The Quasar Array (8) LMS 5400 in (4) Dual Opposed Sealed Cabinets - Page 4 - AVS Forum
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post #91 of 440 Old 10-25-2009, 08:32 PM - Thread Starter
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A few more:
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post #92 of 440 Old 10-25-2009, 08:47 PM
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So far so good, I like the fact that you braced those boxes pretty good, that's how I do my subs, the less vibration out of the boxes, the better. Also, being that you have a huge room 10,000 + cf, I still think you'll get a flatter frequency response (linearity from the subs) with option #2, but I'm sure you'll find out what works best for you.
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post #93 of 440 Old 10-25-2009, 08:48 PM
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that 1" bb is just plain insane. good bracing design as well.

are you planning on fiberglass stuffing or something else?

Listen. It's All Good.
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post #94 of 440 Old 10-25-2009, 08:59 PM
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post #95 of 440 Old 10-25-2009, 09:08 PM - Thread Starter
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Quote:
Originally Posted by LTD02 View Post

that 1" bb is just plain insane. good bracing design as well.

Actually, it is 4 cm thick Baltic Birch... 1.575"

Quote:


are you planning on fiberglass stuffing or something else?

No, as I noted on the first post of the thread, the Qtc is already slightly less than 0.5. No need or benefit for stuffing, which is awesome.
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post #96 of 440 Old 10-25-2009, 09:08 PM
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You new neighbors are going to wonder what him them

Is it another 2 months for LMS delivery?

"Half the world is looking for Jesus, and the other half is looking for more bass..."
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post #97 of 440 Old 10-25-2009, 09:23 PM - Thread Starter
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I'm moving in 2 weeks. The next house will be a detached single family home with no neighbor on one side, and 50 feet to the only neighbor...

I'm not sure what the latest is on the LMS 5400, but lets say my anxiety level will drop when they are ordered, and when I see the baskets fit into the circle cutouts...
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post #98 of 440 Old 10-25-2009, 09:26 PM
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Quote:
Originally Posted by Health Nut View Post

Actually, it is 4 cm thick Baltic Birch... 1.575"



No, as I noted on the first post of the thread, the Qtc is already slightly less than 0.5. No need or benefit for stuffing, which is awesome.

Some big boxes there.

You probably will want to stuff the box anyway. More so to insure there isn't too much tendency for higher frequencies to resonate/reflect in that rigid enclosure than for effective volume changes. It's a PITA to cut, but the recycled cotton bats are a nice absorber for that sort of thing. Note they don't compress much and are much more dense than fiberglass, so you don't need to get crazy with it, but done on the side walls or top/bottom would probably be a worthwhile effort and certainly won't hurt anything in the performance.

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post #99 of 440 Old 10-25-2009, 09:39 PM - Thread Starter
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Quote:
Originally Posted by Mark Seaton View Post

Some big boxes there.

You probably will want to stuff the box anyway. More so to insure there isn't too much tendency for higher frequencies to resonate in that rigid enclosure than for effective volume changes. It's a PITA to cut, but the recycled cotton bats are a nice absorber for that sort of thing. Note they don't compress much and are much more dense than fiberglass, so you don't need to get crazy with it, but done on the side walls or top/bottom would probably be a worthwhile effort and certainly won't hurt anything in the performance.

They are a lot smaller than the Black Hole Subs, that is for sure but will end up being heavier. (80 lbs per driver + stone is going to be a bear!)

Thanks for the suggestion on Quartz by the way Mark. It is hard to find 1/2" Quartz from manufacturers.

I'm not sure I'm following you on any high frequencies resonating inside... The walls will also have 2 different materials, especially now that all six surfaces are going to be covered with MITER cut stone... Given these are going to be used from 5-60 Hz, what high freqencies are you talking about?
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post #100 of 440 Old 10-25-2009, 10:24 PM
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echoes from inside the cab can shoot back through the driver with little decrease in spl.

for a test of this, put a bookshelf inside your sub, play it, you will hear it. most of the spl is coming through the driver even if the cabs are "completely dead".

Listen. It's All Good.
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post #101 of 440 Old 10-25-2009, 11:05 PM - Thread Starter
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Quote:
Originally Posted by LTD02 View Post

for a test of this, put a bookshelf inside your sub, play it, you will hear it. most of the spl is coming through the driver even if the cabs are "completely dead".

LOL!! Forgive me but... Certainly I would expect to hear a speaker playing music inside the cabinet as the driver is of course very thin, relatively speaking. And sure, youd see the cone move also from the bass if a speaker is inside playing loud enough. The question was more about "higher frequency resonances" The suspension of drivers can have some higher frequency mechanical noise when driven hard, but that is still negligible. So where are these high frequencies going to come from? The only frequencies that box will get are from 5-60 Hz (plus filter rolloff). I do appreciate discussion as I know you are trying to be helpful, its just that so far, I'm having some trouble understanding where these "high freqency resonances" are coming from. Certainly, there will be nobody putting a bookshelf speaker inside the cabinets...

