With respect to Veleroc's guidance, my aluminum honeycomb panels have a thickness of just 3/8 inch (roughly 9.5 mm).
I think aluminum foil, while not easy to to handle, might surprise you.
Else, consider the thinest aluminum roof flashing you can find.
Good chance, the thinest aluminum that isn't "foil" will work best.
I cannot visualise what you're describing in the last line, but it does sound like a problem...
If the voice coil moves off its rest position by even 0.5mm when you apply the bracing, then you are going to pick up coil excursion problems.
@aagas - if you are referring to your Valcucine panels they are very different animals compared to EPS skinned alu panels. It looks like the EPS core dampens when glued between two alu sheets, but when the core is honeycomb (like in your alu composite panels) then it acts differently, or there is very little damping then. A honeycomb core seems better in all cases?
It's remarkable how such a tiny change can have such a large impact. The 2k & 3k falloffs may be due to the panel mounting arrangements. Things will be easier when I've done the H frames.
Lordtarquin.
I have been mentioning this problem within the voice coil area for some time now, but I'm afraid little attention has been paid to it.
Regarding the slope after 3k ,thinking about it, some like to adjust the room to a room slope with a downwards slope towards the hf.
So this might be a bit of a plus ?
How have you attached the exciters to the panels, using the sticky pads or using glue?
Steve.
I have been mentioning this problem within the voice coil area for some time now, but I'm afraid little attention has been paid to it.
Regarding the slope after 3k ,thinking about it, some like to adjust the room to a room slope with a downwards slope towards the hf.
So this might be a bit of a plus ?
How have you attached the exciters to the panels, using the sticky pads or using glue?
Steve.
Eucy.
I might be able to get into my room tonight as my wife is going to the cinema.
I'll have to heat the room for an hour or so to warm it up a bit.
But at least I'll have a bit of quality time listening to the dome.
yesterday I managed to home into the differences in sound between the my thinner larger dome and the flat panel.
I do actually have a can dome that I made some time ago but it is only 7/8 of an inch width.
The thicker dome did not seem to be producing as much sound as my thinner dome, I only had a short time to listen.
But I was wondering if the thicker dome was mainly blocking the problems within the coil area ,? I'm not sure ?
Hopefully I can have a better listen tonight in more comfortable conditions.
Steve.
I might be able to get into my room tonight as my wife is going to the cinema.
I'll have to heat the room for an hour or so to warm it up a bit.
But at least I'll have a bit of quality time listening to the dome.
yesterday I managed to home into the differences in sound between the my thinner larger dome and the flat panel.
I do actually have a can dome that I made some time ago but it is only 7/8 of an inch width.
The thicker dome did not seem to be producing as much sound as my thinner dome, I only had a short time to listen.
But I was wondering if the thicker dome was mainly blocking the problems within the coil area ,? I'm not sure ?
Hopefully I can have a better listen tonight in more comfortable conditions.
Steve.
Lordtarquin.
having the pink noise running while moving the microphone around the room is very interesting, plus if you are changing things you can see the response as you are doing so.
So you can see if what you are doing is helping or not.
It is also good to see the average response in your listening area rather than one small fixed piont .
Steve.
having the pink noise running while moving the microphone around the room is very interesting, plus if you are changing things you can see the response as you are doing so.
So you can see if what you are doing is helping or not.
It is also good to see the average response in your listening area rather than one small fixed piont .
Steve.
On the main screen of REW there are two icons that look like this:
The first allows you to generate a variety of signals, including white noise, and pink noise. The signal generator screen looks like this, choose "noise" at the top and then pick from there exactly what noise you want, then click on the green arrow (at the bottom right) to start the signal.
Open also the RTA icon. It will give you a frequency spectrum. Choose what type of spectrum you want using the control panel (gear icon in the upper right), then start the RTA function by hitting the start button just below that. After hitting start you will get a real time frequency spectrum. Both are highlighted in yellow below.
Hope this helps,
Eric
That's would be my strategy too. I'm not sure how thick that is, however.
Eric
Ok Steve... That's good
Must be very cold where you are ☹️🌍
It's 22c @6:30 in the morning at my place 😁
Maybe you should move to sunny Qld. (It's actually misty at the moment, but still warm)
I think it's important to have the perimeter of the dome exactly match the coil diameter. And 7/8" is 28% less area than 1".
I was also concerned that the can base may be too thick but found it worked.. A thinner one may be better... Much work left to do...
And I want to know more about the coil area problems..I know you've mentioned it many times but I'm still not clear.
Eucy
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Many thanks Eric. I'll have a play tomorrow. OB bass + DML mid/top hybrids currently sounding very nice with some Rachmaninov.
Well, someone made them here before, and had two panels working in a stereo mode. The Beer Can Bottom Thingie.. some 3 and half years ago.
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Eucy.
the 7/8 is still on the foot of my exciter so should be similar ?
i could not resist making a recording.
1m in front of the panel on the left , this is the ply panel with dome.
Im holding the phone and am a little close to the panel so it sounds a little bright but its fine further back.
steve.
the 7/8 is still on the foot of my exciter so should be similar ?
i could not resist making a recording.
1m in front of the panel on the left , this is the ply panel with dome.
Im holding the phone and am a little close to the panel so it sounds a little bright but its fine further back.
steve.
You're welcome.
There are a couple of ways to do this, but IIRC, you can use white noise, and the the "spectrum" mode, or pink noise (or pink periodic noise) with any one of the "RTA" modes. Either of these should give a flat frequency response for a perfect speaker. Other combinations ( i.e white noise and "RTA" mode would produce a sloped line rather than a flat line. At least that's what I recall. If someone knows better please correct me, it has been a while since I did measurements like that.
Eric
I wired up my surround sound DMLs (rear channels) to my home theater over the weekend and with my wife and daughter away, spent two glorious days just listening to music and sound tracks. My "Valcucine" panels continue to thrill me.
For the real left & right I used my birch ply panels held in my Abstracta frames.
Brilliant on the Dune soundtrack. The system puts you on the sand in Arrakis ;-)