Publish?
David,
Why not prepare and submit a paper to the AES or ASA that presents the history of your effort and the technology involved?
Bill
David,
Why not prepare and submit a paper to the AES or ASA that presents the history of your effort and the technology involved?
Bill
Hi whgeiger,
The closed end cap at the right turns this into a nested sonotube tapped horn. Cool design.
Regards,
The closed end cap at the right turns this into a nested sonotube tapped horn. Cool design.
Regards,
SWAG
At the building shaking energy levels anticipated, the answer is Yes!
Particularly regarding the stresses on the screw/glue joinery at the driver mounting and end cap.
Have you visited this site?
Pipe & Electronic Organs
Colin Pykett
Organs and organ music for church, home and theater. A reference source by Colin Pykett
Regards,
WHG
At the building shaking energy levels anticipated, the answer is Yes!
Particularly regarding the stresses on the screw/glue joinery at the driver mounting and end cap.
Have you visited this site?
Pipe & Electronic Organs
Colin Pykett
Organs and organ music for church, home and theater. A reference source by Colin Pykett
Regards,
WHG
I ran across this thread while researching. Comments?
http://www.diyaudio.com/forums/subwoofers/55377-folded-sonotube-tl-sub-complete.html
There's no free lunch. But something like this might make for a more compact subwoofer. I just don't know if the juice would be worth the squeeze.
Bach On
http://www.diyaudio.com/forums/subwoofers/55377-folded-sonotube-tl-sub-complete.html
There's no free lunch. But something like this might make for a more compact subwoofer. I just don't know if the juice would be worth the squeeze.
Bach On
I would lend an argument against that idea.
Back When I had hair I did quite a lot of form work and concrete work.
The loads on those tubes are enormous. Concrete is seriously heavy stuff.
And the tubes never burst nor broke.
Your cone will buckle before you have any problem with the form tubes doing anything strange.
Bill.
I have used in back loaded horns chunky sections on turns that act as an acoustical filter.
As elegant as the reflector idea is. In practical use it has not so much benefit on something that is very limited in desired passband.
A simple block on the end would almost be equal to that elegant scoop.
I have used in back loaded horns chunky sections on turns that act as an acoustical filter.
As elegant as the reflector idea is. In practical use it has not so much benefit on something that is very limited in desired passband.
A simple block on the end would almost be equal to that elegant scoop.
Mission Crunch
Do you really want 16 Hz. like it comes out of a 32 ft. organ pipe?
That experience will simply not be available to you in a small room with a sub to match. WHG
Do you really want 16 Hz. like it comes out of a 32 ft. organ pipe?
That experience will simply not be available to you in a small room with a sub to match. WHG
If costs were no object ...
... I would flare the mouth as well.
However, wave reflection is not at issue here, it is mitigation of air flow turbulence that is of concern.
I have not built one of these units, so the design will be conservative in its details for now. If it is built, I want a successful and happy builder.
A static load from curing concrete is not the same a an acoustic wave traveling down the same tube. The tube is going to flex more than you suppose and I am after joint strength not required by the concrete placement application.
WHG
... I would flare the mouth as well.
However, wave reflection is not at issue here, it is mitigation of air flow turbulence that is of concern.
I have not built one of these units, so the design will be conservative in its details for now. If it is built, I want a successful and happy builder.
A static load from curing concrete is not the same a an acoustic wave traveling down the same tube. The tube is going to flex more than you suppose and I am after joint strength not required by the concrete placement application.
WHG
On reflection.
It's those turbulences that act as the filter.
I have done tests on both methods.
If it is desirable to have a wide bandwidth reproduction out of the enclosure smooth lines rule. If you are not wanting a wide bandwidth you can stick to blocks.
A flare with concrete tubes is not really feasible. Wish it was.
And as you have to buy fixed lengths of the big form tubes a stepped flare will get pretty expensive pretty fast.
Check out the wall thickness and the modulus of rupture on the tube walls.
