Last minute sonosub questions

[woodfiend]

Okay I have most of the stuff lined up. Buttkicker amp,terminals from Madisound, driver gasket and port cover from PE, sono and end caps cut to size I am just waiting on the TC Sounds driver which is en route. And I just need to have someone double check my #'s before I complete the sonosub. I am using a TC Sounds 15 inch driver powered by a buttkicker amp. The tube is 24 inch by 48 inches tall which I think is about 300 L. I am not positive though about my volume calculations.

Question 1. I have looked at a bunch of different designs on this site and others and I am not sure exactly what length to cut my 6 inch port (it will be flared on both ends) I would like to get the tuning down to at least 15 hz. I know the typical range is between 25 to 33 inches but does a longer port lower the tuning or raise it? What length should mine be? Sorry I am a noob.

Question 2. lining the tube. I have seen people line it with insulation, poly-batting from Walmart, egg crate foam, accoustic foam, etc.... Would something like egg crate foam used for mattress pads work? I know I have seen them for about 10 bucks for a twin size.

Question 3. If I swap out the 15 inch driver for a different one down the road does that change the tuning of the sonotube? Or does it effectively remain the same? Let's say I switch from a 2000 to a 3000 or one of their 5400 lines? Or would I need to change the port length for the different driver?
Thanks in advance for all your help!!!
Chad.

[ThomasW]

Start by reading this thread. At post #10 I start a little tutorial regarding Unibox. The text and attachments show what happens when change are made in box size, and port size.

https://www.htguide.com/forum/showthread.php?t=23273

Then read this thread

https://www.htguide.com/forum/showthread.php?t=23497

[SteveCallas]

The tube is 24 inch by 48 inches tall which I think is about 300 L. I am not positive though about my volume calculations.

Question 1. I have looked at a bunch of different designs on this site and others and I am not sure exactly what length to cut my 6 inch port (it will be flared on both ends) I would like to get the tuning down to at least 15 hz. I know the typical range is between 25 to 33 inches but does a longer port lower the tuning or raise it? What length should mine be? Sorry I am a noob.

Yeah, that comes out to ~300 effective liters. I'd make that port ~28" long for a tuning between 14.5-15hz.

[woodfiend]

Thanks.

Thanks a lot for your reply Steve. I appreciate the advice.

[ThomasW]

If your endcaps put 1.5"ea inside the tube, you're looking at 313 liters net.

If you use a round-over bit to flare the wood at the endcap you're looking at a total length of....

15Hz length is 25.1"
14.5Hz length is 27.1"
14Hz the length is 30.2"
13.5Hz the length is 32"

If your endcaps put more or less material inside the tube, these numbers change...

[woodfiend]

perfect

Great that is just the info I needed Thomas. Thank you. The bottom cap is 3 layers thick (two inside the tube) and the top is two layers thick (with one inside the tube) So I am within about 3/4 of an inch of the figures you posted so hopefully that won't make too much of a difference. I may try for a tuning of 14.5. Thanks again.
Chad .

[ThomasW]

I recalculated the tuning for the increase in volume and applied a little design optimization.

Again this is for a 6" ID port with one flared end

For a 14.5Hz tuning, the port length is now 26.46"
14Hz is 28.67", 15Hz is 24.47"

[woodfiend]

Hmmm... this may be a dumb question but how much of a difference will it make if I flare both ends? I have the flares for both ends already or should I not use the bottom ones?

[ThomasW]

For dual flares use

25.24" for 15Hz
27.22" for 14.5Hz
29.43" for 14Hz

[parboy]

I have the same sonosub and used a 27" port length. You will enjoy the sound

[johnson]

TC-2000 in a sonotube

[ThomasW]

The effective volume of Chad's tube is 320L