Crossover Problem?????

Sthrndream

Ok here it goes. Full Home Theater systems to include surround backs (7.1)
Equipment List: Polk LSIs all the way around. LSI 25s are biwired to Sunfire Cinema Grand 7 x 400. You can see the rest of equipment list in the signature.

Played at loud volume this weekend for 6 hours straight. Both fuses blew for Current load on the amp. (Sunfire biwiring involves separate Current (+ & - terminal) and Voltage (+ & - terminal) wires going to the Polk LSI. Replaced the fuses. Amp works again no problem. What I did notice is LSI 25s are reduced in volume (ie 5-7 dB loss in sound on each speaker).

Called Sunfire, said for me to check the biwiring thru their said tests. Checks out. Amp is in working order.

Why are my LSI 25s playing at a lower volume than the rest of my system now??? Damaged driver??? Damaged Crossover?? Please help. The speaker doesnt sound bad (like a blown driver) just quieter.


Please Help!!!!!!!

F1nut

Played at loud volume this weekend for 6 hours straight................What I did notice is LSI 25s are reduced in volume (ie 5-7 dB loss in sound on each speaker).

Maybe it's not the speakers as much as the hearing damage you inflicted upon yourself.

Sthrndream

No thats not it. The center channel and surrounds are playing louder. I recalibrated the Surrounds and there is a 10dB deifference between the center and mains.

Polk any thoughts????

[Deleted User]

Hello,
Probably the first thing to do is determine if the problem is a speaker one or not. To do this you would exchange the two speakers, connect the left speaker to the right channel set of wires and right speaker to left set of wires. If the problem remains with the speaker then it is the cause. If the other speaker now is reduced then the problem is elsewhere in the system.
Let us know the results.
Regards, Ken

Sthrndream

Ken,

Thanks for the reply. I talked with Eric this am. THis is what I did. Please follow this closely.

I ran a Calibration test using an SPL meter prior to attempting this. Both main speakers (LSI-25s) are running 9.0 dB below what the other speakers are running. so in essence my listening position 10 feet from the "center stage off to toward the right corner yielded me this Left Main 9.0, Center 0.0and Right Main 9.0 all to yield a 72dB calibration reference. My surrounds and surround backs (LSI-FX and LSI 7 respectively) are from -5.5 to -1.5to achieve a 72 dB reference. THis is ok as I am closer to the rears than the front.

I removed the midrange (lower) from the left LSI 25 and moved over some foam that was stuck to the crossover. I smelled a "toasty burnt smell" and I observed all the caps are not busted, however, one of the little white boxes (lower left) looked either cracked or had some dark glue over the top (cant tell)

The LSIC and the LSI 25 (MW5534 Dec 02)have the same midranges in them. The LSI 7 and the LSI 25 have the same Vifa Tweeters(RD0517-1) in them. I removed the midranges (MW5534-1 Dec 05) from the LSI-C and inserted both of them as well as the Vifa (RD0517-1) from the LSI 7 into the left main speaker. Ouala! I had to lower my gain 9.0 db to achieve a 72 dB reference. So now as it stands my Left main is 0.0 and my right main is 9.0 at 72 dB.

I took each old midrange and replaced the new one with it listening to dB level. dB didnt change. So I said it must be the Vifa tweeter. Guess what It didnt change either. Now Im baffeled and am proceeding to the next speaker (right main). The only thing that come to mind is that something might have been loose, however ALL drivers were connected as i removed them.

Update: I think I solved my problem. What an idiot I must be. The Biwire was in the wrong terminals. not reversed polarity. I had voltage for highs and current for lows. Im relieved. no perceived damage. Thank you eric and ken!!!!!

In todays world POLK LSI rocks.

Now for the right main

[Deleted User]

Hello,
If I understand everything correctly, you have one speaker that is playing much less than the other. You mentioned seeing burned components on the crossover, correct? If so, this could account for the problem. Crossovers are passive circuits that blend the different components, tweeters, drivers and woofers, so they sound cohesive. If the parts on the crossover have been damaged this would change the output produced by the complete speaker. It would be best to remove the crossover, from the back of the cabinet, after disconnecting all of the tweeter/driver/woofer wires and send it to Polk Audio, 2550 Britannia Blvd., Suite A, San Diego, CA. 92154. Please include a short note giving us your name, address and a copy of your sales receipt.
Regards, Ken

Sthrndream

It sounds like it should now. The wires from the amp were in the wrong place (not reverse polarity), the voltage outs went to the tweeters instead of the current

Sthrndream

Problem not solved now. My amp is shutting down at moderate levels now. My Sunfire Cinema Grand manual says to check three things.

1. Check that the + and - speaker wires are not shorted together. (Definitely rule that out because Im running 4 Monster Z3 reference wires 2 to each speaker + on + - on -)

2. Make sure the amp is not overheated and has adequate ventilation ( Yes it has adequate ventilation and hot as hell, but not suppose to be)

3. Make sure no speakers have shorted internally. Take an Ohmeter and measure the resistance , if below 2 they have a short. ( Measured my LSI 7s and measure 4, both LSI 25s dont even register)


SO where do I go now guys....something is wrong. It was sounding normal for a while. FWIW I do smell a pungent odor from the two ports on the LSI 25 (like burned toast, bad battery acid etc.) Ill be able to call you at 10 am EST MOnday, but if you read this, please tell me what your idea is?

and sad

okiepolkie

Got your PM.

If you you aren't getting any reading from the 25's, that is where your problem lies. There isn't a whole lot you can do about that right now.

Ken was right in that you need to remove the crossover and send it to Polk for repair or replacement. Your next step would be to measure each individual driver in each cabinet to determine if your they have been damaged as well. The individual drivers should read somewhere between 3-8 ohms(I can't remember the exact measurements on the LSi's).

Sorry to hear about your misfortunes with the speakers. Polk will make it right for you.

BTW, I don't remember asking you where you are from in OK. If I did ask, I've forgotten.

Sthrndream

Im in Oklahoma CIty serving in the USAF.

Update: I mailed the crossovers three day priority to Polk Audio today. Did tests on the drivers. Midranges are 4.6 Ohm across the board. Tweeters are 3.7 Ohm. Subs are 4.1 Ohm I took my LSI 7s and connected them where my mains would be and Biwired the Sunfire method. My amp doesnt heat up like it did last night. So i think I isolated the problem. I took pictures of the bad crossover and will post them either today or tomorrow. The LSI is a simple but well made speaker. Im very impressed with the quality. What an experience. I got to know more about my speaker than I wanted to.

madmax

You had a lot of current flowing to heat up a sunfire like that!
madmax

Sthrndream

Called Polk Audio today in San Diego.

Spoke with Angel, have 2 new crossovers being Fed EXed two day shipping to me either today or tomorrow. Outstanding Customer Service. This is what is going to keep me happy with my choice in speakers. Customer Service is as important as sound!

Thanks to Eric Wong, Kenneth Swauger, Angel and anyone else in Polk that had a hand in this!!!!

You guys ROCK!

F1nut

Gotta love it!

Sthrndream

Got my crossovers in today after work. Just got them installed. Thank you Polk Audio. You guys are flat out AWESOME