TML Subwoofer sanity check

[LarsJ]

Hi,

Want to get a sanity check of the project before I put to much time and effort in it. Get some opinions if this is a good idea or if it’s just a dead end.

In the living room we have a TV-table (with solid sides) that has only a shelf underneath that is just collecting dust and magazines. Under this table I’m planning to hide a Sub-woofer. Available space is W=110, D=56, H=51 cm. Cover front and back with some nice fabrics, should get quite good VAF on this.

The idea is to build a sub with two 12 inch elements mounted back to back, one at the front and one at the rear, and load them symmetrically with a transmission line with ports both to front and back. What difference would it be with port guidance contra without?

See attached drawing

Will start with a Pioneer drivers used in a pair of “party” speakers at the moment.
TS-W302C: QTS=0.331, VAS=231.38, Fs=21.5 Hz, RMS=150W, IMP=4 ohm.
Yes, I know its car speakers but the plan is to get some better suited later on, what that now would be.

Some opinions or advises before I start?

Br
LarsJ

[Henkjan]

I have a TL sub under the TV as well
tadaaaa.jpg

on the TL: basically a good idea, the 'dual firing' might even help in a better integration in the room
a few tips: try to put the driver at 1/3 of the length; the chamfering of the corners is not needed

[planet10]

Originally Posted by LarsJ

Available space is W=110, D=56, H=51 cm....VAS=231.38, Fs=21.5 Hz

Just a hunch... the available space (308 litre gross) is not sufficient to put even a single driver TL.

dave

[Henkjan]

looking at MJK's allignment tables, 1 should certainly be OK, 2 will be a bit tight...

[LarsJ]

With a simple rearrangement the driver is placed at 1/3 down the line.
First ruff estimation gives L~300 cm, SL/SO~0.35 and Fo~23 Hz
By heavy stuffing of the speaker the mismatch between driver and TML could be masked, becoming more like an open baffle. Loss of efficiency is not so critical for me. With better suited drivers the stuffing could be reduced later on.

Br
LarsJ