I'm just saying I'd appreciate a more solid reason, or more solid explanation of why some stuffing should be added.

By the way, whatever happened to long-haired wool?
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post #102 of 440 Old 10-25-2009, 11:31 PM
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Quote:
Originally Posted by Health Nut View Post

I'm moving in 2 weeks. The next house will be a detached single family home with no neighbor on one side, and 50 feet to the only neighbor...

I'm not sure what the latest is on the LMS 5400, but lets say my anxiety level will drop when they are ordered, and when I see the baskets fit into the circle cutouts...

They still might think there is an earthquake. My old house I had a neighbor at least 50 feet away and up a hill from me. At the time I only had a Velodyne HGS-18 and 2 HSU TN-1225's. One Halloween I was tasked with giving out the candy and that neighbor came over. She asked if we had a surround sound system and I answered yes. She then commented that they sometimes felt a rumble in there kitchen and on there balcony which looked over my home. They always thought maybe it was a helicopter or big truck passing by until she matched up the shaking with the flashing lights coming from the windows in my home! Talk about kick a$$!
Now imagine if I had your set-up! They could have been bounced off of the balcony

I wound be anxious to get my hands on those LMS 5400 as well. I still haven't decided if I will order a pair myself but I still can't wait for them to be available.

Great build, your gonna have a lot of fun.

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post #103 of 440 Old 10-26-2009, 12:02 AM
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Quote:
Originally Posted by Health Nut View Post

LOL!! Forgive me but... Certainly I would expect to hear a speaker playing music inside the cabinet as the driver is of course very thin, relatively speaking. And sure, youd see the cone move also from the bass if a speaker is inside playing loud enough. The question was more about "higher frequency resonances" The suspension of drivers can have some higher frequency mechanical noise when driven hard, but that is still negligible. So where are these high frequencies going to come from? The only frequencies that box will get are from 5-60 Hz (plus filter rolloff). I do appreciate discussion as I know you are trying to be helpful, its just that so far, I'm having some trouble understanding where these "high freqency resonances" are coming from. Certainly, there will be nobody putting a bookshelf speaker inside the cabinets...

I'm just saying I'd appreciate a more solid reason, or more solid explanation of why some stuffing should be added.

By the way, whatever happened to long-haired wool?

The wool isn't bad for midrange absorption, but the cotton bats should stay in place better.

Think of the reflections/resonances like room modes inside the subwoofer. Any distortion products that coincide with such resonances will be magnified, and the bit that does come through the low pass (it's a slope not a wall) will energize and be affected by the same. Many ignore the out of operating band stuff, but it usually is audible. Of course opinions will differ. It's a recommendation you are free to use or pass over.

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post #104 of 440 Old 10-26-2009, 09:19 AM - Thread Starter
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I do appreciate the suggestion. I understand what you are saying... I just wanted some clarification... I mentioned 5-60 Hz plus filter rolloff, so I just wanted to clarify that it was higher frequency from the rolloff. The maximum internal dimension is the height which is 38.85" from what I remember right now... I think that is around 175 Hz or such...

Ok, I agree, it probably can't hurt to throw in some stuffing... I always liked long hair wool though... The space in the top/bottom would be best since it can be held by the shelf brace and is also away from the motors. If I'm going to use something for absorption of 150Hz-1K, may as well use whatver works best for that. Can't you place long haired wool in a bag? or does it need to be 'free' to work best? Do you have a link for the cotton bats or other recommended material?

Maybe I should just fill the entire bottom below the shelf brace, that way nothing has to fall down from the top and I don't have to staple gun/tack anything down?

Thank-you all as usual. I used fiberglass in the Black Hole Subs.

Here are some links, maybe people can compare thoughts on these as well:

http://www.madisound.com/catalog/pro...roducts_id=772

http://www.parts-express.com//pe/psh...44&rak=260-330
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post #105 of 440 Old 10-26-2009, 09:23 AM - Thread Starter
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A reply from Lab Gruppen:


Quote:


Welcome to Lab.gruppen support

PLM is the only way to get access to Lake DSP right now, but depending on when you need the system, we are on the way with a LM26 Lake stand alone DSP. ( more on our web site)

The LM26 is 2 in and 6 out, and it could be a nice setup with FP+ amps and LM26 and a good alternative to 2x PLM 14000. The PLM do not have line outputs from the DSP! And it will not be possible to link FP+ amps with the PLM.

The right Power! And the right amp!

Do you have any chance to test the impedance curve for the driver (together with the box) One thing is the imp. on the label, the most important is the real imp for the amp. In many cases it will be better to have 2x amps on ½ power than one big one.

