18" LMS-Ultra

[doug20]

Originally Posted by SpinMonster

Anyway to put a picture to the post:

The subs are 55" tall, 24" deep, and 21" wide. They are 320lbs each. The peavey amps are a great match. They are 4000 watts at the 8 ohm load bridged. Equalizing a single 18 7.5db to get it to match the 20hz output would require a doubling of power for each 3db or something like 18,000 watts. I had enough trouble getting 60 amp service for the system as it sits.

Each 4000Watt amp can run on 20Amps without a problem. no requirement for 60amp service or 30amp service at all. A 20amp service can easily handle split second peaks that consume even 4000Watts without question!!

Again, you are not equalizing one sealed box, you shouldn't be thinking that way. Its all about displacement, if you want 10Hz you need > 20liters. (Displacement is a function of surface area X Xmax). You need min 4 x 18" woofers to start caring about 10Hz. If that type of footprint doesn't work then everyone goes with LARGE ported boxes tuned to 15Hz or so and they give up the 10Hz goal.

btw, once you get the subwoofer thing down you will have to consider main speaker upgrades if you want to have the cleanest peaks

[DrDyna]

Originally Posted by doug20

Each 4000Watt amp can run on 20Amps without a problem. no requirement for 60amp service or 30amp service at all. A 20amp service can easily handle split second peaks that consume even 4000Watts without question!!

Doesn't he have 2 of those amps, plus all the other gear and amps?

I'd probably opt for 60A service too, the only thing worse than a crappy system is a good system that's on fire.

[doug20]

Originally Posted by DrDyna

Doesn't he have 2 of those amps, plus all the other gear and amps?

I'd probably opt for 60A service too, the only thing worse than a crappy system is a good system that's on fire.

Yes, I guess my post wasnt clear. Simply run multiple 20 amp services. 60Amp service is a waste honestly and its a bitch to run (ask any electrician about the codes behind it).

I have 4 20 amp circuits in my HT room to use. 3 of them go to 4000Watt amps and 1 20 amp is used for all other electronics. I did have them wired so that I could upgrade the circuit if needed but I have yet to see a need for > 20 amps (10G wiring).

[DrDyna]

Originally Posted by doug20

Yes, I guess my post wasnt clear. Simply run multiple 20 amp services. 60Amp service is a waste honestly and its a bitch to run (ask any electrician about the codes behind it).

I have 4 20 amp circuits in my HT room to use. 3 of them go to 4000Watt amps and 1 20 amp is used for all other electronics. I did have them wired so that I could upgrade the circuit if needed but I have yet to see a need for > 20 amps (10AWG wiring)

Ah, ok that makes more sense. Yeah, I can see a single 60A circuit being a pain, as you'd have to make sure your panel had big enough rails, use pretty heavy gauge romex, plus...do they even make single receptacles that are rated at 60A? You'd be coming off of your 60A circuit with a bunch of 20A receptacles anyway, so 4-6 20A circuits would be easier, but anyway..I'll stop derailing this, lol.

[doug20]

My electrician says even 30amp circuits have special recepticles. Yeah, sorry about any derail on the LMS5400 discussion.

To try and summarize why people find the LMS5400 to be a special driver, I will say its all about the < 20Hz performance it has in a small box. Illka's numbers show its an incredible choice for specific needs. I personally like having 4 cuft boxes vs 10cuft boxes and I hated port noise, of course it took real comparisons to know there is a difference. The only new design I want to try these days is a PPSL design, maybe try 4 LMS5400s in that sort of design, would I still get the extension?

[DrDyna]

Originally Posted by doug20

My electrician says even 30amp circuits have special recepticles. Yeah, sorry about any derail on the LMS5400 discussion.

To try and summarize why people find the LMS5400 to be a special driver, I will say its all about the < 20Hz performance it has in a small box. Illka's numbers show its an incredible choice for specific needs. I personally like having 4 cuft boxes vs 10cuft boxes and I hated port noise, of course it took real comparisons to know there is a difference. The only new design I want to try these days is a PPSL design, maybe try 4 LMS5400s in that sort of design, would I still get the extension?

I remember bjorno posted a T-TQWT sim with an LMS 5400 Ultra and it looked brilliant on paper, I didn't save it though, dangit. I should have, because if I ever got a couple of 5400's that's probably what I'd try first.

[doug20]

Imo, Transmission line and/or quarter wave tube type designs are for main speakers and are not meaningful for subwoofer design. Atleast what I consider subwoofer requirements. At that point you might as well design a nice horn design. (Interesting you post that, I was reading that TH or T-TQWP thread )

[DrDyna]

Originally Posted by doug20

Imo, Transmission line and/or quarter wave tube type designs are for main speakers and are not meaningful for subwoofer design. Atleast what I consider subwoofer requirements. At that point you might as well design a nice horn design. (Interesting you post that, I was reading that TH or T-TQWP thread )

Oh, the frequency response looked phenomenal. I wish I could find it again. As far as the quarter wave tube sub, I've had them for a while and I love em more than any of the sealed or vented boxes I've had over the years. I'll never build another BR or sealed sub as long as I live

[doug20]

Not a fan of subwoofer horn type designs myself, too big and they do not extend low enough for my requirements. Hence the reason a driver like the LMS5400 exists.

[DrDyna]

I think the one I saw f3'd at about 13 cycles or so, but without the sim he posted I can't say for sure.