Magnetic Recording and Reproducing
C. Hickman · The Journal of the Acoustical Society of America · 1937
This paper describes an improved method of recording sound magnetically on steel tape, similar in principle to that of the Poulsen telegraphone. By making use of perpendicular instead of longitudinal magnetization, the speed of the tape may be reduced as low as 8 inches per second for recording speech. The low tape speed eliminates many of the difficulties encountered with those systems which made use of longitudinal magnetization. The ratio of the signal to the background noise has been substantially reduced. The recording medium is a steel tape having a thickness of about 2 mils and a width of about 50 mils. A small recording and reproducing machine will be demonstrated.