 
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
|
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
124.189.3.118
In Reply to: RE: How to lower the resonant frequency of a structure? posted by andyr on May 12, 2022 at 21:39:29
After the above post, I tried 2 different scenarios, to reduce audible 'buzzing':
1. glueing additional pieces of steel to the U-frame structure, to a. increase mass and b. provide damping.
2. making a 2nd set of U-frames out of aluminium. Obviously, these were lighter ... but aluminium is less stiff than steel (so has a lower 'Q').
Unfortunately, neither of these efforts was successful - I could still hear buzzing from the metal frames at certain frequencies ... even though I had to turn up the volume from my sig-gen, to achieve this.
So then I decided to try solid frames - same dimensions as the metal U-frames but made from birch ply. See here:
Success at last! :-)) I can still feel the wood supports vibrating - but this does not produce any audible buzzing.
The only problem is ... wifey doesn't like the wood colour - so I have to get the wood supports sprayed red, to match the bases. :-((
Andy
Follow Ups:
Gee......I suggested wood in my original post...WAY above, before Geoffkait derailed.....
Glad you have discovered the benefits of wood.
You would have Hated my other suggestion if I had actually made it!
Too much is never enough
Add mass.
Isolation is the new dampening or mass loading. Didn't anyone get the memo?
Edits: 07/27/23
Late to the discussion as I don't frequent this forum. In any case, your solution reminds me of discussions that occurred on the Planar Forum upteen years ago with Peter Gunn and wood frames for Maggies.
"Our head is round in order to allow our thoughts to change direction." Francis Picabia
In this latest case, I guess it simply boils down to the fact that the birch-ply structure (with its wood/glue interfaces) simply flexes in response to the vibrations created by the mid/bass driver frames and attenuates these vibrations by converting them to heat - whereas all the metal frames can do ... is continue vibrating!
Andy
Wood can be considered a 'natural composit' and as such has multiple resonant frequencies, many of which self-cancel.
As an experiment? Send off for some samples of PLYBOO. this is a manufactured product which is made of various orientations of Bamboo in strand or cross 'grain' configurations.Link is to STRAND while you can get EDGE or FLAT......each of which has a different presentation.
I like the Neopolititan which also happens to be the heaviest.
I'm including an idea I worked on. Rear triangulation of panel.....very rigid without being heavy or resonant. Single link to base, which if you do it right can provide variable tilt....
Other features posssible......
Too much is never enough
Edits: 07/26/23
Of course any vibration of the structure is bad for the sound, right? That's why they are isolating speakers these days, or using cabinet dampeners, the cabinet vibration modulates the acoustic signal, no?
wood has excellent self damping porperties. You never hear anyone say "it rings like wood." And before anyone starts pointing out that very hard dense woods ring, yes I know that. Talking about more common woods softer medium desnity woods.
| FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
||||||||||||||
This post is made possible by the generous support of people like you and our sponsors:
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2024, Audio Asylum, all rights reserved ]
