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View Full Version : A somewhat off topic question...

danieldroukas
10-08-2006, 04:09 PM
For halloween we were thinking we would make an apparatus like the one in the link below:
http://www.youtube.com/watch?v=8etoZveTix4

Our idea was to just hook up my signal generator to a an amp and subsequent speaker. The speaker would be mounted to a metal bowl to produce the effect seen in the video.

However, we listened to what 80 and 120Hz sound like and it would prove quite annoying for a party environment. So here's my question: Is there anyway to produce a mechanical vibration using my signal generator that would not produce much if any sound? Could I still use a speaker somehow?
vibroverbus
10-08-2006, 04:40 PM
would not produce much if any sound? Could I still use a speaker somehow?
cool. looks like it would work fine from this video where they use an actual speaker to replicate the effect. and where it is also annoying loud per your point.

http://www.youtube.com/watch?v=NKxKVpHZe5Q

how about a heavily insulated box with the driver at the bottom, and a hole in the top that the bowl / container rests in. keep most of the sound in the box. might even be able to use some old speaker box but use the hole for the bowl/container, and leave the speaker down inside. also i'm wondering if a bowl is the best or if a flat bottom container might propagate the waves better...? the lowest freq that works will be less annoying - a low hum is more spooky/weird instead of a whining buzz. and what if the container is glass or plastic and you have a colored lightbulb down in the box as well? OK I'm getting carried away...
teleamp
10-08-2006, 05:30 PM
Might try to see how recorded music would work, have an ext speaker set-up with the metal plate. If it works, cool, also, not annoying for the party.
Old Tele man
10-08-2006, 05:59 PM
...uh, what "key" is Holloween BOO in? (wink,wink)
teleamp
10-08-2006, 09:12 PM
...uh, what "key" is Holloween BOO in? (wink,wink)

Dropped D, my guess.
Old Tele man
11-01-2006, 07:25 PM
...the frequency would have to be either: (a) sub-sonic, ie: below about 20Hz or (b) super-sonic, ie: above about 20KHz...to be beyond audible range.
slhguitar
11-01-2006, 08:55 PM
Would the frequency not have an effect on how it would work? I really want to try this, does anybody have any suggestions on how it could be done practically?