Possible to repair woofer? It's buzzing

reking · 23rd January 2011, 05:02 PM

Hello, I'm a complete beginner to audio stuff, so bare with me.
I receieved some old loudspeakers from my dad, they seem quite nice. They are Mission Cyrus 780s. However one of them seems to resonance annoyingly at low frequencies. I have uploaded a video to youtube showing what I mean.

YouTube - Woofer rattle (I tried filming it fom different angles but there's nothing to see really, just listen to the high frequency noise that comes when I apply a low frequency (between 50-100 hz sine wave)

Now from reading a little bit about this, it could be the spider-thingy that has come loose, perhaps simply because the whole thing is kind of old. I never played them very loud. Gently pushing the cone in makes a very small "clicky" sound, which I can't seem to hear on the working woofer. Is this something I should even begin to think about attempting to fix myself? Can I get a replacement woofer easily?

mige0 · 05:31 PM

Forget that chassis and try to get the same speaker for cheap if you have fallen in love with those.

There are replacement parts - but mostly for PRO chassis only - not for HIFI speakers.
As far as I know Misson has used chassis specifically made for them, at least with their newer lines.

From your video it sounds to me as if the voice coil no longer is perfectly glued to the membrane.

If you hear a rubbing sound when gently moving the cone then the VC is no longer in the center of the gap and remounting the chasis upside down some times helps - but a "click" as you mentioned - no idea...
(possibly the VC former has bottomed once and got damaged at its end - so no longer fit into the gap precisely)

If you are curious, you can always try to open the spider but you should not expect to being able to repair this speaker - sorry.

Michael

mige0 · 23rd January 2011, 05:36 PM

Possibly also check if the litz wire to the membrane / VC is not sloppy

Michael

MisterTwister · 23rd January 2011, 06:05 PM

I had similar problem. it was detached cone. try to push cone out and look if there are any gaps between voice coil former and cone. if there is, just glue it back together.

reking · 24th January 2011, 08:55 AM

Thanks for the replies.
I'm not familiar with all these terms so I had to look them up. Mounting the chassis upside down or sideways didn't change. The wire does not seem sloppy or loose. I can not see any gap between the cone, but it may not be visible... To glue it back together, I'd have to take it apart first, no? The whole thing has no screws, just used glue to sit together. I think it will be hard to re-do it, and I may just have to look for new speakers.

mige0 · 24th January 2011, 03:47 PM

Quote:

Originally Posted by reking

I think it will be hard to re-do it, and I may just have to look for new speakers.

23rd January 2011, 05:02 PM	#1
reking diyAudio Member Join Date: Jan 2011	Possible to repair woofer? It's buzzing Hello, I'm a complete beginner to audio stuff, so bare with me. I receieved some old loudspeakers from my dad, they seem quite nice. They are Mission Cyrus 780s. However one of them seems to resonance annoyingly at low frequencies. I have uploaded a video to youtube showing what I mean. YouTube - Woofer rattle (I tried filming it fom different angles but there's nothing to see really, just listen to the high frequency noise that comes when I apply a low frequency (between 50-100 hz sine wave) Now from reading a little bit about this, it could be the spider-thingy that has come loose, perhaps simply because the whole thing is kind of old. I never played them very loud. Gently pushing the cone in makes a very small "clicky" sound, which I can't seem to hear on the working woofer. Is this something I should even begin to think about attempting to fix myself? Can I get a replacement woofer easily?

23rd January 2011, 05:28 PM	#2
mige0 diyAudio Member Join Date: Jan 2005 Location: Austria, at a beautiful place right in the heart of the Alps.	Forget that chassis and try to get the same speaker for cheap if you have fallen in love with those. There are replacement parts - but mostly for PRO chassis only - not for HIFI speakers. As far as I know Misson has used chassis specifically made for them, at least with their newer lines. From your video it sounds to me as if the voice coil no longer is perfectly glued to the membrane. If you hear a rubbing sound when gently moving the cone then the VC is no longer in the center of the gap and remounting the chasis upside down some times helps - but a "click" as you mentioned - no idea... (possibly the VC former has bottomed once and got damaged at its end - so no longer fit into the gap precisely) If you are curious, you can always try to open the spider but you should not expect to being able to repair this speaker - sorry. Michael __________________ Audio and Loudspeaker Design Guidelines Last edited by mige0; 23rd January 2011 at 05:31 PM.

23rd January 2011, 05:36 PM	#3
mige0 diyAudio Member Join Date: Jan 2005 Location: Austria, at a beautiful place right in the heart of the Alps.	Possibly also check if the litz wire to the membrane / VC is not sloppy Michael __________________ Audio and Loudspeaker Design Guidelines

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23rd January 2011, 06:05 PM	#4
MisterTwister diyAudio Member Join Date: Feb 2006 Location: usa Blog Entries: 1	I had similar problem. it was detached cone. try to push cone out and look if there are any gaps between voice coil former and cone. if there is, just glue it back together.

24th January 2011, 08:55 AM	#5
reking diyAudio Member Join Date: Jan 2011	Thanks for the replies. I'm not familiar with all these terms so I had to look them up. Mounting the chassis upside down or sideways didn't change. The wire does not seem sloppy or loose. I can not see any gap between the cone, but it may not be visible... To glue it back together, I'd have to take it apart first, no? The whole thing has no screws, just used glue to sit together. I think it will be hard to re-do it, and I may just have to look for new speakers.

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