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4 18" 5400's powered by 2 qsc rmx 5050's

post #1 of 1767
Thread Starter 
I currently have 4 18'" 5400's and am going to order the rmx 5050's asap. Any opinions on the 5050's would be appreciated.

If anyone is interested, I will post The theater photos and updates as I go.


Thanks, Robert
post #2 of 1767
What kind of power will be available to the amps? (circuit wise)
post #3 of 1767
Thread Starter 
I have 100 amps available to the theater equipment itself. The whole house was rewired in 2000 when we built the theater and the rest of the addition. The cable that runs the theater is the stuff that someone on this board was talking about on the (closed) thread. That stuff was expensive even though I got it at cost from the dealer. I have a total of five 20 amp circuits for the audio/video system only. Also, the lighting and the fans and other electrical outlets in the theater are on their own circuits. I am currently running 3 rmx 850's, and 2 rmx 2450's. All have been installed for five years now, but are 6 years old. No problems so far. I add the 5050's and they are going to draw 40 amps, but I will be removing some of the bass signals from the 2450's, so hopefully I will reduce the amperage from those amps.

I'm looking at

rmx 850 roughly 7 amps each total 21 amps

rmx 2450 roughly 10 amps each total 20 amps

rmx5050 roughly 20 amps each (max) total 40 amps

roughly 20 amps left over from the dedicated circuits and I still have access to the other outlet circuits from the wals in the room. About 40 amps total.

We really only use the theater when other things aren't being used. I hope I will have enough power. My father is definitely a whiz with electricity and he says I should not have a problem. He and I wired the entire thing. Hope this helps. Thanks
Robert
post #4 of 1767
Well, sounds like you have it covered pretty well.

Four 18" LMS-5400s is definitely awesome, btw. Wow.
post #5 of 1767
Thread Starter 
I currently have six jbl 2241h's running the bass duties and they are crossed at 50hz. I plan on having the 5400's running 30 down as low level effects channel and using the jbl's for the front and rear bass on the main channels. I may even add a sub to the center channel, but that is down the road and will require more crossovers and more amplifiers. I will be the jbl's at for the 50-30hz range. Since this is a hobby, I guess we all keep looking to add to what we have.

What do you think about the bass setup?

Thanks,

Robert

PS I also have bass shakers mounted to the bottom of the riser for the seating area.
post #6 of 1767
Thread Starter 
By the way what do you think of the rmx 5050?
post #7 of 1767
Quote:


What do you think about the bass setup?

Substantial.

I can't add any thoughts on the rmx5050 really. There are all types of amps out there to choose from though. How much were you gonna spend on each 5050?
post #8 of 1767
Thread Starter 
$1280 each with 0 % and not due for 15 months. $2560.00 total and don't have to pay till next year.
post #9 of 1767
Robert,
I like your brand of insanity, um scratch that, sense of style

Just thinking over the box
I know it would look amazingly cool to have both LMS-54K on the front, but be warned you are talking of pushing a little over a kilo of active moving mass with QSC 5050's.
It's gonna make the enclosure buck like a rodeo bull on meth
With this sort of mass and motor power you really should do opposing drivers and PR's to cancel out the forces.

The LMS-54K's are dual 2 ohm, so you would most likely have an 8 ohm nominal load per enclosure, unless you planned on running the RMX 5050's at 8 ohm mono, why not just do one amp like the Series 3 PL 380 that's probably a more cost effective way to go and you'll get 2KW per driver, while eliminating any siginal and/or level matching issues.



I'll go away now
Dan
post #10 of 1767
OK, I suck.
That PL380 is like $2.7K, my bad, but you can get by just fine on one RMX 5050.


Damn you guys are funded
Later
Dan
post #11 of 1767
I agree totally with Dan about opposing drivers.
post #12 of 1767
That PL380 specs out nicely

http://www.qscaudio.com/pdfs/Specifi...ight3_spec.pdf

Input gains work with 1.2v
selectable high pass 3Hz, 30Hz, 50Hz
speakons and powercons
1db detents on the gains, and removable knobs and security cover plate

sounds like someone at QSC is listening
post #13 of 1767
Thread Starter 
Yes, I was thinking of many possibilities, I'm trying to get the best fit for my room and also the ability to move them if I needed to. I was looking at putting the enclosures almost directly against the walls. so I am almost eliminating the rear because of such close proximity of the woofer to the wall- I think.

It is such a big decision. Every time I think I am ready to go, I end up asking myself more questions.

So far, what I do have for this upgrade is 4 5400's and the hurricane t-nuts. Everything else for this upgrade is in a state of flux. Nothing is definite, so I am entertaining all thoughts on the matter, but I hope to nail some designs down soon.

