Non-stationary STSF

Non-stationary (NS) STSF (Spatial Transformation of Sound Fields) Type 7712 is the only acoustic holography application that can be used for investigating truly non-stationary phenomena. NS STSF includes special averaging and filtering functions to support detailed analyses of sound from engines. Approximating a true run-up using successive stationary conditions typically gives misleading results for noise radiation. The reason is that load conditions on many engine components are quite different under non-stationary conditions. With non-stationary STSF, it is now possible to locate and assess noise sources accurately during a true run-up. Results can be filtered to either fixed frequency bands, order bands or fractional octave bands.

Highly transient noises
Since Type 7712 works in the time domain, it can also analyse highly transient and non-repetitive noises such as those generated by office machinery or car brakes. You just record a single event and can analyse it later with a time resolution down to one sample of the recording.

By displaying the radiated sound as a contour plot or an animation directly on top of a picture of the object tested, Type 7712 gives an intuitive documentation of noise problems that can also be understood by non-acousticians.