Synergy horn directivity
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URL: https://forum.speakerplans.com/forum_posts.asp?TID=101720
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Topic: Synergy horn directivity
Posted By: LeruSound
Subject: Synergy horn directivity
Date Posted: 22 April 2018 at 1:35am
Direct and simple, I'm thinking on it for a while: how can a conical horn like the synergy ones from danley guarantee a good dispersion at high frequency with that huge mouth? Is there a wavefront shaping with the mid-range emissions? But even so would be impossible to spread VHF wavefronts.. so? How can it be 60x40 with 1 inch throat to that huge mouth at HF?  
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Replies:
Posted By: fatfreddiescat
Date Posted: 22 April 2018 at 11:58am
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There's a good thread on DiyAudio about waveguides, well a few actually but one to search for is Geddes oblate sheroid waveguide, vhf dispersion being more a function of the throat diameter, initial profile and matching to the exit angle of the compression driver.
A good read on horn theory: https://www.grc.com/acoustics/an-introduction-to-horn-theory.pdf" rel="nofollow - https://www.grc.com/acoustics/an-introduction-to-horn-theory.pdf
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Posted By: LeruSound
Date Posted: 22 April 2018 at 6:34pm
| Yep, thats a document i already read, also the keele "Whats so sacred about exp. horn" but none of the mentioned horns seems to be near synergy's one. |
Posted By: toastyghost
Date Posted: 23 April 2018 at 4:12am
The synergy patent explicitly referenced this paper and conical horns with flat walls |
LeruSound wrote:Posted By: FrederikMA
Date Posted: 23 April 2018 at 6:13pm
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The mouth being several wavelengths in dimensions at high frequencies does not reduce hf response. The large mouth flare is actually a legacy from keele's CE horns, which serves to reduce midrange narrowing (improving directivity). Theoretically, conical horns provide optimum hf directivity, all other things being equal. The reason for the poor directivity of progressive horn flares does not lie n the mouth either - these hon just often comes with a long narrow bells which provide very narrow hf directivity. For conical horns in practice, however, the sudden change of flare rate between driver and horn creates diffraction and HOMs, which manifests in the directional response. Reducing this is the major benefit of the OS waveguide. Danley makes an effort in mating driver\horns though. And yes source and throat size affects any non-diffracion horns, including OS. Best regards Fred |
Posted By: LeruSound
Date Posted: 10 May 2018 at 7:23pm
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Thank you all, i recently had no much time to read and study further, but I'll go through the topic. i.e. I miss the meaning of HOMs, and also I would love to have a clear explaination of what differ from a diffraction horn to a non-diffraction horn. Is there any common definition or is it just about when diffraction acts the more in the expansion path of a horn? (Like the flare change near the throat) Thanks!
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Posted By: FrederikMA
Date Posted: 11 May 2018 at 7:20pm
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Higher Order Modes (HOMs) is closely related to reflection and diffraction but it is not the same. Diffraction is the change in radiation pattern of any freely radiating signal when it encounters an obstacle of similar size to the wavelength in question. While diffraction changes the radiation of the fundamental propagating wave, HOMs are new signals of higher order to the fundamental radiation and has origin and apparent source at that obstacle, which is why it manifests itself as image shift and degraded source localization. Generally, if you can tell that the horn has a negative flarerate after the throat, it is considered a diffraction horn. Also, a lot of horns use diffraction to manipulate directivity between the vertical and horizontal plane way down the hornpath. If the source driving a 1PI horn is small directivity is good all the way up to 20kHz. The problem is small sources are ineffecient across the wide band we require them to operate, which is why you often see these awful combinations of two-inch driver horns using hard diffraction to restore directivity up high. One reason we are moving away from these devices is that small compression drivers has become so very effecient across a wide band, that we can once again focus on directivity and distortion. Best regards Fred |
Posted By: tthorsten
Date Posted: 22 May 2018 at 1:59pm
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