Sequels Buzzing

[chp35mm]

This is my first post and I hope that someone might be able to help me. I have a pair of Martin Logan Sequels which I purchased in 1987 and they have always sounded great except for one thing. The problem is that one of them has a very bad resonant buzzing sound on certain bass notes coming (apparently) from the crossover area. When it makes the sound I can sometimes stop it by placing my hand on the back cabinet and pressing down. The buzz comes back immediately when I lift my hand. Is there any way to fix this?

 

[Jeff Zaret]

chp35mm,

In a word yes. Do you mean the enclosure where the electronics are, the bass enclosure or the back of the panel? I believe they are are fixable. A little more specific detail would help. My guess the panel may need to be "stretched" if that is what is buzzing. When was the last time they were vacuumed? Were they ever washed? Are they the original panels?

Everything else is basic cabinetry and there is nothing like a shim or some vibration absorbent material to fix this kind of similar buzz.

Lets us know.

Good Luck

Welcome

Jeff

 

[JonFo]

chp35mm,

The Sequel crossover is a metal box on the back shelf of the speaker, your buzzing could either be components inside the box buzzing against it, or the surface of the box itself.

From your description, it sounds to me like it might just be the box surface, but mine have never made a sound.

An easy thing to do would be to make some sand-filled 'pillows' and pop those onto the crossover box. This does two things: 1- Dampens the resonances 2- weighs down the rear-lower part of the speaker, giving it better stability and coupling to the floor.

I've done that with my sequels for a decade.

If the buzzing remains, you'll need to open the crossover box and see what's gotten loose or rubbing.

Hope this helps.

Oh, and :welcome: to the club

 

[aliveatfive]

When I bought my Sequel IIs way back in '91 they did the same thing. I found the buzz was caused by an internal cabinet vibration. What worked for me was a 2x4 cut to fit the cabinet and place at the area where the problem was detected. You have to investigate very carefully to find where the buzz emanates. You might find that the used of a stethoscope helps!

 

[chp35mm]

Buzzing Sequels

Thank you all so much for the help. The part that is buzzing is the box that contains the crossover, not the electrostatic panel. They have never been vacuumed, just dusted. I've looked inside and I can't find anything loose. If the screws that hold the top of the crossover are loosened a bit it helps a little but the buzzing is still noticeable. I'd like to find a way to fix this without using a sandbag. When I open the back, there is a very fine red wire that pulls tight and prevents me from opening it completely, so it could be that something inside is loose, I just can't tell. aliveatfive----did you put the 2x4 inside the cabinet or outside?

Once again, thanks for the help,
Loren

 

[aliveatfive]

Thank you all so much for the help. The part that is buzzing is the box that contains the crossover, not the electrostatic panel. They have never been vacuumed, just dusted. I've looked inside and I can't find anything loose. If the screws that hold the top of the crossover are loosened a bit it helps a little but the buzzing is still noticeable. I'd like to find a way to fix this without using a sandbag. When I open the back, there is a very fine red wire that pulls tight and prevents me from opening it completely, so it could be that something inside is loose, I just can't tell. aliveatfive----did you put the 2x4 inside the cabinet or outside?

Once again, thanks for the help,
Loren

Inside - I thought the problem was the woofer (which I removed and ML replaced) so access to the box was easy.

 

[MotorToad]

One of my crossover/transformer boxes would buzz sometimes, and I had a grill that buzzed. 25 lbs on each speaker top fixed the former, and bending and retaping the grill fixed the latter.

 

[Dreamer]

I had a similar intermittant buzz in my 1st-gen Sequels last fall. I tracked it down to one of the woofers--the rubber surround had come unglued for about 1" where it attached to the basket rim. I called ML, and they told me that clear silicone adhesive would do the trick, but to use it VERY sparingly, and I'd probably have to take the woofer out and place it face-down on a flat surface after re-gluing, to be sure it was properly set.

They didn't even mention trying to sell me replacement woofers, they just told me how to fix it for free. When I asked them abou tpurchasing replacement woofers, they were very nice, and gave me a quote that was very reasonable.

I may replace them yet, but they sound great after a few dabs of the correct adhesive...

I've never had any instances of the cabinet, panels, metal cover, or internal electronics making any sort of noise other than music, and I've had these speakers for over 10 years. (knock on wood!)

--Richard