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I just read an article, that I wish that I bookmarked, but he was talking about doing contact mics on pipes and things like that. The shit sounded amazing. Completely otherworldly, and it was just water running through pipes!!

I think they're cheap from what I'm gathering, and I wanted to pick a couple up. I have no problem with soldering, are they just piezos and cables? I'll make them if necessary, but if there are decent brands, i'd sooner check that out.

Thanks for your help!

Dave
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7 Answers7

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I use Cold Gold, a few other hand-made ones, and the rubber contact-mic adapter for the Aquarian Audio H2a hydrophone. The C-Ducers sound pretty compelling - high noise floors are common with cheap piezos - but the H2a is a stellar contact mic...provided you can attach its heavy bulk to something effectively. Tim Prebble and others also like the Barcus Berry instrument contact mics, and the audible results are impressive, as one would expect from a higher-price mic.

NoiseJockey
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    @NoiseJockey +1 on the H1a with contact mic adapter. Awesome response! BTW, they recommend adding a bit of water in the rubber cap as it apparently enhances the contact mic capabilities. I've only ever tried it without water, as I've usually been recording vertical surfaces. Have you tried this out? – Colin Hunter Nov 28 '12 at 19:14
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    @Colin, adding a bit of water to the cup is a great suggestion - my experience using the H1a with the rubber adaptor has been mixed, and I usually ditch the cup altogether because it can be so finicky. I'm definitely going to give that a try. – Jay Jennings Nov 28 '12 at 19:47
  • @Jay That's what Robb at Aquarian recommends. As I said, the problem is that the rubber cap needs to be on a horizontal surface for that system to work. Bit tricky if your recording guy lines or vertical panels. I've also found that the weight of the capsule can be counter-productive on vertical surfaces. Dunno what your experiences have been like on that? – Colin Hunter Nov 28 '12 at 19:59
  • @Colin, no, those drawbacks that you describe are tough to work around. I've used a big "X" of gaffer tape to hold it tight, which works sometimes, but yeah, they're so heavy (owing to their intended use as hydrophones) that they do dampen oscillating objects. – NoiseJockey Nov 29 '12 at 22:56
  • Shameless self-promotion of other weird-ass s!#& you can do with that hydrophone as a contact mic: http://www.noisejockey.net/blog/2010/10/28/the-bear-locker/ and http://www.noisejockey.net/blog/2010/05/12/magnet-hydrophone/ – NoiseJockey Nov 30 '12 at 03:05
  • @NoiseJockey I love that magnet effect. Remember seeing that when you first posted it. Was that seriously two years ago...? Madness! – Colin Hunter Nov 30 '12 at 14:40
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    @Colin, FWIW I tried adding a bit of water to the rubber cup and I couldn't really discern any difference. Worth a try, though. And regarding how to mount the H2a to a non-horizontal surface, I've had decent luck with custom-made velcro straps that wrap around and hold the capsule tight and upright. Another plus is that it's clean, no sticky tape residue to clean up. – Jay Jennings Dec 02 '12 at 07:49
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contact mics are pretty cheap.

I own some cold gold ones as well, but I never use them anymore. Now I roll with my Jez Riley French C series ones.

here's some classic laser stuff I did with them:

[soundcloud]rcoronado/guy-wire-contact-mics-huge[/soundcloud]

I run them through (inexpensive) hosa MIT-129 impedance transformers to get them matched up to my preamp, and they sound kickass. This is a pretty crucial step BTW. Contact mics are similar in impedance to guitar pickups. You wouldn't plug your guitar into a preamp without an impedance xformer either - and for the same reasons.

Mismatching impedances ruins your low end.

Tim Prebble had a great post about this kind of stuff a while back - located here.

