My rebuild of some Aerius i speakers.

MartinLogan Audio Owners Forum

Help Support MartinLogan Audio Owners Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

winno

Member
Joined
Oct 25, 2009
Messages
17
Reaction score
0
Location
Brisbane, Australia
A few years ago now, I was introduced to panel speakers through some Apogee Calipers at a hi-fi show in Auckland, NZ.

Since then and after listening to various panels (Magneplanar, Audiostatic, Martin Logan, etc) I have always wanted to own panels. Apogees came up a couple of times but I couldn't afford the amplification that was required to drive them properly. My short time with some Maggie SMGa speakers at home left me unimpressed, but I think that was more an amp and speaker synergy issue at the time.

I became involved in the industry for a few years and almost purchased some Martin Logan SL3s. Alas, the timing and circumstances weren't quite right and the SL3s were put out of my mind. I had more recently auditioned the new Electromotion speakers from ML. These are much more affordable at nearly half the cost of the Aerius. But a regular favourite of mine over the years has always been the Aerius. It was well suited to the smaller to average sized rooms I've had, was relatively easy to drive, and it just sounded right and balanced.

When a set of the Aerius i came up for sale recently, and for what was effectively straight swap for my lovely Aurum Cantus Leisure II stand mount speakers, I jumped at the chance.

Yes, I got them very cheap but there were issues I knew I'd have to deal with once I got them home;

* The serial number indicated that they were made in May 1998. That makes them 15 years old and I know that the coating on the Mylar doesn't work so well when older. Many owners report a softening of the sound on their panels with age, sometimes one panel is worse than the other.
* My panels had the original Mylar recoated but it wasn't done properly.The coating was applied over the diaphragm portions that were stuck to the spars on the stators. It's supposed to only be applied between the spars. Not a biggie anyway as the original factory coating is applied across the entire film anyway from what I know.
* One diaphragm was damaged at some stage and so the Mylar was cut out of the very top of one panel above the top spar.
* There were wrinkles at the top and bottom of the film.

6atyde6y.jpg


* There was some MacGyver (dodgy) wiring done to run the signal to both sides of the rear stator panel. It looks like tonearm lead out wire - very thin indeed.

y9ezu8aj.jpg


bezutuzu.jpg


* The stator halves were not stuck back together securely and the front halves were mixed left to right so the spars on each speaker didn't align properly.
* The enclosures were knicked and scratched in places.


Despite these issues, the speakers actually sounded very good off the end of my Chinese integrated valve amp (better in my view to the newer Electromotion, if you can believe that - more weight down low and a smoother mid and treble, perhaps at the expense of the EM's outright detail) but I had some work to do in fixing them up. I love doing this though and I'm not afraid to tackle less technical jobs in the quest to repair and/or improve something. I'd previously changed all the audio op-amps in my Sony cdp-XA5ES CD player for Burson fully discreet modules and loved the result.

I have big plans for these speakers that include;


* New 6 micron German made Hostphan film diaphragms (ML factory film is 12 micron Dupont Mylar) and coating (thank you Rob @ ER Audio in Western Australia for a full refurb kit - copper foil tapes, diaphragm tensioner, glues, etc)

syjytuja.jpg


* Full capacitor replacement with Mundorf Polypropelene M-Caps and M-Cap Supreme bypass caps (thanks to Soundlabs Group in Sydney)

4a2etyru.jpg


* A full rewire with Kimber 4TC internally to replace the cheapie Monster Cable already in there. I'll also be replacing the factory Kimber PBJ interconnect style lead to the stators with heavier Kimber 4TC.
* Internal woofer enclosure treatments with Dynamat and sTp panel deadening.
* Stator support strengthening and rear diffraction treatment
* A respray in hi-fill textured paint in black for the cabinets and maybe something special for the wood trims that run down the front edges of the speakers.

I've been taking pictures of things and will post these up as I get the chance.

More updates of progress soon.
 
The first work done was stripping the speakers back to components.

This is the Aerius i as a shell.

ja5ugahu.jpg


The runners that the stators sit back on are only lightly glued in place and one had started to come away from the frame. I decided to screw the suckers on and this is the result:

ybysahyq.jpg


I also treated the enclosure walls with some Dynamat to make them a little more inert.

y3a4a9a9.jpg
 
I picked up 6m of Kimber 4TC speaker cabling for all internal wiring. This was chosen because it's a nice sounding cable and matches the cables from the amp. It's also Teflon coated so will suit the HT part of the project.

su6egyge.jpg


I also picked up some hardware: gold plated, solid brass oversize binding posts to suit my bare wire 8TC runs from the amp, and some really solid cone feet to replace the flimsy spikes.

aretagug.jpg
 
The cross overs were stripped of the caps, inductors and all wiring and the new Mundorf caps were fitted.

