Characteristics of the IC-756Pro2/3 Mic Equaliser

by Adam M. Farson VA7OJ/AB4OJ

Fig. 1: Equaliser characteristic curves.
Fig. 1: Equaliser characteristic curves. Chart courtesy Icom Inc.

 

The IC-756Pro2/3 microphone equaliser is described in Reference 1, p. 17. To paraphrase the text:

A closer inspection of Fig. 1 reveals several interesting points:

  1. The crossover point of the bass and treble equalisation curves is 650 Hz, rather than the more common 1 kHz.

  2. The bass and treble boost/cut values are configurable in 1 dB steps.

  3. Bass: Datum Line D1 indicates that each 1 dB step changes the response by 1 dB at 300 Hz.

  4. Treble: Datum Line D2 indicates that each 1 dB step changes the response by 1 dB at 1 kHz.

As discussed here, the lower and upper cutoff frequencies for the WIDE, MID and NAR TOBW settings (respectively) are as follows.

A vertical line drawn at any one of these frequencies, intersecting the selected equalisation curve, will yield the actual boost or cut at the corresponding cutoff point.


References

  1. "IC-756Pro II Technical Report", Icom Inc., 2003. (PDF) mirror site


Text copyright  2006 A. Farson VA7OJ/AB4OJ. Image courtesy Icom Inc. Last updated: 28/07/2017.
Page created on Microsoft SharePoint Designer 2007 by A. Farson VA7OJ/AB4OJ.