This sounds like a classic case of some foreign material caught in the gap between stator and diaphragm. During large excursions, this foreign material may be causing a small arc, which temporarily drains the charge from the diaphragm. This can usually be remedied by fully discharging the speaker, (described above, except I would recommend leaving the pin plugs disconnected after discharge) and then gently banging your open hand on the panels' surface. The idea is to cause the offending material to drop out of position. This process may need to be repeated several times. As a last resort, you may have to remove the grille cloth and gently vacuum both sides of the panel (a process which also may need to be repeated several times). A very gentle application of compressed air may also be helpful. Just be sure the panel is fully discharged each time - any remaining charge will tend to "hang on" to whatever is causing the problem.
Or, this could also be a case of driving the speaker too hard, which can yield similar results. Is this a new problem that didn't exist before?
AAM, I often thought the coating location (default is front?) determined the phase or polarity (dare I screw that up again?), so reversing the panel puts coating on the reverse side, so wont the four stator wires need to stay where they currently are?
My head hurts thinking about this....
Thanks for your reply!
Let's see if I can illustrate simply the position/direction of the bias wires"
-I -I -I top three panels
I- I- I- bottom three panels
I wish to run the bias wires down the two interior panel mount vertical members. The top left and bottom right panel bias wires point to the outside of the frame, rather than towards the interior members. Reversing them front to back would position the bias wires to run down the interior members along with the other 4 panels. Simply interchanging the top left and bottom right panels would indeed put the bias wires in an inward facing direction but then then the stator wires would be at the opposite ends of frame compared to the other 4 panels.
When reversed, I would just reverse the stator wiring as well to wire the now front stator wires as the front wires. Does the location of the coating have any effect as mentioned above?
Again, thanks.
I appreciate your response. I only got to test the speakers for a short time before I purchased them and the issue didn’t present itself then. The issue only occurs with one of the speakers and cranking up the volume extra loud will get it to kick on but then they will start to go muffled and crackling again on and off. When the sound kicks in it still sounds a little baffled compared to the other speaker.
Here is a video where you will hear the sound go from muffled/crackling to kicking on at higher volume about 6 seconds in. Please let me know your thoughts, thanks.
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@AcoustatAnswerMan
I inspected the interface board and discovered the socket for the white wire was lifted at one of the solder joints so I reflowed and it seems to have resolved the issue. I need to do my homework on the design of the speakers. Do you recommend replacing any caps on the board or mods?
I inspected the interface board and discovered the socket for the white wire was lifted at one of the solder joints so I reflowed and it seems to have resolved the issue. I need to do my homework on the design of the speakers. Do you recommend replacing any caps on the board or mods?
Attachments
@AcoustatAnswerMan
The pin lost its solder connection but was only slightly lifted. I pulled it back more so it was visible for the photo before I resoldered it.
The pin lost its solder connection but was only slightly lifted. I pulled it back more so it was visible for the photo before I resoldered it.
I'm glad you found that issue and were able to repair it. Did this fix the problem? I would be surprised that a loose stator connection would have the effect you described, but stranger things have happened. I'm always open to learning new cause-and-effect scenarios.
You are correct, unfortunately I spoke too soon and the issue just happen to not present itself afterward but then returned 🙁
Some times the issue occurs at lower volumes but will definitely occur at higher volumes while the other speaker has been totally fine.
If the issue is due to some foreign material inside then would it make sense that turning the volume up higher can help to get the sound to unmuffle like in the video I shared?
How do I go about removing the grill cloth if necessary?
Thanks for your help!
This VERY MUCH sounds like you still have a bad solder joint or flaky connection somewhere. When you turn it up, you are able to overcome the resistance of the bad connection temporarily, getting usable output.
Seems like it's time to go across every connection on the low voltage side of the system and poke around/inspect the solder joints and wire conditions. I bet you find another bad spot somewhere
Seems like it's time to go across every connection on the low voltage side of the system and poke around/inspect the solder joints and wire conditions. I bet you find another bad spot somewhere
@TrueTaylor
Thanks for your input. That was my thought what was happening with the stator connection I resoldered. Are you speaking of connections on the interface board? The one interesting thing is how the issue sometimes doesn’t occur to higher volume then I have to lower the volume and increase it to get the sound to kick back in.
Thanks for your input. That was my thought what was happening with the stator connection I resoldered. Are you speaking of connections on the interface board? The one interesting thing is how the issue sometimes doesn’t occur to higher volume then I have to lower the volume and increase it to get the sound to kick back in.
I'm speaking generally. Every connection on the board is suspect at this point 😆. Solder joints can fail over time, and this sounds like a pretty typical bad solder joint/flaky connection. It is certainly unusual that it would sometimes require lower volume to come back, but it's not unheard of. It happens fairly often with moving lead-wire connections to speaker cones/coils.
There is enough complexity in this design that it could certainly be in the HV side of things, or transformer, but it's pretty easy to start by just inspecting all of the low voltage stuff first to rule it out. You might get a wooden dowel or ruler (at least a foot) and poke around at the components while it's playing (to stay clear of the transformer/HV side) to more easily locate the issue. Avoid using a pencil as the graphite is conductive hahaha.
Have you already inspected your main speaker wires from the amplifier? Maybe it is time to physically swap the wire to the speakers side to side (keeping the wires attached at the amplifier side. This swaps WIRING AND AMPLIFIER CHANNEL to rule out, or identify both at once). Rule out one piece of the puzzle at a time 🙂
There is enough complexity in this design that it could certainly be in the HV side of things, or transformer, but it's pretty easy to start by just inspecting all of the low voltage stuff first to rule it out. You might get a wooden dowel or ruler (at least a foot) and poke around at the components while it's playing (to stay clear of the transformer/HV side) to more easily locate the issue. Avoid using a pencil as the graphite is conductive hahaha.
Have you already inspected your main speaker wires from the amplifier? Maybe it is time to physically swap the wire to the speakers side to side (keeping the wires attached at the amplifier side. This swaps WIRING AND AMPLIFIER CHANNEL to rule out, or identify both at once). Rule out one piece of the puzzle at a time 🙂
@TrueTaylor
I appreciate your suggestions and have ruled out the speaker wire and amp. How do I go about getting grill cloth off the speakers if necessary?
I appreciate your suggestions and have ruled out the speaker wire and amp. How do I go about getting grill cloth off the speakers if necessary?
@ el.pablo,
If the Spectra 3 circuit is similar to the Spectra 33, you might try swapping in a new 5A fuse(in series with the step up transformer primary), and or check fuse holder contacts for corrosion.
If the Spectra 3 circuit is similar to the Spectra 33, you might try swapping in a new 5A fuse(in series with the step up transformer primary), and or check fuse holder contacts for corrosion.
Items for sale must be kept to the swap meet and bazaar areas. Offending posts removed.
Thank you.
I have a model 4 from a couple of years, they play very nice but I'm not sure how the played when new! Do they need re-coting or not?
Thanks!
Thanks!
Acoustat panels do NOT require re-coating like some brands of ESLs. Acoustat's proprietary coating bonds to the mylar diaphragm. In any case, the panels are not meant for disassembly, so re-coating is out of the question.