How do you know if your panels are going out?

[Lightloopy]

I have SL3's from 1998 and they just didn't sound right after 10 yrs. Lost it's clarity, detail and just were not doing their thing. Repaneled them 10 yrs ago and back to normal and sound great still. I don't use any DSP so I am sure that complicates the picture as discussed. Don't think I will repanel due to cost/availability.

 

[JonFo]

This is a typical gain-structure issue, as Roberto shared, the Aragon needs a good bit of input to reach max output. IIRC, the Marantz more typically expects to output 1.4v as Max.

More on the general topic in this article: Amplifier Voltage Gain Explained – Matching Amp to Preamp

I deal with this constantly on my rig, which is why my active crossover (DriveRack 4800) has adjustable gains on input and output. I can match my Marantz Pre (8802A) to Sunfires and Sanders ESL amps, and of course the Pro-level DriveRack.

 

[JonFo]

When I turn it on to "reference" or even "flat" they sound much better but then much of the base is gone from them. I have a depth i sub I use for the base. I think the audyssey set the fronts to cut off at 40 HZ, so maybe thats why the base is gone when I turn it on? The base sounds better to me with Audyssey off but then the higher frequencies sound like crap. Somehow the audyssey makes it sound better.

Audyssey typically results in people noting the lower bass, but that's because most systems have way too much bass due to room modes. The Audyssey mitigates the modes, and while the result measures flatter, most want a bit more low-end. If your Marantz supports the Audyssey App, you can set a target curve with a 2 or 3db bass lift. Alternatively, turn up the subwoofer post-correction. I run a 2.5dB low-end lift in my target curve.

If the highs sound overly bright with Audyssey off, then panels would seem to be in good shape.
'Reference' has a high-end roll-off that neatly matches the old-age roll-off in my 27-year old rear Sequels. The Front Monoliths sound fine on flat or reference as my room is massively treated. Which is one suggestion I was going to make, as the Prodigy is a big panel, and mitigating the rear wave can help. For one, it reduces comb-filtering, which in turn causes Audyssey to perform fewer corrections in the highs. It also improves mid-bass performance, as acoustical treatments minimize the negative impacts of dipole operation.

As for the crossover to the sub, yes, I'd raise that to 60Hz minimum, and better at 80Hz.

 

[JonFo]

Repaneled them 10 yrs ago and back to normal and sound great still.

Same here (SL3 and Monolith panels in '08), and there is zero difference 12 years later, I expect they'll go 25+ years with care (regular vacuuming, windowless man-cave).

 

[Robert D]

Same here (SL3 and Monolith panels in '08), and there is zero difference 12 years later, I expect they'll go 25+ years with care (regular vacuuming, windowless man-cave).

If my panels are original, they are 20 years old. Sound great as long as audyssey is turned on. If its off they sound dull and a bit lifeless.

I dont know if the original owner repaneled or not, since he passed away. The speakers were about 12 to 15 years old when I got them.

 

[JonFo]

If my panels are original, they are 20 years old.

Check the serial number on the panels themselves (not the unit) against the serial number decoder to confirm actual age https://www.martinloganowners.com/attachments/martin-logan-serial-number-decoder-pdf.20392/
Look at the speaker from behind and on the top-right (??) of the panel, there will be black text on a white background with the serial #.

 

[jedi35]

Check the serial number on the panels themselves (not the unit) against the serial number decoder to confirm actual age https://www.martinloganowners.com/attachments/martin-logan-serial-number-decoder-pdf.20392/
Look at the speaker from behind and on the top-right (??) of the panel, there will be black text on a white background with the serial #.

Ok, thanks for that info. I'm sure that my Monoliths are outside of their life expectancy. Sadly, I haven't given them a listen since before 2016. And also, I have failed to do regular vacuuming, so I guess I would deserve it if they sound horrible now.

 

[JonFo]

Ok, thanks for that info. I'm sure that my Monoliths are outside of their life expectancy. Sadly, I haven't given them a listen since before 2016

Hey Jedi, good to hear from you. If they have been unused, then no problems, just vacuum them before the next use. But yes, guessing they are on the downslope of performance.

 

[Robert D]

Check the serial number on the panels themselves (not the unit) against the serial number decoder to confirm actual age https://www.martinloganowners.com/attachments/martin-logan-serial-number-decoder-pdf.20392/
Look at the speaker from behind and on the top-right (??) of the panel, there will be black text on a white background with the serial #.

