I'd like to get a speaker and a microphone inside a cello. Part of the idea is to project sounds and tones into the cello to get it to resonate and act as a filter for the incoming audio. The mic would pick up the combined speaker audio and resonating instrument.

It might be better to do this all with an externally mounted speaker and mic on a boom stand but, thematically, it is important that the sounds are coming from inside the cello. I'm mostly struggling to find a powerful enough speaker that's thin enough to slip between the f-holes but I also am not sure that this is actually the best way to get the instrument and strings to resonate. I, unfortunately, spent all my physics classes playing Doom 2.

Neat idea.
Pretty sure Zappa used a closed grand piano as a sort of reverberation chamber.

uglysound wrote: Wed Jun 02, 2021 6:43 am Maybe consider using a surface transducer to make the cello itself the speaker?



They seem to project sound really well, so the filtering wouldn't be as severe but, between transducer and mic placement, there's probably a lot to explore there.

Great idea! Honestly, can't believe I didn't think of one of these. Thanks for the tip, I'll look into them.

Leeplusplus wrote: Thu Jun 03, 2021 6:02 pm

uglysound wrote: Wed Jun 02, 2021 6:43 am Maybe consider using a surface transducer to make the cello itself the speaker?



They seem to project sound really well, so the filtering wouldn't be as severe but, between transducer and mic placement, there's probably a lot to explore there.

Great idea! Honestly, can't believe I didn't think of one of these. Thanks for the tip, I'll look into them.

I used to have one of those and had a ton of fun with it. Styrofoam boxes, like the ones they transport organs in, offer some great sounds. Shipping tubes also.

The effect will be very different from a normal speaker, however. For a tiny speaker that might work, look for a busted portable radio or kid's music toy. The speakers in those are often quite small and thin. They might offer such speakers at some electronics supply stores. They will be lacking in the bass, though the transducer would do that job better.

If you want to go further with onboard mic/speaker noise, check out the Tornipulator circuit as seen in this jag.

A speaker in its most basic form IS a moving coil dynamic microphone (sub kick anyone?), impedance mismatches notwithstanding. So maybe try two SM 57 capsules? One feeds sound into yer box, one captures it. Yeah, band limited to hell, but maybe that's ok.

bishopdante wrote: Sun Aug 29, 2021 8:04 am If you want an audio exciter to vibrate your thing... these are what you want: https://www.tectonicaudiolabs.com/audio ... -exciters/ Comes with built-in double sided tape, you can just peel & stick. Best place to glue one of those in likely on the outside where the bridge would go. Possibly even stick a block of wood on top of the driver, apply some braided stainless steel cable instead of a string, and clamp it down with a string, tailpiece and machinehead. That'll put more tension onto the top, and move the resonant frequency / top end extension upwards by preloading and stiffening the top skin, much the same on on a drum.

The tectonic people bought all the NXT bending wave / distributed mode speaker technology. They're nice people, I like 'em loads.

B-Dog!! Hey, would you mind perusing what I am going on about in this thread (viewtopic.php?f=26&t=69575). I'd love to hear your ideas on this sort of madness.

Leeplusplus wrote: Thu Jun 03, 2021 6:02 pm

uglysound wrote: Wed Jun 02, 2021 6:43 am Maybe consider using a surface transducer to make the cello itself the speaker?



They seem to project sound really well, so the filtering wouldn't be as severe but, between transducer and mic placement, there's probably a lot to explore there.

Great idea! Honestly, can't believe I didn't think of one of these. Thanks for the tip, I'll look into them.

I ended up buying the exciter recommended in this video and got these results:


It's pretty cool! Since my main application is cello, I think I might buy one about twice as big. I want big, pure low notes and this thing distorts pretty early on.

Holy shit, I was trying to think the best way of doing feedback in home recording situation where I didn't have a speaker cabinet. Wasn't aware of surface transducers. This is really cool!

I've bought a wild assortment of Dayton Audio transducers (you can get them from parts express) for exactly this purpose. Good price, sounds good