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
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).
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.
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?
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?
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.
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 )
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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
I am trying to hold power at a set amount to compare two different sub systems. One is 4 15's and the other is 2 18's. No one is talking about one sub box and no one is talking about 500watts. Given 8000watts, a real number that is reachable by most people, the 4 15s are more efficient than the 2 18's. Yes you can add lots of subs and amps but thats not the point. By the way, you can seal the 15's if you have to have that. The 15's do model deeper than the 18's sealed too.
You completely missed the point with the quoting of 500watts. My point was that 4 TC 15's ported need only 500 of those watts at 20hz than the 2500watts you need with a TC 18 to hit the same SPL. The 4 15's are 7.5db more efficient at that frequency. Thats quite a bit of headroom in the fixed power scenario.
You seem to think the home theater experience is all dependent upon 0-15hz output. I dont. To some, definition and articulation is more important than extension. We have to agree that application is the key here. I like concerts on Bluray and you like things blowing up and shaking your house. I dont think that 18 will do justice to an accoustic bass guitar like 2 15's can. An 18 cant move as fast.
I want to say that I havent disresepcted you in any way. I dont have 150k experience but I have had the exact same driver in a sealed and ported configuration in my room and in every case, the sealed was blown away by the ported version as I dont limit my judgement of the result solely by what a sub does at 10hz. I just recently changed my truck sub from a 15 to a 12. I lost a bit of extension and it is faster, tighter, and blends better to the rest of the system. Extension is not by a long shot the end all of a sub system. Yes we can add 20 18's and a dozen Lab Gruppen 14000 watt amps to the equation and I would say yeah, thats better.
Thanks for your opinion and for keeping it civil. People should be allowed to disagree without getting insulted by it.
EDIT: my testing is with a 31 band RTA and a handheld SPL meter with a frequency generator. If I seal the 15's they drop 7.5DB at 20 to gain only under 14HZ. Since there is little musical info at those frequencies it doesnt apply to me.
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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
My home theater consists of 4 amps not just two sub amps. In addition, I have the projector, all the sound processors and my massgae chair.
On the opposite side of the room is the refridgerator....another expansion to the optimum home theater experience.I never suggested using one sub box. I was trying to reduce the equipment discussion down to one box with an 18 as compared to one box with 2 15's. I know you need more than one sub in a room.
The main speaker thing will never happen as audio reproduction is the primary concern for me. The mains must be capable of serious accuracy on their own. The rest of the system is krell/cambridge audio. Pitch definition is my main concern on bass. If it sounds like mud but extends to 8hz, its a loser to me. Hence 2 15's are more accurate by speed alone. Thats why this thread was asking about transient response and such. The port delay is a real concern but given my power amp limits, I think I have a good balance. Im not buying more amps so I was trying to maximize what I have by learning. It seems all I can find is ported suks and sealed at 10hz is the whole thing, when I was asking what things improve a ported system.
I need 60 amps.
Thanks for the input.
OK, I'm laughing now at the whole thing.
Yes Doug, I have 3 20 amp circiuts now. I misunderstood.
What amps do you have?
The above is completely wrong. Generalizations like this are based on myth. There are many lengthy discussions on the subject on many forums if you do a search. Bass is inherently slow by definition. Many 21's would be considered much higher fidelity than some 10" actually no matter how many 10's you throw into the equation. For example you mention comparing TC12's and LMSR-15's versus the Ultra. I have tested all of these, which one has the most linear response, the better top end, BL^2/RE and inductance control? The 18". It is the better driver for the acoustic bass guitar you mention. Adding multiples won't change that. I'm serious about this BTW the 18 is the better driver for > 80Hz out of those 3.
Typically there are 2 main restrictions when building a subwoofer system. Available budget and size. Then there is intended application to consider. Where you happen to be on these items will have a large impact on what the "best" option
is for you. People always ask about the 'best" it gets on my nerves since it is relative for everybody. One guy might have a very large 10000cu ft room to fill with sound and a budget of $700 for the subwoofer which took him 2 years to save up. He is game to put a 60cu ft subwoofer enclosure in his room if that's what it takes for him to maximize his $700. Another may have $9000 for the system, but he has a 2000cubic foot room and cannot fit anymore than 2 subwoofers that are 7 cubic feet externally. Guy #3 has $4000 for a sub system but he is doing live sound for rock and electronica groups, DnB and Dubstep events. His system will be hauled 4 times a week to outdoor areas, large warehouses etc...He needs to design 4 enclosures that are manageable by 2 strong guys that have truck pack dimensions and will all fit in a small box truck with the rest of the rig. Obviously the needs for any of these guys is quite different. One size does not fit all.
You are correct that if you start comparing 2 or 3 15's to one LMS yes they will probably outperform it. Why stop there? What about 6 RS15HF's or maybe 10 Dayton classic 18's? Surely 6 15's should be better in just about every regard than 1 18 no matter which one. If you can fit the 6 15's yes you should do that. At some point you have to decide where to get off of that train of thought and figure out how much space you can devote to the enclosures and what your budget looks like. The LMS is for when you have limited space and plenty of funds. I can put one in a 2.5cu ft sealed enclosure and power the hell out of it and it will do astounding things for a system of <3.5cu ft external. Will it outgun a vented 6x15" system that is 50 cu ft? Hell no. Drivers like the LMS are for when you have a finite space and want to extract every last ounce of bass out of it.
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Thank you for making my point.
Budget is why you stop.
Yes I considered 4 of the TC 12 LMSr per side but it was cost as the consideration.
One TC 18 = $925 Good
Two TC 15s = $860 Better
Four TC 12s = $1520 Best but near twice the price.
The TC LMSr 12 is in my Hummer and its the best sound I've had in there. I run a Rockford Fosgate T4000BD amp. Its fast and clean, and no, the TC 15 in that rediculous size box wasnt in the same ball park. The 15 went deeper and played louder but it had less definition.
The day you can get a semi truck to out accelerate and stop faster than my corvette, I'll believe the BS about heavier cones being as fast. You cant see that in frequency response graphs.
One variable could be the box. The wall thickness in relation to the size of a side has the bigger box flexing more.
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Given the same motor strength, a bigger heavier cone (like your semi/Corvette analogy) will sound “slower”, it does not “start or stop” as fast as a smaller cone with the same motor strength, so upper bass detail is blurred.
The trick to “tight” or “fast” bass (which as Josh Ricci pointed out is inherently slow by definition) is a motor that has enough strength to control a stiff cone, not the size of the cone.
And that super heavy motor is why the LMS 18 can outpunch the 15 or 12, but you have to pay dearly for that.
Most big bass purchasers won’t pay that price, and if the music they listen to consists of droning kick and synth bass lines, mud motors suffice just fine
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