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

post #31 of 1767
Quote:
Originally Posted by robertcharles View Post

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 .

I'm using regular WinISD pro alpha, 0.5a7, not the early .6 release.
I can't even come close to those numbers in any design {sealed or ported} with
only 2500w 'to the system', meaning 625w driving each woofers. Someone needs
to triple check this.
post #32 of 1767
Quote:
Originally Posted by NEO Dan View Post

a little more bracing



time for me to go to work
Later
Dan

Killer. I would love to see these built.

Dan, you went from revision 1 to 2 in ten minutes. Amazing.

My new favorite phrase....You may be able to reach the "brown note" with these.

I love it. Pictures, pictures, pictures!
post #33 of 1767
Thread Starter 
how do I insert the winisd results to you?
post #34 of 1767
Print screen + paste in mspaint
post #35 of 1767
Thread Starter 
I'm still having trouble posting the winisd results. I am not particularly good at this.
post #36 of 1767
"The LMS-54K's are dual 2 ohm, so you would most likely have an 8 ohm nominal load per enclosure"

Why not 2 ohms for 3X the power?

"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."

For some amount of seconds, I guess.

There's a lot more copper in the 5400's VC, but I remember Dan Wiggins saying that 1 kW fed to a 15" Tumult would raise the VC temp to 200 C in a couple of sec.

If two 5400's were fed 5 kW continuously (picture four toasters with many feet of resistance wire glowing red)) inside a sealed and insulated wooden box, I'd be worried about the box bursting intoi flames, let alone the VC's cooking.

It may seem like I'm harping on this issue, but you keep making arguments based on max continuous power levels, which have no bearing on real world usage conditions.

The average power in use is more like in the tens of W, if that much.
post #37 of 1767
Thread Starter 
I was hoping that is the answer to my puzzle. I was hoping that the amps- rmx 5050 rated at 3200 in 8 ohms bridged would be enough for the MOST I would need. I am only driving the woofers below 30 hz, so the signals from the dvd's would only be sporatic in that range. No continuous power would be required to be sustained for long periods of time. Dynamic range is what I'm looking for more than actual sound pressure, although I do want the sub system to function properly. Any thoughts.
post #38 of 1767
Robert,
As long as your not planning to run a pair of 5050's at 2 ohm mono, I think we will let you slide

You can get by on just one amp then, it might be cleaner with two, but you won't hear it.

Running at 4ohm mono, a RMX 5050, or PL380, and your good



Later
Dan
post #39 of 1767
"The LMS-54K's are dual 2 ohm, so you would most likely have an 8 ohm nominal load per enclosure" Why not 2 ohms for 3X the power?

Four woofers each with dual 2 ohm voice coils can be wired;

1. Each woofer can be 1 ohm or 4 ohms.
2. Two woofers can be wired for 1/2 ohm, 2 ohms or 8 ohms.
3. Four woofers can be wired for 1/4 ohm, 1 ohm, 4 ohm or 16 ohms.

If you use option 2 @ 2 ohms *and* your subwoofer design is modeled
for 2500w each, then you need 5000w into a 2 ohm load so each woofer gets
2500w. The common proamp is not rated for 1ohm/ch or 2 ohms bridged, so that rules out bridged mode if you want to drive two woofers with a final load of 2 ohms. But you can drive those two woofers in stereo or parallel mode on
one channel and drive the other proamp channel for the second set of woofers,
or drive all four woofers using option 3 @ 4 ohms and run the proamp in bridged
mode. Both methods work. All you need one 10kw proamp to drive all four
woofers. Or use two proamps, but you don't get optimal wiring and you lose
1/2 the power. One proamp bridged per 4ohm LMS {like Jai's rig}, or one
monster proamp for all four. Two proamps don't fit well in this situation.

There's a lot more copper in the 5400's VC, but I remember Dan Wiggins saying that 1 kW fed to a 15" Tumult would raise the VC temp to 200 C in a couple of sec.

Different woofer, different situation, and Adire is history, lol..

If two 5400's were fed 5 kW continuously (picture four toasters with many feet of resistance wire glowing red)) inside a sealed and insulated wooden box, I'd be worried about the box bursting intoi flames, let alone the VC's cooking.

We can only trust the claims.
http://www.tcsounds.com/lms5400.htm

"2500 watts continuous power (8000 watts peak) "

Just like anything else, the word 'continous' is misleading. In amplifier testing,
they also use that 'continous' word. I have issues with this too.

Continous as in 1 second or 3 weeks ? You get the idea. The time element
is important and those variables are never told. Other variables are ambient
temp when testing. Did you test the woofer/amp in the cold winter at -10 degrees
or did you go and test the woofer/amp in the desert with 110 degree temp?
There is alot of comedy with amp and driver ratings.

It may seem like I'm harping on this issue, but you keep making arguments based on max continuous power levels, which have no bearing on real world usage conditions. The average power in use is more like in the tens of W, if that much.

