No more bass. Crossover or Blown Speakers?

[guydm]

I've been dealing with my left front channel bass cutting in and out for some time, and finally it just stopped altogether. Also, my right channel sounds pretty distorted as well; both of the right channel drivers seem to be making sound, but there is definitely a buzz/crackle apparent on the lower frequencies. These speakers are fairly new (1998) RT7, so I don't think they are just worn out. However, I do have a teenage son that is very keen on the BIG BASS in his hip-hop tunes. My guess is that perhaps they may have been driven pretty hard while mom and dad were out of the house.

I took both speakers apart. The left speaker (the one that was not producing any bass) does not seem to exhibit any visible damage. Perhaps there is an issue with the crossover on that one. ??? The right speaker (the one that made the electric grinding noises in the bass) definitely was not in such good shape. The cone is split at the bass near the driver area. Ouch!

I think I would like to replace the woofers, assuming replacement parts are available and not cost prohibitive. If so, that would seem to solve part of the problem. Then there still may be an issue with the crossover(s). How can one tell if crossovers circuits are working properly? If not, are they replaceable components as well?

Any other ideas or suggestions or something that I should consider or look into?

Thanks for any advice or assistance in helping me to resurrect these speakers.

..guy

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[Kenneth Swauger]

Hello,
Sorry you're having a problem. The 7.5" driver, in the RT7, is the MW8002. The best thing to do is to send both of the drivers to Polk Audio, 2550 Britannia Blvd., Suite A, San Diego, CA. 92154, attention: Gil Palmer. Please include a short note giving us your name, address and a daytime telephone number. We have made arrangements to have those drivers re-coned. Meaning they are stripped down to the bare frame and all of the moving parts (voice coil, cone, surround and spyder) are replaced. The charge for this is $35.00 each plus shipping. However it is best to wait until the drivers are finished before providing payment. Allow four to six weeks for the process.
For the most part crossover damage is usually visible, pull the crossover out of the back of the cabinet and see if you see any burned or scorched components on the circuit board.
Regards, Ken

[guydm]

Ken,

Thank you for the reply and arrangements indicated below. Re-coning sounds like a good solution.

Meanwhile, I think that I have determined that only one of the speakers was in fact damaged. Oddly enough, a problem with my amplifier (one channel died) saved one speaker. So, my next questions is: would it make sense to only re-cone the damaged speaker? or would it be best to do them both so they match? In other words, would there be a noticeable or significant difference between an original speaker on one channel and a re-coned one on the other? Of course, if you tell me the re-coned one is going to sound better then I will surely go ahead and have them both fixed anyway. :-)

Again, thanks for the information and insight. I look forward to getting these speakers back in action as soon as possible.

..guy

Originally posted by Kenneth Swauger
Hello,
We have made arrangements to have those drivers re-coned. Meaning they are stripped down to the bare frame and all of the moving parts (voice coil, cone, surround and spyder) are replaced. The charge for this is $35.00 each plus shipping. However it is best to wait until the drivers are finished before providing payment. Allow four to six weeks for the process.
Regards, Ken ;)

[Kenneth Swauger]

Hello,
I believe it would only be necessary to re-cone the non-working driver, the other one should be fine. The goal is to have the driver sound the same as the original so there shouldn't be any mismatching. It may take awhile for the re-coned driver to break in, perhaps 20 or so hours of normal play.
Regards, Ken