What sort of pressure do you envisage can be produced by the driver?
Thanks to David we can simulate it quite accurately.
This is not something new to me.
I have designed horns with compression ratios that many thought were going to produce a very short lived driver. But that was not the case.
And as more of a question.
As we are creating a pressure pulse down a tube, isn't a tube the ideal vessel to keep all the pressure equal on all the surfaces?
I remember having quite a time cutting the 16 inch sized tubes. The 24 inch size was cut with a skill saw. The wall thickness was a nominal 1/2" (on the hairy side of 5/8" actually) of quite hard pressed paper.
Hence leading me back to my assertion that pressure is not really going to be an issue in this application.
We can easily simulate maximum particle velocity off of the cone and the pressure produced.
Maximum displacement is already posted on this thread in the revised T/S parameters.
@ whgeiger
Re ACW15
Nice idea 🙂 I have a patent saved somewhere for this type of design, but without the TH addition. Be interesting to see the test results, if anyone builds it 😉 Without the head scratching that goes with trying to convert a usual TH sim into reality, i might have a go myself @ some point 😀
Re ACW15
Nice idea 🙂 I have a patent saved somewhere for this type of design, but without the TH addition. Be interesting to see the test results, if anyone builds it 😉 Without the head scratching that goes with trying to convert a usual TH sim into reality, i might have a go myself @ some point 😀
Problem: Not Designed Here
I am not prepared to invest the time necessary to address all the issues you care raise concerning my design decisions. If I was building a large bass horn, it would be fabricated out of reinforced and pre-stressed concrete. If I am building it out of cardboard tubing, I want it as stiff as I can get it. I am focused on driver selection, which is a far more important issue at the moment, than just 'nit-picking' the design as it is.
WHG
I am not prepared to invest the time necessary to address all the issues you care raise concerning my design decisions. If I was building a large bass horn, it would be fabricated out of reinforced and pre-stressed concrete. If I am building it out of cardboard tubing, I want it as stiff as I can get it. I am focused on driver selection, which is a far more important issue at the moment, than just 'nit-picking' the design as it is.
WHG
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Fair enough.
I'm wrestling with the sim.
As in getting Hornresp to simulate this properly.
And I think I may have a way to do it finally.
Fourth try is a charm.
Right?
I'm wrestling with the sim.
As in getting Hornresp to simulate this properly.
And I think I may have a way to do it finally.
Fourth try is a charm.
Right?
whgeiger
I DO want a subwoofer that will produce 16 Hz. like it came out of a 32 ft. organ pipe. And I know that obtaining that sound at a higher SPL is a tall order. I've got two subs that will produce that frequency. But I doubt the SPL is going to be very high.
Our pipe/speaker chamber is a small room.
What I'm trying to determine is what subwoofer will fit in our jam packed room and come closest to providing that 16 Hz. with greater authority.
Bach On
Acousic Gunnery
You got my best guess as to what will get that job done for you at minimum cost. The alternatives that use more/larger drivers will be more costly solutions. The single 15" long-throw driver you will need, isn't cheap either. See Tom Danley's white paper on tapped horns for details on design and driver requirements. In the meantime I will explore driver candidates. Here is an example. This one is capable of 'launching' an 173 cu.in. cannon ball of air down both horn columns at a velocity of 1128 ft/sec. WHG
https://www.mtx.com/95-series-9515-22-15-1500w-rms-dual-2-ohm-subwoofer
You got my best guess as to what will get that job done for you at minimum cost. The alternatives that use more/larger drivers will be more costly solutions. The single 15" long-throw driver you will need, isn't cheap either. See Tom Danley's white paper on tapped horns for details on design and driver requirements. In the meantime I will explore driver candidates. Here is an example. This one is capable of 'launching' an 173 cu.in. cannon ball of air down both horn columns at a velocity of 1128 ft/sec. WHG
https://www.mtx.com/95-series-9515-22-15-1500w-rms-dual-2-ohm-subwoofer
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