[wooferman]

I have never built this type of sub, but I just recently acquired a heavy duty mailing tube, 12 " internal diameter, with 3/8" walls. If my math is right, I will have 3 cu ft to work with. I know it's not ideal for LLT, but what drivers do you guys think would be a candidate. I would assume with the 12" diameter, I will be looking at 10" subs. Thanks for any ideas.

 

[Mike P.]

First off let's check the math to make sure we have the correct internal volume. What is the length of the tube?

 

[Robert_J]

To get 3cf, it would have to be almost 46" long.

Yes, a 10" sub would work. But I would use a base plate like SVS and make that a little larger than 12" just to give you more stability.

Driver choices, look at the 10" versions of the usual suspects. Dayton (PE), Exodus Audio, Fi Car Audio, etc. all have 10" models. If you really want to go high powered, there are some Lightning Audio 10's on Ebay with the high excursion baskets.

-Robert

 

[wooferman]

It is actually 52" long.

 

[Mike P.]

Then the volume is 3.3 cu.ft. Is this a HT build?

 

[wooferman]

I was allowing for driver and end cap displacement in my guestimation. I have a 12" TC 1000 SVC that takes up a lot of space, but I probably over estimated. The use will be 50-50 music & HT.

 

[Mike P.]

The CSS SDX10 looks good in 2.8. cu.ft. Tuned to 20 hz with a 4 inch flared port the air speed is under 26 m/s with 300 watts input. A Bash 300 with a high pass filter at 18 hz would keep the excursion in check. SPL would be 105 db at 20 hz, plus room gain.

Disregard the driver numbers in the bottom right hand side. That was a driver in the sonosub.exe database.

 

[wooferman]

Thanks, Mike. I see the sonosub calculator is using the Dayton Reference for the displacement calculation. Is this close enough to the CSS driver you are recommending?

 

[Mike P.]

Yes, the difference in displacement volume or height won't have any effect.

 

[wooferman]

Thanks, again. Regarding the 18 hz high pass filter, what is the best way to implement? I have a Bash 300 but I am not sure what the rumble filter is set at.

 

[SteveCallas]

Using a 10" driver in a 12" tube....very little material in the bottom cap. Maybe mount it sideways with a wooden, arched stand?

 

[Mike P.]

I believe the Bash 300 does have a 18 hz high pass filter. Where did you get it from?

 

[Robert_J]

I've measured and there is more than enough material. The outer caps usually have a larger diamter than the tube so they will be at least 12.5" in diamter. With a 9" hole for the driver that leaves almost 1.75" of MDF/wood on the driver end.

-Robert

 

[Mike P.]

Using a 10" driver in a 12" tube....very little material in the bottom cap. Maybe mount it sideways with a wooden, arched stand?

The cutout would be about 8 inches allowing 2 inches of material around the sub. I've built 12 inch Shivas in 14 inch tubes with no problems at all.

 

[wooferman]

I got it at PE - the info that came with the amp was of no help.

 

[Mike P.]

The default high pass filter in the PE Bash 300 is 17.7 hz. You're good to go. :T

 

[wooferman]

Thanks to all - my weekend is now planned.