If the degradation happens gradually, the users compensate by volume potmeter. They say: all OK. I saw a lot of seriously burned Audiostatic transformers. The hybrids show the problem earlier, because the tonal balance ceases. However, the users can adaptate, especially if the users are owners (and later, sellers
)
)In my experience they can degrade over 10 to 20 years depending on the environment. This degradation can happen slowly over time and one may not really be aware of it. On my Ascent i speakers I thought something was up but it wasn't confirmed until I played pink noise through them while checking channel balance. Clearly they were getting duller sounding with the top rolled off and the overall level dropping. They still work but without comparing them to a good working pair you might not be able to tell, they would just sound dull.
I had ordered replacement panels a couple of years ago from Martin Logan. They were still making them to order. The customer service was very good. If you're looking at a used pair you can't evaluate I'd factor in the cost of replacement panels which for me was around $1700 in 2020. Compared to replacing the speakers I thought it was worth it and hadn't realized how much they degraded.
I had ordered replacement panels a couple of years ago from Martin Logan. They were still making them to order. The customer service was very good. If you're looking at a used pair you can't evaluate I'd factor in the cost of replacement panels which for me was around $1700 in 2020. Compared to replacing the speakers I thought it was worth it and hadn't realized how much they degraded.
After 15 or 20 years they might still work. But typically nowhere near the original performance. As stated above, the volume knob compensates until something burns out.
If you are uncertain about buying a used set, you can either buy a new set, a recently rebuild set, or buy a broken set and rebuild it yourself.
The degrading process in fact offers a great opportunity for the diy-er.
When the panels degrade to a point the speakers are no longer usable, they loose most of their commercial value as outsourcing a professional rebuild often costs more than the going market price of a working set. So there is no shortage of offerings of sets in poor or terminal state, often for beer money. Costs of a diy rebuild are very low. It's just time consuming.
If you are uncertain about buying a used set, you can either buy a new set, a recently rebuild set, or buy a broken set and rebuild it yourself.
The degrading process in fact offers a great opportunity for the diy-er.
When the panels degrade to a point the speakers are no longer usable, they loose most of their commercial value as outsourcing a professional rebuild often costs more than the going market price of a working set. So there is no shortage of offerings of sets in poor or terminal state, often for beer money. Costs of a diy rebuild are very low. It's just time consuming.
When they want to sell their ESL, they say that it is working fine. Maybe (small chance) it does but for how long? I always prepare for refurbishment and expect the price to be like it needs refurbishment. Because of their age most audiostatics offered today already have been "refurbished". Results can be questionable, sometimes they are permanently damaged.
What would be the mechanism that would attenuate the highs? There are two instances here on diyaudio where individual panels in Acoustat were missing highs (a thread maybe two years ago and a post by me in the Acoustat thread last week), and in both cases the answer was that the panels might lose sensitity as they age but their frequency resposnse should not change.
Maudio, MJ: the offerings I have seen recently were in the range of € 600 - 2500, so a lot of beer, unfortunately. Audiostats seem to have a particular reputation for strong degradation, is the impression I get from reading posts.
Does anyone have a source for foils? And how would one know how to get the right weight and resistance? Just using any replacement might change the character of the speakers considerably.
Does anyone have a source for foils? And how would one know how to get the right weight and resistance? Just using any replacement might change the character of the speakers considerably.
I bought es100 for around 250 euro depending on their finish. ES200 ia bit higher. But this is some years ago and prices seem to inflate.
Audiostatics have one of the most reliable stators one can get. Thick PVC. As long as someone didnt mess up with them....... like burning them or cracking glue joints.....it is one of the safest options.
Audiostatics have one of the most reliable stators one can get. Thick PVC. As long as someone didnt mess up with them....... like burning them or cracking glue joints.....it is one of the safest options.
I agree Audiostatics are your best bet for a diy rebuild project. Easy model for this and very good stator design. Degree of difficulty somewhat varies depending on the glue type used, I noticed Audiostatic used different glue systems over the years. And a lot of panels have already been rebuild so it is always a bit of a surprise what you find. But usually they can be saved.
I never paid more than 100 euro for a pair of ES200's that were in need of a rebuild but cosmetically in perfect condition. The 200 uses a smaller panel compared to the 100 and 300 models that both use the same larger panel.
