LS 90 Question

stubby

Hey all, just picked up a pair of pretty nice LS 90s and one of them is showing some strange behavior. The top two midwoofers will occasionally flutter with even a low signal sent to them. They don't bottom out and they don't do it all the time. Any suggestions as to what may be the problem?

I will also have to replace the tweeters as they have some off brand titanium jobbers in them now. Are there replacements available from Polk?

Thanks in advance - looking forward to getting these puppies back into shape!

stubby

EndersShadow

stubby wrote: »

Hey all, just picked up a pair of pretty nice LS 90s and one of them is showing some strange behavior. The top two midwoofers will occasionally flutter with even a low signal sent to them. They don't bottom out and they don't do it all the time. Any suggestions as to what may be the problem?

I will also have to replace the tweeters as they have some off brand titanium jobbers in them now. Are there replacements available from Polk?

Thanks in advance - looking forward to getting these puppies back into shape!

stubby

If Polk doesn't sell the tweets, I guarantee you someone here has a set.

DollarDave

I've got a driver or two and some tweets that I won't probably use in the near future - if interested, PM me and we can work something out.

ohskigod

switch a good driver with the one that is fluttering. if the problem follows the driver, it is the driver.....if it doesnt. its in the crossover (my guess, as I assume it has aftermarket tweets for a reason.

I had a pair of those, badass speakers....worth a little effort to get them 100%

dorokusai

If it's what I'm thinking of what your describing, they're just old and the driver vc and spider are worn out. They will eventually fail so I'd look for replacements now.

FTGV

stubby wrote: »

. The top two midwoofers will occasionally flutter with even a low signal sent to them. They don't bottom out and they don't do it all the time. Any suggestions as to what may be the problem?

First thought would an air leak but if the top drivers share the same volume as the other two they all would exhibit the behaviour.You might try swapping sides with the speaker cables to be sure the problem isnt something source/amp related.

Tony M

stubby wrote: »

Hey all, just picked up a pair of pretty nice LS 90s and one of them is showing some strange behavior. The top two midwoofers will occasionally flutter with even a low signal sent to them. They don't bottom out and they don't do it all the time. Any suggestions as to what may be the problem?

I will also have to replace the tweeters as they have some off brand titanium jobbers in them now. Are there replacements available from Polk?

Thanks in advance - looking forward to getting these puppies back into shape!

stubby

If you take the bad speakers out, look at that accorian looking disc behind the cone and see if it has come loose from the cone or metal basket. If it has, you can reglue it.

FTGV

I would think if a spider was detached there would be obvious audible side effects with it flopping around.

skrol

That would be my guess too, detached spider. I've seen it before.
Stan

stubby

Took the drivers out and they look OK. Re-installed them and could not duplicate the flutter, but there is a rasping sound coming from them, especially noticed at low sound levels. If you push on the driver slightly, the rasping sound stops for a while. I think the voice coil is on it's last leg.

Many thanks for all the help, and DaveMuell you have a PM about some spare parts!

stubby

stubby

As an aside, has anyone considered upgrading the internal wiring on their LS series speaker? I swear it looks like 18 guage out of a Monitor 4. I know size isn't everything but..........

stubby

FTGV

stubby wrote: »

Took the drivers out and they look OK. Re-installed them and could not duplicate the flutter, but there is a rasping sound coming from them, especially noticed at low sound levels. If you push on the driver slightly, the rasping sound stops for a while.

Well since you are actually hearing distortion even at low levels it may be that the spider has separated from the base of the cone.By pushing in the cone you might be momentarily realigning them?

saabracer23

I had a woofer with that problem (the audible problem) and I eventually had to buy a new driver.

Dan

Polkie2009

Sometimes you can get a temporary fix to the problem by gently pushing in the driver from the outer edge. It may last for a couple of minutes or a couple of hours,lol, eventually you'll get tired of doing that and just buy some used or new replacement Polk drivers. They are a breeze to replace. Dave's a great guy and will fix you up:)

DollarDave

Polkie2009 wrote: »

Sometimes you can get a temporary fix to the problem by gently pushing in the driver from the outer edge. It may last for a couple of minutes or a couple of hours,lol, eventually you'll get tired of doing that and just buy some used or new replacement Polk drivers. They are a breeze to replace. Dave's a great guy and will fix you up:)

I think I jsut figured out why I can't find my surplus drivers - I sold them to you with the 90's, didn't I?

Polkie2009

Lol, Dave I thought maybe you had found a couple more somewhere:) Stubby, I need to hang onto these in case I need a backup in the future. Hopefully someone else can chime in with some extras for you. Or you can get new ones through Polk Audio ,tell them you're a CP member and you'll get a discount:)

stubby

Polkie2009 wrote: »

Lol, Dave I thought maybe you had found a couple more somewhere:) Stubby, I need to hang onto these in case I need a backup in the future. Hopefully someone else can chime in with some extras for you. Or you can get new ones through Polk Audio ,tell them you're a CP member and you'll get a discount:)

No worries, I understand the need for spares. I have seen the tweeters on ebay and Polk is just a call away. Thanks to all for their input.

stubby