Stuffing a horn |
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tommysb
Registered User Joined: 24 April 2006 Location: Finland Status: Offline Points: 1036 |
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Posted: 27 September 2006 at 1:32pm |
Ok, so I've heard that stuffing a transmission line with wool
effectively 'reduces the speed of sound', thus making the t-line appear
longer, and reducing the cuttoff.
Can one do the same with a horn, effectively making the horn path longer? If yes/no, why? Cheers, |
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gingerbiscuit69
Registered User Joined: 23 September 2005 Location: United Kingdom Status: Offline Points: 2540 |
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no ...... thats just plain stupid! would just muffle it and loose DB!
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adambomb
Old Croc Joined: 10 April 2006 Location: United Kingdom Status: Offline Points: 3220 |
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You are correct about the wadding in a TL slowing down the speed of sound (and absorbing higher frequency sounds)... I have a 2 page paper on the subject if your interested...
Using this theory for horns.. dunno.. I would have thought it would defo work for Scoops (which are of course TLs)... but I have no idea about horns.. in theory it should lower the cutoff.. but I don't really have any experience with designing horns... Edited by adambomb - 29 September 2006 at 10:10am |
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godathunder
Old Croc Joined: 19 July 2004 Location: wicklow Status: Offline Points: 1833 |
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adambomb, Id be interested in a little looksie at that paper if you have it in electronic form
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LOUDER THAN LOUD
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kevinmcdonough
Old Croc Joined: 27 June 2005 Location: Glasgow Status: Offline Points: 3749 |
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In a reflex box, or in the rear chamber of a horn, then yes like you say the wadding will absorb the sound and slow it down. The sound effectivly thinks it takes longer to reach the sides, and therefore the box/chamber acts as if its bigger than it actually is.
However in the actual horn path of a horn/scoop/TL (or inside the actual path of the ports in a reflex), i would think that it would just block the flow of air and mess things up. kev |
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tommysb
Registered User Joined: 24 April 2006 Location: Finland Status: Offline Points: 1036 |
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Definately works in a T-line, i think sheeps wool at a density of
8kg/m3 is recommended, trying to think which book i read it in (an
oldie), but i also know someone who's put it into practise, i think his
t-line has an f3 of about 17Hz!
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adambomb
Old Croc Joined: 10 April 2006 Location: United Kingdom Status: Offline Points: 3220 |
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The Loudspeaker Design Cookbook has a few pages dedicated to this... The paper I have is about the above, but also avoiding standing waves with the enclosure (no panels square to each other, very interesting read)... its just a photocopied article.. so I will have to scan it and post it here for you... might have to wait a bit as my scanner is burried somewhere..
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djtosco
Registered User Joined: 26 September 2004 Status: Offline Points: 58 |
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The problem is that the stuffing material increases dramatically the losses... thus reducing the efficiency of the horn!!
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