Instrumentation for Acoustic Modeling

Acoustic models are usually built so that one can make the same kind of measurements one would make if the full-sized space or structure were available. Thus, much of the instrumentation needed for model work is the same as that used to evaluate completed projects. Other instruments must be high-frequency analogs of conventional equipment in order to accommodate the model's frequency and time scale factor. This paper will deal with instrumentation and techniques that have proved useful in acoustic models with scale factors ranging from about 1:3 to 1:24. Suitable high-frequency microphones, spark-discharge sound source, cathode-ray-tube “graphic level recorders,” and similar equipment will be discussed.