I don't know if it's crazy but I notice at the back of Boeing 787 engine, there are a series of half-moon cut out. My guess is it reduces air turbulence when air exists the nozzle. The same technique is being used in the new 737 MAX engines and the new 747 as well.
So I was wondering if you can do the same for your woofer hole cut out? Most people probably already chamfer the back side of the cut out. Maybe this will help as well.
So I was wondering if you can do the same for your woofer hole cut out? Most people probably already chamfer the back side of the cut out. Maybe this will help as well.
An externally hosted image should be here but it was not working when we last tested it.
I think the problem behind the woofer is not turbulence but the fact that the ring of wood makes a little resonant chamber, reflects some sound energy directly back to the cone, or partially blocks the air from passing from the rear of the diaphragm into the enclosure. So people chamfer it to open up the space a bit.
https://aviation.stackexchange.com/...ne-nacelle-exhaust-have-such-an-unusual-shape
I have a feeling this sort of thing isn't quite applicable to speakers.
I have a feeling this sort of thing isn't quite applicable to speakers.
I'd imagine that any such resonant chamber created in the baffle would be far less of an issue in the frequency range at which a woofer / sub would be operating than say for a 3" light weight cone full range driver, which generally have very shallow baskets and tight clearances to mounting hole. Designing the side and back walls to "deal with" / scatter reflected waves would likely yield more measurable and audible improvements.
An externally hosted image should be here but it was not working when we last tested it.
Check out my post history, I've build something like you describe. Works very well.
The idea behind those chevrons on the Boeing is to break the coherence of vortex shedding, which is a powerful mechanism to generate (unwanted) sound. Less coherence means less noise. The same happens at car antennas, which use a helix wound around them to break up the coherence.
Air velocities in loudspeaker applications are too low for vortex shedding to happen.
Air velocities in loudspeaker applications are too low for vortex shedding to happen.
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.