Dang it. In the middle of viewing a movie I smelled something burning and immediately shut down all components. I was afraid the TV was burning up. Nope. Everything looked and smelled fine with the TV. The burning smell dissipated before I could pinpoint where it was coming from. SO.....I cranked back up and couldn't hear the movie dialogue.

Inspection of the Polk LSiC center revealed no sound coming from the right-hand (higher-frequency?) driver. That's where the burned smell was coming from, too.

So, my question is.......is this unusual? I've had the LSi's for about a month-and-a-half. The only change I've made was replacing my Onkyo receiver (which I was using as a preamp with an Outlaw 7700 amp) with the Outlaw 990 preamp a few days ago. Been working fine until now. Is there any chance that has anything to do with the LSiC driver blowing?

Crutchfield will ship out a replacement, but the tech support guy said they almost never have any problems with the LSiC. (Of course, I also had to have an LSi25 on the same shipment replaced because the first one's sub was non-functional).

Someone on the Polk forum suggested that the problem might be a bad channel on the 990. (Say it ain't so!)

Any thoughts, guys?

(oh.....Cobalt speaker cables and Outlaw interconnects, by the way)

The right-hand and left-hand drivers both get the same signal (the middle driver is the tweeter, which handles the highest frequencies). A burning smell from a driver sounds like a significant failure. Did the left driver still work? If not, I'd suspect a failure in the crossover network, but if it still worked than it was just that one driver that died.

I don't see how it could be a bad channel in the 990 - the 990's only a pre/pro, with the 7700 actually driving the speaker. The person on Polk's forum may have been thinking that the 990 was a receiver with internal amps. To a certain degree, anything is possible, but I don't see how the 990 could be responsible for blowing one of the drivers on a speaker.

Thanks, gonk. That makes me feel a little better......the left-hand driver still works perfectly.

I was also wondering if it could be related to the trigger cable between the 990 and 7700. There's a brief, but rather disturbing "BUZZZZZZZZZZZZ" when I turn the 990 on. I was wondering if that might be related.

Thanks for your help.

As far as I know, all crossovers include a capacitor in the tweeter line, for shaping and to protect it.
Cheaper filters use an electrolytic here, these CAN dry out but short circuits are seldom.
Doesn't sound like your amp is to blame.
My 990 will arrive here on Tuesday so I don't know about your buzz.
Barend (NL)

Okay, this is probably a dumb question, but I'm trying to learn here, so be gentle with me!

The LSiC has a mylar bypass capacitor in the high-end crossover, and uses a cascade tapered array for separate 2400hz and 200hz crossovers for the two drivers. How does that arrangement correspond to DC blocking and possible speaker damage? Might the different driver crossovers be the reason why only one of the drivers would blow?

As a former Polk dealer...I'd say the speaker simply failed. It's a very common thing from Polk.

Well, it looks like I've been barking up the wrong tree. This is obviously a power issue. I hooked up an old Infinity Primus center speaker that I still had. When I turn on the 7700 I get bad noise (which seems to be lasting longer each time now)......and that old familiar burning smell started coming from the center. It's not blown (yet), but now I'm thinking that I've overloaded the AC circuit, and the damage is cumulative every time I power up the preamp/amp.

So (here's my ignorance showing again) do I need some sort of power conditioning......or a dedicated 20-amp circuit? Or something else. Right now I have everything shut down and am afraid that I'll do more damage if I keep powering up.

A dedicated 20 amp circuit isn't needed. I think you may have something wrong with the 7700 or possibly the 990. I wouldn't power it up until you have a chance to call Outlaw tech support.

did you check your speaker cable? it sounds like it may be something like that also. What size speaker cable are you useing? When I first read you complaint I thaught that you melted a speakercable.

I agree with Daryl that you shouldn't need additional power. It still seems unlikely that the 990 could have a defect that would kill speakers and the 7700's apparently been in the system for a while, but it seems appropriate not to rule anything out yet. Speaker cabling is definitely a candidate.

I'm using Cobalt cable (10AW), which I switched to last Thursday......same day I got the 990. However, I just tried replacing the center cable with the old 14AW..........same awful buzz from the center when I turn the 7700 on. Will update after I talk with Outlaw. Thanks!

(changeout of center IC = same awful buzz;

center IC disconnected from 7700 = no startup buzz)

Since I last posted I hooked the center channel back up through the Onkyo receiver instead of the 990, and the 7700 started up silently and played perfectly, so now I know it's not the speaker, the speaker wire or the interconnects. I also have no startup racket when powering up the 990/7700 with the center channel not connected.

