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Discussion Starter · #1 ·
I have fried both of my CSS SDX15 once each, now I fried another one watching Django a couple of days ago with the help of Sam Adams Seasonal Collection (movies and too much beer is bad for HT equipment). I need to make a change. I have an EP4000 bridged to each, use a Reckhorn HPF set at 19hz, each sub has a 6.6 cu ft enclosure tuned to 19hz.


I'm looking for some advise, and here are a few options I am throwing around:


Turn it down

Stop buying such delicious beer

rebuild the driver, about $200

buy 2 new 15" drivers, switch brands

buy 2 new 18" SI

buy 4 new 18 SI and build sealed

buy 2 new LMSU 18s


A couple of these options just aren't realistic. I admit that I abuse them, but I love to feel the bass, I know I don't have to justify that part to you guys. I listen to music 24-7, loudly quite often, and watch movies at close to reference 4 nights a week. I'd love to modify and reuse the enclosures, but I'd enjoy building more. They will have to occupy the same footprint. 2x2x7'


Here is a pic of the current drivers in the current cabs.

http://s20.photobucket.com/user/ocd_reef/media/Home Theater/IMG_5539.jpg.html
 

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Quote:
Originally Posted by d_c  /t/1472600/fried-a-driver-3rd-time-now-what#post_23311607


I have an EP4000 bridged to each,
That would explain it. Bridging isn't about power, it's about doubling voltage swing into a high impedance load that the amp would not otherwise be able to drive to its thermal or displacement limit, whichever is lower. I'd say you don't have that problem. The only safe way to bridge is if you have a limiter to prevent excess voltage swing.

You're also probably trying to get way too much out of two fifteens, and they'd probably work better placed on opposite ends of the room.
 

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Discussion Starter · #4 ·
I would hate to lose the low extension Jay, which I think would happen if I dropped an 18 in to each cab - unless I sealed the port which would be easy. One part of me wants to get 4 lower cost 18" drivers, build new enclosures, and seal them. That way I have enough power on hand already, ie the Daytons or the SI. The other part of me hates to have all that space to utilize and not have two vented enclosures. I enjoy watching the build threads of the 8+ sealed driver configurations, but it is not realizstic for the space I have to use. I love the performance of the CSS drivers, but I keep killing them due to my own negligence. I need something that will accomplish the same or more and be safer from my urge to keep turning it up.



enclosure specs:

36x24x17

Two 4" x 25.5" ports

6.6 liters Total volume

19hz tune
 

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Discussion Starter · #5 ·

Quote:
Originally Posted by Bill Fitzmaurice  /t/1472600/fried-a-driver-3rd-time-now-what#post_23311884


You're also probably trying to get way too much out of two fifteens, and they'd probably work better placed on opposite ends of the room.

That is the sum of it. I always want more. My pair of THTLP in the same place wouldn't pass wife approval, or fit in the space!


See? This petite T48 barely fits
http://s20.photobucket.com/user/ocd_reef/media/box2.jpg.html
 

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"Bridging isn't about power..."


sure it is.


it is a way to get the maximum power out of an amp from both channels into a single load.


"I have an EP4000 bridged to each..."


then you need drivers that can take that kind of power.


FOUR alpine swr 12d4's should be able to work in that cabinet and take that power.
 

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Quote:
Originally Posted by LTD02  /t/1472600/fried-a-driver-3rd-time-now-what#post_23312310


"Bridging isn't about power..."


sure it is.


it is a way to get the maximum power out of an amp from both channels into a single load.
It would be with parallel bridging, which doubles the current capacity into a low impedance load. But very few amps use parallel bridging. They series bridge, which doubles the voltage output, not the current output. That's why in most cases the minimum impedance load for a bridged amp is twice that of each channel separately. With the EP 4000, for instance, it's rated 2x 2,000 into 2 ohms, 1x 4,000 into 4 ohms. If it was me I'd be running only one EP 4000 channel per driver, if 1400w into 4 ohms isn't loud enough you don't need more volts, current or power, you need more speakers.
 