Woofers are more demanding than midranges and tweeters are the least
demaning of all. That's why we get so many different perceptions on bass
authority and people don't understand the root cause. They assume it's
damping factor, they assume amplifier specs are reality, they assume it's
some magic circuit design topology, the list goes on. The reaility is this
and it will shock people. The reason why some audio systems are perceived
to have stronger bass when amp swapping is because one of those
amplifiers offered more power than the other in spite of what the published
specs say, bottom line, amps need to be tested to see what they really do.
Even after they get tested, everyone has a different AC line loss scenario which
can reduce power.

The only reason I harp on the power issue is because people assume their
EP2500 can do 2400w because the specs say so. Chuck tested that amp
at 2kw with a variac to hold the AC line at 120VAC. Per Chuck's comments,
the amp will run into thermal protect in a minute. Even with playing music
and not a test tone, you will go into thermal protect eventually.

Most people don't install variacs on their power amps so they may experience
severe AC line sag. I couldn't even test my simple PLX3402 on the common
garage 20A circuit because the AC line dropped under 100VAC and the amp
just turned off. lol .. But I can operate two of those PLX's running tweeters
and midranges because the load is easy. If I do subwoofer duty, I'd have to
dedicate a 20A line to that amp. Bottom line, that EP2500 that Chuck tested
seems to correlate with Binks J2500 test {another cloned amp} and from
these two tests we can figure out a worse case scenario of ~1200w - 1400w.
That is not very close to the published spec of 2400w. hehehe

The other issue music. We know that music is lower in duty cycle but
*what if* you come across a sustaining low frequency note? For simplicity,
what if your audio source {music, movies, etc} had a continuous tone for
a few seconds. Do you want your subwoofer to get the power level as you
modeled or do you want that tone to cause a 50% loss of power that drives
your sub? and/or, do you want to reset your house breaker everytime a
demanding situation manifests?

Overkill is good for a hassle free audio system. Jai's install is a perfect
example. While everyone is suggesting the typical amplifier pathway,
EP2500, I harped on him to get a CE4000 as it seems to be a perfect fit
for one LMS woofer. I've heard other people clip their EP2500's, PLX's
on a good subwoofer design using lesser woofers, but he said he hasn't
clipped this CE4000 yet. He has excellent headroom, who wants clipping
on a demanding situation?

Why settle for good when you can be great.
post #40 of 1767
Quote:
Originally Posted by robertcharles View Post

I was hoping that is the answer to my puzzle. I was hoping that the amps- rmx 5050 rated at 3200 in 8 ohms bridged would be enough for the MOST I would need. I am only driving the woofers below 30 hz, so the signals from the dvd's would only be sporatic in that range. No continuous power would be required to be sustained for long periods of time. Dynamic range is what I'm looking for more than actual sound pressure, although I do want the sub system to function properly. Any thoughts.

3800 watts per two woofers will be more than enough. You might not push them (woofers) to their limits with that power, but that isn't always necessarily or even preferred.

Another thing. I would definitely mount them opposed to each other (as pairs). That way you can make your boxes much lighter and won't have any rattle or "walking" problems.
post #41 of 1767
Quote:
Originally Posted by robertcharles View Post

I was hoping that is the answer to my puzzle. I was hoping that the amps- rmx 5050 rated at 3200 in 8 ohms bridged would be enough for the MOST I would need. I am only driving the woofers below 30 hz, so the signals from the dvd's would only be sporatic in that range. No continuous power would be required to be sustained for long periods of time. Dynamic range is what I'm looking for more than actual sound pressure, although I do want the sub system to function properly. Any thoughts.


To get a answer from your puzzle requires some clues.

What type of subwoofer did you decide on? Sealed, PR, ported? size?

Something is weird with your WinISD .6 model vs. when I used .5 model,
the two don't even correlate at all.

My suggestion is to use the proven WinISD Pro Alpha and not the early 0.6 release, that way you can exchange project files to verify the model.

Once you figure this out, then you can estimate the SPL levels with
different power input and you can choose what you like from there.

You can operate the LMS with a one watt tube amp, but that isn't practical.
You can get some good bass with 500w, but why do you need an LMS if it's
sitting on the beach drinking Margaritas and not doing any hard work?

The real reason you want LMS is to exploit it's potential and one way
isn't by starving it for power.
post #42 of 1767
Thread Starter 
Just got off of the phone with mike and kyle a tc sounds. They like NEO box idea and say they see no problems as far as the woofers being to close together. I guess that is how it will be done. Now for actual exact measurements. I would like to be a little clearer as far as HxWxD dimensions. Also bracing needs to be superduty they say. Thanks NEO,

Robert Pizzolato
post #43 of 1767
Thread Starter 
As far as the CE4000 goes, how much power does it provide to each woofer if it was used?

Remember, I only have about 40 amps for sub duty-could be 60 or 80 if I wanted to rewire or use remote amp locations. I am trying to stay clean install and nothing exposed.
post #44 of 1767


drawn exactly to the dimensions, as you requested
2.25" baffles
1.5" shell
good bracing
I'd use MDF, it is messy. But the uniformity and ease of machining are worth the mess.

