Hand-Held Megaphones: Rubber ring around edge of Horn

[thekma...@gmail.com]

Hand-Held Megaphones: Rubber ring around edge of Horn


Besides performing the obvious functions - protecting
the horn from damage, and preventing the appliance
from sliding around(on hoods of cars, on rocking boats) -
does this ring augment the sound coming from the
megaphone, in any way?


I read somewhere, pre-internet, that it DID, and a diagram
was provided showing the propagation of sound from
megaphones both with and without this rubber ring on the
edge of the flared horn. Cannot seem to find it nowadays.


Anyone?

[N_Cook]

Or do you mean a rubber acoustic barrier between the speaker part and
the microphone part, to avoid microphony?

[thekma...@gmail.com]

N_Cook:

See that black thing on the edge of the widest part of
the megaphone?

https://jet.com/product/pdp/bfec71f641d1435e9a4ef536ff6a90b7?jcmp=pla:ggl:cwin_electronics_a3:audio_bullhorns_a3_other:na:na:na:na:na:2&code=PLA15&k_clickid=67872188-ced8-47d1-9bdb-963ffdb2cc68&gclid=CjwKEAiAstCyBRDiqu75hvnX82kSJACgYI_QrQ4JhTcp5WnemAgaDGlXq_ifOupNfSHoNJUHvVj3aRoCXifw_wcB


That is what I'm referring to.

[Clifford Heath]

I suspect it has a major effect in damping the high-Q mechanical
resonances of the cone, and so improving the sound quality.

[jurb...@gmail.com]

I am sure it does affect the sound, but in a very small way. If you did it with alot large horn and an audiophile driver in it, I am sure the "golden ear" crowd could tell the difference.

The way to test it would be a short burst tone and a scope to read the ringing. Or perhaps a square wave and you watch the leading edges. Or course it might only be difference of 8 cycles versus ten cycles.

[Adrian Tuddenham]

It would reduce ringing in the metal or fibreglass 'bell' of the horn.
Just tap the horn and listen to the 'clang' sound with and without the
ring.


-- ~ Adrian Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to
reply) www.poppyrecords.co.uk

[gregz]

It would only affect top frequency by diffraction. With a good flaring of
the mouth, might not do anything with the sharp edge. These things don't
have very good highs to begin with.

Greg

[thekma...@gmail.com]

GS wrote: "- show quoted text -

It would only affect top frequency by diffraction. With a good flaring of
the mouth, might not do anything with the sharp edge. These things don't
have very good highs to begin with.

Greg "

^^ The BEST explanation by far!!
And that diagram I glimpsed a long
time ago alluded to this. Thanks.