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In the Forum: Horn-Loaded Speakers
In the Thread: German Odeon horns.
Post Subject: horn surfacingPosted by Markus on: 4/3/2007
Sorry if this is OT - I could start a new thread but my post is inspired by the quote below -
 drdna wrote: |
| the lathe-work is rough on some of the horns. |
|
I can't decide whether that's good or bad. I'm slowly working up to getting some midrange horns. The inside finish is something I have been mulling about. Should the surface be shiny or is some roughness possibly beneficial?
B&W make use of golfball-alike dimples in their BR ports. They take advantage of little air vortices which mean that the air that is moving in and out of the port is cushioned on air and meets less resistance than in a smooth port (reducing chuffing noise) at least that's B&W's explanation, and it tallies well with what I have read about golf balls. I also remember some experiments done on aircraft hulls with a paint that gave a slight roughness (modelled on shark skin IIRC); again, a reduction in resistance was observed.
What I can't fathom yet - the sound waves in a horn have more to do with pressure variation than with air actually moving. Do the same principles apply?
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