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]

..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]

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]

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

 

[justint]

so thats really all there is to this box? 1 board down the center basically, no angles no nothing? Just pull out the saw and glue and i bet i could do one of these in under 2 hours if I tried

 

[bjorno]

so thats really all there is to this box? 1 board down the center basically, no angles no nothing? Just pull out the saw and glue and i bet i could do one of these in under 2 hours if I tried

Yes, It's that simple, This week I'm gluing a very similar sized box (T-QWP) using the same driver for a friend to be used in his recording/mixing studio.

b

 

[Don Snyder]

This thing can be made from one sheet of ply! (with minor changes).

 

[bjorno]

This thing can be made from one sheet of ply! (with minor changes).

Great, This will save money,especially if using Baltic Birch.
The remaining leftover wood can be used to reinforce a detachable driver access-lid and maybe pieces glued to brace the top and bottom too.

b

 

[Djim]

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.

Hi Don, may I ask where you found these Thiele-Small parameters from the 3015LF?

 

[Charles Darwin]

Interesting box bjorno!

Couple of questions: Does this need a high pass like a tapped horn and could one fit the driver the other way around (again a la TH) for ease of access if one reverses polarity?

Thanks!

 

[Don Snyder]

Bjorno - no need for access panel, I simmed it in CAD and it went in with an inch to spare.

Djim - Eminence has brought out a new version of the 3015LF but I'm still using the old version numbers.

 

[Djim]

Justin, I think you should check your 3015LF's first because the 'new' version seems to be quiet different.

 

[Djim]

The difference in Don's design:

 

[bjorno]

Bjorno - no need for access panel, I simmed it in CAD and it went in with an inch to spare...

Hi Charles,Don:

You don't need any HP-filter at all if you stay below~63W input( i.e. ~ 116 SPL and 1 Hz safe).
Mount the driver like a TH or a T_TQWT: The performance differences will IME be benign, but mounting like an TH has an advantage when stuffing is used as it's easier to minimize the minimum required stuffing for smoothest response (sometimes needed (Hi-Fi)) and if used, would be easier to evenly distribute the damping material at the 'throat side' whereas otherwise would be occupied of the basket and magnet volume.

Thanks again Don !: I oversaw the possibility to avoid using a lid, I'm too focused on T-TQWT designs where an access lid is an evil necessity to incorporate.

b