Contact Mics

Any more info on this build? I’ve been intrigued by it for a while, but would love some tips on where to start.

Quick question for the people using Plasti Dip to protect their piezos, do you cover both sides or leave the one side bare? Does it matter?

I’m less inclined toward DIY, so I picked up a Korg CM-200 contact mic meant for tuners. I was curious to see how well it would record a mandolin (answer: poorly, but mount it in an f-hole and it has a nice “wax cylinder” quality to it that could be useful). Not bad for more percussive uses, picking up movement noise and humming fans and triggering Rings, etc.

I was instantly seduced by a barcus berry, when i was told that the piano i was listeng to was recorded with it. The low end on that recording was out of this world, really clear and precise.
Haven‘t bought one yet as i‘m fiddling with the fieldkits piezos-this is fun but not hifi. The barcus berry seemed the perfect tool to record a piano and i’m sure lots of other broadband sounds too. On another note, nice thread!

Plastidip both sides, just dunk it! No problems in my experience.

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One of my classmates in grad school had a Barcus Berry and everything she made with it sounded incredible, from soundboards to flagpoles to marina docks. Highly recommended.

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Which Barcus Berry are y’all referring to? The Piezo Contact Pickup or something different?

Since nobody seemed to be against it, I went ahead and split this topic.
While transdcers/exciter speakers are somewhat related to contact mics, they are different enough to warrant separate discussions.
You can find the new topic here: Transducers / Exciter Speaker

Let me know if there’s anything that ended up there, which wasn’t supposed to

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http://barcusberry.com/product.cfm?ProductID=9

I’m referring to the Planar Wave system, in this case the 4000. It’s also important to have the associated preamp for impedance-matching reasons.

The pre amp is really the most important part of a contact microphone. Second most important in my experience is how and where the contact microphone is attached. Moving it around will give you very different results. if the mic and vibrating surface isn’t coupled very well it will also result in a more lofi sound.

I just bought a little pack of different piezo mics and speakers for practically nothing.

Some of these are really a mystery to me. Can I make something useful out of the smaller stuff? What are they?

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They look like the piezos (piezi?) that come with the Arduino starter packs. They’re used as touch sensors in some of the projects in the book that comes with the kit, and sometimes very simple (and tinny) speakers. If using them as outputs/speakers be careful as I blew a couple just by dropping them or sending a signal out that was too hot… they’re pretty fragile!

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The 2 small ‘metal cans’ are electret microphones. (middle under and one below top left)

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Thank you for taking time to answer this

Has anyone played with contact mics in series or mixed somehow? I’m interested in picking up one of those toy glockenspiels.

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there’s this sound artist called Lee Patterson who seems to connect a number of pickups to one single output at times (i know that’s definitely the case on the container he immerses the chalk pieces in - it sits on the table in the video but is not mentioned any further there)

i’m no expert on this but i also connected 3 piezos in an self built electroaccoustic sound machine to one single output jack and it worked without issues. no resistors or anything involved. quite crude, really. but the sounds were of the subtle kind in general…….

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Yeah, this usually works well, in fact there are commercially available guitar pickup systems that do this. If DIYing, just make sure you have all the polarities the same (all the ground wires are connected to the outer part of the disc). Depending on what you’re mic’ing, there might be phasing issues, so I still like to run them individually into a mixer so I can mix to taste.

Are you wanting to put a contact mic on each bar? If so, it might dampen the sound, depending on how you attach it. If that matters for your purposes.

I tried this years ago; just a heads up that you’ll get a significant “thunk” with each strike of the keys so consider running it through a filter. Besides that, it worked fine even with just one homemade one.

Has anyone tried this approach for making a DIY balanced piezo contact mic?

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While I’m on the topic of contact mics and preamps… if you’re having 50/60Hz interference problems, try completely shielding the entire circuit and all external cables before trying to come up with clever solutions. I spent this evening trying to tweak the interference out of my piezo preamp circuit, before finally discovering that the solution was just to cram it in a grounded cake form with a lid on…

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