Weird gradually degrading sound in Prodigy speaker

[jshowalter]

We have had these speakers for a several years, and they have been wonderful, but over the past several months something weird (and hard to describe) has been happening to the sound coming out of the speaker on the right.

In the high-midrange to low-treble area, the speaker is making a sound that sounds like harsh sibilance, verging on unpleasant. It's kind of a brittle/metallic noise, kind of like a buzzing sound, but also not (I said it's hard to describe). It sounds like a cracked speaker cone, except these speakers don't have speaker cones.

The speakers have never been cleaned, if that matters. Also, the panels on both speakers have slid down in the frames about an inch, and I keep putting off dismantling them to add some stops at the bottom Martin-Logan sent, if that matters.

I don't see any tears or other problems with the panels.

Does this symptom sound remotely familiar to anyone?

 

[robertawillisjr]

Time to clean, wash and perhaps replace panels. There is information on the first two on this site. I don't remember seeing anything about misplaced Prodigy panels. Call or e-mail ML for more information.

 

[jshowalter]

Time to clean, wash and perhaps replace panels. There is information on the first two on this site. I don't remember seeing anything about misplaced Prodigy panels. Call or e-mail ML for more information.

The PDF posted here:

http://67.19.167.226/~tdacquis/forum/showthread.php?t=604&highlight=cleaning

no longer works. Is there another place to find cleaning instructions?

Regarding the slipping Prodigy panels, it's a known problem, and Jim (now gone) sent little angle-iron widgets to fix it.

 

[GaryG]

Check the Prodigy owners manual for cleaning tips. You can find it on line by going to www.martinlogan.com. Go to products followed by product museum and then prodogy. Look under FAQ's on page 22. There is a thread in this forum on a shower technique if the vacuuming described in the manual does not work. Beyond that you can contact Dana Brown at ML. I understand that he built 70% of the Prodigy's. Good luck the Prodigys are a great speaker when all is working well.

 

[Tosh]

My SL3's make a buzzing as you describe with certain sounds and played fairly loudly. I have a particular song that really excites them, and I can hear and feel the stators vibrate. I figure it's the glue on the spars letting go....

 

[jshowalter]

These aren't being played loudly.

 

[Tosh]

It sounds like a cracked speaker cone, except these speakers don't have speaker cones.

You're sure the buzz isn't coming from one of the two woofer cones?

 

[jshowalter]

It's definitely coming from the panels.

 

[robertawillisjr]

It's definitely coming from the panels.

Is there a dealer you can see? If not, ML seems to be your remaining option.

 

[Tosh]

But the buzz is coming from only the right panel? Is it coming from all over the panel or from certain sections (like an edge)? Does it seem like it's embedded in the signal or from the panel vibrating with the music?

Either way, perhaps you should re-position the panels and install the anti-slip clips and see what happens?

 

[jshowalter]

Well, the problem continues

Replaced the panels and the DECs, and there is still a weird brittle rasp in the high midrange/low treble.

 

[timm]

Uggghhh. What amp and or pre do you have? Any tubes in the mix? I thought it was only one speaker if I read correctly? Did you switch the l/r connections. Sorry might be stupid questions.

 

[Necrosuit]

Timm is right,
If you have tubes in the mix that could be the culprit.
I recently had a very faint buzzing in my new CLX and freaked out!
I swapped cables, amps and then tubes, yup it was the tubes.

 

[jshowalter]

The noise is in the front left/right speakers.

The noise isn't a buzz. It's kind of hard to describe--basically when a singer hits a note in the high-midrange/low-treble, instead of pure, sweet sound coming out, it breaks up into an unpleasant rasp, as if all timbre has been lost. The effect is more pronounced for some singers than others.

The front left/right speakers are connected to a pair of VTL monoblock 100 tube amps.

The center channel and rear left/right speakers are connected to a three-channel solid-state amp.

Swapping the amps to use solid state for the front left/right speakers doesn't fix the problem, so it doesn't follow the amps (or tubes).

The noise is in both speakers, so it's not a side-to-side problem.

Changing the source from a CD/SACD player to an Oppo has no effect on the noise, so it's not a player problem.

Swapping the connections to send the front signal to the rear left/right speakers makes the problem go away, so it's not the preamp.

Playing the same source material in a CD player with headphones does not exhibit the problem.

It can only be the speakers.

 

[timm]

so it definitely looks like you did your due dilligence.... So, since you got new panels/ DECs....(not sure what those are...) - and still have the problem - can you call ML and get anything from them? Is there anything else in the speaker that could cause it? But, since it is in both... I still have my doubts about whether it is the speaker....Since I know you now have a surround system - any chance of interference that maybe the Prodigys are more susceptible to? Any new video equip in the room / new cable hookup?

Just shooting from the hip.... but, again since you say it is both speakers (and earlier I thought it was 1) - I don't believe both speakers would be bad... I just think the odds are slim unless you had some sort of spike in voltage or something which caused something in the speaker to semi-fry...

guess first thing I would do is unplug everything from the wall (including video) - use the solid state amp only - and go from there...

 

[Hocky]

I occassionally get a noise very similar to what you're describing from my Cinema. I am interested to hear what you find.

 

[Tosh]

I assume OP meant that he re-installed the same panels, not new panels.

I just read that an Ascent owner found a bad solder joint in the XO, so perhaps an examination of all the internal connections should come next?

 

[jmschnur]

I have found I need to vacuum my vantages and cinema I every two months or so. If I do not I get some of the symptoms described in this thread