Hi All
some more stupid Questions !
1. according to theory, the smaller the pefrated % will have a lower resonace frqz. so can we build a deep low bass just 2" thick by drilling less and smaller holes on the front panel ? Did anyone builded any of these Perferated bass trap, how are thier effecients, seems no one in this forum ever mention this panel.
2. if i use a 1" thick 2ft x 4ft board and machine cut the slot through it, will it be the same as using separated slats ?
3. same as Q 1 apply to the slat bass trap ? ( just use wider slat and leave only 2 or 3, 1/16" slots )
OK! end of stupid Questions !
feni
Perforated Panel Absorbers
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knightfly
- Senior Member
- Posts: 6976
- Joined: Sun Mar 16, 2003 11:11 am
- Location: West Coast, USA
Hi, Feni - let's give this a shot -
1. The problem with theories is that they tend to fall apart when we push them too far. You're right, not many people try to build the perforated traps, myself included. In my case, it just seems easier to get the actual percentage you want by using slat/slot construction, than to buy perforated material, then try to figure out what the percentage of perforation is, then adjust the other parameters to get the results you're looking for. One of the problems in going too low with traps is the large physical dimensions of the front panel in order for the panel to "see" enough of a long wavelength to respond - also, I think that if you put too FEW holes in a panel it would act more like a panel absorber, causing the panel mass to take precedence over the number/size of holes. As for efficiency, Hemholz resonators are really efficient at their resonant frequency. Using heavier cloth behind the slats, according to Barefoot, will dampen the action and broaden the frequency response of the trap.
2. Exactly the same, perhaps even better. The only problem would be finding a blade that's the right thickness for your calculations, especially if you're doing very narrow slots. You might have to cut a slot, then measure it and adjust the other dimensions to compensate for the slot width.
3. Yes, it will work up to a point. Experimentation and careful measurements would still be necessary to find out just how well it worked.
Most of the above is only conjecture on my part since I've not built these, so I'm hoping Thomas from the Speaker Design forum will see this and grace us with his greater understanding in these areas... Steve
1. The problem with theories is that they tend to fall apart when we push them too far. You're right, not many people try to build the perforated traps, myself included. In my case, it just seems easier to get the actual percentage you want by using slat/slot construction, than to buy perforated material, then try to figure out what the percentage of perforation is, then adjust the other parameters to get the results you're looking for. One of the problems in going too low with traps is the large physical dimensions of the front panel in order for the panel to "see" enough of a long wavelength to respond - also, I think that if you put too FEW holes in a panel it would act more like a panel absorber, causing the panel mass to take precedence over the number/size of holes. As for efficiency, Hemholz resonators are really efficient at their resonant frequency. Using heavier cloth behind the slats, according to Barefoot, will dampen the action and broaden the frequency response of the trap.
2. Exactly the same, perhaps even better. The only problem would be finding a blade that's the right thickness for your calculations, especially if you're doing very narrow slots. You might have to cut a slot, then measure it and adjust the other dimensions to compensate for the slot width.
3. Yes, it will work up to a point. Experimentation and careful measurements would still be necessary to find out just how well it worked.
Most of the above is only conjecture on my part since I've not built these, so I'm hoping Thomas from the Speaker Design forum will see this and grace us with his greater understanding in these areas... Steve
Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...