3015lf TH @ 35-40hz but only 20" deep help

[justint]

I am starting to work on this years boat project a 28foot pontoon.. I have bought 2 - 3015lf for subs and I want to put them under the seats so I have 18" wide I can go, 20" deep and however high I need as technically I will be laying the boxes on there sides.. Anyone have a link for a box build or any ideas.. looking for loud and low with good efficancy as I am running off a generator. Thanks for all the help!! Pictures of the beautiful 1985 pontoon boat to come. this is going to be a total transformation for this beauty.

[weltersys]

You would probably end up with a "thinner" version of what Don Snyder built, I'd suggest searching his posts.

The size restrictions you have may make a bass reflex cabinet a better choice, as a "thinner" TH will end up with less gain and may have more peaky frequency response problems.

[Don Snyder]

Hi Justint - This TH is 17.5 x 21 x 60. The 21 inch dimension can be reduced to 20 or even 19.5 without doing much harm. Attached is a text file that can
be imported into HornResp.

[justint]

thanks Don, to be honest I am horrible at Hornresp .. but I guess really all I need to know is how much space between the front of the driver board and the top of the box and then how big should I make the opening? the rest I can figure out as I have made about 5 TH's now

[bjorno]

Originally Posted by justint

..I have bought 2 - 3015lf for subs and I want to put them under the seats..

Hi,

IMO, A T-TQWP concerning your application is smaller and simpler to build and would outperform the TH in post #3.

Compare the performance here:

b

[justint]

bjorno, thanks for the research.. I am not at all familiar with what a T-TQWP is ? can you post me a picture and if possible some dimensions for this box ? that would be a huge help.. thanks again for the input..

[Don Snyder]

Here it is ... 17.5 x 19.5 x 43" & made from 18mm or 3/4 inch plywood. The
mouth opening and the turn-around are both 8.25"

[justint]

thanks don that looks pretty easy!! you guys are the best.. any input on bjorno's box idea?? I have never seen or built one of those.

[Don Snyder]

Originally Posted by justint

thanks don that looks pretty easy!! you guys are the best.. any input on bjorno's box idea?? I have never seen or built one of those.

This IS Bjorno's box. Smaller & easier to build than my TH. Bjorno did a GREAT job simming this box!

[bjorno]

Originally Posted by Don Snyder

This IS Bjorno's box. Smaller & easier to build than my TH. Bjorno did a GREAT job simming this box!

Hi Don,Justint,

Thank you Don...

Justint,

Maybe the design I proposed and named: T-TQWP is a name misnomer and should better be a T-QWP(Tapped Quarter-wave -Pipe).
A T-TQWP (Tapped-Tapered-Quarter-wave-Pipe) or a T-QWP are both folded like a TH's but only the T-QWP uses a constant CSA(Cross Sectional Area).

My superfluous !!? version:A simple picture showing the T-TQWP:

b