#239

sure - might be a few days until i can get back to my studio for pictures though.

basically these two long bars mount to the vibraphone frame, and each bar has connections to contact mics for each key - one bar for the naturals one for the accidentals

the mics are connected to the bottom of each key, doesn’t seem to affect resonance at all. the two long bars connect to each other via 1/8”, and the bar closest to the player has a volume knob and a 1/4” out.

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#240

A friend & recordist Michał Fojcik did a comparison test/shootout of different attachment methods:

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#241

i’m a little confused… silicone adhesive for use on the ears?

i’m able to find silicone for pool usage - but it appears to be for caulking around vents and tiles. still, it says it’s non corrosive and all sorts of things that sound good for my purposes… is this what you meant?

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#242

I use these small glue clamps very often together with piezo mics to attach them temporarily. Isn’t applicable in every situation of course

#243

Not adhesive, ear plugs. Apparently it’s common for sports stores to sell soft, malleable gobs of silicone that swimmers ball up and put in their ears to keep water out. I guess the thought was that you could take one of these gobs and flatten it out so it’s thin and wide enough to cover the surface of the element. Definitely meant as a non-permanent solution that’s gentle enough for surfaces like violin tops.

Maybe these are them?

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71HvhUoVeKL.AC_SL15001052×1434 137 KB

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#244

Just to add, I’ve been using a B&K Accelerometer (Type 4519) with their preamp (and then BNC out to XLR too). Still finding uses but every once in a while something wonderful. The wind moving some fairly hollow trees in my yard last week went nicely. Probably way too niche for it’s own thread but would be curious about some ways people are using them. I’ve primarily used accelerometers in collaboration with a biologist, listening to insects through plant stems and branches

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#245

Interesting I’ve been using contact mics on trees to pick up the sounds going on in trees. There are some amazing sounds there. Problem I encounter is that I have to gain the signal so much that recordings get very noisy. How is that Wii the accelerometer?

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#246

it’s so sharp and clear. Almost too bright, but I mixed it with an air mic for an upcoming web/radio show by Luke Fowler. I have the B&K going into a Sonosax preamp and no problems with gain. I’ve used contact mics with preamps or at least active DI boxes for years and often very nice results. This is a whole different kind of sensitivity (doesn’t mean better for all things, just ultra sensitive)

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#247

I’ve definitely started emailing college science departments and watching eBay for the requisite battery preamp and the accelerometers are all over eBay. I’m very interested in joining this club.

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#248

Anyone have experience with the barcus berry “insider” and “outsider” contact mics? Listening to the comparison that timp posted 9 days ago, the bb planar system sounded worlds better than the JRF to my ears (although this may be due to the buffer situation). I’m looking for something approaching that level of transparency but dont want to shell out 300 for a planar system. I was wondering if I may be able to get anywhere close with an “insider” and the diy barcus berry 3000A layout. This is for daxophone style use btw

#249

If its of any consequence, I have tried using other contact mic elements with the BB preamp, and same with the Trance Audio preamp (eg trying TA mic element with BB preamp and vice versa, as well as other third party mic elements) and the results were not great, and nowhere near that of using the matched mic with the preamp.

I am no electronics expert, but the only theory I have is that when designing a preamp for a contact mic, each company has done a lot of testing as to impedance and frequency response of the mic element and have then designed the preamp to match and compensate for specific mic element response (since if it was purely down to impedance, then swapping mic elements of the same impedance should generate similar results)

Also having broken a few of the BB mic elements, their design is quite different to other contact mics I have seen in that the piezo element seems to be wrapped in foil and is fixed, solidly bridging a brass U shape about 2cm across (which has a plastic cover over it) Brass is a good neutral conductor of vibrations so maybe this is a way of preserving vibrations via a brass conduit between the object and the actual mic element? Most other contact mics I’ve seen appear to be cast in plastic or resin - materials which would have a different frequency response than brass…

FWWIW I first got interested in contact mics from reading an article about Alan Splet and Anne Krober who used a FRAP contact mic when making sounds for DUNE. They mention using plexiglass as a conduit: “Anne went out with a FRAP and bonded it with a piece of plexiglass in the sand in a playground and did all sorts of things to it, rubbing sand over the top of it, scraping it, dragging it…”
I did similar at a beach with a length of plexiglass, and it was like the contact mic element was extended by the plexiglass… and retained low frequencies (lines tells me I posted link to Dune article before)

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#250

finally got a picture. here the G bar has a mic, the A’s has fallen off.

i saw a different vibe pickup company uses essentially gorilla glue… thoughts? really concerned with damaging the metal.

IMG_2953.HEIC
IMG_2953.HEIC4032×3024 1.77 MB

#251

how do these sound? I would have assumed that you’d get such a huge spike with each mallet strike that it wouldn’t be useful. maybe they’ve figured that out?

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#252

Which preamps do you both use (cc @solaris)? I’m in the process of adapting a B+K 2634 charge amp to take phantom power and condition the output further for my mixpre as I’m searching for a small portable solution. Also does any of you have experience with the CCLD accelerometers?

#253

I’m using the B&K -1704-A-002- 2-channel CCLD Conditioning Amplifier with Acoustic Filters, Battery and Mains powered
I haven’t used anything from CCLD. My collaborator has ones from http://www.mistrasgroup.com/ for her biology lab and it worked wonderfully, though I get the sense that the B&K has higher output

#254

I like the idea of using phantom power to power the amplifier, but doesn’t that one have batteries already? I’m also wondering what you’re doing to condition the output, does it need compression or limiting to calm transient spikes or something?

#255

they sound awesome - i have some control of the output, they definitely like a light touch and soft mallets.

maybe a little too “honest” of a signal - the bars sound great in a room and around other sounds, but the pure sound of them isn’t so great. i’d never use it dry.

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#256

I never used CCLD accelerometers, only charge accelerometers.
and the preamp (2635) I use with them goes directly to a MixPre via line input, no need for phantom power.
I don’t understand why you want to have phantom power on the accelerometer preamp, what would you want to do? curious to know.

#257

Sorry for the misunderstanding, CCLD is a type of accelerometer from B&K. The advantage of them in comparison to charge accelerometers is that the cable is not so prone to handling noise (and thus better suited for the field?).

The 2635 has batteries, but the smaller 2634 doesn’t, although it (mistakenly?) says so on the B+K website. Have no way to confirm as I’ve failed many times to open the preamp, its really solid. I plan to buck power from phantom could make the whole thing into an elegant package. Although I’m considering a CCLD acc+preamp on the long run.

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#258

thanks for the explanation. Sorry for my misunderstanding.