Bottom ported/bottom driver'ed sonosubs?

[Bent]

Has anyone ever tried a DIY of Adire's "tube in a tube" ported Sadhara? This would leave a undistrbed top cap, rather then the vent at the top.

I'd think this would be kinda cool, what increments are sonotube available in?

[ThomasW]

Most of the larger tube is available in 2" increments

[Bent]

hmmm.

Brain is working now - be back later....

[Dennis H]

Interesting idea Ben. Just for yucks, I threw some numbers in Excel to see what kind of port area you'd get that way. Numbers in inches. I assumed a .25" wall thickness for the tubes.

Inner	Outer	Effective Round Port Diameter
16.5	18	7.19
16.5	20	11.30
18.5	20	7.60
18.5	22	11.91
20.5	22	7.98
20.5	24	12.48
22.5	24	8.35
22.5	26	13.03
24.5	26	8.70
24.5	28	13.56
26.5	28	9.04
26.5	30	14.06
28.5	30	9.37
28.5	32	14.55
30.5	32	9.68
30.5	34	15.02

[Bent]

To me, the better sizes are the 20.5" and 24" as inner and outer tubes.
Correct me if I'm wrong, but this would mean 20" inside tube diameter for the 20.5 and 24" inside diameter for the outer - giving an equivalent port diameter of 12.48 inches^2.

"spacers" or shims could be used to help seperate the tubes to make up the port, and a side benefit would be that they'd help to reduce port area (shortening the required port length to a manageable amount.

Now to determine how the gap at the top where the inside tube terminates into the outer chamber (port).

BTW, I'm obviously thinking of a 15" driver as opposed to a 12"er (why re-invent the wheel when we can re-invent a bigger wheel...?)

[SteveCallas]

Please don't take this the wrong way, but does one gain anything with this added complexity? Seems kinda like a slot port with no flaring for a sonosub.

[Bent]

no gain to be made - just another way to skin the proverbial cat.

I'm not sure about the lack of flare, but I'm kinda guessing (bare with me here) that with the slot firing downwards that chuffing would be somewhat silenced by the floor anyways.

[Owen Bartley]

For some reason I've never been a huge fan of sonosubs before, I just tend to prefer boxes... but this one has got me thinking. Maybe it's just the coolness factor, but I'm interested. I'm even having trouble picturing the finished product, and how you determine the length of both sections, etc. Let's just say I will be following this thread and hoping for good things.

[Dennis H]

this would mean 20" inside tube diameter for the 20.5 and 24" inside diameter for the outer - giving an equivalent port diameter of 12.48 inches^2.

Right, 20" and 24" tubes and 12.5" diameter port (not inches^2). Obviously chuffing wouldn't be a problem with a huge port like that. Even 20" + 22" and an 8" port shouldn't chuff with one driver. Of course those numbers are just ballpark. You'd need to measure the actual tubes' diameter and thickness to finalize the design.

As an aside, this would be a way to build a ported version of Thomas's Tubezilla with a driver on each end. Hard to do with a conventional round port.

[jacoviii]

ok had a tube once loved it stupid and got rid of it 1 15 jl w3 8cu ft tuned low 150wat sound preaty good out in the open tryed moveing it around finely stuck it in a empty closet and man it went crazy took the door of
man stuff started to fall out the celien


but any way


take the first tube 20" er make a face plate to hold the sub
now lets say total hight is 46" and port length is 40"
take the 20" er cut it to 40" long
screw 4 48" 2x2 or 1x2 to the out side of the 20"er leav 6" at the top 2"at the bottom
make a end cap for the 24"er and slide it over the 20"er screw the cap to the 4 2x2 and screw down the sides of the 24"er were it tuches the 2x2

just a ruff idea sorry for gramer at work no time