Tuning a sound system requires an understanding of the hardware, a discerning ear, accurate measurements, and a disciplined and systematic approach. We doubt that any two system tuners approach the problem exactly the same way. Also, the process necessarily differs, depending on the complexity of the system in question. The transfer function of a system can be displayed in either the time or frequency domain. Interpretation of this data is straightforward, as 0 dB represents the same amount of energy into the system as out, for a given frequency.
Negative values represent cancellations, while positive values represent resonance.
This configuration allows the test signal to be noise, music or almost any broadband signal. Measuring the transfer function of the equalizer is particularly useful when the resulting transfer function is inverted and overlaid on top of the previously-stored loudspeaker measurement. The need to switch between measurement points within a system suggests that the use of an external mixer, as shown in Figure 2, may prove extremely useful in the field. The ability to measure the transfer function between two signals that have been aligned in time allows sound system performance to be measured using a variety of test signals including noise and music. This measurement technique provides an easily understood measurement that can be used to optimize sound system performance.