ES100's are the most common but I do not recommend them. The frame is too flimsy. The ES300 uses the same panel and interface in a much better frame.
I prefer the 200 size panels as they image more realistically imho but that is a matter of personal taste.
For mylar and coatings try ER Audio in Australia. Mylar can be found elsewhere, even in Europe, but for high quality coating ER Audio is basically your only option these days. They supply complete kits with mylar, coating, glue and everything else you need.
I never paid more than 100 euro for a pair of ES200's that were in need of a rebuild but cosmetically in perfect condition. The 200 uses a smaller panel compared to the 100 and 300 models that both use the same larger panel.
ES100's are the most common but I do not recommend them. The frame is too flimsy. The ES300 uses the same panel and interface in a much better frame.
I prefer the 200 size panels as they image more realistically imho but that is a matter of personal taste.
For mylar and coatings try ER Audio in Australia. Mylar can be found elsewhere, even in Europe, but for high quality coating ER Audio is basically your only option these days. They supply complete kits with mylar, coating, glue and everything else you need.
Well, I searched for ER audio and found this (cf. posts #3 and 6 of this thread):
Our Clear conductive coating is available again after a long period of being out of stock
The coating is supplied as a concentrate and should be diluted with distilled water unless you require a low surface resistivity or high frequency only reproduction.
Surface resistivity is typically around 200 MΩ/sq but can be varied by dilution and gauge of application. Supplied as a concentrate to be diluted from 1:0.5 to 1:1 with distilled water. Typical coverage is 1.0 ml per 900 sq cm (1 square foot)
So why would a low surface resistivity give you preferential treble reproduction? Does it mean that a degraded coating becoming highly resisitive will not play treble? I don't quite understand what the physics behind such an effect could be.
Our Clear conductive coating is available again after a long period of being out of stock
The coating is supplied as a concentrate and should be diluted with distilled water unless you require a low surface resistivity or high frequency only reproduction.
Surface resistivity is typically around 200 MΩ/sq but can be varied by dilution and gauge of application. Supplied as a concentrate to be diluted from 1:0.5 to 1:1 with distilled water. Typical coverage is 1.0 ml per 900 sq cm (1 square foot)
So why would a low surface resistivity give you preferential treble reproduction? Does it mean that a degraded coating becoming highly resisitive will not play treble? I don't quite understand what the physics behind such an effect could be.
To minimize distortion, the total charge on the membrame should not only be constant but it should also be evenly distributed over the surface. With the membrame in neutral position the distance towards the stators is equal everywhere so the charge will be evenly distributed. But when the membrame starts moving towards one of the stators, it tends to form a dome shape with the middle section being closer to the stators. Under those conditions the charge wants to migrate over the surface. It's the surface resistance that limits this movement. The better conductive the membrame, the faster the charge can move around. And since at lower frequencies there is more time for migration, higher surface resistance is needed for panels that play low. For a full range speaker choose the resistance as high as is possible without running into charging problems (as there is always some leakage).
I recall Mr Streng once published a good article about charge movements in ESL and the effects.
I recall Mr Streng once published a good article about charge movements in ESL and the effects.
Here's a case study of a rebuild of Martin Logan SL3.
https://www.hifi-zenit.de/elektrostaten/detailbeispiel-sl3
They wrote that they had seen this shelving of highs from abou 1.5 - 2 kHz upwards often in ML panels and attributed it to a hardening of the segmentation bands. This particular pair had additional problems such as a blow 'lytic and a torn surround in the woofer.
https://www.hifi-zenit.de/elektrostaten/detailbeispiel-sl3
They wrote that they had seen this shelving of highs from abou 1.5 - 2 kHz upwards often in ML panels and attributed it to a hardening of the segmentation bands. This particular pair had additional problems such as a blow 'lytic and a torn surround in the woofer.
I recommend to buy ~2003-2005 ML Ascent 'i' with the Gen2 clear spar panels, as they are glued together and don't use double-sided foam tape. Around the SF Bay Area these show up often enough asking ~$1500 (+/- $500!). I helped a friend pick up a pair of Ascent 'i' a couple of months ago for $1000, and I would say the used market for ML's is pretty hot. No way I'm paying ML almost $2k for new panels....
In newer models they use 'clear spar' spacers, made of a transparant plastic material. My guess is that those clearspars are way harder material compared to the foam stuff and the resonance problem isnt solved