Recording low frequency heartbeat sound

[arnab913]

I'm struggling with recording heartbeat sound of 20-180 Hz. I've tried several android apps to record with stethoscope integrated with condenser microphone. But it records low sounds from far away, but not heartbeat. So, what can I do now? Would I try to make an audio amplifier to amplify it first? But that includes noise much and a very hard task to make it noise free...:sad:
what is the setup for recording such low frequency sound accurately?
Thanks in advance.

 

[BradtheRad]

The heartbeat is low volume and low frequency. Not easy to pick up on audio equipment.

Here is a recent thread about this topic.

https://www.edaboard.com/threads/312040/

 

[Audioguru]

A heartbeat is actually a DC thump, not a low frequency but it produces a low frequency of about 16Hz like at the beginning of the song, "The Dark Side Of The Moon" by Pink Floyd. Maybe the skin under the stethoscope head is vibrating at 16Hz.

 

[arnab913]

Thanks for sharing the thread. Can anyone share a specific frequency-microphone? Or such setup. I need to proceed in a effective way...

 

[Audioguru]

I tried an electret mic from a cell phone and another electret mic from a cheap toy. They both picked up my heartbeat clearly when they were mounted in the plastic lid from a jar of peanut butter and connected with shielded audio cable to my preamp circuit.

Use my circuit linked here in post #2.