Ok,didnt think of that! Couldn't find a thing. Maybe the only way to view it is to remove the panels? Something i hate doing. Had them out 2 times, putting in those metal pieces to stop them from going down.

 

[Robert D]

Oh, did just see it. Its a tiny little sticker at the bottom corner of the panel. Had to take a picture and then view it. PSLG. So they are 20 years old, original.

 

[Robert D]

Suppose one could assume they aren't at their top performance being that old. Don't yet know how much new panels would be. I also read on here that the early models like mine have had trouble with replacement panels not wanting to fit. Screw holes off for some reason. Found a thread on here. Don't know if I could do it on my own.

 

[JonFo]

So they are 20 years old, original.

And from the Pic, they actually look cleaner than the Sequel panels I have, so they should be fine. Maybe need a bit of EQ from the Room Correction, but that's fine. I'd say keep-'em.

 

[Robert D]

Vacuumed them and they might sound a bit better, can't say for sure. They sound good using audyssey, missing a bit of mid bass perhaps but thats it. The depth I sub is good, but its got issues too, if youve seen my other thread. Feel like its all degrading.

 

[Nuri58]

You can easily check. Unplug the power to the LS wait 5 min or so. Play something, listen, and plug in the power again. That will at least give you an idea if the panels are working at all.

 

[R.I.P]

Do not use Audessy because i guess adjusts for panels supposed low efficiency and artificially improves panel performance by boosting mids and highs and lowering bass. To find out truth about your situation of panels Please switch off Audessy and only use receiver as a pure 2 channel preamp feeding signal to monoblocks.

If now Prodigy sound base heavy with muddy sound from panel or highs missing.Then your panels are dusty and need a wash with neutral temp tap water followed by rinse with distilled water. Do not use any cleaning agent like soap of any kind. New Prodigy panels given their size may be around I guess 3k. If the panels have lost visual transparency they may be dusty. If after washing panels their is no improvement then you may need new panels.

 

[gwyko]

Serious question. How exactly do you vacuum? Like what sort of vacuum and attachment? I worry that by vacuuming I’ll somehow damage the panels.

aside from that the mere thought of cleaning them in the shower makes me very scared indeed!

 

[Robert D]

Do not use Audessy because i guess adjusts for panels supposed low efficiency and artificially improves panel performance by boosting mids and highs and lowering bass. To find out truth about your situation of panels Please switch off Audessy and only use receiver as a pure 2 channel preamp feeding signal to monoblocks.

If now Prodigy sound base heavy with muddy sound from panel or highs missing.Then your panels are dusty and need a wash with neutral temp tap water followed by rinse with distilled water. Do not use any cleaning agent like soap of any kind. New Prodigy panels given their size may be around I guess 3k. If the panels have lost visual transparency they may be dusty. If after washing panels their is no improvement then you may need new panels.

What you say here is what I suspect. When audyssey is off the speakers do sound bass heavy and dull.

I vacuumed and sound might have improved slightly, but nothing great. Im scared to wash them, worried I might damage something. Ive had the panels off before and wish I had known about washing then. Taking them on and off is a pain, but i can do it.

I dont have to worry about the wiring harness getting wet? Maybe put a plastic bag around it with a rubber band?

I've seen the posts on here and videos. So after rinsing them I should pour some distilled water down the panels to get any minerals off? Just kinda pour it down the panel?

How long to dry them before use? 24 hrs?

 

[Nuri58]

Standard vacuum cleaner with a small brush works for me. ML recommends that and the actual film is quite strong.

 

[Robert D]

Serious question. How exactly do you vacuum? Like what sort of vacuum and attachment? I worry that by vacuuming I’ll somehow damage the panels.

aside from that the mere thought of cleaning them in the shower makes me very scared indeed!

Me too. I just use my Dyson vacuum attachment. Dont use a brush on it. It didn't hurt mine. I used the narrow head on it to develop good suction and just ran it in grids left to right and then up and down.

 

[Robert D]

Standard vacuum cleaner with a small brush works for me. ML recommends that and the actual film is quite strong.

Ok, so a brush can't damage the film? I read some saying it might be risky so I played it safe.