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Discussion Starter · #8 ·
I have them gained down by 50% to aim for around 2k per driver, as they are rated at 1800w. The blown driver is making a scraping noise, so would that be from mechanical failure? I smelled the coils cooking when I roasted the last ones, resulting in no sound. I dialed gains way back since then.


Has anyone completed a vented build with the SI18 yet? Looks like that driver would work in my same enclosures as they recommend 5-6 cubes tuned at 20hz. That would be cost effective.


I noticed on Data-Bass that the sealed SI beats the SDX15 by at least 3db all the way across the board. Would the same be true for vented?
 

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Here's a clip of me blowing an LMS Ultra.


I'm sure you don't feel so bad now.





The SDX-15 is rated for 1200watts RMS.


The LMS-U is rated for 2000watts RMS and 8kW peak. It's 10db louder than each SI below 20hz, according to data-bass.


I migrated away from dual SDX-15's to quad LMS-U's and 2 21's. It's much-much better and louder too






The LMS can take a lot of punishment (but it's still not invincible. I learned that the hard way!
)



Your EP4000's will likely go into melt-down before it will stress the LMS-U's much
 

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Quote:
Originally Posted by d_c  /t/1472600/fried-a-driver-3rd-time-now-what#post_23313012


I have them gained down by 50% to aim for around 2k per driver, as they are rated at 1800w.
Gain controls do not limit the amp output, they merely attenuate the source signal. If that signal is hot enough the amp will still deliver full output, even clip. Read the last page of your T48 plans on preventing driver damage.
 

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Quote:
Originally Posted by d_c  /t/1472600/fried-a-driver-3rd-time-now-what/0_80#post_23317225


Would trying to push an lmsu with an ep4000 be pointless, or would the results be better to push two si 18s?

Pointless, no. Optimal, no.


2 Si 18's would be in the sweet spot with a bridged EP4000. It would cost less too. Keep in mind, the SI's are far from bullet proof though. An LMS-U on an EP4000 would be pretty indestructible.
 

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Discussion Starter · #13 ·
Anyone have a minute to post a model of 4 sealed si 18d2 with 750w each vs. 2 sealed lmsu at 1900w (4000 peak) or whatever it is that the ep4000 actual outputs bridged at 4 ohm
 

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Discussion Starter · #17 ·

Quote:
Originally Posted by Mrkazador  /t/1472600/fried-a-driver-3rd-time-now-what#post_23319736


Alright so now its 3800w for the two LMSU.





Thank you!! I appreciate you guys. I realize this subject has been beaten to death the last few months.


Using only two instead of the four SI would be 3 or 6 db less?


I could spend another grand on the fp14000 and double the power to the LMSU to add 3db. Are there other benefits beyond?
 

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Quote:
Originally Posted by d_c  /t/1472600/fried-a-driver-3rd-time-now-what#post_23320137


Thank you!! I appreciate you guys. I realize this subject has been beaten to death the last few months.


Using only two instead of the four SI would be 3 or 6 db less?


I could spend another grand on the fp14000 and double the power to the LMSU to add 3db. Are there other benefits beyond?

Two less SI drivers would be 3db less, but you'd have to be careful not the blow the drivers with dual ep4k amps.


Doubling the power of the LMSU with the lg clone would be a 3db increase.


Also take into account that the measurements above are with the SI drivers taking up twice the space with 16 cu.ft compared to 8 cu.ft. If you have the space this is obviously a non-issue.
 

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Discussion Starter · #19 ·
I may have a solution:

I downloaded winISD and am stumbling through it. I may have it effed up, but 2x LMS-U with my current ported enclosure is 4+ db from 5-50 hz above the 4x SI sealed in 16 cubes using my two EP4000. Does this sound right?


the enclosure is:

hz

36x24x17

Two 4" x 25.5" ports

6.6 liters Total volume

19hz tune
 

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It probably sounds right but anything below 15hz is a moot point since you're using a subsonic filter.


LMS-U's don't like big ported boxes, so to get deep enough tuning folks usually use passive radiators. Check your port speed to see what it says given your input signal. An SDX-15 should push the limits of those 4" ports and an LMS-U should easily push those limits. If you've not heard any port noise before, then you might be safe.
 
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