Please let me know if you have the imp curve?

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post #106 of 440 Old 10-26-2009, 09:29 AM - Thread Starter
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"In many cases it will be better to have 2x amps on ½ power than one big one."


Doesn't anyone make pro monoblocks by the way, so that you have better performance without bridging?

Does anyone have an impedance curve with LMS 5400 in sealed enclosures? Preferrably closer to 150 liters, since mine are about 280L (2 drivers).

Also, I'd think that an amplifier that was designed to work only on 220V would have advantages over an amplifier that is selectable 110/220. (Given that you would be using 220V).

Could you, if neccessary, use power splitter adaptors to 220 outlets? Turn a single 220V outlet into a 2 or 4 outlet?
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post #107 of 440 Old 10-26-2009, 11:59 PM - Thread Starter
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Any opinions on Acousta stuff?

http://www.amazon.com/Acousta-Stuf-P.../ref=pd_cp_e_1

I have to be careful or I will overdampen... I'm already at 0.48 Qtc. What do you think, one 5 lb. bag each subwoofer, fill the bottom chamber only?

Also, what do you use for gasket tape/closed cell foam?

I think I used this before... anything else to consider?

http://www.parts-express.com/pe/show...number=260-542

http://www.madisound.com/catalog/pro...roducts_id=768

Also, what about heavy duty threaded inserts. I don't think I'll go with T-nuts this time... Anyone have a link?
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post #108 of 440 Old 10-27-2009, 02:20 AM
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post #109 of 440 Old 10-27-2009, 06:12 AM
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With the type of wood you're and the thickness, I doubt you need to worry about threaded inserts. Just using longer screws will easily give enough bite. I guess if you want them for looks, go for it. But I don't see much of a benefit in this situation unless you plan to remove the drivers 75 times.
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post #110 of 440 Old 10-27-2009, 06:47 AM
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Agreed, if your going with trim rings, I don't really think you need to use threaded inserts - I wouldn't - just a nice long wood screw.... just make sure you get one with a decent head like torks bit or allen head or something of the like...

I used stainless size 10 or 12 [#3 head philips] or posidrive heads.... they work just fine, but allen or torks would be better... I went heavy duty - the size was a tiny bit bigger then the holes on the LMS's, so I drilled out the holes on the basket ever so slightly - basically taking the paint off the inside of the hole. Just predrill the wood on the birch - it will be more then ample, trust me... I only used 3/4 birch and I have no issues with the screws.
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post #111 of 440 Old 10-27-2009, 08:25 AM - Thread Starter
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More Lab Gruppen correspondence:


Hi Christian

If I take the data you send me I get the following imp curve for the driver in a closed chamber at 150L:

(can't get the graphs out of his email).

The lowest imp will be 4 ohm, but in the working range from 15Hz to 70Hz the imp will be over 6ohm!
Max x = 17Hz

If the driver is label 2x 2500W and 2x2ohm then one coil can handle 70V = 2500W in 2ohm ( 35A) and if you have them as 5000W in 4 ohm then it will be 140V rms instead ( 35A ). ( 200V peak)

The 14000 can deliver 195V peak and more than 60A rms ( 100A peak ) so I think you shall try to test the system with 4x coils on one out put ( 2+2ohm 2x ) = 2ohm together. It’s a little below the spec. but I think I will be enough, but try it out…

If I was making an closed design, then I would put the magnet out of the box ( inverse the driver ) If you put 5000W into a box off 150L it will be extremely hot !!! If you have the magnet and coil out of the box you will get the cooling from the air and the driver has a chance to stay on a OK temp!

=================================================


1) Would you tell me what, if any, subharmonic filter is used in the Lab Gruppen amplifiers? For instance, Crown uses 8 Hz, QSC Audio uses 5 Hz... What does Lab Gruppen use for a subharmonic filter?

It will depend on the model. FP 14000 is 1.5Hz and the highest is around 6Hz

2) I have heard someone mention that a stand alone Lake processor would be coming out... Any idea when the LM26 will be available?

End this year if we stick to the plan.
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post #112 of 440 Old 10-27-2009, 09:39 AM - Thread Starter
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I have to say the FP 14000 is a very impressive amplifier. How nice is it that they only employ a filter at 1.5 Hz... That is the lowest I have heard from any amplifier.

In any case, in terms of what you can get for the same price, would you take:

A. (2) Lab Gruppen FP 140000 (1.5 Hz filter)

B. (4) QSC Audio PL380 (5 Hz filter) http://store.djhardwares.com/qscplpo3seam.html

C. (8) Marathon MA-5050 (not sure of filter) http://www.brilliant-electronics.com...on_ma_5050.htm

D. ( ) other amplifier.
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post #113 of 440 Old 10-27-2009, 09:46 AM - Thread Starter
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Kyle talked about custom screws that were made for the LMS 5400 (supplied). I think they were machine screws though. Maybe he can chime in on the supplied screws again. They are on page 2 or 3 of this thread.

