User manual

6.4. INSTALLATION OF THE SYSTEM 6. Operating guide

Figure 6.6: Delay adjustment, SUB signal lags in phase.

proceed with the physical measurement of the distances involved and utilize the values obtained from

this to set the delay in the processor. This method will allow you to begin with a delay value which is

very close to that which is exact, without introducing possible errors caused by uncertainty, misuse or

malfunction of the external measurement instrumentation.

Now, we will examine the use of Smaar tLive for the alignment of the Sub pass band. The comments

here, however, are valid for any system capable of taking similar measurements. In order to take reliable

measurements in the frequency range reproduced by the SUB and MID-L outputs in the crossover

region it is necessary to use the measurement microphone in a ground-plane conﬁguration

. On the

other hand, it is necessary to resist the temptation to use the automatic delay ﬁnder available in the

software application: in the working frequency range of the SUB pass band, the errors possible with the

automatic procedure can be enormous.

The correct procedure is to measure initially the delay of the MID-L/HIGH pass band and input that

data to SmaartLive, in order to have a “clean” readout of the phase diagram, and then measure the

response of the MID-L and SUB pass bands. The situations that can be revealed here are still two: the

SUB is ahead in phase of the MID-L or the SUB is delayed in phase with respect to the MID-L. Figure 6.6

is a screenshot of Smaartlive demonstrating a system with the SUB output behind in phase. Figure 6.7,

instead, shows a system with the SUB ahead.

Working with the ﬁne delay adjustment for the SUB pass band

, it is possible to cancel the difference

in phase decline in the crossover region, and perfectly align the system. Figure 6.8 shows a screenshot

of the measurement of the system previously measured with the SUB ahead in phase, correctly realigned

with a slight increase in the delay time preset in the processor for the SUB output.

Supplementary Delays

In the case where the sound reinforcement system requires a secondary system for the coverage of the

stage front or for areas not covered by the main system, it is necessary to impose supplementary delays

in order to realign the phase of the secondary systems with the main system in the areas where coverage

will be superimposed. This can be done either geometrically, as described above for the alignment of

For further details see Appendix B.

Or, consequently, on the MID-L/HIGH pass band if that was the pass band delayed.