Vol. I No. 10

In regard to the principle I describe in No. 4, that playback accuracy depends on the identicalness of the playback configuration with the record configuration, I had an interesting experience.

Having learned that microphones can function as speakers and vice-versa, I assembled a pair of headphones replacing the original miniature speakers with microphone elements taken from ordinary inexpensive microphones sold at Radio Shack.

I was listening to Fulfullingness' First Finale, an album I recommend and which I had listened to many times before. (It is by Stevie Wonder.)

Someplace in the middle of side 2 I heard a one syllable spoken voice expression which presumably got onto a track and into the mix during the recording process and was never detected. In all my previous listenings to this record I had never heard it.

The Shack microphones, if I remember correctly, are listed as having an impedance of 200 ohms, whereas a typical speaker will usually be in the range of 4-32 ohms. This corresponds to a voice coil - the coiled wire that juxtaposes the signal to the magnet in a speaker or microphone - which is substantially longer or thinner or both. It is likely that the microphones used to record FFF also had an impedance in a much higher range than typical loudspeakers.

It seems to me that a longer coil would place the musical signal in proximity to the magnet over a longer duration than a shorter coil. In a sense, it would allow each musical instant to manifest itself more separately from the next. A thinner coil might tend to be less able to bear signal energy within itself, thus in a sense repulsing or expelling it, thereby disposing it to be acted upon by the magnet to a greater degree.

In any case I challenge the interested reader - in a friendly sense, of course - to listen carefully to side 2 (or B) of FFF to determine whether or not they can hear this out-take or 'blooper'.