? Is it done in stages to minimize inrush current? I'd imagine you have some massive dedicated circuit for the equipment. Do you use a power conditioner? Sorry for the offbeat questions but I'm trying to get some insight on this fascinating system.

[nyt]

Re: (4) 2x 18" LMS Ultra 5400 in 15hz 27cube slot ported enclosure

Thanks. Here's another noobish question. With all that amplifier power how exactly do you manage to turn the equipment on? Is it done in stages to minimize inrush current? I'd imagine you have some massive dedicated circuit for the equipment. Do you use a power conditioner? Sorry for the offbeat questions but I'm trying to get some insight on this fascinating system.

Each amp is on its own 30A circuit. Each amp is plugged into a relay box which is triggered by the receiver's 12v trigger outputs.

[steveo]

Re: (4) 2x 18" LMS Ultra 5400 in 15hz 27cube slot ported enclosure

"The walls still flex a good deal. It's interesting that as I raise the levels I see some room modes disappear or shift frequencies."

I experienced this over the summer at my first SPL competition with my car. doing medium volume sweeps the resonant freq was 43hz. but when I went full tilt during my runs, my peak number ended up being at 48hz.

[nyt]

Re: (4) 2x 18" LMS Ultra 5400 in 15hz 27cube slot ported enclosure

"The walls still flex a good deal. It's interesting that as I raise the levels I see some room modes disappear or shift frequencies."

I experienced this over the summer at my first SPL competition with my car. doing medium volume sweeps the resonant freq was 43hz. but when I went full tilt during my runs, my peak number ended up being at 48hz.

Interesting, some t/s parameters change with larger signals, might be related.

[badman]

Re: (4) 2x 18" LMS Ultra 5400 in 15hz 27cube slot ported enclosure

I see a minimum of bracing in that enclosure- is that for weight savings? Such large panels must surely have some baloon modes- as well as a significant limitation on high freq extension, with nothing in the box to prevent resonances with such large dimensions.

You could improve the box design by converting the woofers to a push-pull manifold loading- you've already built the large part of a "PPSL", you could gain some reduction in box resonance and even-order distortion with a fairly simple conversion.

None of that probably matters that much with this much displacement at any reasonable level, but with so much invested, a few improvements could yield substantial gains.

[nyt]

Re: (4) 2x 18" LMS Ultra 5400 in 15hz 27cube slot ported enclosure

I see a minimum of bracing in that enclosure- is that for weight savings? Such large panels must surely have some baloon modes- as well as a significant limitation on high freq extension, with nothing in the box to prevent resonances with such large dimensions.

You could improve the box design by converting the woofers to a push-pull manifold loading- you've already built the large part of a "PPSL", you could gain some reduction in box resonance and even-order distortion with a fairly simple conversion.

None of that probably matters that much with this much displacement at any reasonable level, but with so much invested, a few improvements could yield substantial gains.

The box is braced, I just didn't post any pictures of it. PPSL intrigues me, but with a design like this i wouldn't want to reverse mount a 90lb sub. I considered it when building the box, something like the old m&k designs, but it would take up too much extra space. These are actually constrained by the square footage I have in the corners. The bracing in it is fairly basic and kind of ugly, as a good bit of it was added after the box was built. I left space so I could lengthen the port to reach the right tuning frequency, since there was some debate on the accuracy of slot port modeling. All measurements and audible tests give me clean results. I'll do some distortion testing eventually. I need to finish the spackle on it today, sand it, then get some coats of duratex on it.

[LTD02]

Re: (4) 2x 18" LMS Ultra 5400 in 15hz 27cube slot ported enclosure

" If anyone on AVS wants to tell pabueno7 and rmlowz that I'll respond to PM's here or on data-bass it would be appreciated."

done.

[GrogNak]

Re: (4) 2x 18" LMS Ultra 5400 in 15hz 27cube slot ported enclosure

awesome set up, nyt. Do you get a free massage with that ?

[nyt]

Re: (4) 2x 18" LMS Ultra 5400 in 15hz 27cube slot ported enclosure

awesome set up, nyt. Do you get a free massage with that ?

You could say that


Waiting on this to dry now...

[xmax]

Re: (4) 2x 18" LMS Ultra 5400 in 15hz 27cube slot ported enclosure

Awesome build! do those amps run on 120vac?

[nyt]

Re: (4) 2x 18" LMS Ultra 5400 in 15hz 27cube slot ported enclosure

Awesome build! do those amps run on 120vac?

yeah, can order em as 240 also