Sorry for the confusion. 2.86m folded pipe, no taper, pipe area is 1864 cm^2. This should give nice even response down to about 30Hz or so. In sim'ing I noted that a longer line could give response similar to EBS and get me another 1/2 8va or a bit more.
I will build the 30Hz version first as that should make a pretty nice sub of reasonable size.
mike
I will build the 30Hz version first as that should make a pretty nice sub of reasonable size.
mike
This is a crude sketch (I need to download a drawing program) of the layout. I think I should probably include some bracing. The red lines are what I have in mind for bracing. Somewhat randomly placed sections of MDF or 1x boards. Is that the kind of thing that I should do? Should the edges of the boards be radiused for smooth airflow or does it really matter?
mike
mike
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Greets!
True, or you can either reverse taper the line or add a vent at the open end. FWIW, my best results were from reverse tapering the pipe (TQWT) and fine tuning it with a straight vent pipe, allowing <20 Hz tunings in much smaller cabs than a (folded) straight pipe.
Unless the brace boards are really thick and/or a wide BW alignment is desired, it's not an issue since the WLs are so large WRT the pipe's CSA that they're acoustically invisible. FWIW, on large CSA pipe designs I just ran a vertical angle iron down the sides offset horizontally in a golden ratio (1.000:1.618). Note that I used no-void 3/4" marine grade ply, a suitably rigid cab material to ensure mass quantities of bracing wasn't required.
GM
True, or you can either reverse taper the line or add a vent at the open end. FWIW, my best results were from reverse tapering the pipe (TQWT) and fine tuning it with a straight vent pipe, allowing <20 Hz tunings in much smaller cabs than a (folded) straight pipe.
Unless the brace boards are really thick and/or a wide BW alignment is desired, it's not an issue since the WLs are so large WRT the pipe's CSA that they're acoustically invisible. FWIW, on large CSA pipe designs I just ran a vertical angle iron down the sides offset horizontally in a golden ratio (1.000:1.618). Note that I used no-void 3/4" marine grade ply, a suitably rigid cab material to ensure mass quantities of bracing wasn't required.
GM
Great. I have a bunch of 1x4 pine boards lying about so I will probably use them for bracing. When you speak of a port at the open end do you mean closing it off partially and leaving an open port? How do you go about calculating that? Would such a thing lower the sensitivity too?
I am planing a trip to Lowes after payday.
Will need more MDF and some clamps. Can't wait.
mike
I am planing a trip to Lowes after payday.
Will need more MDF and some clamps. Can't wait.mike
Well I still haven't gotten the NDF that I need to build this thing but it might be just as well because I have modified it a bit. Right now I am planning on making it a 2.0 taper line which ends up giving a little bit more space efficient package. I also found a program that lets me do screen captures of the full screen EGA graphs that the simulation program makes so I can post the latest sim results.
I am including a picture of the layout as I planned it using the scraps I now have but I think I will wait and get some 3/4" material so that I can do it right. The pic gives the general idea though.
In the next two posts I will include the design parameters and the simulated response plot at full Xmax at 25Hz (assuming an estimated xmax of 6mm).
I am including a picture of the layout as I planned it using the scraps I now have but I think I will wait and get some 3/4" material so that I can do it right. The pic gives the general idea though.
In the next two posts I will include the design parameters and the simulated response plot at full Xmax at 25Hz (assuming an estimated xmax of 6mm).
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