4equ8yje.jpg


Because the new caps are so much larger, there was no room on the board for the inductor anymore. It was relocated further away from the other two inductors and oriented to have less interference from them. It was hot glued and strapped into place where you see it at the top right of the enclosure back.

qupura2y.jpg
 
Last edited:
The new binding posts were fitted.

y3e6e5u9.jpg


4upa9ere.jpg


And the Kimber 4TC was added using the other cross over as a template.

agavusas.jpg


More soon.
 
The factory bass driver screw holes were drilled out and some butty T-nuts added

jy5u6ure.jpg


I also made a tensioning frame for when I replace the diaphragms. Its curve is traced off the rear of the stators so it's the same profile.

vy9asu4y.jpg


The stators were pulled apart and the old film, foil tape, and adhesive was disposed of.

Once really clean, new 3M VHB tape was added to the stators. I'm replacing the black spars with clear this time for a cleaner look. I ended up with red backed tape as shown in the pics. If I was shopping again, I'd try for clear backing.
Why?
Clear backed tape means you can leave the backing on the tape that's on the front stator half so that the two halves can be separated easily in future.
Because I want clear spars, I need to remove ALL backing and this means that BOTH stator halves will be stuck fast to the Hostaphan film rather than only the back half. This means I had better get this right first time!

dyreqy2e.jpg


uhe7u3u5.jpg


And that brings you up to date with today's progress.

More to come.
 
Last edited:
Funny you should mention that...
I'm thinking of offering this as a service here in Australia.

I'm not sure how viable it would be though as a rebuild of just the panels is very time intensive and Electromotions here are only AU$3500 or so.

The caps for the xover were $400 and the cable was $100 used.

I think it'll remain a hobby.
 
Cheers.
I'm not really sure what the coating is made from.
It used to be available as crystals or powder and it was dissolved in distilled water.

Rob at ER Audio now offers it as a strong solution now to make it easier. I'll just have to add one part of his chemical to so many parts water when it comes time to coat the diaphrams.

Search for ER Audio on the web. I know you can also buy the same powder on eBay.
 
Great work... do you know what's in the conductive coating and is it a water based fluid? I was able to find another Aerius rebuild and they used a drop of black permanent ink with clear PVAc glue in a water based solution.

http://www.diyaudio.com/forums/atta...anel-20130621_recoating-my-aerius-panel_1.pdf

Hi #ZERO,

I try use PVA glue and permanent ink to my panel but it doesn't last long due to high humidity in my place (I live in tropical country) so I have several choice of coating.
I decide to use Licron from TechSpray due to availability in my place.
It's 1 year now from I apply the coating and still remain good.
The only difficulty is when apply the coating as Licron use can spray and very difficult to get even coating.
 
Cheers.
I'm not really sure what the coating is made from.
It used to be available as crystals or powder and it was dissolved in distilled water.

Rob at ER Audio now offers it as a strong solution now to make it easier. I'll just have to add one part of his chemical to so many parts water when it comes time to coat the diaphrams.

Search for ER Audio on the web. I know you can also buy the same powder on eBay.

Hi Winno,
Good to see you successful re-panel your ML.
ER Audio is very helpful and I learn a lot from Rob how to apply the Mylar into stator.
He is a nice guy.
 
Cheers.
I'm not really sure what the coating is made from.
It used to be available as crystals or powder and it was dissolved in distilled water.

Rob at ER Audio now offers it as a strong solution now to make it easier. I'll just have to add one part of his chemical to so many parts water when it comes time to coat the diaphrams.

Search for ER Audio on the web. I know you can also buy the same powder on eBay.
They must be using something similar to Dupont Elvamide which comes as a crystal powder form. To bad ML doesn't sell the original 0.0005-inch thick polyethylene terathylate (PET) diaphragm material that is plasma-deposited with a conductive coating for the DIY rebuilds.
 
Nice work Winno, please keep posting pics and summaries of the re-build. I admire that you even built your own tensioning rig.
 

Latest posts

Back
Top