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Infinity Crescendo 3008 6 1/2" Mid-Bass Replacement

Lefty314

Lefty314

New Member
Hello, I recently purchased a pair of Infinity Crescendo 3008s from eBay. I wish I could say I got a good deal, but when I set the speakers up I heard an awful distortion. I isolated it to one of the 6 1/2" mid-bass drivers. It produces sound, but the sound is very distorted. I checked polarity, connections, swapped cables to isolate the driver and I have no doubt as to the driver being kaput.

So my question is, rather than try to return the speakers, I want to replace the driver. The part number is 902-6778 76198 IMG. I saw a pair on eBay yesterday that needed work. They went unsold so they may return. Tonight I see "Infinity 6 1/2 Mid-Bass Kappa 8.1 9.1 8.2 9.2 Renaissance 90 Sigma IRS Speakers." The photo shows a part #902-5239. The driver looks identical in size, design, color and function. Is this driver interchangeable with the 902-6778 I'm looking for? Thanks in advance for any comments and guidance.

Regards,
Bill R.
 
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ivandezande said:
Did someone botch the re-foam job on that driver? Might just be unaligned.
Click to expand...

Thanks for the comment Ivan. I am beginning to believe this may be the case. The finish on the surrounds leads me to believe the units have some age and although the description on eBay doesn't mention a re-foam, the foam looks brand new. It is an idiosyncrasy of these drivers that the dust cover is very difficult/not practical to remove, so shimming, I'm sure, did not happen. I am considering a re-foam of the re-foam. What I did not mention in my initial post was that I did check out the speaker with a multi-meter. That driver read 3.5 ohm with no open circuits. The unit as a whole checked out as well, so the problem is most likely not electrical.
 
I bet it's a bad refoam job, though they don't look it usually, the foam on the mids falls apart over time also, I've got two sets of mids out for refoam now, and will likely have to do the other four sets afterword....jesus, I have too many speakers.
 
I removed the troubled driver last night and bounced the cone. No doubt the coil is rubbing in at least two quadrants. I am going to try a re-foam of the re-foam. There is a good YouTube video of a gentleman re-foaming the woofer version of this driver for a CS-3007. Just waiting for the foam kit to arrive. In the meantime, I see a pair of 902-6778s on eBay for $120. Hopefully I won't need them.
 
Refoam completed. The glue is dry and reauditioned the Infinitys this morning. Yes - Close to the Edge and Rush - Farewell to Kings both sounded fantastic! Thanks all for the good advice
 
One thing is for sure, they are worth the try, the Cresendo line are very special speakers I've owned 3007 and 3009's those big ole monkey coffins are something I'll tell ya. I've read a few articles talking about the 08's being the sweetest one in the line.
 
Lefty314 said:
It is an idiosyncrasy of these drivers that the dust cover is very difficult/not practical to remove, so shimming, I'm sure, did not happen. I am considering a re-foam of the re-foam.
Click to expand...

Not at all. The dust covers can easily be removed with nothing more than your finger nail, and then a plastic spreader. These IMG cones are remarkably tolerant of solvents, so Goof-Off can be used on a q-tip to remove any glue.

The pictures in this thread might be useful :

http://audiokarma.org/forums/index.php?threads/infinity-crescendo-cs-3007-restoration.599202/

Lee.
 
leesonic said:
Not at all. The dust covers can easily be removed with nothing more than your finger nail, and then a plastic spreader. These IMG cones are remarkably tolerant of solvents, so Goof-Off can be used on a q-tip to remove any glue.

The pictures in this thread might be useful :

http://audiokarma.org/forums/index.php?threads/infinity-crescendo-cs-3007-restoration.599202/

Lee.
Click to expand...

Thanks for the information Lee. If I had it before I did my reform I might have tried it. I used the information and method from this YouTube video

It worked and the speakers are performing well so I’m not thinking about making any changes to the drivers. I am considering some recaps in the crossovers. I am also going to try to refinish the cabinets. The veneer is pretty thin so I’m a little nervous about sanding. I don’t really want to reveneer them.
 
7.62 said:
One thing is for sure, they are worth the try, the Cresendo line are very special speakers I've owned 3007 and 3009's those big ole monkey coffins are something I'll tell ya. I've read a few articles talking about the 08's being the sweetest one in the line.
Click to expand...

I’ve only had a little time to listen to them Gearhead, but what I have heard is pretty sweet.

Bill
 
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