I spoke with Steve at Outlaw tech support. He said that the 990's usually very reliable, but since I've pretty much isolated the problem to the 990 center channel he's shipping out a replacement today. I'm keeping my fingers crossed. (Great tech support, by the way!)

Thanks everyone for the input.......I'll keep you posted.

I thought I would let you know that I'm having a similar problem. I've been having center channel audio drop outs and random center channel popping noises with the 990. No burning smell, though.

However, I've gone the route of the online tech support. They had me swap some connections that caused the drop outs and popping to come out of the left speaker. I guess they were eliminating the center speaker as the culprit.

I reopened my support ticket, and expect to hear something this afternoon. So far, tech support has been good to deal with.

I'll update when I hear something.

Not on the LSiC, the left side plays only bass while the right side plays mids and bass.

BTW, good job on trouble shooting though.

Eric
Polk Audio Tech Support (with a Outlaw 990).

So it's a 2-1/2 way design? Interesting...

Update: Received replacement 990. Hooked it up. Same scary-sounding buzz from center speaker when 7700 is powered on, lesser but similar buzz when powering 7700 off. Obviously my faulty 990 deduction was......er, faulty. So much for my troubleshooting skills!

Today's troubleshooting efforts:

1. Hooked center speaker cable to old cheap speaker which I
don't mind blowing!
2. Changed from unbalanced to balanced IC's between 990 and
7700. Buzz.
3. Swapped center and surround back left IC inputs to the 7700.
Hmm......buzz STILL from center speaker. Interesting.
4. Changed IC's back to normal connection. Swapped center
and SBL speaker cable out of 7700. Hmmmm...buzz now
comes from SBL speaker.
5. Repeat #3 & #4 with different speaker cable, trying both
bananas and bare wire. Same results.
6. Repeat all of the above with 990 powered off when the 7700
is powered on. No difference. Buzz.
7. Connect my old Onkyo receiver's center preamp out to 7700
center in, and my DVD player's center IC output to the
Onkyo's center DVD input. Silent 7700 startup, no buzz,
center channel sounds good when I play a DVD.

Now, since my track record so far isn't good I'm hesitant to even posit a new deduction. But I gotta. It seems the problem (DC?) always comes from the 7700's center speaker output.....but ONLY when there's an IC input from the 990 (any channel) to the center 7700 input.

If anybody's still awake after trying to follow all that, I'd appreciate your opinions. Of course, I'll be humbly crawling back to Steve in TS with the news that the 990 swap didn't make a bit of difference. I sure don't want to have to try swapping out the 7700......I'm still bent over from the last time I had to lift it!

so from what i can tell. it sounds like it's NOT the 990.. and may be the 7700 instead? OR speaker or speaker wire/cable to me. Or did you fry a crossover in your LSiC? does the LSi center work ok on your Onkyo?

Skyblazer wrote: "so from what i can tell. it sounds like it's NOT the 990.. and may be the 7700 instead? OR speaker or speaker wire/cable to me. Or did you fry a crossover in your LSiC? does the LSi center work ok on your Onkyo?"

Quick summary to catch you up:

1. Originally had onkyo receiver as preamp with 7700, and all was right with the world.
2. Replaced onkyo with new 990. Bad "zzzzZZZZTTTT" buzz from center speaker on startup/down.
3. Eventual burning smell & dead higher-frequency driver in LSiC.
4. Not the speaker. Same buzz problem with any other speaker connected as center.
5. Not the speaker wire, improper connection or the 990 itself (see troubleshooting above).
6. Problem isolated, I think (also see above troubleshooting), to 7700 center speaker connection, but only when interconnected to 990, not the Onkyo.

that's e'ffed up....

so to me if i understand it correctly.. the 7700 center speaker connection ONLY has a Buzzz when it's connected to the 990 pre amp output? but not when connected to the Onkyo? odd.

you probably did this already. but when if you take the center channel pre amp output from the 990 to another input on the 7700? Does the buzz follow to any input on the 7700?

Yep, already did that. See troubleshooting #3 above.

Does it sound like a 60Hz Hum? Grounding loop. I can't remember where I read this but your problem might be a grounding loop in a hi-fi/electronics system/circuit. Not sure why it would be just the center channel though...

Try plugging the 990 or the 7700 on a separate circuit totally... Long extension cord may be needed.

Here is what I found online...

http://www.epanorama.net/documents/groundloop/

I tend to think that something is wrong with the 7700 and it's interaction with other components in your system.