Hi Wachara,
I have not glued the panels yet. I want the frame done first so I can put the panels under preasure from the start.
I'll most likely try the thin tape and some glue on the spacers as you sugested!
I'm using water based paint on the frames and the back side one with the wing, is a ...
... to paint as it dries so quick => hard to get an even texture on th surface!
/R
I have not glued the panels yet. I want the frame done first so I can put the panels under preasure from the start.
I'll most likely try the thin tape and some glue on the spacers as you sugested!
I'm using water based paint on the frames and the back side one with the wing, is a ...
... to paint as it dries so quick => hard to get an even texture on th surface! /R
I finaly got one frame painted and ready to test mount a panel!
For the bass panel I use 6µm Mylar. Handstretched at first, then heattreated and after that tensioned to abt. 3kg/5cm.
I used thin doublesided tape on the spacers as glue and a 5mm aluminum strip around the perimiter as bias loop.
The element mounted and connected to the electronics in my hybrid speakers = ~1:80 and 2750V bias
I have not had time to measure the frequency response yet, but I'll do that as soon as I have my new trannys and EHT-unit hooked up!
/R
For the bass panel I use 6µm Mylar. Handstretched at first, then heattreated and after that tensioned to abt. 3kg/5cm.
I used thin doublesided tape on the spacers as glue and a 5mm aluminum strip around the perimiter as bias loop.
The element mounted and connected to the electronics in my hybrid speakers = ~1:80 and 2750V bias
I have not had time to measure the frequency response yet, but I'll do that as soon as I have my new trannys and EHT-unit hooked up!
/R
After playing my test tracks on the panel (Yello - The race...etc) I notice that I can get the film to hit the stators when I crank up the volume.
( Using 1:40 trafo and 4kV EHT )
I would like to have some more head room before this happens, so I'm thinking off different solutions.
I have not measured the resonace frequency, but I guees it is in the same range as my previous test panel - abt. 30-40Hz.
I'm thinking off testing:
1. 2nd order HP-filter set to abt. 50Hz (passive and/or active)
2. Notchfilter (passive and/or active)
3. Lower the distance between spacers (now 1:70, opting for abt 1:35)
4. Increse d/s to 4mm
What would you guys do?
/Roger
( Using 1:40 trafo and 4kV EHT )
I would like to have some more head room before this happens, so I'm thinking off different solutions.
I have not measured the resonace frequency, but I guees it is in the same range as my previous test panel - abt. 30-40Hz.
I'm thinking off testing:
1. 2nd order HP-filter set to abt. 50Hz (passive and/or active)
2. Notchfilter (passive and/or active)
3. Lower the distance between spacers (now 1:70, opting for abt 1:35)
4. Increse d/s to 4mm
What would you guys do?
/Roger
Pretty loud, but I would like to be able to play louder!
When driving my hybrids with the same setting on preamp and PA, it's absolutely in the lower "party-volume-mode"!
The new panels play deep bass, så I guess I'll have to restrict the lower end some how as I imagine it's the resonance peak that's causing the film to hit the stators!?
/Roger
Yes, it is most likely the resonance peak. A silicone dot injected in the middle of each section as chinsettawong recommend will not eliminate the resonance but will reduce it's amplitude while retaining the low resonance needed for deep bass. If you reduce the distance between spacers, the resonance may go up in frequency more than you desire.
I have had good luck damping with silk screen mesh and thin felt attached to the outside of the stators.
Thin 1.5mm crafting felt is cheap and easy to work with. You might give that a try first to see if you like the results.
Here is a link to some plots for comparing damping with felt and silk screen mesh.
http://www.diyaudio.com/forums/plan...con-dots-resonance-control-3.html#post1958582
Hello Wachara,
You only need to put the felt on the back of the rear stator.
The easiest way to apply the felt is with contact cement applied only around the outside edge of the rear stator, basically where the spacers run up the sides, top, and bottom between the rear stator and diaphragm.
For a quick test to decide if you like the results, you could just tape the perimeter of the felt down to the stator.
Much easier to remove and less messy than contact cement.
Also, you will find that once the bias voltage has been on for a few hours the felt will acquire a charge that will cause the felt to be attracted to the stator helping to hold it in place.
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I tried siliconedots but the problem is still there! 
I'm starting to think there is something else causing the sound/distorsion when I crank up the volume?
I think I'll redo the panel using my old 1mm double sided tape on top off the 3mm PVC-spacers for a total off 4mm d/s.
And I'll try dividing the area into 5 cells for better stability and a bit lower spacing.
Roger
I'm starting to think there is something else causing the sound/distorsion when I crank up the volume?
I think I'll redo the panel using my old 1mm double sided tape on top off the 3mm PVC-spacers for a total off 4mm d/s.
And I'll try dividing the area into 5 cells for better stability and a bit lower spacing.
Roger
Sorry Bolserst, I missed to comment on your sugestion about damping with felt!
As the speakers are quite large I had to compromise with my better half, if I was to have them in our living room - they have to be "see through"!
/Roger
If they have to be see-thru your best option is an electronic notch filter placed between preamplifier and amplifier.
Another option I have used when building an ESL for a friend that wanted them see-thru was to stick pieces of 1mm thick, stiff see-thru plastic to the rear stator in the middle of each section. Size the pieces to be about one quarter the dimensions of each section. This will damp the diaphragms fundamental resonance while not being too reflective on a percentage of total area basis.
Martin Logan has used this technique to tame resonances in some of their wider sectioned panels.
That is where I got the idea.
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