Sony PCMD100 Portable High Resolution Audio/Voice Recorder Offers solid state storage, Built-in electret condenser microphones Native recording including DSD, WAV and MP3 Simple uploading to computer, Supports USB 2.0 "Built-in Mic: Electret condenser microphones. Max input level: 128 dB SPL. Frequency response 20 Hz to 20 kHz Mic Input (Stereo Mini Jack): Input impedance: 22 k ohm, Rated input level: 2.5 mV; Minimum input level: 0.7 mV"