Also, we were discussing the use of closed cell foam gasket tape and also the custom rubber gasket supplied with the LMS 5400. I was thinking that if people get leaks with supplied gaskets, it is probably from the space/wood irregularity between the cabinet surface and the rubber gasket, but not between the rubber gasket and the driver frame. I was thinking of using gasket tape between the wood and the supplied rubber gasket. Thoughts appreciated.
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post #114 of 440 Old 10-27-2009, 10:55 AM
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I posted what I was using.... the foam weatherstrip works just fine, with or without the supplied rubber gasket. If you are choosing to not use the supplied gasket, then the allen bolts will stick out about 1/2" from the frame, otherwise the supplied socket head cap screws with rubber gasket make for a perfectly flush mount. If you were going to use a trim ring instead of the rubber gasket - it shouldn't matter, you can use the supplied screws - they will be hidden.

Both drivers use weatherstrip closed cell foam.
LMS driver no rubber gasket - flush screw


TC-3000 with rubber gasket, supplied allen cap screw, you can see where the rubber gasket sticks out beyond flush with the weatherstrip and 3/4" birch ply


Supplied Screws and closed cell foam
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post #115 of 440 Old 10-27-2009, 11:39 AM
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Hey Chris,

I see your cabs are looking rock solid. That 1.5" stuff is nice.

I agree with Mark S. put a little damping/stuffing in there to knock down reflections. It's not for lowering the Q. Acoustastuff is decent, but expensive. A 3 dollar pillow from Wal-mart can do about the same thing. Perhaps try the material that Mark suggested.

I do have an impedance trace of my LMS in about 150L or close enough. I'll see if I can dig it up for you. Being that it's a sealed box it's a relatively simple load. I believe the z-min was about 4.3ohm.
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post #116 of 440 Old 10-27-2009, 11:59 AM - Thread Starter
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This foam looks useful also...

http://www.parts-express.com/pe/show...number=260-516

Even thicker:

http://www.parts-express.com/pe/show...number=260-515

Quote:


Only for high frequencies
Thursday, July 5, 2007
Alex S from NY

Works only above 2KHZ by reducing 10db of sound pressure.

Lets be honest... with a 12db or 24 db/octave rolloff... We shouldn't be concerned about anything above 1K in a subwoofer... So if the foam is only capable of attenuating 2kHz and up, then the foam is a complete waste. What material works best in the 150-1K range?
How accurate is that review?
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post #117 of 440 Old 10-27-2009, 01:59 PM - Thread Starter
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More correspondence with Lab Gruppen.

Yes the filter is 1.5 Hz

Please remember that the amps are build for LIVE sound and they have fans! So if you use them for home application then place the amps in another room!

You can down load the SW from our web site, make a registration, and you have access.
You can upload an offline PLM 10000Q and try to work with the system (LM 26 will have the same features). Some of the filters LS filters can go down to 16.5Hz or 31Hz depending on the slope of the filter.

http://www.labgruppen.com/support/software_firmware/


120 or 230V: we have two versions one for 120V and one for 230V. Both of them have a regulated switch mode power supply and the 230V version will still have full power output if the main power drop down to 180V! Internally you have 200V rail voltage to the amp modules!

Enjoy
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post #118 of 440 Old 10-27-2009, 03:56 PM
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"Both drivers use weatherstrip closed cell foam."

Are you sure it's closed cell?

That would make it a lot stiffer and might bow the basket out between the screws if a person were to keep tightening until it felt solid..

"This foam looks useful also...

http://www.parts-express.com/pe/show...number=260-516"

Foam is the easiest to work with and neatest.

"So if the foam is only capable of attenuating 2kHz and up, "

Foam has significant absorption at a couple hundred Hz.

Noah
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post #119 of 440 Old 10-27-2009, 04:00 PM - Thread Starter
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Quote:
Originally Posted by noah katz View Post


"This foam looks useful also...

http://www.parts-express.com/pe/show...number=260-516"

Foam is the easiest to work with and neatest.

"So if the foam is only capable of attenuating 2kHz and up, "

Foam has significant absorption at a couple hundred Hz.

Is there a comparison of materials at how effective they are at absorbing certain frequenices? Really 200-1K is the only thing that matters in subs. I am happy to hear that that review on Parts Express about the foam is wrong!!
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post #120 of 440 Old 10-27-2009, 04:08 PM
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Are you seriously concerned about this...?
all you are trying to do is seal the driver so it doesn't leak air around the mounting surface... wow - talk about overthinking things here...
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