I suspected it would work. sand only moves one way though, it compresses and does not spring back. water has the advantage of being easy to drain out again for maintenance. cheaper too.
I think in theory the design could be changed to eliminate the issue. I've often seen steel tanks with flat sides flexing in and out at the slightest provocation. it does not happen where the tank is round on all surfaces.
Another poster mentioned explosive tank formation in jest but that would actually deal with the issue, though i would never seriously consider it. I did meet a bipolar fellow who loved playing with explosives made from fertilizer years ago though.
I guess if you curled the front and back of a voigt pipe, then most of the issue would be eliminated. I do know a man with a steel roller who would be willing to do it, I used his services in the past.
I think in theory the design could be changed to eliminate the issue. I've often seen steel tanks with flat sides flexing in and out at the slightest provocation. it does not happen where the tank is round on all surfaces.
Another poster mentioned explosive tank formation in jest but that would actually deal with the issue, though i would never seriously consider it. I did meet a bipolar fellow who loved playing with explosives made from fertilizer years ago though.
I guess if you curled the front and back of a voigt pipe, then most of the issue would be eliminated. I do know a man with a steel roller who would be willing to do it, I used his services in the past.
I've heard that video before, found it appallingly boring.
I was looking up commercial voigt pipes and found a company that was using mdf for one surface and birch ply for the other. I know everyone hates the deadness of mdf but a composite design makes a lot of sense.
suppose i used steel for the back and plywood for the front, then the cavity couldn't resonate to the frequency of steel or wood. it would have to settle somewhere in between and be naturally damped by the mismatch.
I was looking up commercial voigt pipes and found a company that was using mdf for one surface and birch ply for the other. I know everyone hates the deadness of mdf but a composite design makes a lot of sense.
suppose i used steel for the back and plywood for the front, then the cavity couldn't resonate to the frequency of steel or wood. it would have to settle somewhere in between and be naturally damped by the mismatch.
No need to listen to it all.
Could resonances build up in a similar way in your box with constant stimulation?>Could resonances build up in a similar way in your box with constant stimulation?
It depends what direction the resonances travel in. as i understand the function of a triangular voigt pipe is to bounce the resonances from the front to the rear until they are forced out. these are not usually audible or intended to be.
If i had to hazard a guess then the problematic resonances are bounced from one triangular side to the other parallel triangular side. therefore there would be no advantage in changing the front to a wooden material.
The cure to my issue would then be to change the side material to wood, though in theory one side and either the front or rear from wood should annul the issue.
This would present manufacturing challenges to me though, i would prefer that three sides were steel, to provide a clean mating surface between the wood and the steel.
It depends what direction the resonances travel in. as i understand the function of a triangular voigt pipe is to bounce the resonances from the front to the rear until they are forced out. these are not usually audible or intended to be.
If i had to hazard a guess then the problematic resonances are bounced from one triangular side to the other parallel triangular side. therefore there would be no advantage in changing the front to a wooden material.
The cure to my issue would then be to change the side material to wood, though in theory one side and either the front or rear from wood should annul the issue.
This would present manufacturing challenges to me though, i would prefer that three sides were steel, to provide a clean mating surface between the wood and the steel.
Is it possible to configure the design in such a way as to avoid the ringing issue heard in my audio file to not need damping. I am wary of it as i think that it will be a constant thorn in my side, like a tv i had with ghosting that made me move the antenna whenever i changed channel.
it's also a matter of availability.
i don't mind treating my cabinet as a test bed for a better design when i have more access to drivers etc.
i understand that you may not know as to my knowledge nobody has done this before.
it's also a matter of availability.
i don't mind treating my cabinet as a test bed for a better design when i have more access to drivers etc.
i understand that you may not know as to my knowledge nobody has done this before.
@gipetto; "Is it possible to configure the design in such a way as to avoid the ringing issue heard in my audio file to not need damping."
Yes, you could add "bracing". Bracing is additional internal structure consisting of frames, boards, pillars, posts, scaffolding - etc. The trouble with bracing is that is subtracts from the cabinet's internal volume - it has to be accounted for in the cabinet design...
You could put it on the outside, but then it looks funny. Imagining a 2X4 on edge running the length of the back, sides - maybe a couple pieces for the front. Bolted down against the steel, or simply glued on using a strong acrylic construction adhesive...
My mind keeps coming back to coating the whole insides with something like driveway sealer, but I wouldnt wish that experience on anyone. (Probably smell so bad you couldnt bring it into the house for a year!) But a good thick coating of tar might do it. People have done that to the insides of wood cabinets; there was even a commercial product I think it was called "black hole" or something.
Yes, you could add "bracing". Bracing is additional internal structure consisting of frames, boards, pillars, posts, scaffolding - etc. The trouble with bracing is that is subtracts from the cabinet's internal volume - it has to be accounted for in the cabinet design...
You could put it on the outside, but then it looks funny. Imagining a 2X4 on edge running the length of the back, sides - maybe a couple pieces for the front. Bolted down against the steel, or simply glued on using a strong acrylic construction adhesive...
My mind keeps coming back to coating the whole insides with something like driveway sealer, but I wouldnt wish that experience on anyone. (Probably smell so bad you couldnt bring it into the house for a year!) But a good thick coating of tar might do it. People have done that to the insides of wood cabinets; there was even a commercial product I think it was called "black hole" or something.
A slope with parallel sides is a parabolic horn expansion, i.e. expands very fast. The Voigt's sloped front/rear eigenmodes can only properly decay to insignificance if > 1:12 [> 4.76 deg], which at ~1:8.2 is too steep, so needs some added damping.
Typical speaker cabs are < 500 Hz [5 octave] devices where half the acoustic power of music resides, so even thinner metal than you used is the ideal since we want it to 'ring' at least an octave higher [1 kHz] or the other extreme of massive/rigid enough to push its 'ring' [normally driver Fs] ~an octave below the lowest note it's required to reproduce.
Lofty goals and not normally practical, so we compromise with a high MOE rated wood product [0.75"/19 mm Marine, Baltic Birch, Apple or similar plywood panels the norm] or make it massive with low MOE MDF or HDF or go all the way with concrete, marble, etc..
If you want to experiment in extremes, make the baffle, one side of thin sheet metal and the other two out of thick Styrofoam sheet packing [no air leaks] attached with construction adhesive and the bottom of something massive to 'anchor' it to the floor.
In theory you'll only need to add some wadding at the peak to smooth the pipe's vertical 1/4 WL eigenmodes and have quite a 'conversation piece' as folks wonder why and/or think you're completely clueless WRT speaker design.
Is there a way around the bass notch flaw by using two different length cabinets with 4 ohm drivers in series for an 8 ohm load, or use a different cabinet for each channel, but i guess symmetry is important for authentic reproduction.
maybe that would cause issues with maintaining a constant volume level.
I know you're going to say that's what a subwoofer is for but i just have a 2 channel amp.