Thinner is fine. There is a slight improvement with up to 0.006" thick material, but after that the patterns begin to degrade the performance. Not much but noticeable in a direct A/B comparison. A hard material is usually best here as damping materials introduce other losses, some that will be quite audible.
We are not damping, period! I know this is what is intuitive, thinking to damp resonances. What we are doing is not allowing the null sector of a resonance to effect changes in propagation once the signal is in the air. This does include the surfaces that the airborne signal crosses. Think of it as a dispersal rather than damping. And, once the patterns are in their proper place it doesn't take much of a difference to achieve this dispersal.
Bud
We are not damping, period! I know this is what is intuitive, thinking to damp resonances. What we are doing is not allowing the null sector of a resonance to effect changes in propagation once the signal is in the air. This does include the surfaces that the airborne signal crosses. Think of it as a dispersal rather than damping. And, once the patterns are in their proper place it doesn't take much of a difference to achieve this dispersal.
Bud
OK, I think I got it now. Not damping!
You're right, I was thinking damping, or cancelling out of "bad" frequencies or waveforms. Your dispersal analogy makes sense. Something like the difference between treating a room with diffusors vs. "soundproofing," right?
I went to my local A.C. Moore and bought a roll of clear acrylic shelf covering. All they had was something called Clear Cover self-adhesive covering, made by Kittrich of La Mirada, California. There's no mention of thickness or any other specs, other than it being a 9' L by 18" W roll. I hope it's close enough to the right stuff.
I have a pair of Alpair 10.2's that will be going in the cabs from an old pair of B&W bookshelf speakers. The cabs are 8.5 liter internal volume. I glued a 3/4" MDF baffle on the front for mounting the new drivers. Once I've mounted the drivers and they're broken in, I think I'll listen to them for a while and get the hang of what they sound like, then try to enABL their baffles. Should be interesting...
I have other speakers I could try this with. I think Snell Type J/III would work well, as they have a smooth, shiny finish on a very squared off baffle. Hmmm....
--
You're right, I was thinking damping, or cancelling out of "bad" frequencies or waveforms. Your dispersal analogy makes sense. Something like the difference between treating a room with diffusors vs. "soundproofing," right?
I went to my local A.C. Moore and bought a roll of clear acrylic shelf covering. All they had was something called Clear Cover self-adhesive covering, made by Kittrich of La Mirada, California. There's no mention of thickness or any other specs, other than it being a 9' L by 18" W roll. I hope it's close enough to the right stuff.
I have a pair of Alpair 10.2's that will be going in the cabs from an old pair of B&W bookshelf speakers. The cabs are 8.5 liter internal volume. I glued a 3/4" MDF baffle on the front for mounting the new drivers. Once I've mounted the drivers and they're broken in, I think I'll listen to them for a while and get the hang of what they sound like, then try to enABL their baffles. Should be interesting...
I have other speakers I could try this with. I think Snell Type J/III would work well, as they have a smooth, shiny finish on a very squared off baffle. Hmmm....
--
I've been following this thread with interest.
I've got round baffles on my FE166e BIBs. I wonder if I could get a vinyl sign shop to make a Enable pattern.
How would I determine the pattern?
I've always wondered if the baffles were too large or the wrong shape.
Thanks, Mack
I've got round baffles on my FE166e BIBs. I wonder if I could get a vinyl sign shop to make a Enable pattern.
How would I determine the pattern?
I've always wondered if the baffles were too large or the wrong shape.
Thanks, Mack
An externally hosted image should be here but it was not working when we last tested it.
'Round' is the worst shape since it has a theoretically infinite number of eigenmodes and why you see horns with either huge round-overs or covered with open cell foam to deal with them.
WRT baffle size, ideally it's just large enough to smooth the transition through the speaker's acoustical XO BW, so normally either has to be arrived at by measurement or empirically. Don't know if any software can sim it.
GM
WRT baffle size, ideally it's just large enough to smooth the transition through the speaker's acoustical XO BW, so normally either has to be arrived at by measurement or empirically. Don't know if any software can sim it.
GM
) with "Thumb-nail" profile routed edge (you want a big-boy router such as Porter Cable 7519 to machine those without chatter)
You're welcome!
No, but most speaker drivers are round, so the rows out by the surround in theory should work.
GM
I like the elliptical 'look', but they too have pretty strong eigenmodes. Amorphous shapes are best, but not very attractive. Salvador Dali's timepiece comes to mind: Salvador Dali - WikiPaintings.org
GM
G'day Mack,
Have a look at the EnABL calculator in my signature.
You can easily cut the blocks yourself using contact paper or vinyl. If you give me the diameter of your supra baffles I can tell you what block size you need.
In fact, if you provide the external dimensions of your BIBs I'll show you how to treat them also.
Cheers,
Alex
PS: Once you know the block sizes needed, you can take it to the sign shop and get them to cut it if you prefer not doing it yourself.
Thanks Alex, I'm going to square up my Baffles/Waveguides to avoid troublesome eigenmodes. (Perhaps they should not be square but rectangular ?)
Front baffles will be 26.5mm square, same width as the BIBs. 'Wonder if they should be wider then the enclosures?
BIBs are:
26.5 wide
173 high
36 deep.
The FE166es have always had a bit of harshness in the mid-range. 'Makes you instinctively reach for the vol. control to turn them down.
Amp at the moment is a newish Dynaco ST 70.
Cheers, Mack
G'day Mack,
Have a look at the Groundside electrons link below in my signature.
This will help with the harshness but won't cure it.
Enabling the drivers would allow you to get the best these drivers have to offer. BudP is the man to talk to.
With the supra baffles, don't chop them just yet. Give me the diameter across the front where it is flat ie. not including the round over.
Cheers,
Alex
Have a look at the Groundside electrons link below in my signature.
This will help with the harshness but won't cure it.
Enabling the drivers would allow you to get the best these drivers have to offer. BudP is the man to talk to.
With the supra baffles, don't chop them just yet. Give me the diameter across the front where it is flat ie. not including the round over.
Cheers,
Alex
supra's
Hi there M: A while back Mr. GM suggested making these add on baffles the shape of an artists pallet, without the thumb hole. Overall, the advice seems be: to use shapes that have no symmetry. ...regards, Michael
Hi there M: A while back Mr. GM suggested making these add on baffles the shape of an artists pallet, without the thumb hole. Overall, the advice seems be: to use shapes that have no symmetry. ...regards, Michael
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