My goal is to use 3D printed router templates to make reasonably sized cylindrical enclosures from stacked 19mm pieces of MDF, not unlike what's been done for several line-array setups on this forum. I want to to create a model that accommodates different drivers and/or response requirements by varying stack diameter and height.
The bottom half would be a down-firing subwoofer as described below. Top half would be front-firing FR, either sealed or ported, potentially with 'clockable' multiple drivers for dispersion.
The idea started while browsing smallish subwoofers and playing in Basta; I noticed the the port length is quite long. I came up with the following design, and wonder if it will work. The design is a long port folded 5x within the cylindrical shape. The ports will "bend" via plates that connect 2 triangles. These top & bottom "joining" plates are clocked so that the port "flows" clockwise.
Working backwards from these "joining" plates, I calculated the triangular port angle so the area would match as best possible, to try to maintain the same cross-sectional area throughout.
A sample design, based on the Tang Band W3-2088SOF. I envision using similarly routed "rings" for the box itself, down-firing.
-160mm outer diameter
-10mm walls
Here's the Basta 'recommended design'. I believe Port Velocity is OK for chuffing at a max of ~14.22m/s?
Here are the 4 "plate" designs required to make this work:
Here's the example cab design. Solidworks tells me that internal volume (aka port volume) is 2560cm^3, which is pretty close. Obviously the bottom "box" and top "cap" are missing:
Long story short - aside from the labor to actually cut all these pieces, is this an idea worth pursuing?
The bottom half would be a down-firing subwoofer as described below. Top half would be front-firing FR, either sealed or ported, potentially with 'clockable' multiple drivers for dispersion.
The idea started while browsing smallish subwoofers and playing in Basta; I noticed the the port length is quite long. I came up with the following design, and wonder if it will work. The design is a long port folded 5x within the cylindrical shape. The ports will "bend" via plates that connect 2 triangles. These top & bottom "joining" plates are clocked so that the port "flows" clockwise.
Working backwards from these "joining" plates, I calculated the triangular port angle so the area would match as best possible, to try to maintain the same cross-sectional area throughout.
A sample design, based on the Tang Band W3-2088SOF. I envision using similarly routed "rings" for the box itself, down-firing.
-160mm outer diameter
-10mm walls
Here's the Basta 'recommended design'. I believe Port Velocity is OK for chuffing at a max of ~14.22m/s?
Here are the 4 "plate" designs required to make this work:
Here's the example cab design. Solidworks tells me that internal volume (aka port volume) is 2560cm^3, which is pretty close. Obviously the bottom "box" and top "cap" are missing:
Long story short - aside from the labor to actually cut all these pieces, is this an idea worth pursuing?
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You might want to do some testing before you go to all that trouble. I suspect that the sharp turns will introduce audible turbulence in the port.
Very original design! Did you account for port resonance since it's so long? What passband do you anticipate on using?
Interesting and good point. Is it correct to assume that it's the inside square edges that will primarily cause this? If so, will rounding them with a router bit prior to assembly help?
Thanks! I had not thought of nor attempted to calculate port resonance, and looking now, it seems most equations are based on square or round ports. Do you have any suggestions on how to estimate this and/or how I could reduce? I was planning on stuffing the tubes prior to assembly.
I have a minidsp 2x4 I plan on using for eq & crossover.
Rounding the edges will certainly help, but it's the series of U-turns that may do the damage. I tried something similar a few years back and the design was unusable. You look like you might have more room to negotiate the bends, so you may do better.