LSI 9 Fluttering

bogo

Hi All,
Not sure how to describe this but my left LSI 9 has started to flutter. I really cant pinpoint where it is coming from, it seems towards the back of the cabinent. Under high load with bass this channel makes a fluttering sound lyet the other is rock solid, it really has just started to occur.

The other channel is rock solid, if it helps I am powering these speakers in a bi-wire config with a NAD C272 with Kimbre 8TC. Had no problems for years. Is something broken with a driver or is the cabinet not sealing. It really sounds like that back part where the power port is the issue. I really cant find where this problem is, any advice?

ohskigod

is it almost like a whistling flutter sound, and comes out the back port?

Eric W

Hi, its possible it could be something in the cabinet or one of the drivers themselves. Try this- remove the top driver from both speakers (6 Phillips head screws, then unclip the wires) and swap them from the Left channel to the right channel. While doing the swap, peek inside the speaker to make sure there is nothing floating around inside or loose. After doing the swap, try again, see if the problem follows the driver or stays within the cabinet. Repeat for the lower drivers, then let us know what you find.

bogo

Yes it is exactly like a fluttering whistling coming out of the back port Ohskigod. I will try and rip this speaker apart tonight. Last time I did this I cracked the finsih as my other cabinent had similar issues.

dorokusai

I think there is a wombat in your speaker.

XJRGUY

It could be a Tribble.

The affect your treble, you know.

bogo

Hi Eric,
I opened up the cabinent. To me it seems like this rattle is coming from the Acoustic Resonance ports. Both seem to be loose and can touch the side of the cabinet. Any idea on how to secure these?

bogo

Hi Eric,
I just did the unthinkable. SO angry at myself but to late now. I slipped with a screw driver and punctured the ring radial tweeter. Now two problems.

The issue still exists even after tightening the the acoustic resonance ports, it seems the cabinent is not sealed properly

Can you help me now with a replacement tweeter. The retailer in AUS is very expensive. Can you give me a quote for a LSI 9 tweeter?

ohskigod

bogo wrote:

Hi Eric,
I slipped with a screw driver and punctured the ring radial tweeter.

DOH!!!!!!!!!
woops!


yeah, I heard that with my 9's too, but they were being driven at very high volume with a particular song that I know has a deep bass rumble. This was being driven at the time by 500 watts of Carver power (and in a very large basement), so I figured I was just pushing the envelope too much anyway.

In the surround duty they currently serve, I have not heard the problem, but keep me posted on this ok?

I am not the most mechanically inclined person in the world. Your a Microsoft tech and you dinged a tweeter, good lord, what would I do if I took these apart without insight it would be a greek tragedy to say the least

thanx bud

bogo

Yeah I am really dirty at myself, usually so careful. Was in a rush. Very silly.

The thing is the left channel is rock solid. I am driving them with over 200 watts of power. I would expect both to do it.

Does anyone know what a tweeter is worth. It is saturday here in AU and I am expecting the retailer in Melbourne to say like 450 dollars

F1nut

I think it's about $90.00 US.

bogo

If I end up paying 180 AU (90US is only 135 AU) I will be pretty happy. The issue with the rattle still exists. It has to be those ports as they have play on this speaker.

From where I stand those two ports on the front of the speaker are the issue, they simply are not secured well enough. All that is supporting them is where they mount to the front of the cabinet. The picture at http://www.polkaudio.com/homeaudio/products/lsi9 could not illustrate my point better. Is this a flaw in the design of these speakers. I feel its just the carboard banging against the sides of the speakers.

jcaut

I know what you mean about those port tubes. Those cardboard tubes aren't high-tech, but they're cheap and non-resonant, and that's what most everyone uses.

If you have enough room to get in there through the driver holes, I think you should be able to secure them to the side of the cabinet with a drop of hot-melt glue. Maybe use some sort of spacer, if necessary. They're probably supposed to be attached more securely to the plastic flares that mount on the baffle: Being as long as they are, my guess is that they tend to work their way loose in transit.

Jason

bogo

I totally agree with you Jason, given that these are $3000 speakers in Australia I think it's quite a shame an extra couple bucks could not be spent in manufacturering these speakers.

bogo

Just letting everyone know I got these fixed, they ended up putting a heap of silicon against the accoustic resonance ports. They said they have had to do this to a lot of LSI series speakers. Hope the people at Polk can use this information and that from their service departments to build better speakers in the future.

dorokusai

You seem to be the first to find this problem and record it in about 3 years, so I'm sure they are doing just fine.

Eric W

I agree I've never heard of an issue with the ports coming loose with the LSi's, but thats not to say something has not happened. I am curious though, who said they had to do this with alot of LSi speakers? Bogo, please PM/email me regarding the tweeter you stuffed the screw driver through.

ohskigod

my nine's have done it, so I will look into it, but as I said above, only when they are driven REALLY hard.

which of the ports is the accoustic resonance port, the 2 little ones in the front or the big one on the back?

Airplay355

ARC port is in the front i think. Power port in the back.

bogo

The top of the two ports of mine was loose as buggery, you could feel it from the front. Only one speaker did it on mine but would not be surprised if the other speaker has the same issue some time......

bogo

Just wondering if I am the only that this has occured to do others use these as primary speakers. My Lsi'9s are my only two speakers and are driven quite hard and loud but like ohskigod it only happened when driven really loud.

jcaut

The ARC port on one of my RT55i's was loose when I got them, but they obviously had a very rough ride on their way to my house. It was no big deal: I just glued it back. I checked the other one and found that it was fairly loose, too, but not to the point of falling off.

Jason

tonyb

dorokusai wrote:

I think there is a wombat in your speaker.

Man o Man,you just made my day !!!:)