As far as size goes, the boxes will be about 15-16 ft each- that much I know.
The layout is adjustable, but I just can't seem to get away from being so close to the walls. As far as bucking goes, I was thinking of actually strapping the sub to the walls with some kind of anchor system thereby hopefully eliminating any movement. What do you think? Maybe some kind of steel or aluminum struts that bolt into the boxes and into the walls. I failed to mention this when I described it to you in the PM.
post #14 of 1767
Thread Starter 
the opposing drivers was definitely on my list. Ifc they oppose, then the box will have to stretch wider or deeper to accomodate the magnets and the baskets. I have a bunch of things to look over.
post #15 of 1767
worst case,
imagine a jackhammer with a 11hp motor and a 2.25lb bit moving 4" peak to peak, something will most likely fly apart , mount, box, or house, just make sure to get it on video


I'm not saying you can't do it, but it's likely to be a destructive situation.




Dan
post #16 of 1767
Thread Starter 
I agree. The 6 jbl's cause things to jump and vibrate many rooms away. I really am not up to date with these "super woofers". I have two definitive technologies pf1800's in my pro logic setup and they are sealed cabs with an 18 and 500 watt amplifier. These are the closest thing to the new stuff that I have- so I really don't know what to expect.
post #17 of 1767
Quote:
Originally Posted by robertcharles View Post

I agree. The 6 jbl's cause things to jump and vibrate many rooms away. I really am not up to date with these "super woofers". I have two definitive technologies pf1800's in my pro logic setup and they are sealed cabs with an 18 and 500 watt amplifier. These are the closest thing to the new stuff that I have- so I really don't know what to expect.

I think you should expect to send those LMS-5400s to someone in need. *Cough*me*cough*

I don't even think 4-8 PF1800s can touch a single LMS-5400 down low.
post #18 of 1767
the least intrusion into the room would be a tall shallow box with 2PR's and an active driver on each side say.

Diagnosis:
bipolar side firing PR, SW, PR, with shallow tendencys.

That'll get you thrown in the looney bin




I'm done for tonight
Later
Dan
post #19 of 1767
Thread Starter 
I had that in mind, but I was trying to get away from having two 2.25" baffles on each box. But I definitely like that idea and am going to put the measurements in the mix now. Thanks,

Robert
post #20 of 1767
Thread Starter 
The mounting depth is 13.25" so I guess if the enclosures are 30 inches wide and the last layer of the triple thick 3/4" baffle allows for driver recess, then I should have about 2-3 inches between the drivers. With this setup, if the vents in the magnets are that close, what do you think will occur -good or bad situation?
post #21 of 1767
I definitely wouldn't want the drivers to have only 2-3 inches between them, but I certainly don't know what the effects would be if they were.

And man...if you did go with PRs...you could tune your subs to like 12Hz (or lower). That'd be such an improvement over sealed in that range, for sure.
post #22 of 1767
Thread Starter 
I am definitely going PR. I just wish I could get them from tc.
post #23 of 1767
Quote:
Originally Posted by robertcharles View Post

I am definitely going PR. I just wish I could get them from tc.

I believe you still can, just give them a call. I heard they might have a few more left.
post #24 of 1767
Any opinions on the 5050's would be appreciated.

I sent you the 'general amplifier broadcast message' via pm.

Before you order any amp 'asap', model your subwoofer design and see what
kind of power you need to drive the design to it's mechanical limits.

If your design needs 2kw per woofer then you may have issues with many proamps.
ie, check the RMX4050/5050 specs and look at the power draw vs. AC cord used. While
this may be good for music playback, under heavier stress don't expect 4000w - 5000w
from a 120VAC 20A circuit. lol

LMS is a woofer with a thermal rating of 2500w rms. That by itself would imply each
woofer needs it's own 20A circuit if you operate the woofer to it's limits. But on the
other hand, if you have a subwoofer design that is optimized for 1000w, then your
AC line requirement is less.
post #25 of 1767
Check this out.
http://www.avsforum.com/avs-vb/showthread.php?t=878681

Read the funny test they did on three proamps, two of which are 8kw amps.

A burst test caused the 120VAC, 20A circuit to trip the breaker often. Pretty silly
to test a monster amp with a crippled AC supply.

Even the PLX3402 tripped the 20A breaker and this amp is not even in
the same league as the other two. lol
post #26 of 1767
Thread Starter 
i am looking at all of the stuff you posted. i am plotting the output in winisd.60a1 and with four drivers with 2500 watts to the system the cone excursion approaches 38 mm at 10 hz with no filtering. I get roughly 125 db at 20hz and down to 14hz- 124.5db, 10hz-113db. Plenty enough volume and way more extension than I currently have. Now I am going to look at the amp question .
post #27 of 1767
nice! another quad-18 setup.

btw, thlantr hit it in the nail as far as modelling the subs and see the power consumption you will need to reach its Xmech; I have a hunch you won't need that much power, but I haven't modelled it.

oh, and this crowd will eat you alive if you don't start to post some pics, even if it's of the raw materials, pretty soon here
post #28 of 1767
Quote:
Originally Posted by ssabripo View Post

nice! another quad-18 setup.

oh, and this crowd will eat you alive if you don't start to post some pics, even if it's of the raw materials, pretty soon here

Another? Lets see the pics of the the aformentioned!

Dr V
post #29 of 1767
5.9 cubes x 3



Dan
post #30 of 1767
a little more bracing



time for me to go to work
Later
Dan
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