DIY Stethoscope Mic

It’s been a while since i’ve written anything here as I’ve been wrapped up in studying for my MA and working at my new job at Doghouse Post but this week I decided I should get back on writing this blog and making some recordings.

With that in mind, and inspired by Akash Thakkar and Rene Coronado, I decided to make a stethoscope mic. I’ve only recently come across these as a concept, and Akash’s GDC talk about the sound of Hyper Light Drifter (which you can find here) made me decide to give it a go myself!

The build was based off of Akash’s design and both he and Rene were (as far as I know) inspired by Diego Stocco so thanks Diego for inspiring me by proxy! My version is substantially lower budget than all of these guys, but I was able to make it in under an hour, for under a tenner and mostly out of stuff I already had lying around.

The ingredients were as follows:

1 x Stethoscope – From Ebay – £3.99 inc. postage.

1 x Lav Mic – I already had this from my previous DIY parabolic mic build, I decided to reuse it for this as the parabolic mic was a bit fragile and just all round not that good.

1 x 3cm section of garden hose – From my garden hose! Thankfully my housemates didn’t seem to mind me cutting up the hose.

1 x Shitloads of gaffer tape

That’s it. The build was super easy and the end result looks a bit like this (I’ve since added more gaffer around the hosepipe section, please excuse the state of my sofa!)

I haven’t had much chance to make recordings yet this week as I’ve been pretty busy with work, but hopefully I’ll get the chance to make some and share them here in the next few weeks. I did, however, take a quick test recording of my own heartbeat.

As you can hear, the noise floor is pretty high, but I expected this from a mic that cost less than £10 to build. It’s running through my Zoom H1 which has quite a high noise floor anyway, but i’m still pretty happy with the result and will be running around like some kind of weird sound doctor for the next few weeks, i’ll share the results here when I make some more recordings.

Learning Granular Synthesis Pt 1

In the last couple of weeks on my MA course, we’ve been learning about editing audio using phase vocoder based technologies, and granular synthesis. This is frankly, all a bit technical and mind bending for me, but I think i’m starting to get my head around it and I’ve been playing around with editing some of my field recordings to create ambient/drone pieces.

On the 2nd of November I was out and about around the Harbourside in Bristol making some field recordings.


Field Recording on the pontoon beneath Prince’s Street Bridge

I borrowed some kit from the universities asset store (Sound Devices 552, Rode NT4) and made some basic stereo recordings from various points around the Harbourside.

Here’s one of those recordings, after normalisation and trimming in Audacity.

As you can hear in the above clip, theres some pretty prominent violin playing from a guy to my right at the start (he was pretty good!)

I decided that it might be fun to try and use some spectral editing to remove some of the partials that were not his violin, with the aim of making his playing more prominent and hopefully without completely trashing the original sound in the process.

I used SPEAR to do this, which is pretty fun to play around with and free! Here’s the result.

As you can hear I (somewhat) succeeded in making the violin more prominent, however I kind of turned the rest of the recording into a strange, banshee like sine wave fest. Not exactly what I was aiming for, but since SPEAR actually re-synthesises the sound, it’s kind of impossible to avoid this if you remove lots of the quieter partials. At least for me it is, more practice and time with it will help i’m sure.

Anyway, I then took this file and fed it into MacPOD (another cool piece of free software) and did some granular synthesis mostly just using snippets from the first 10 seconds or so where the violin is playing. Here’s the result of that.

I’m pretty happy with this as both something substantially more listenable (to my ears at least) than the original re-synthesis, and significantly far removed from the original field recording.

I’m currently playing around with Max, building a very basic granular synth patch, in part 2 I’ll talk about that, share the patch and hopefully some interesting sounds I’ve made with it!

Fun with Hydrophones

This month I have begun my MA program and so far it seems like it’s going to be loads of fun.

The other folks on my course all seem very nice and they have a diverse range of interests in all kinds of things sound related, from the super high tech, to the very low tech.

So far, aside from the obvious beginning of essay writing, I have mostly been focusing on making some underwater recordings.

I hired out some Jez Riley French hydrophones from the uni’s asset store and have been making lots of recordings with them. Mostly this involves trying to get them to stay underwater by sticking them in slightly awkward places like this:

Results have been varied to say the least but I’ve got some recordings that I’m pretty happy with and the process itself really encourages you to listen and experiment with placement a lot, which has been very fun.

I’ll update this post with some of the recordings I’ve made in the next week or so.

Update: Here’s a recording I made at Bristol Harbourside from the end of a pontoon. I dropped the hydrophone about 4 metres down into the water and came across this terrifying scraping sound. Ten nerd points for anyone who can identify it. My best guess is some kind of sluice/valve thing or some part of a boat (although there were no obviously moving or loud boats around at the time)

First Transmission

Over the coming months I will be using this blog to keep a diary of my work.

I hope to be able to keep track of my projects here, whilst also sharing my thoughts and feelings about the various things I’m working on with the aim of improving my writing skills and creating an ongoing document of my work.

I’m currently in the process of building a DIY hydrophone and a parabolic reflector to use for field recordings.

I will be sharing my progress and any subsequent recordings I make with them here over the next few months.
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