Rene
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  • @Rene Thanks for the heads up on the Jez Riley mics, I hadn't run across those before. – Seph Lawrence Nov 29 '12 at 17:25
  • Rene, thanks for this, I checked out your site and french's stuff. So I have a question that i'm almost embarrassed to ask, I'm plugging into my H4n, would i really need the impedance transformers since the h4n has a built in pre? – Dave Nov 29 '12 at 20:37
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    You wouldn't but not because the H4n has a built in pre. Instead its because the H4n is designed to act as an instrument input, and so would generally match impedances correctly in instrument level impedance loads. that said, they wouldn't hurt either. :) – Rene Nov 30 '12 at 14:42
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The key to a good contact mic lies more in the preamp than in the transducer itself. Contact mics will inherently pick up sound from a very unique perspective, but you need preamp circuitry that will not only keep noise low but will also provide the necessary impedance to match the high load of the mic itself. Because impedance is a frequency-dependent resistance, a poorly-matched preamp will skew the frequency response of the transducer. Tim Prebble gave a fantastic explanation of the effects of a mis-matched contact mic preamp on his blog when he released his contact mic library.

I personally use a pair of C-Ducers as my contact mics. They come in a neat and very light kit with 2 phantom-powered preamps. The large surface area makes for a fantastic signal-to-noise ratio, and they're also flat if you need something low-profile (e.g., micing an instrument live). Finding good double-sided tape can be tricky, but once you find a brand that works well you're golden.

Best,
~Matt

Matt Glenn
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  • @MattGlenn, what kind of tape do YOU use and have good results with? – NoiseJockey Nov 28 '12 at 17:49
  • I've used this stuff in the past:

    http://www.findtape.com/product398/3M-Scotch-928-ATG-Tape.aspx?cid=44&idx=18&tid=1&info=Removable%2b%2526%2bDifferential%2bAdhesion%2bTapes

    It's pretty sticky, even with slightly grainy or dirty surface. Not quite as solid as the tak-y stuff that came with the C-Ducer package (I can't think of what it's called off the top of my head) but certainly fine for anyone doesn't want the mic placement to be permanent.

     – Matt Glenn Nov 29 '12 at 00:55
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They can definitely be tricky to get usable material out of but with some experimentation can yield some amazing source.

I have a bunch of various contact mics from these guys:

Cold Gold http://contactmicrophones.com/

They make an interesting and affordable selection of various transducers. They also sell some of the bare parts for making your own projects.

Seph Lawrence
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Though I don't own any, Barcus Berry contact mics sound awesome. I use the Aquarian Audio H2a contact mic adapter. I also bought a contact mic a couple of years back from these guys. Don't think they sell their mics anymore, but there is a useful guide on how to build your own.

I'm also looking forward to hearing more about the new Trance Audio stereo set that Tim Prebble posted recordings of recently.

Also shouldn't forget Jez Riley French's Contact C Series which I've also heard very good things about.

Colin Hunter
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In response to Colin, I too am curious about the stereo Trance Audio rig, so I wrote them.

They responded with the following specs:

The stereo Inducer is a custom-built specially designed low-noise high-definition stereo system that's aimed towards sound designers. The Inducer runs 2 Acoustic Lens transducers, the heart of the system. The Lenses, which can have a cable length of up to 10 feet, employ multiple sensors to create a well defined sonic image of whatever its attached to.

Features of the Inducer stereo:

  • Runs on a single 9V battery for 100+ hours with an LED low battery warning indicator
  • Has a greater than -100dB idle noise floor, 115dB S/N ratio, better than .005% THD.
  • Has external gain contols for up to +55dB gain adjustment
  • Has XLR balanced outs for each channel, plus TRS 1/4" outs (balanced or unbalanced) -Has a phase switch for each channel out
  • Plugging a pickup into either input powers up the unit. The inputs are normally shorting, so no noise from an unused input should only 1 transducer be in use.

Stoked!

..jenn

jlew
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Found this

http://blog.makezine.com/2011/12/20/collins-lab-diy-contact-mic/

Dave
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