Monolith Panel Issue? Advice needed

[Paul V]

Hello to all. This is my first post.
I am the original owner of a pair of ML Monoliths. They are the Monolith 1 but they were updated to Monolith 3 (passive X-over) when that upgrade was made available.
I bought a new Surround Sound preamp, the NAD T187. It has the built in Audyssey system, but you can also set the speaker levels manually with the built in tone generator.
Just so you know, the rest of the 7.1 system is a Stage, a Descent and 4 Scripts.
I thought there might be an issue with the T187 as it lowered my max volume to -15db. Further investigation showed the front left speaker level as +7 and the front right as +12 - which is the most it can be raised. Even at that +12 level the speaker can only get to 74db max when using the tones or Audyssey. I was trying to average 75db as suggested.
My dealer, NAD, and now Martin-Logan think it is a speaker efficiency issue. I have been advised to replace my 28 year old stat panels with new ones.
I am willing to do this despite the cost. From what I was told, the new panels are custom built to order using the new panel technology, the micro-perf stators and the clear spars.
I am asking this community if it seems logical that the panel efficiency would be part of the aging process. They haven't failed at all, still sound pretty good, have been vacuumed but not washed. My understanding is that washing them might resolve a sound issue but not an efficiency one.
So that's the question. Does this community think - or know - that the age of my panels is responsible for the lost efficiency?
Thanks in advance for the advice.

 

[soundacct]

Hello, and welcome!

I didn't see you list your amplification? Can I assume you did the cable swap dance (switching inputs and outputs to see if the trouble follows the speaker, the output channel of the preamp, or amp, etc?

I am not an expert in electrostatic speaker technology, but I dont see how an aging panel would result in dramatic loss of sensitivity. I can see a dirty or humid / moist panel having reduced output (has happened to me resulting in a dehumidifer and air filter purchase - to great effect)

There are some folks here capable of literally constructing their own electrostats, hopefully someone will chime in.

BTW, 28 years with a ML Monolith is a happy life in my book!

 

[twich54]

28 years......time to go !

 

[roberto]

Yes, it is time to change the panels. But you will get the old technology, not the new clear spars and the micro perf stators. You will get the same stat panels that you have now. They will come with a 5 year factory warranty. Happy listening!

 

[Paul V]

I didn't see you list your amplification? Can I assume you did the cable swap dance (switching inputs and outputs to see if the trouble follows the speaker, the output channel of the preamp, or amp, etc?

Amp is a McIntosh MC207...7 channels x 200 watts per. I swapped the speaker to another channel and it stayed the same. So it isn't the preamp/amp.

The only other thing could be speaker placement..which I doubt...or maybe a crossover issue...but I've seen the insides of those and they seem very robust to me.

 

[edwinr]

Paul, did you have this loudness issue before you introduced the NAD? I am wary of the new NAD stuff. I had a bad run with NAD stuff last year when I was trying to match their products with a pair of Theos speakers.

So, just check it's not the NAD preamp before you blame the speakers for this issue.

BUT... I agree with the other guys. 28 years is a long time for any speaker without some kind of maintenance. You should budget for panel replacement sooner rather than later. Even if the NAD is contributing to your absolute loudness issues, your Monoliths just cannot be operating as good as they could be with tired panels. If you give your pair of ladies new lingerie, they'll be very grateful...

 

[Paul V]

Paul, did you have this loudness issue before you introduced the NAD? I am wary of the new NAD stuff. I had a bad run with NAD stuff last year when I was trying to match their products with a pair of Theos speakers.

Yes I switched amp outputs and the problem stayed with that speaker. Plus all the other channels other than front left and right have very modest adjusted db levels.

 

[edwinr]

Ouch...

What do you reckon? Is it worth buying new panels? If not, what would you replace the Monoliths with for the same money as new panels?

 

[#ZERO]

From what I was told, the new panels are custom built to order using the new panel technology, the micro-perf stators and the clear spars.

I would wash & swap the panels in each speaker just to make sure the problem is a defective panel. From my understanding the new monolith panels are the same as the old design but have a flat black powder coating on the stators.

 

[soundacct]

I would wash & swap the panels in each speaker just to make sure the problem is a defective panel. From my understanding the new monolith panels are the same as the old design but have a flat black powder coating on the stators.

