Andy,
Excellent, thank you for providing this. Thanks for the circuit walk through, very helpful and interesting. Should be able to work on these this afternoon.
Best regards,
Steve
Vacuumed the socks, took them off (those staples are a real joy) to wash them. With the socks off, I did a close inspection of the panels themselves and their wiring. They seemed to be in good shape - no obvious physical damage could be seen anywhere, and everything was quite clean (the socks however were pretty discolored and dusty). So anyway, the panels and their wiring look good.
I inspected the interfaces but could see no obvious physical indicators of serious degradation. As described in an earlier post, when I disconnected one speaker from its interface, the conductors to the bias voltage pin-and-sleeve connection pin simply broke off right at the pin. In the process of desoldering the pin to prep it for re-termination to those bias voltage wires, a bunch of green oxidation debris came out of the pin’s socket area. I cleaned it up with some flux, cut back the diaphragm conductors .25" to ensure clean copper, stripped, tined and landed them in the cleaned up pin. I then repeated this procedure on the other speaker for good measure to keep them matched.
One small difference discovered when inspecting the interfaces was the audio input fuses. These were different, and not of the type that Roy Esposito recommends. I replaced these with the correct versions.
Oh, one more small change: I loosened the tap location on the HF balance resistor so I could clean up that connection on both interfaces.
I put the speakers back together and fired them up. They seem fine now! I cannot perceive any difference in sound between any of the panels. The speakers image correctly and the sound field is uniform and consistent.
So I think it was due to the badly oxidized connection in the pin that connects the diaphragm wiring to the bias voltage supply board that was causing a difference in biasing voltage to one panel, causing it to sound muted compared to the other three.
Right now I’m running them without the socks. Not looking forward to putting them back on. Are there any parties that make replacement socks out of spandex or something similar?
Finally, how long can I run them without socks? I live in New Mexico. Dry and dusty most of the time.
Steve in NM
I inspected the interfaces but could see no obvious physical indicators of serious degradation. As described in an earlier post, when I disconnected one speaker from its interface, the conductors to the bias voltage pin-and-sleeve connection pin simply broke off right at the pin. In the process of desoldering the pin to prep it for re-termination to those bias voltage wires, a bunch of green oxidation debris came out of the pin’s socket area. I cleaned it up with some flux, cut back the diaphragm conductors .25" to ensure clean copper, stripped, tined and landed them in the cleaned up pin. I then repeated this procedure on the other speaker for good measure to keep them matched.
One small difference discovered when inspecting the interfaces was the audio input fuses. These were different, and not of the type that Roy Esposito recommends. I replaced these with the correct versions.
Oh, one more small change: I loosened the tap location on the HF balance resistor so I could clean up that connection on both interfaces.
I put the speakers back together and fired them up. They seem fine now! I cannot perceive any difference in sound between any of the panels. The speakers image correctly and the sound field is uniform and consistent.
So I think it was due to the badly oxidized connection in the pin that connects the diaphragm wiring to the bias voltage supply board that was causing a difference in biasing voltage to one panel, causing it to sound muted compared to the other three.
Right now I’m running them without the socks. Not looking forward to putting them back on. Are there any parties that make replacement socks out of spandex or something similar?
Finally, how long can I run them without socks? I live in New Mexico. Dry and dusty most of the time.
Steve in NM
So glad to hear you have the speakers operating properly, and that it was a simple fix. The repairs you did seem consistent with the symptoms you experienced.
I am not aware of anyone offering grille cloth fitted to the speaker. There used to be a company offering such a service (Acoustat's original supplier), but they no longer make grill socks, probably because they ran out of the raw material. Therefore, you are on your own to select a suitable fabric and sew them into "socks". Due to different stretchiness of various fabrics, it might be a good idea to make a short sample and test fit to the speaker before committing to a large enough piece to cover the whole speaker. Perhaps some other Acoustat owners who have replaced their socks can offer some suggestions.
I've always considered the grille cloth to be more of a cosmetic covering than a dust shield. Granted, the grille cloth will prevent the bigger chucks of dust (and insects, etc.) from settling on the panels, but I doubt it does much for fine dust. I wouldn't be overly concerned about operating them without socks for some time. Ultimately, you'll probably want to cover them more because they aren't so pretty without the socks. Before applying grille cloth, it would be a good idea to use a gentle application of compressed air to blow out any loose dust from both sides of the panels. This should be done with the speaker de-energized. Good luck and happy listening!
I am not aware of anyone offering grille cloth fitted to the speaker. There used to be a company offering such a service (Acoustat's original supplier), but they no longer make grill socks, probably because they ran out of the raw material. Therefore, you are on your own to select a suitable fabric and sew them into "socks". Due to different stretchiness of various fabrics, it might be a good idea to make a short sample and test fit to the speaker before committing to a large enough piece to cover the whole speaker. Perhaps some other Acoustat owners who have replaced their socks can offer some suggestions.
