New Posts  All Forums:Forum Nav:

Double Layer Cylinder Sub

post #1 of 4
12/13/07 at 10:09pm
Thread Starter 
I have two svs drivers that I want to make into a vented or ported dual cylinder sub. I thought of the design below for a vented sub. Basically it's one 12" diameter sonotube that has 4 large sections cut out in the middle, with say a 16" diameter sonotube surrounding it, acting as vents on the top and bottom. I'm making these numbers up because this is my problem.

I can figure out the volume for a sealed cylinder sub, obviously, but for a vented it's tricky. Will any program help me figure out how much larger the outside tube should be and what the vent might sound like (air velocity)? I haven't used Unibox so maybe it does this, but it seems sort of complex. I figure I can't be the only one who thought of this design though. Of course this sub would have feet as well but that shouldn't affect the sound at all, so this is just a basic sketch(up). Is this way too problematic math-wise? Is this just ridiculous? Should I just incorporate bent ports? I just realized that I could also seal one end. Anyway, thanks for any and all help.

EDIT: I think this is probably impossible for my level of skill. I'm going to use a diameter of sonotube that permits me to put normal ports around the drivers in an otherwise sealed tube. But if anyone thinks this original idea is completely possible, feel free to let me know

Attachment 675
525x525px-LL-vbattach675.jpg
Reply
post #2 of 4
12/14/07 at 3:15pm

Re: Double Layer Cylinder Sub

Port tuning is determined by the cross sectional area of the port and its length.

Your port cross section would be the area (pi*IR^2) of the 16" tube minus the area of the 12" tube (Pi*OR^2). You would want your openings in the 12" tube to match this cross section.

To calculate the port length with WinISD: the box = the volume of the 12" tube. Enter a port diameter or slot dimensions that creates a "cross area" that matches the calculation above.

I think.

Adire did something like you're proposing with their Sadhara? It was part of a big multi-issue subwoofer shootout in one of the magazines.

-Brent
Reply
post #3 of 4
12/14/07 at 3:16pm

Re: Double Layer Cylinder Sub

PS. Engineering a way to support the outer tube properly over the inner tube is left as an excercise for the reader.
Reply
post #4 of 4
12/16/07 at 2:22am
Thread Starter 

Re: Double Layer Cylinder Sub

Quote:
Originally Posted by Brent_S
PS. Engineering a way to support the outer tube properly over the inner tube is left as an excercise for the reader.

I thought I'd make the end-caps with arms that extended to the outer tube. I'll post when I know what i'm doing. I wish I owned a house so I could make an infinite baffle into the attic or basement; no giant tube or box in your viewing area. I've been reading about that design and I'm jealous. For now, giant box or tube though.
Reply
New Posts  All Forums:Forum Nav:
  Return Home