Handbook for Sound Engineers

1626 Chapter 46

examines the ratio between early energy, late energy,
and noise, the measurer must place cursors on the dis-
play to define these parameters. These cursors may be
placed automatically by the measurement program. The
result is weighted with regard to decay time, so this too
must be defined by the measurer. Analyzers such as the

TEF25™ and EASERA include best guess default

placements based on the research of Peutz, Davis, and

others, Fig. 46-27.

These placements were determined by correlating

measured data with live listener scores in various

acoustic environments, and represent a defined and

Figure 46-26. The time window increases with length as frequency decreases.

Figure 46-27. The ETC can be processed to yield an intelligibility score, TEF25.

Left cursor on first arrival

Right cursor 10 dB down (Early-decay time)

D cursor divides early from late

Metrics based

on cursor placement