We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.
Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.
SOUND-RECORDING MACHINE 237
sponse of the RA-1142 cardioid microphone is quite flat and smooth throughout the frequency range, the correction equalizer shown is primarily intended as a voice-effort equalizer. As is the case with velocity microphones, cardioid microphones require that a speaker be no closer to the microphone than about 2 feet ; if the distance should be less, the recorded speech will be unnatural and tubby.
All microphones described have sufficient high-frequency response for good recording ; all have substantial response beyond 10,000 cps. Should high-fidelity recording be practicable, these microphones are capable of providing it if used properly and if associated with suitable equalizers.
The Sound-Recording Machine
Since the amplifiers and their equalizers and adjuncts are intended to correct for the transmission losses in all other parts of the recording and reproducing system, it is well to consider the recording machine before discussing the characteristics of the amplifier equipment.
In the last decade the sound-recording machine has seen major changes. The film-transport system — although still simple — has been improved to the point where flutter and wows audible to the average ear are practically unknown. No commercial 16-mm sound-recording machine now uses a rigidly coupled film-driven flywheel; all machines use more complex filtering arrangements and are manufactured to surprisingly close tolerances. To take advantage of the excellence of these machines, film manufacturers now supply sound-recording film of high resolving power (150 lines per mm) on base material that can be guaranteed to have less than 0.5% shrinkage (Eastman 5372).
Film Transport
The RCA PR32 16-mm sound-recording machine (Fig. 51) has a filmtransport mechanism that is a modification of the RCA 35-mm machines. The film moves past the exposure light beam on the surface of a smooth drum ; on the other end of the shaft which carries the drum is a large flywheel. The film transport system may be described briefly as a tight loop film path using a solid type flywheel on the drum shaft. This basic design, although historically quite old, was pioneered commercially about a decade ago by Maurer in the Model D Sound Recording Machine. Its performance with regard to flutter is surprisingly good; it represents a simple yet effective solution to the very difficult design problems that must be solved for a machine that is to be designed for satisfactory opera