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Tapped Horn or Transmission Line
Tapped Horn or Transmission Line
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Old 10th May 2009, 03:26 AM   #1
mrevie is offline mrevie  Australia
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Default Tapped Horn or Transmission Line

Performance wise - is there much difference between a folded transmission line and a folded tapped horn?

Designing and building a folded TL is much easier than a folded tapped horn. I'm having real difficulty calculating accurately the length and flare of each folded section with a tapped horn.

Any suggestions
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Old 10th May 2009, 05:38 AM   #2
GM is offline GM  United States
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Yes there's a considerable difference between a TH and tapped pipe (TL) since the TH is tuned somewhat below the driver's Fs to load it to Fs while the TP is normally tuned to a 1/4 WL of Fs. The upside is it's a lot smaller and easier to build for a given driver with the downside being that in theory it will take two TPs or at least two drivers in one big pipe plus 2x the amp power to match the TH.

Another downside if you want a wide BW 'sub' is that the TP will have a deep notch at the pipe's 3rd harmonic (its effective 1 WL length), so while a great place to put an XO, it defines the TP's lower cut-off too, i.e. for an 80 Hz XO, its lower cut-off is only ~20 Hz, etc..

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Old 16th May 2009, 11:38 PM   #3
Patrick Bateman is offline Patrick Bateman  United States
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Because a transmission line is generally tapered, the rear wave of the woofer doesn't contribute more than a decibel or two to the overall output. I've found that most good transmission lines sound a lot like a sealed box.

OTOH, in a tapped horn you can see gain on the order of 3-6db over the same woofer in a sealed box.

One thing I might recommend is taking an existing and proven tapped horn design, then putting YOUR driver in it. That can be a lot quicker than figuring out a good folding scheme.

I understand how time consuming it is to fold the line; in the last design I published it took almost eight hours to tweak the volume of the line until it fit in the box. I use a 2D program called Xara, as it allows me to adjust the volume at S2, S3, S4, etc... (Using horn response, of course.)
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Old 17th May 2009, 11:44 AM   #4
MaVo is offline MaVo  Germany
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Default Re: Tapped Horn or Transmission Line

Quote:
Originally posted by mrevie
I'm having real difficulty calculating accurately the length and flare of each folded section with a tapped horn.

Any suggestions
Designing a single fold TH is really easy. Just imagine the whole horn as a single trapezoid shape, cut it in half in the middle and put the two pieces next to each other, so that they form a rectangle. As for a double folded one, you can find a good explanation here: http://www.volvotreter.de/dl-section.htm I build my horn by this and it works just like it should.
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Old 17th May 2009, 07:38 PM   #5
Patrick Bateman is offline Patrick Bateman  United States
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Default Re: Re: Tapped Horn or Transmission Line

Quote:
Originally posted by MaVo


Designing a single fold TH is really easy. Just imagine the whole horn as a single trapezoid shape, cut it in half in the middle and put the two pieces next to each other, so that they form a rectangle. As for a double folded one, you can find a good explanation here: http://www.volvotreter.de/dl-section.htm I build my horn by this and it works just like it should.
If you have the space for a very large box, and a low F3 is important to you, a conical tapped horn is easy to fold. But if you want to keep the box size small and flatten the response, then it gets trickier. Here's some food for thought here.
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Old 21st July 2017, 10:55 PM   #6
darkmatter is offline darkmatter  United Kingdom
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I am contemplating the very same thing TL vs TH

I will be looking for 16Hz bass performance
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Old 24th July 2017, 01:06 AM   #7
phivates is offline phivates  United States
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Does size matter?
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Old 25th July 2017, 05:41 AM   #8
Crashpc is offline Crashpc  Czech Republic
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Very good question, indeed.
But the answer is not that easy.
I found that for restricted volumes and good low extension (both at once), TH is of no use :-(
It shines for driver utilization though, and in larger setups. I would not do TML if I specifically didnīt want it for some reason.
With hornresp, none of these is hard to simulate. One just moves the numbers under he understands what each number really does. Takes one evening and two beers :-D.
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