Hi

I am involved in a university project that makes have a university project that involves using a microphone to pick up sounds that are inaudible by the human ear. Such an example is the noise that laptop makes when booting up. This then would be represented in a graphical manner, maybe using images or vector graphics

I need help in deisgning a patch to do this. Can anyone help me design a patch for this project?

yeah of course we'll help you with the pd stuff. just get your patch started, and when you have specific questions about how to do something in pd, you're welcome to post them here.

i don't know anything about microphones, but i think you'll definitely have to read up and find out how to record tiny sounds without getting too much background noise. first idea that popped into my head was that you might try to find a nice soundproofed box, and then put something insde that box with a good microphone.

i often see on those nature documentaries when they'll have a close up of a caterpillar eating a leaf or something, and the sound is the caterpillar chewing....but i'm not sure if those are actual recordings, or just sound effects added later to the video.

the standard visual part of pd is called GEM. it comes 'pre-installed' in pd-extended, which you shoudl download from here if you don't have it already: http://at.or.at/hans/pd/installers.html

just thinking more about that idea with the box....it would probably be quite easy to make one for yourself. just get an ordinary polystyrene box...like the ones they put fish or vegetables in...and then put a few more layers of old material or foam around it to make it really soundproof.

if you don't do something like that, then your microphone is just going to pick up the ambient sounds of the room, which i don't think is what you want.

the other thing i just thought of is you could use something like a stethoscope..you know..the thing your doctor listens with.

good luck.

you can also try a type of microphone like the ones on the adress below. I use similar set-up for recording sounds like the ones you're planning to, and I am pretty happy with the result. And, they are cheap too!

http://www.musiciansfriend.com/product/Matrix-MPU2-ClipOn-Tuner-Mic?sku=270020

http://www.musiciansfriend.com/product/DiMarzio-Acoustic-Model-For-Acoustic-Guitar-Bass?sku=302720

I have bought a telephone pick-up device with a 3.5 jack socket (I think its this size as it fits into my laptop mic socket fine).

what is the best way to show my patch on here - for everyone else to view?

poly, use the attachment box below the message box and post your ".pd" patch

BTW just wanted to point out that you are picking up electromagnetic radiation from the different electronic devices and not necessarily "sounds" with that coil i.e. radio waves full of electrons vs. sound waves full of air <-- of course I am oversimplifying, but that's the basic picture.

Makes for some interesting sound output. I think Christina Kubisch has done some cool work with this effect.

What you have to consider here is also pre-amplification: how you are going to boost the signal before you begin recording it. Check with your university peoples and ask if they have any good pre-amps for you.

Another issue, this one for more advance PD user then myself, is how to get the 60Hz (50 if you are in Europe and ...) AC hum out of your recorded material. AC power lines are all around you and you will have their carrier frequency all over you recording. I imagine you need to do some FFT analysis stuff to get rid of it. Read up on how to do this after you get you signal recorded.

good luck!

As Digi says, those telephone contact mics are electromagnetic pickups. What you probably want is the tiny electret condensor tie microphones, and like Hardoff says, a stethoscope tube seems a great way to capture and channel sounds.

You may also want to obtain or build a very sensitive pre-amp, and be mindful of your shielding on the cables which will pick up lots of hum at gains of 1000 or more. To avoid the hum Digi mentions, you should use a differential amplifier and double braided screen twisted pair cable, one shield earthed at the ground of the per-amp, and the other to the body of the mic. That cable is the same kind used for oscilliscope probes.

Look forward to hearing what sound effects you pick up.

Here is my patch - so far. Any comments would be appreciated

http://www.pdpatchrepo.info/hurleur/test2.pd