The CE4000 only has the small 15A IEC, to get that amp to not be limited by that connector you need a 220V line, there is a pdf on the crown web page that points this out.

That being said, a single RMX 5050 or PL380 are better choices. I'd do the PL380 as it's of a higher build quality(most likely for operation at a higher duty cycle) and because it's more efficient and has a proper power connector it is less limited when run at 4 ohm mono.



Later
Dan
post #45 of 1767
Thread Starter 
I'm having trouble posting the pictures, if you can help, I will post what I have. All of the pictures are on a cd in my disk drive waiting to be loaded. Thanks, Robert
post #46 of 1767
Thread Starter 
http://s111.photobucket.com/albums/n...slideshow=true

Pictures of the progress up to 2004 are at link above.
post #47 of 1767
ain't no hiding your musical roots

I like how you've put the space to use, it's not just a dark theater.


Dan
post #48 of 1767
Thread Starter 
I have a complete lighting setup that I still am putting together. I have spots, gobos, lasers, and rorating heads. It sure is cool when we watch music viseos. I especially like Pink Floyd-Pulse. We saw that concert in the superdome back in the day and it sure was cool. It is raining down here and I am waiting for tc sounds to call me about the passives. Hope I can order them today, then I will be able to start to finalize the box design.
post #49 of 1767
"My suggestion is to use the proven WinISD Pro Alpha and not the early 0.6 release"

Unibox is more sophisticated and I believe more accurate; it's respoonse results are closer to what LEAP gives.

The one big thing it lacks is plotting multiple drivers.
post #50 of 1767
"*what if* you come across a sustaining low frequency note? "

I suppose that could happen, but it hasn't ever to me.

I still wouldn't rule out amps based on tripping breakers at continuous full power.

And re "continuous", I believe for speakers that means "continuous music power" or somesuch, which IIRC includes a 6 dB crest factor, so it's really only 1/4 of the number given.
post #51 of 1767
Quote:
Originally Posted by noah katz View Post

"*what if* you come across a sustaining low frequency note? "

I suppose that could happen, but it hasn't ever to me.

I still wouldn't rule out amps based on tripping breakers at continuous full power.

And re "continuous", I believe for speakers that means "continuous music power" or somesuch, which IIRC includes a 6 dB crest factor, so it's really only 1/4 of the number given.

I'm not a bass freak like others. I just like high SPL full range sound, like
a concert

But I remember a track on this CD that was pretty brutal on having
some sustaining low notes that caused the amplifiers to get punished bad.
http://www.telarc.com/images/covers/0123.jpg

.. damn keyboard musc ....
post #52 of 1767
Just thought of something - what are the chances that a sustained note is going to have the highest peak levels in the track?

Pretty slim, I'd wager.
post #53 of 1767
Ever listen to a pipe organ? Not so slim at all, quite likely, I would even guarantee it. Also, with the level of compression on some of our music these days, it may not matter if a single note is sustained, the signal may be pinned at 0dBu for quite a while.
post #54 of 1767
"Ever listen to a pipe organ? "

Good point.
post #55 of 1767
Thread Starter 
Looks like $2400.00 for the 8 passives. I was expecting more like $1600-1800. How does $300.00 each sound? Any opinions?

Thanks, Robert
post #56 of 1767
Thread Starter 
My amp choices are still up in the air. Mike at TC sounds told me they use rmx 5050's and that they are monsters for the money. Very hard to beat for sub duty. I am really confused. I can get 5050's brand new w/6 year warranty, or try to find 2 used crown ce4000's and hope for the best. The crowns really do look impressive.

NEO dan, I might have to increase the height to 64 inches, keep the width at 30 inches, and reduce the sides(baffles) to 22 inches. What do you think? I feel that the extra space between the drivers will allow better bracing and easier mounting.
How does that sound?
post #57 of 1767
Thread Starter 
Passives are ordered. I am now waiting for them to arrive.
post #58 of 1767
Quote:
Originally Posted by robertcharles View Post

Looks like $2400.00 for the 8 passives. I was expecting more like $1600-1800. How does $300.00 each sound? Any opinions?

Thanks, Robert

You made a good choice. You paid more than me, but that is life. What I can tell is, they are still worth the price. There is nothing else in the market that I know of, that compares to these in build quality and specs (in that price range).
Enjoy and don't think too much about how much you paid. At EOD, what matters most is if you are happy with them and if you like the way it sounds. I think you are on the right track. Don't look back
post #59 of 1767
Thread Starter 
Nice to here that. I think that I made a good choice also. I was wondering if you upgraded your 20 amp circuits yet or are you running both amps off of one 20 amp circuit? Thanks, Robert.
post #60 of 1767
This is incredible, 4 LMS's and 8 Passives, powered with about 7,000watts, you are in for a real treat. I remember when I used to think that a single 12" sub made a formidable HT, now, a pair of 18's is old news.
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