tapered port?

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SemperFi

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Joined 2002
#1
I found two nice looking pieces of machined bronze tubes 4" long. They have openings on one side that is 3" diameter and end up with 4" diameter at the other end. The tube wall is about 1" thick so they are pretty heavy.
My question is if they can be used as ports on a small two-way or someting like that?
Kind of crazy designing a speaker with the ports as starting point, but they are too nice to not use for something fun.
 
#4
Saturnus said:
Yes. It's the volume of air in the port that defines it's resonance.
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... i strongly doubt that. Because a given port's enclosed volume can be brought into different shapes
resulting in a different resonance frequency when coupled to a cabinet.

Those "found" bronze tubes may be used, but do not have favorable - inner - shape to make a BR-port.

A simple cylinder would be better.

And far more better would be an optimized profile like those tested here:

http://www.aes.org/tmpFiles/elib/20150106/11094.pdf


Kind Regards
 
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#10
Having a narrower section of port drops tuning, while the wider exit ought to reduce turbulence. I haven't seen much data on this, though, but DSL does it with their 12" ported cab.

A 4" long 3-4" diameter port might end up tuning quite high, depending on cabinet size. Worth playing with Hornresp, though!
Make sure you support the free end inside the cabinet - a jolt could knock it out of place.

Chris
 
#11
lutkeveld said:
I've read something about a horn-reflex, using a tapered port reduces standing waves and noise?
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The paper LineArray linked to above actually explains and demonstrates how tapered ports works. You just have to read it carefully and not be confused that much of it discusses port flares and flanges, and not tapering.

Most up market ("hi-end") ports are both flared and tapered.
 
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#13
SemperFi said:
I found two nice looking pieces of machined bronze tubes 4" long. They have openings on one side that is 3" diameter and end up with 4" diameter at the other end. The tube wall is about 1" thick so they are pretty heavy.
My question is if they can be used as ports on a small two-way or someting like that?
Kind of crazy designing a speaker with the ports as starting point, but they are too nice to not use for something fun.
Click to expand...

It's not immediately obvious, but Hornresp can simulate this.
It's pretty neat, you can do all kinds of strange port shapes.
Kidney shaped ports are arguably the best, but the shape that you're using will definitely work also, and it CAN be simmed.

To do this in Hornresp, just do the following:
1) put a coupling chamber in front of the woofer.
2) and then the "horn" part of the enclosure isn't a horn, it's actually your port. IE, model the "horn" using the length, width, and depth of your port.
 
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