Yes, of course! It’s just a DIY contact microphone made up of a piezoelectric recovered with liquid rubber. Here you can listen to my children’s toy piano (raw recording, no edit at all):
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timp
2296
Do you have a test with some low end? Thats where the impedance mismatch shows up ie “when wired to a normal 50 kilohm line input this forms a 200Hz high-pass filter…”
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I see… I’ll try. Any idea of what I can record at home? Maybe the dishwasher?
timp
2298
big deep resonant things - car bonnet? garage door? large cooking pot or wok?
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Since we’re on the subject of contact mics, preamps, and deep bass sounds, here is an example that includes audio from a Barcus Berry Planar Wave and 4000XL preamp. This contact mic and preamp are designed for harp or piano and has a pretty wide range.
The field recording elements of this are created using that pickup & preamp attached to a power pylon on the Wa‘ahila Ridge in Hawai‘i. The pylon is made of steel clatters a little bit as it changes temperature and as gear attached to it moves in the wind. The pylon also gathers ambient sound including that of the power cables vibrating in the wind at a very very low frequency.
As the recording progresses I add other things (including a DPA in the air outside the pylon which picks up some aeolian harp effects in the acoustic environment, double bass, modular synth resonators and feedback and so on). But in the first few minutes, you will hear an example of the kind of deep sounds available to a contact mic/preamp that is designed for full range sound.
Headphones or good speakers for bass reproduction required to hear it of course (laptop or phone speakers won’t do it): https://www.youtube.com/watch?v=g-L7P38lZwE
(give it a thumbs up if you can to help encourage the radio to support more experimental work)
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timp
2301
confirmed, they sound ‘thin’ - not much bottom end at all.
@Gahlord by comparison made my subwoofer move
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Something like BigAmp Piezo - TRITONAUDIO should help on the lower end of the spectrum.
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Thank you so much! I’ll keep it in mind.
@timp You’re right 
And what a difference, as you said!
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timp
2304
FWIW I wrote a blog post back in 2011 when I re(discovered) contact mics after reading an article in American Cinematographer Mag about Dune and Alan Splet & Anne Krobers work & use of them… So I always (wrongly) presume anyone interested in contact mics has found it via random google searches (or prev posted here Oct 27, 2023 apparently)
its worth a quick read, as is the Cine mag article - scan here
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The issue with using H1 is that it only provides PIP power, and most solutions for connecting contact mics to recorders require P48. The solutions I was able to find so far are Pulp Logic CTACT or Aquarian Audio PA1, but neither is available in EU 
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timp
2306
You can buy external battery powered 48V phantom boxes easily eg a quick search of Amazon, this is not expensive & is rechargeable (caveat I do not own it & have not tested it) - I appreciate it means carrying & managing another box, but it could be viable in short term.
Sorry, been away for a while: Size AE Rycote with a suspension lightly modified by Gotham Audio for standard low profile XLRs for either 8040 or MK4+CMC1U pairs
1 Like
Here you can listen to a quite quiet recording with my h1 essential and DIY external mics (with PRIMO EM172 capsules): radio aporee ::: maps - sounds of the world
As said before, self-noise is present. Not so bad, but quite obvious. What do you think?
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Another question for the mixpre users here - what are people using for power that are running larger set-ups? I had borrowed a mixpre 6 the other day while some of my other gear was on loan to try out the workflow. it seems pretty power hungry compared to my usual set-up and I ran in to some issues that it would only run in low-power mode, giving me only 2 channels of Phantom. Luckily my second pair of mics were ribbons so while it meant I couldn’t get the impedance I wanted I could just discard the boosters and be ok, but the way it gave me the notifications was a bit odd causing me some grief and time to figure things out since it isn’t my machine. My bank should actually have had sufficient power, and I had a sled full of NiMH AAs in as back-up. I am guessing the lower power mode maybe came rather from the max current out my power bank could deliver, so time for an upgrade. While it seems power banks are all fine and good for stereo set-ups if I want to be running 4 or even 6 channels phantom I am guessing maybe it is time to look in to NPF or V mount batteries? Or anyone have a power bank they have had decent running time with 4+ phantom channels?
bphenix
2310
Anker Powerbank. It just needs to be PD ready (supporting more than 8w of draw).
I have one that is overkill (the 737 model) but it is square and fits nicely under the MixPre in the Orca bag.
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I use a v-mount battery with a d-tap out to the mix pre, it also has usb-c so I can power a bunch of other stuff from it. Maybe overkill but I tend to work mostly from weird locations (in my car, in a wind battered tent on a mountain, etc) so it’s good having something robust.
A set-up I’ve been playing with recently is;
v-mount > powered iPad Air case via usb-c
mixpre > iPad Air usb-c port, providing power to the mixpre and using it as a mixer/ interface for AUM
Mics direct to mixpre, instruments through a little sub-mixer into the line in point, using the +2 plugin to make my 3 into a 5/7
With this setup I can power 2x phantom mics, my iPad, mixer and whatever I have plugged in all day.
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Does anyone here run a sound devices 7 series via usb powerbank?
dspk
2313
hi, wondered if you could expand on this a bit more… just had a bit of a search for the d-tap thing and not quite sure how that connects to the mix-pre? new area for me!
i’ve been using a powerbank with USB-c direct to the mixpre but always a bit worried about how sturdy that usb-c socket is!
yeah sure - it requires a replacement to the battery sled - something like this - SD-1 - Sound Devices - Hirose DC input sled - and a d-tap to hirose cable.
I prob wouldn’t recommend this as a solution unless you run other hirose devices (I have a BMPCC that I also power from it) - it’s not cheap but is a very secure solution…
A lot of v-mount batteries do have usb-c out, and tend to offer a much more stable and reliable power supply, which is a good solution
re: usb-c socket, I keep meaning to 3d print something for this, I did so for my BMPCC and it’s worked a treat…
