# 6th order bandpass tline?



## pandalizer (Dec 26, 2014)

Is it possible to make a 6th order-type box with the front and back chambers as transmission lines? 

I did a little mock up, but didn't know if it would actually sound good.


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## Brian Steele (Jun 1, 2007)

Yes, it is possible.


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## pandalizer (Dec 26, 2014)

Brian Steele said:


> Yes, it is possible.


What do you think output will be compared to a single transmission line?


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## thehatedguy (May 4, 2007)

It would be too large to do with anything larger than a 6.5.


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## Brian Steele (Jun 1, 2007)

thehatedguy said:


> It would be too large to do with anything larger than a 6.5.


Like every other alignment, the overall box size will be proportional to the driver's Vas.

Higher-order alignments do tend to be a bit larger than a simple vented alignment using the same driver. Like 4.70 cu.ft. net and 5.91 cu.ft. gross for my last build that uses just one 12" driver. And yes, it does fit in my car, though it's only placed there for transportation purposes


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## Brian Steele (Jun 1, 2007)

pandalizer said:


> What do you think output will be compared to a single transmission line?


That would depend on what compromises you make in the design.

Download a copy of HornResp and get used to using it first, before trying a complicated build like that. It's got a bit of a steep learning curve, but once you get used to it, you'll see that it can model this and almost any other exotic design you manage to come up with.


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## Jroo (May 24, 2006)

last year there was a guy selling a 6th order T line box for a pair of Hybrid 6 inch subs. I wanted to buy the box to deconstruct it and figure out the math behind it. A couple of people knew about the box and referred to it as "ant hill". I remember a few that heard it said it played really low but sound good especially for 6 inch subs. If memory serves me, PWK designs was behind the orginal design.


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## Patrick Bateman (Sep 11, 2006)

A Bose Acoustic cannon works like this. Transmission line in front of the driver, transmission line *behind* the driver.


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## XSIV SPL (Jun 24, 2014)

Pandalizer- correct me if I'm not seeing this correctly, but at a glance, the front and rear lines appear to be about the same length. That would give you two apertures next to each other at 180 degrees phase differential if built as sketched. These will cancel each other.


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## Patrick Bateman (Sep 11, 2006)

Good point 

Don't do that.

There's a reason the Bose sub has the mouths ten feet apart. It basically acts like two subs instead of one.


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## Lycancatt (Apr 11, 2010)

Patrick Bateman said:


> Good point
> 
> Don't do that.
> 
> There's a reason the Bose sub has the mouths ten feet apart. It basically acts like two subs instead of one.



please explain how any commercial sub has its mouths 10 ft apart? is this through folding and as the crow flies its much less?


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## TwistdInfinity (Jun 7, 2015)

Lycancatt said:


> please explain how any commercial sub has its mouths 10 ft apart? is this through folding and as the crow flies its much less?


Did you see the picture of the bose unit a few posts before? It's about 5 meters ling with the sub about 3/4's the way to one end

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## Patrick Bateman (Sep 11, 2006)

He's blind.


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## Focused4door (Aug 15, 2015)

Patrick Bateman said:


> A Bose Acoustic cannon works like this. Transmission line in front of the driver, transmission line *behind* the driver.



Wonder if ABS pipe or even a sonotube would be stiff enough. Would take a lot of resin to glass something that long if it wasn't.


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## Patrick Bateman (Sep 11, 2006)

Yeah I think it's plain ol' PVC pipe. The big stuff that Home Depot doesn't sell. You see it on construction sites, it's usually light green in color. Obviously Bose paints it.


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## TwistdInfinity (Jun 7, 2015)

I hate going OT but I really have to ask now, if I built a really long transmission line bandpass box where each end outputs were on the outside of the front speakers would that act like having two subs in terms of keeping room nodes down? 

Like mount that bose unit behind the TV lengthways horizontally on a solid mount... 
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