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LMS 5400 Subwoofer Build

post #1 of 12
Thread Starter 
LMS 5400 Subwoofer Build

Questions:
1. Are people using polyester (Dacron) polyfill for a SEALED LMS 18" sub?
2. Is it a good idea to use vibration dampening sheets on your sealed subs?
3. Should I add additional bracing?

Here are photos to check the dry fit all components before gluing the panels - looks air tight. I've had the LMS 18 for 3yrs, did all the WinSD modeling, etc., but finally got around to building it now.

http://www.flickr.com/photos/94098724@N03/?saved=1

Before gluing, I was planning to line the interior with Cascade Vb-2HD 0.075" vibration dampening sheet.

Gross Internal volume = 124L (4.4cft.)
Double thickness MDF: 2.13" front, 1.5" all other sides
Amp: EP 2500 (~1700W)
Xover/EQ: Behringer DCX 2400
HT Room: 24'x23' with 12' tented ceiling

Thanks
post #2 of 12
article on stuffing: http://www.data-bass.com/data?page=content&id=79

vibration dampening sheets not useful in a subwoofer.

bracing is better than double thick walls for making an inert cabinet, but i'm not sure what the difference would be between a double thick mdf cab such as your design and one that was only single thickness but included some simple window or stick bracing.
post #3 of 12
Thread Starter 
Thanks LTD02! I guess it might be worth adding polyfill - a decrease in peak impedance, lowering of the resonant frequency, smoothing of the FR curve, increase in the infrasonic range. I'll skip the dampening sheets in favor of internal bracing.
post #4 of 12
do you have an amp and eq?
post #5 of 12
Thread Starter 
Yes, I'll be using a Behringer EP2500 (~1700W) and a DCX 2496 crossover/EQ. I may upgrade the amp later, but have to keep balance with the pioneer V74 HT receiver. May go with ATS 5ch amp. Mating to Paradigm Studio Series speakers - S40v4, CC690, ADP-170

I am concurrently making a Scanspeak 8"/7"/1" 2.5-way full range speaker with series fed passive crossover with all Mundorf Supreme components. Here's a photo http://www.flickr.com/photos/94098724@N03/9553049568/
post #6 of 12
Dampening sheets are a waste of money.
Definitely brace it.

I went with a triple 3/4 thick baffle, flush mount.
Some people do a quad recessed mount, offers more protection and mates with a grill better.

The EP2500 will usually clip and overheat and explode trying to power the LMS 18 to the max.
You'd be hard pressed to reach full excursion with it... which might be considered a good thing.

A bridged CV-5000 is more like what the doctor ordered, or better yet, a clone 14k.
post #7 of 12
Thread Starter 
How does the MA-5050, CV-5000, and FP14000 compare in terms of: Reliability? Damping factor? Ability to handle 10Hz range? Fan noise?

Can the FP14000 run on 115VAC? How do you order from Sanway? What are most people running on the LMS 18 these days?

Thanks
post #8 of 12
Quote:
Originally Posted by 88man View Post

How does the MA-5050, CV-5000, and FP14000 compare in terms of: Reliability? Damping factor? Ability to handle 10Hz range? Fan noise?

Can the FP14000 run on 115VAC? How do you order from Sanway? What are most people running on the LMS 18 these days?

Thanks

I can only comment on the FP14000 clone vs EP4000.

There is significantly more usable power from the Sanway when powering an LMS. I had one ep4000 per driver for about a year, then moved to a single clone to power both LMS 18's (sealed, 4cubic ft each), and it is truly remarkable. I can't say I was ever displeased with the ep4000 - I just felt the drivers had much more to give so I went for the clone (which was always my goal... sometimes it takes a while to get around to it). I knew it would be louder when needed, and having one less amp in the stack is always nice. What I didn't actually foresee was:

1 - How much deeper the clone would go. It is unreal to watch the LMS cones hammering away at 5Hz and lower. The ep4000 was not even in the ballpark. It is so much more that a highpass filter is needed for driver protection, I use the mini dsp.

2 - Sound quality improving. In my fairly uneducated view it is from available peak power that the ep4000 did not have. Bottom line is no clipping the FP14k vs easily clipped ep4000. Sure you could clip the clone with the LMS, but it is not common as far as I know. I also know there is more to sound quality improvements regarding the design and type of amplification the FP14k uses, but I am not in a position to make a fool of myself and try to impart those facts to you wink.gif

3 - It actually makes me crave more. More drivers, more amps, more clean deep bass. It's hard to explain, but I feel it must be the effortless low distortion of the system. With the ep4000's I liked it... even loved it. I never really craved more though. I am wondering if I was picking up on distortion/anomalies brought on by beating on the ep4000's too hard and clipping them. Now that I am using the clone I feel I can tolerate and in fact enjoy more dB's of bass. Who would have thought an upgrade to the bass system which I was satisfied with has left me wanting even more of an upgrade... even though I am much more satisfied than I was...rolleyes.gif

This was all using a 15amp 110v power outlet. I have since moved and am in the process of setting things up again, now with a 20amp line. So far no difference has been noticed, but it has only been a day and I have no projector screen yet.

They can be ordered directly though the dealer, all info was very thoughtfully put in this thread by notnyt.
post #9 of 12
buy an ipr2-7500 puts out more power then the clones
post #10 of 12
I thought the IPR2-7500 put out 2x 3850wRMS but the Clones put out 2x 4400wRMS?
post #11 of 12
Quote:
Originally Posted by MemX View Post

I thought the IPR2-7500 put out 2x 3850wRMS but the Clones put out 2x 4400wRMS?

The IPR2-7500 will that that 3850w at 2ohm stereo. The clone is 4,400 peak at 4ohm stereo, and isn't 2ohm stable.
post #12 of 12
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