I've always considered the grille cloth to be more of a cosmetic covering than a dust shield. Granted, the grille cloth will prevent the bigger chucks of dust (and insects, etc.) from settling on the panels, but I doubt it does much for fine dust. I wouldn't be overly concerned about operating them without socks for some time. Ultimately, you'll probably want to cover them more because they aren't so pretty without the socks. Before applying grille cloth, it would be a good idea to use a gentle application of compressed air to blow out any loose dust from both sides of the panels. This should be done with the speaker de-energized. Good luck and happy listening!
Andy,
Very much enjoying these speakers now. Very good sounding stats. ESL clarity and nuance, huge soundfield, great imaging. My girlfriend is amazed (never heard ESLs before), thinks they are witchcraft.
Excellent information and explanation regarding the socks and their minor absolute need for the welfare of the Acoustat panels. I've got the originals soaking in Oxiclean, hopefully that will brighten them up, because physically they are in very good shape. But making new ones does not sound that hard - spandex and a seamstress would get the job done economically.
I actually like the way they look without the socks. Very industrial and "tech" in my opinion. GF disagrees strongly, so I should appease her.
Steve
Very much enjoying these speakers now. Very good sounding stats. ESL clarity and nuance, huge soundfield, great imaging. My girlfriend is amazed (never heard ESLs before), thinks they are witchcraft.
Excellent information and explanation regarding the socks and their minor absolute need for the welfare of the Acoustat panels. I've got the originals soaking in Oxiclean, hopefully that will brighten them up, because physically they are in very good shape. But making new ones does not sound that hard - spandex and a seamstress would get the job done economically.
I actually like the way they look without the socks. Very industrial and "tech" in my opinion. GF disagrees strongly, so I should appease her.
Steve
Hello! Happy to have come across this wonderful forum and resource! I have a pair of Spectra 2200's that I really enjoy. However, one of the bass panels has a rattle when sudden low frequency audio signals are played, that of a jazz bass, or thumping kick from a drum kit, or deep and low organ. I seem to be able to temporarily 'fix' the issue by tapping (or lightly banging) on the side of the frame and/or back of the panel where the foam is attached to the grid panel. But then the next day it rattles again. When I knock on the speaker I feel like I can hear either arching and/or debris falling down the speaker. Other than this rattle, the speakers are excellent, with incredible clarity and a sonic balance that I really am fond of, so I would like to keep them as original as possible other than the necessary up-keep. I have yet to pull the original sock down and take a look underneath, as the socks are in perfect condition, I am afraid of damaging their aesthetics.
1) Perhaps someone might know if this is a problem that can be easily fixed? Is a rattling on low frequency hits tend to be due to low tension in the mylar or debris since it does not happen all the time and cane be temporarily fixed?
2) Perhaps someone could point me to a step-by-step for removing the socks?
3) What are your recommendations? Remove socks and vacuum the panels? Replace the foam and re-glue?
4) What should I expect to see as far as condition/age of an untouched pair of 2200s at this age?
Thank you!
-Zach
1) Perhaps someone might know if this is a problem that can be easily fixed? Is a rattling on low frequency hits tend to be due to low tension in the mylar or debris since it does not happen all the time and cane be temporarily fixed?
2) Perhaps someone could point me to a step-by-step for removing the socks?
3) What are your recommendations? Remove socks and vacuum the panels? Replace the foam and re-glue?
4) What should I expect to see as far as condition/age of an untouched pair of 2200s at this age?
Thank you!
-Zach
Dear Zach,
While I have no experience with the Spectra 2200 series, please allow me to share some experience from restoring my beloved Acoustat Model 2 series.
1) Is a rattling on low frequency hits tend to be due to low tension in the mylar or debris since it does not happen all the time and cane be temporarily fixed?
Bringing my own Acoustat Model 2s out of storage after 20 years noted several mechanical issues.
a) When tapping / lightly banging the frames by hand I also heard some sounds of debris falling, as you did.
b) When moving the speaker's position around the room, there was a 'snare drum' sound coming from the diaphragms.
c) As my system is bi-amped at 140 HZ (separate power amps driving the Model 2s and the Acoustat Spectra Woofer SPW-1), I didn't notice any low frequency rattling on bass notes. However, while repairing one of the power amps, the working power amp was driving the Model 2s in full range, and in that configuration, I did hear a rattling or slapping noise on bass notes.
Pleased to report all these mechanical issues were successfully resolved with through cleaning and fixing the stator's broken glue joints and bent stator wires.
Report, "Acoustat Stator Wire Repair: Hints and Lessons Learned" https://www.diyaudio.com/community/...wire-repair-hints-and-lessons-learned.404881/
As documented in the report it's not a difficult job, but a time consuming and tedious process so please take your time to do it properly and don't rush it.
2) Perhaps someone could point me to a step-by-step for removing the socks?
Again, this is repeating my experience with the Model 2s.
