measure audio level with ADC

[fvnktion]

I have a requirement to be able to be able to measure the audio level of an audio line. I am wondering if anyone has done anything like this using an adc of of PIC?

I am thinking about setting up an integrator circuit with some time constant to capture how much audio signal was present over a period. The ADC value would roughly correspond to the volume?

Any thoughts on how well an ADC would interpret this as the level of volume?

[languer]

Do you have a definition for the audio signal? Frequency Range? Periodic or not?

Ideal would be an RMS-type detection (integrator comes close), or LOG-detection. Less ideal, but widely used would be peak-detection.

Few links which showed up in Google:

• http://www.seattlerobotics.org/encoder/200003/larryb.html
  
• http://www.seattlerobotics.org/encoder/200005/audio_detector_circuit.html
  
• http://www.allaboutcircuits.com/vol_6/chpt_4/5.html
  
• http://www.scary-terry.com/audioservo/audioservo.htm
  
• http://www.alanovington.com/audio_detection_circuit.htm
  
• http://sound.westhost.com/project38.htm

[fvnktion]

I'll have a look at the links.

[asmboy]

a full wave RMS or simple 2 diode AVErage value detector will make the ripply DC input you are after - feeding audio direct will just return random trash