Suggest me some low sensitive Sound sensors.

[rama1001]

I am doing a module to adjust the noise in a motor such that motor inside piston stroke is touching some mechanical part leads to small noise. I would like to adjust these by using sound sensoror presser or vibration sensors. I don't know which one to use in that sistuation but my guess is sound sensor. can some help me to choose sensor and company name. Note, the sound is very low(noise) so that the options shoud be consider this.
Hope some will give suggestions.

[Studiot]

Old fashioned engineers (mechanics) used a stethoscope and their own ears for this.

[rama1001]

Any modern ideas that can be smart. I am looking for sensible sound sensor...

[Studiot]

Look for an electronic (eg piezo) type engine stethoscope.

http://www.alibaba.com/countrysearch/CN/engine-stethoscope.html

http://www.etoolcart.com/electronicenginestethoscope-1.aspx