What is the Difference between a Waveguide and a Horn?

poynton · 21st March 2010, 11:39 AM

Hi.

Can someone explain in simple terms and, with a diagram or two?

Thanks and apologies if it has been covered before.

Andy

.

FrankWW · 21st March 2010, 01:19 PM

this is helpful, i think:

http://www.gedlee.com/downloads/Horn...ry%20reply.pdf

winslow · 22nd March 2010, 04:44 AM

Horns provide gain and pattern control.

Waveguides provide pattern control.

That might be too simplified for some though.

David_Web · 22nd March 2010, 08:57 AM

A horn is an impedance converter. Basically converting pressure at the throat to velocity at the mouth. (velocity at the mouth due to the apparent low impedance of air, but is really pressure as well.)
Just lite a transformer.

A waveguide does the same but also takes into account the propagation if the pressure wave throughout the guide/horn and the desired shape of it when it leaves at the mouth.
One can balance the propagation properties vs efficiency and impedance matching.

That is at least how I see it. A horn is a waveguide if you start looking at propagation and care about shaping it.

doug20 · 22nd March 2010, 12:36 PM

Quote:

Originally Posted by winslow

Horns provide gain and pattern control.

Waveguides provide pattern control.

That might be too simplified for some though.

Waveguides provide gain too.

badman · 22nd March 2010, 03:16 PM

I view the whole "Horn vs. Waveguide" thing as a continuum. It's a 3 dimensional problem with diffraction, size, and constant directivity. Geddes and most other "waveguides" are on the extreme side of low diffraction and controlled directivity. LeCleach, Tractrix, and some other variants are low diffraction but more optimized towards size (for a given bandwidth) at the cost of constant directivity. There are Size/Directivity optimized horns like we often see in P.A. apps- diffraction throats on biradial horns or the like.

Sonically, in my experience, diffraction is pure bad, and so I would optimize on a 2 dimensional line. I also like the idea of maintaining CD, so my opinion is heavily towards the geddes solution, but I'd consider the LeCleach---Geddes "line" all "good" horns if executed well.

This is all prefaced with the fact that I'm fairly raw so far as horns are concerned. I've read a lot of theory but have thus far only built 1 system with a horn anywhere but as a supertweeter.

ThorstenL · 22nd March 2010, 04:40 PM

hI,

Quote:

Originally Posted by poynton

Can someone explain in simple terms and, with a diagram or two?

The difference is pure semantics.

In oldspeak they are both FNORD "Horns".

The newspeak term "waveguide" is used for marketing to distinguish a Horn aimed at pattern control first from a FNORD horn aimed at gain first.

As I am FNORD oldworld and speak FNORD oldspeak I normally prefer to call a spade a spade and a FNORD horn a horn...

Ciao T

badman · 22nd March 2010, 05:35 PM

Fnord?

ThorstenL · 22nd March 2010, 07:26 PM

Hi,

Quote:

Originally Posted by badman

Fnord?

An oblique reference to the late Robert Anthony Wilson - Illuminati Trilogy especially...

More at the home of all Fnord's, wikipedia:

Fnord is the typographic representation of disinformation or irrelevant information intending to misdirect, with the implication of a worldwide conspiracy.

Ciao T

badman · 22nd March 2010, 10:37 PM

Quote:

Originally Posted by ThorstenL

Hi,

An oblique reference to the late Robert Anthony Wilson - Illuminati Trilogy especially...

More at the home of all Fnord's, wikipedia:

Fnord is the typographic representation of disinformation or irrelevant information intending to misdirect, with the implication of a worldwide conspiracy.

Ciao T

That was the first hit on google and made some sense... but I thought it a little lightweight for you, fella!

BTW: welcome back. Have you exited the industry? Care to point me towards your work?

21st March 2010, 11:39 AM	#1
poynton Magneto the Gravity Man diyAudio Member Join Date: Mar 2005 Location: A life on the ocean waves when I'm not at home in N. Wales (but I'm not Welsh so no sheep jokes!)	What is the Difference between a Waveguide and a Horn? Hi. Can someone explain in simple terms and, with a diagram or two? Thanks and apologies if it has been covered before. Andy . __________________ If it ain't broke, break it !! Then fix it again. It's called DIY !

22nd March 2010, 03:16 PM	#6
badman Custom Title diyAudio Member Join Date: Sep 2003 Location: Sunny Tustin, SoCal	I view the whole "Horn vs. Waveguide" thing as a continuum. It's a 3 dimensional problem with diffraction, size, and constant directivity. Geddes and most other "waveguides" are on the extreme side of low diffraction and controlled directivity. LeCleach, Tractrix, and some other variants are low diffraction but more optimized towards size (for a given bandwidth) at the cost of constant directivity. There are Size/Directivity optimized horns like we often see in P.A. apps- diffraction throats on biradial horns or the like. Sonically, in my experience, diffraction is pure bad, and so I would optimize on a 2 dimensional line. I also like the idea of maintaining CD, so my opinion is heavily towards the geddes solution, but I'd consider the LeCleach---Geddes "line" all "good" horns if executed well. This is all prefaced with the fact that I'm fairly raw so far as horns are concerned. I've read a lot of theory but have thus far only built 1 system with a horn anywhere but as a supertweeter. __________________ I write for www.enjoythemusic.com in the DIY section. You may find yourself getting a preview of a project in-progress. Be warned!

22nd March 2010, 05:35 PM	#8
badman Custom Title diyAudio Member Join Date: Sep 2003 Location: Sunny Tustin, SoCal	Fnord? __________________ I write for www.enjoythemusic.com in the DIY section. You may find yourself getting a preview of a project in-progress. Be warned!

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21st March 2010, 01:19 PM	#2
FrankWW diyAudio Member Join Date: Jul 2004 Location: n/a	this is helpful, i think: http://www.gedlee.com/downloads/Horn...ry%20reply.pdf

22nd March 2010, 04:44 AM	#3
winslow diyAudio Member Join Date: Aug 2005	Horns provide gain and pattern control. Waveguides provide pattern control. That might be too simplified for some though.

22nd March 2010, 08:57 AM	#4
David_Web diyAudio Member Join Date: Sep 2008	A horn is an impedance converter. Basically converting pressure at the throat to velocity at the mouth. (velocity at the mouth due to the apparent low impedance of air, but is really pressure as well.) Just lite a transformer. A waveguide does the same but also takes into account the propagation if the pressure wave throughout the guide/horn and the desired shape of it when it leaves at the mouth. One can balance the propagation properties vs efficiency and impedance matching. That is at least how I see it. A horn is a waveguide if you start looking at propagation and care about shaping it.

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