Microphone to use for recording internal body sounds?

[Eric VanEpps]

I'm part of a group working on a device to record internal body sounds, such as gastrointestinal sounds, but we're having difficulty finding an appropriate microphone to use. We'd prefer something that can plug into our power board via USB or something similar to this design (Heart Sound Sensor [SEN42771M] - $59.00 : Seeed Studio Bazaar, Boost ideas, extend the reach), but haven't found anything currently available for sale.

Any advice that could be offered would be a huge help. I'm not an audio expert at all, but this seemed like the right place to go based on similar threads I've seen from the past. Thanks!

[Chris Hurd]

Hi Eric, welcome to DVi.

Have you thought about using a digital recording stethoscope, such as Digital Stethoscope | ADInstruments

[Eric VanEpps]

Yes, we were originally considering using a digital stethoscope, but have had difficulty getting those microphones to hook up and work with our program, so I was wondering if there might be a better alternative. That said, is there an easy way to take the input from a digital stethoscope and connect it via USB? If so, we might still be able to make it work.

[Don Bloom]

Eric, First welcome to DVi...I'm sure someone will come up with something for you. We've got some of the best talent in the world here.
By the same token I have to say when I read your post I almost had to laugh because the picture that immediately came into my head was someone swallowing a Sanken COS-11D or a Countryman B6 with the tail hanging out of their mouth hooked up to a wireless mic pak. I'm really sorry but that's what hit my head as my stomach was making enough noise to be recorded without the use of any microphone. Please forgive my sense of humor I really do apolgize. I'm pretty sure someone who is a lot more audio tech savvy than I will respond. Once again Welcome and good luck.

[Chris Hurd]

I'm wondering if some sort of specialized PZM mic might be the way to go... or maybe I'm way off track?

[Greg Miller]

Welcome!

First of all, what do you mean by "power board"? In my mind, that would be the disconnect panel where commercial line voltage comes into the building... I doubt you want to connect the mic to that.

Do you mean an audio mixing board? If so, does it have balanced inputs, and if so do they have phantom power? Or is it some sort of consumer board with unbalanced inputs, and if so do they have "plug in power"?

And what is a digital mic? A mic is an analog device that converts analog changes in air pressure to an analog voltage, so most simply the output is analog. Having said that, some mics incorporate some digital electronics to convert the mic signal, usually, to USB format. In that case, you can't connect it to an analog mixing board, but rather you need to connect it to a computer's USB input.

BTW, the "Digital Stethoscope" is very specialized. It appears to be a [analog] microphone in a stethoscope bell, combined with some digital processing to somewhat "clarify" the sound, and then analog outputs again which presumably can be recorded on a normal audio recorder. (But the description at the linked website is not entirely clear about this.)

And what sort of internal body sounds are you hoping to capture, out of curiosity? Something specific, or all body sounds? The nature and frequency range of the sound(s) could be very relevant to your question.

Please try to define more clearly what you already have -- make & model number would be helpful -- and we can give you some more specific solutions!

[Shem Kerr]

There is an existing thread on a similar topic
http://www.dvinfo.net/forum/all-thin...lp-please.html

What mic you use depends on the end use of the sound: audio for documentary or drama; or interpretive for diagnostics. From where I understand things,it is a case of making or modifying a USB mic or other to get good skin (or perhaps bone ) contact .

[Chris Hurd]

Thanks for pointing out that other thread, Shem -- much appreciated!

[Allan Black]

Eric, I think you're coming at this from the wrong end, nope I don't mean that :)

Whatever you record with a body mic won't sound like you imagine it, it won't be good enough. It's got to be 'animated', sound 'internal'
and be quickly recognised by your listeners.

So use your imagination. Slowing the recorded speeds of sounds is my first thought.

Get short lengths of plastic tubes, each with a different diameter. Fill a big bucket with water, a wide brim bucket in a very quiet room < very important.

Blow bubbles and record them, fast and slow. The more you do the better you'll get, try the tubes at different depths in the bucket.
The aim is to slow down the best of them.

Flush toilets and record water gurgling down various drains. Load them to your NLE at different speeds. Add various explosions and lions growling
at speeds and mix to taste.

We did the Whale Exhibition for the Australian Museum like this, a whole floor as an undersea location, including the lighting.
All various blue hues, with slow rotating coloured lights. Huge woofers playing 24 track whale/bubble/growling sounds, with giant skeletons.
My satisfaction was watching the wide eyed school kids, I tell you there is nothing like it :)

Cheers.

[Greg Miller]

I was assuming, from the way the OP phrased his question, that he wants to record authentic internal body sounds, perhaps for diagnostic or instructional purposes.

[Allan Black]

Yes Greg, but either way, I think you've got to animate it, like Hollywood does, larger than life to get the point across.

Cheers.

[Greg Miller]

But not if he's using the recording to train medical students about how the body should actually sound. If they're learning how a heart should sound on their stethoscope, you don't want them listening to a slowed-down toilet flush!

[Allan Black]

In that case I'd recommend using Stethoscopes. No offence Greg, but I think you've missed the point of my post 9. Indeed Eric might want a mic
for this job, but those were my recommendations.

Cheers.

[Greg Miller]

No Allan, I don't think I missed your point. If I understand you correctly, you were saying that for a "show biz" use, artificial sounds might be more "dramatic" or "impressive" than the real thing, viz a viz your "wide eyed school kids." I certainly don't have any argument with that.

My point was simply that if the intent is to use the recording for something serious like medical training, then I think a realistic recording would be more appropriate than manufactured sound effects.

Since the OP said "record internal bodily sounds," rather than "produce bodily sound effects" I assumed he was after realistic audio. And, indeed, one device the OP looked at was modeled on a normal stethoscope; that simply reinforced my belief that he's after a realistic recording of the actual bodily sound.

But for your school kids, I'm sure slowed-down bubbles are great.

[Noa Put]

Even though Eric doesn't specify what he will be using the sounds for I also read that he wants the real stuff, if he would have said he was doing a horror movie or a episode of house then I could understand you could use your imagination but if he needs the material to use in med school for educational purpose then I can understand Greg's point about the toilet sounds :)