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

[badman]

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

Do you know the XO freq on the 4722N? I believe those horns are screw-on 1 3/8 throats, is that how yours are configured? I actually have a pair of 2 x 2035h cabs in the garage.

[nyt]

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

Do you know the XO freq on the 4722N? I believe those horns are screw-on 1 3/8 throats, is that how yours are configured? I actually have a pair of 2 x 2035h cabs in the garage.

800hz, 1.5" cd

http://www.jblpro.com/www/products/cinema-market/screenarray-systems-2-way/4722_4722n

[kanemack]

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

i am scared of these.


really though they look great.

[joeybutts]

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

COME. DOWN. WITH. THE. SICKNESSSSSSSSSSSS.

So awesome nyt. Make it rain.

[greywarden]

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

COME. DOWN. WITH. THE. SICKNESSSSSSSSSSSS.

So awesome nyt. Make it rain.

you should put a bunch of dollah bills in the ports and fire it up the first official time with the THX sweep and make it rain.

[badman]

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

Except that you'll suck some into the cab, then have to try to lift one of those drivers out

If you try it, lay some wadding in the vent so that doesn't happen hahahaha

[JCSquats]

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

I'd offer my meathead powerlifting services to assist you with the positioning of your remaining cabs; I'm certain Joey would as well. :D Shame I live so far away.

Absolutely astonishing work and HT system! Cannot imagine what an experience it is.

[Tin_Ears]

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

I'd offer my meathead powerlifting services to assist you with the positioning of your remaining cabs; I'm certain Joey would as well. :D Shame I love so far away.

Absolutely astonishing work and HT system! Cannot imagine what an experience it is.

That is a shame. How far away is your love? Skype might help. :D

[nyt]

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

i am scared of these.

Me too!

Between these and the new Crowson transducers, it's a ridiculous experience. I'll gladly demo if anyone around Long Island NY wants to see. Going to try to get some lumber to finish the last two in the next day or so.

I took some vid (think i posted it earlier?) of holding some thin plastic in front of the port. It gets moving when testing with sine waves at tuning frequency, but most of the time the air velocity is so low you can't even notice.

[nyt]

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

And #3 almost done... updates for this are boring since it's just building multiples.

progress...

bracing


yay warped wood


and assembled

[kanemack]

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

you gotta be careful, small children might get sucked into those vents.

[kevintomb]

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

This seems to be a fairly well though out set up, but was interested in the comments about lack of resonance control, and lack of damping in the enclosure etc.

I do agree to some extent that only running the subs at very low frequencies will limit the "Need" for damping for sure, but I have found that when employing other drivers very close to another box, that is not damped, that the un-damped box will resonate when excited by the drivers in the other boxes.

This may or may not matter to the OP, but something to consider.
Of course that would apply to walls or anything else that resonates, but an un-damped box can just as easily be excited by "other" sounds emanating from other speakers.


I'd try a sweep from 100hz to perhaps 500hz from the main left and right speakers, and then look for resonances in the sub boxes.

Sympathetic resonance.

[nyt]

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

This seems to be a fairly well though out set up, but was interested in the comments about lack of resonance control, and lack of damping in the enclosure etc.

I do agree to some extent that only running the subs at very low frequencies will limit the "Need" for damping for sure, but I have found that when employing other drivers very close to another box, that is not damped, that the un-damped box will resonate when excited by the drivers in the other boxes.

This may or may not matter to the OP, but something to consider.
Of course that would apply to walls or anything else that resonates, but an un-damped box can just as easily be excited by "other" sounds emanating from other speakers.


I'd try a sweep from 100hz to perhaps 500hz from the main left and right speakers, and then look for resonances in the sub boxes.

Sympathetic resonance.

Interesting, I'll check it out. The mains I use have fairly high directivity. Either way, the resonances of the boxes are negligible, spectogram below to 200hz, xover at 80 or 90, don't recall.

[badman]

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

high directivity above a certain frequency- in your case, around 1kHz. At 100-400 Hz, your mains are effectively omni.

[nyt]

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

high directivity above a certain frequency- in your case, around 1kHz. At 100-400 Hz, your mains are effectively omni.

True... Either way, haven't noticed anything.

Almost done with the build, #4 is about to get finished today. I ran out of PL last night.