+1

Would be a shame to drop the money only to find out they're still something wrong....plus washing them might just do the trick.

My ML's literally stopped working this summer during a heat wave, turns out they were dirty and the humidity got em. Well, one panel had only lower mid frequencies but very quiet, and one made almost no sound at all. No panic though!

I suspected dirt / humidity, so I fired up a dehumidifier and air filter, unplugged overnight, vacuumed the hell out of them, hit em with low psi compressed air...good as new. It's been humid before (in a finished basement) with no issues, so it seems that's only a problem when they're dirty too.

Hopefully it's a simple wash for you, but seriously it's not like you're going to be able to replace those monolith's for the price of new panels (aren't they somewhere in the $1500-ish range? I saw a price list somewhere, but i didn't pay attention to the monoliths as I dont expect to ever own a set).

Good luck

 

[Paul V]

Just to reply to the above…

Humidity has never been an issue here as the AC is pretty much on all the time. Then the heater takes over which further dries the air. There is about a 3 week buffer between the AC and the heat twice a year.

Plus there has been no sonic fallout, at least as far as these 60 year old ears are concerned.

I only began to notice the issue a few weeks ago when I attempted to blast the system. I noticed that only the amp's right front channel's Power Guard light would flash. (The McIntosh amp has this circuitry that prevents any clipping by lowering the IP signal for 1/1000 of a second and flashes the lamp). That's when I noticed the Audyssey had the RF @ +12 and the left @ +7 whereas the center was 0 and the surrounds were +2 or 3.

I was told the washing would improve them sonically but would do nothing for efficiency by ML support.

The new stat panels are…gird your sphincters…$2600 list. Even so I will still get them as there is really no other avenue. Once you go ML you never go back…

 

[Tosh]

If there's 28 years of dirt on them, I would expect some of the HV charge to be leaking to the stators and causing a drop in output. So wash them (and dry them thoroughly) and let us know what happened.

$2600 is beyond unreasonable for these old things, considering what used working MLs go for. Call up Russ at justrealmusic to hear what he says. He reconditions ML panels.

 

[edwinr]

$2600 is a lot of dosh. Still... if the panels were replaced, you would have a pristine pair of electrostatics that'll last another decade or so.

 

[Paul V]

$2600 is list price. I will be paying less than that. Again- there has been no noticeable degradation in sound quality. They are vacuumed regularly. It does seem to me that age has to be a factor although I don't KNOW that for sure..

I just moved the left front to the right and vice versa. The left channel is now +8 from 7 and the right is +10 from 11. Please note the left side is nearer a corner.

So it seems the lack of efficiency followed the right speaker to the left, even though it is somewhat more balanced due to the near corner placement. Plus now it is the left amp channel light that will flash.

The only thing I really need to find out is if age has an actual proven effect on the efficiency of the electrostatic panels.

 

[denden11]

It is not the panels. I had Monolith II's and had the same problem. I replaced the panels with new panels and still had the same problem. Jim Powers had me remove the electonics section inside the speaker and send it to him. He replaced a cap and a transistor. The problem was fixed.

 

[soundacct]

It is not the panels. I had Monolith II's and had the same problem. I replaced the panels with new panels and still had the same problem. Jim Powers had me remove the electonics section inside the speaker and send it to him. He replaced a cap and a transistor. The problem was fixed.

good thinking....why not swap the electronics from right to left and see if the problem follows?

 

[Paul V]

I thought I should "close the circle" on my issue.

I finally ordered the new replacement panels. The only physical difference is the new ones have black spars and the old ones were white. I also understand the Mylar sheeting is improved.

At any rate, the panels went from +8 and +11 db boost before to +0 and +2 after. So it would seem that 27 year old original panels do age out in terms of efficiency.

The improvement was so great that I hesitated ordering my new amp. But then I figured "it's Christmas" so I put the order in for a new McIntosh MC452. I'm thinking that this new amp will give the Monoliths what they crave- power power power. Should be a LOT less meter needle movement compared to the MC207.

Also- thanks to all who posted. Much appreciated!

 

[JonFo]

Paul, great to hear it got resolved.

And yes, the new panels are indeed more efficient and perform better than the earlier builds thanks to updates in the materials used. The bigger amp will also give you the headroom necessary to play louder cleaner.