Loudspeakers as High-Quality Microphones
It is established, using the reciprocity principle, that if a voltage-driven loudspeaker has a flat axial frequency-response, then such a response will also be obtained when it is used as a microphone, provided the associated amplifier has zero input impedance and a V out/I in response rising with frequency at 20dB/decade throughout the audio spectrum. The design of a suitable amplifier raises problems with regard to signal-to-noise ratio and the ability to handle the very large low-frequency input levels that are liable to be produced. Two different approaches are described, both leading to practical designs. In conclusion, consideration is given to the use of the technique for subjective loudspeaker quality assessment, and for the measurement of frequency response and absolute sensitivity.
Click to purchase paper or login as an AES member. If your company or school subscribes to the E-Library then switch to the institutional version. If you are not an AES member and would like to subscribe to the E-Library then Join the AES!
This paper costs $20 for non-members, $5 for AES members and is free for E-Library subscribers.