A syntetic felt with some ari resistance closest to the stators is good, since it is exactly here where the air speed is highest. In close proximity to a wall the air speed is zero (pressure high) so damping material is useless! This is a common misunderstanding by loudspeaker manufacturers.
There is some speakers where they actually fill the cavity in the center of the box and close to the speaker element, they have understood this...
Stig Carlsson @ Carlsson speakers did this in the 60ies And J B Lansing decades before that, KEF and B&W did this in the 60-70ties. In some older speakers you can see that they wrap wool on the backside of the drivers! And the rest of the box was empty... Anyway.. rule of thumb: place damping material where the airspeed is highest, and do not bother wasting it where the air movement is zero.
There is some speakers where they actually fill the cavity in the center of the box and close to the speaker element, they have understood this...
Stig Carlsson @ Carlsson speakers did this in the 60ies And J B Lansing decades before that, KEF and B&W did this in the 60-70ties. In some older speakers you can see that they wrap wool on the backside of the drivers! And the rest of the box was empty... Anyway.. rule of thumb: place damping material where the airspeed is highest, and do not bother wasting it where the air movement is zero.
Ugh, I'm not a cabinet guy, my brain hurts....
That seems exactly backward to me, won't placing the heaviest stuff right against the driver raise my resonant frequency?
I'm trying to damp the wall of the cabinet, not the transducer itself.
That seems exactly backward to me, won't placing the heaviest stuff right against the driver raise my resonant frequency?
I'm trying to damp the wall of the cabinet, not the transducer itself.
If you wan to reduce "echo" in the box that eventually bounce back from the box towards the membrane then you shall damp as I described.
If you want to make the box stiffer and less resonant the it is bracing. two different thing.
If you want to make the box stiffer and less resonant the it is bracing. two different thing.
OK here's what I did. Side pockets came out great and I feel 'problem solved'. Rear panel got a lot better but perhaps needs to be quieter still. Someday.
...And just to show how everybody, even me, happily skips right over the basics sometimes I will now report that a lot of my rear panel troubles were caused by half the damn screw holes being stripped! That's been fixed.
...And just to show how everybody, even me, happily skips right over the basics sometimes I will now report that a lot of my rear panel troubles were caused by half the damn screw holes being stripped! That's been fixed.
Did you ever try leaving the back panel off with just the foam as a loading
resistance or laying carpet padding over the foam and listen ? That would solve any resonance straight away..,
Does this panel really need that kind of sealed volume to bring up the low end that could be adjusted
out with a powered sub to compensate maybe ?
Golf tees broken off into your screw holes will restore the loose holes
resistance or laying carpet padding over the foam and listen ? That would solve any resonance straight away..,
Does this panel really need that kind of sealed volume to bring up the low end that could be adjusted
out with a powered sub to compensate maybe ?
Golf tees broken off into your screw holes will restore the loose holes
No I never thought of leaving the back off entirely.
This cabinet is not run fullrange, I imagine there must be a frequency above which the cabinet works about the same with the back on or off. (assuming all that foam stays in place)
Stiffening the cabinet has changed the perceived sound. A little less warmth, a little less energy at the lower registers. Or so I've convinced myself...
This cabinet is not run fullrange, I imagine there must be a frequency above which the cabinet works about the same with the back on or off. (assuming all that foam stays in place)
Stiffening the cabinet has changed the perceived sound. A little less warmth, a little less energy at the lower registers. Or so I've convinced myself...
cvanc.... why not put the ribs 90 deg angled so they ar reaching the stiff sides?
Making the back a lot less resonant?
Making the back a lot less resonant?
It's a Beveridge, there are no stiff sides ":^)
The patent drawing planet10 posted a while back convinced me adding lightweight stiffeners parallel to the long axis was the good approach.
...And darn it AVWerk now I'm thinking about deleting the rear panel entirely, just run open and let the foam do all the work. I usually cross these over at 100Hz with the steepest slope I can generate. The lowest I've ever used is 50Hz, but as huge as these coffins are they do not make much by then and are well into their rolloff. I wonder at what frequency the rear panel ceases to matter.
Thanks all, fun conversation.
The patent drawing planet10 posted a while back convinced me adding lightweight stiffeners parallel to the long axis was the good approach.
...And darn it AVWerk now I'm thinking about deleting the rear panel entirely, just run open and let the foam do all the work. I usually cross these over at 100Hz with the steepest slope I can generate. The lowest I've ever used is 50Hz, but as huge as these coffins are they do not make much by then and are well into their rolloff. I wonder at what frequency the rear panel ceases to matter.
Thanks all, fun conversation.
🙂
Since their designed to face each other , attaching to each side wall with carpet padding just behind your foam
should work wonders
Would love a set of these marvelous speakers
Since their designed to face each other , attaching to each side wall with carpet padding just behind your foam
should work wonders
Would love a set of these marvelous speakers
This sounds a little less like feng shui and more like putting them up on cinder blocks in my yard like an old Buick lol!
My back panels got a visit from a screw gun and a bunch of fender washers - unless something fails I'm not revisiting. I feel good about the progress made and am convinced the sound tightened up down low, just as one might think it would.
My back panels got a visit from a screw gun and a bunch of fender washers - unless something fails I'm not revisiting. I feel good about the progress made and am convinced the sound tightened up down low, just as one might think it would.