After removing the top metal bar plate for the first time, the fabric remains fastened to the top of the wooden frames with what seemed like hundreds of staples. These multitude of staples can be safely removed one at a time by gently prying up with the straight edge of a screwdriver.
With all staples removed, gently pull down the socks with both hands, keeping an even pull on both sides.
When putting it back together I found far fewer staples are needed, in my case about a dozen staples per speaker frame was sufficient to hold the fabric in place until it could be compressed in place by the top metal plate.
I've had these socks on and off many times now, nothing damaged and they still look like new.
3) What are your recommendations? Remove socks and vacuum the panels? Replace the foam and re-glue?
As described in the above report, the thorough vacuuming and cleaning each of the broken joints before gluing, and repeating this process as needed, fixed all mechanical issues. I'm very pleased with how this turned out, the speakers perform like they were new.
Just a side comment, others have remarked on benefits of heat-treating loose diaphragms. I also experimented with this, but my results were inconclusive, possibly because the diaphragms in my speakers were still reasonably taut with no signs of looseness.
Report, "Acoustat Mylar Diaphragm Heat Shrinking: Hints and Lessons Learned"
https://www.diyaudio.com/community/threads/acoustat-mylar-diaphragm-heat-shrinking-hints-and-lessons-learned.407546/
Finally, some advice should you ever need to replace the foam pads and re-glue using "3M 77" https://www.diyaudio.com/community/threads/acoustat-answer-man-is-here.183168/page-173#post-7880559
Good luck, let us know how it worked out for you.
Thank you,
John
While I have no experience with the Spectra 2200 series, please allow me to share some experience from restoring my beloved Acoustat Model 2 series.
1) Is a rattling on low frequency hits tend to be due to low tension in the mylar or debris since it does not happen all the time and cane be temporarily fixed?
Bringing my own Acoustat Model 2s out of storage after 20 years noted several mechanical issues.
a) When tapping / lightly banging the frames by hand I also heard some sounds of debris falling, as you did.
b) When moving the speaker's position around the room, there was a 'snare drum' sound coming from the diaphragms.
c) As my system is bi-amped at 140 HZ (separate power amps driving the Model 2s and the Acoustat Spectra Woofer SPW-1), I didn't notice any low frequency rattling on bass notes. However, while repairing one of the power amps, the working power amp was driving the Model 2s in full range, and in that configuration, I did hear a rattling or slapping noise on bass notes.
Pleased to report all these mechanical issues were successfully resolved with through cleaning and fixing the stator's broken glue joints and bent stator wires.
Report, "Acoustat Stator Wire Repair: Hints and Lessons Learned" https://www.diyaudio.com/community/...wire-repair-hints-and-lessons-learned.404881/
As documented in the report it's not a difficult job, but a time consuming and tedious process so please take your time to do it properly and don't rush it.
2) Perhaps someone could point me to a step-by-step for removing the socks?
Again, this is repeating my experience with the Model 2s.
After removing the top metal bar plate for the first time, the fabric remains fastened to the top of the wooden frames with what seemed like hundreds of staples. These multitude of staples can be safely removed one at a time by gently prying up with the straight edge of a screwdriver.
With all staples removed, gently pull down the socks with both hands, keeping an even pull on both sides.
When putting it back together I found far fewer staples are needed, in my case about a dozen staples per speaker frame was sufficient to hold the fabric in place until it could be compressed in place by the top metal plate.
I've had these socks on and off many times now, nothing damaged and they still look like new.
3) What are your recommendations? Remove socks and vacuum the panels? Replace the foam and re-glue?
As described in the above report, the thorough vacuuming and cleaning each of the broken joints before gluing, and repeating this process as needed, fixed all mechanical issues. I'm very pleased with how this turned out, the speakers perform like they were new.
Just a side comment, others have remarked on benefits of heat-treating loose diaphragms. I also experimented with this, but my results were inconclusive, possibly because the diaphragms in my speakers were still reasonably taut with no signs of looseness.
Report, "Acoustat Mylar Diaphragm Heat Shrinking: Hints and Lessons Learned"
https://www.diyaudio.com/community/threads/acoustat-mylar-diaphragm-heat-shrinking-hints-and-lessons-learned.407546/
Finally, some advice should you ever need to replace the foam pads and re-glue using "3M 77" https://www.diyaudio.com/community/threads/acoustat-answer-man-is-here.183168/page-173#post-7880559
Good luck, let us know how it worked out for you.
Thank you,
John
John, thank you for your response and links to your detailed posts. I appreciate your attention to detail, photos and thorough walk-through. It is definitely nice to dive into this project with your processes well documented!
The stator wires are embedded/glued to the styrene louvres. They sometimes detach. If there are multiple detachments in a row they can rattle against the louvre. A close inspection will reveal the condition. I've had a few at the ends where they turn back around but that didn't cause any buzzing or rattle. However I did reglue them with some airplane model cement.