Transmission line boxes

[Danman_tocf]

I have a couple of q's about these boxes,
for a short background i have a Illusion audio nd-15 fs of 25hz

1st question - Can i tune the box to 25 hz

2nd- 1127/25 = 45 and 1/4 of that is 11ft, when i build the tunnels that long do i have to add a chamber for the sub,

3rd and last for now, with the port size affect the tuning.

Thanks Dan

[Danman_tocf]

I found this at http://geocities.com/rbrines1/Pages/...nt_Pipes.html,
"The first TL example is a "Rule of Thumb" TL. The length of the pipe is 1/4 wave-length at fs. The wide end area is 2*Sd and the small end area is Sd"
What do they mean by the wide end area is 2*Sd and the small end area is SD, is that refering to the end and beginning of the tunnel?

[Volenti]

Originally posted by Danman_tocf
I have a couple of q's about these boxes,
for a short background i have a Illusion audio nd-15 fs of 25hz

1st question - Can i tune the box to 25 hz

2nd- 1127/25 = 45 and 1/4 of that is 11ft, when i build the tunnels that long do i have to add a chamber for the sub,

3rd and last for now, with the port size affect the tuning.

Thanks Dan

1, yes

2, not in a traditional TL, the sub is in the line it's self.

3, a larger area line (up to a point) will increase output and have some effect on the overall response, but won't effect tuning.

[GM]

Originally posted by Volenti

3, a larger area line (up to a point) will increase output and have some effect on the overall response, but won't effect tuning.

Greets!

True, but that wasn't the question. The expanding pipe (horn) in BB's example will have a higher Fp referenced to a constant expanding pipe (TL), ergo a reverse taper (TQWT) will have a lower Fp, so it can be said that the port size does affect tuning.

Regardless, based on the minimal published specs, this driver's Qts is a bit low for a Fp = Fs TL, being much better suited for a much shorter, higher 100 Hz Fp, but is ~ideal for a proper 2:1 CR B@#$ Wave Cannon if a nominal ~16.7 - 50 Hz BW is acceptable.

GM