MFJ-616 Speech Intelligibility Enhancer
TM
Instruction
Manual
6
How to adjust your Speech Intelligibility Enhancer
TM
for Maximum Speech Intelligibility
There are four-frequency boost (increase in amplitude) and cut (decrease in amplitude) knobs
spaced an octave apart in frequency. The center frequencies are approximately 300, 600, 1200
and 2400 Hz. With a knob set at 12 o’clock, there is no boost or cut. Turning the knob
clockwise boosts an octave of frequencies by up to 12 dB while counterclockwise rotation gives
more than 12 dB of cut.
Adjusting your
Speech Intelligibility Enhancer
TM
is based on the following three principles.
First
, drastically
reduce
the speech energy below 500 Hz. These frequencies contribute only 4 %
of intelligibility but has 55 % of the speech energy. Do this by turning the 300 and 600 Hz knobs
fully counterclockwise. This will drastically reduce the speech in those two octaves. You may
want to increase the amplitude in this range a little by rotating the 600 Hz knob to 9 to 12
o’clock. Use the bypass switch to compare.
Second
, drastically
increase
the speech energy above 1000 Hz. These frequencies contribute 48
% of intelligibility but has only 4 % of speech energy. Do this by turning the 1200 and 2400
knobs fully clockwise. You may want to experiment with less levels of boost with the knobs set
12 o’clock to fully clockwise. Use the bypass switch to compare.
Third
, your hearing characteristics are unique. People’s voices are different. Experiment by
boosting and cutting each frequency range based on the two principles above until you find a
combination that gives
you
best speech clarity.
For example, you may have frequency response “holes” in your hearing that you can “fill in” by
boosting those ranges of frequencies. You may be having a QSO with a YL or XYL with a high
pitched voice or someone with a booming low voice or poor microphone. By adjusting the knobs
based on their voice characteristics, you can optimize speech clarity.
Remember -- 12 o’clock is flat (no boost or cut), clockwise is boost and counterclockwise is cut.
Don’t forget to use the bypass switch often to make comparisons.
Be sure to adjust the balance control so the sound appears to be equally loud in each ear.
If you use a hearing aid, try removing them and use the
Speech Intelligibility Enhancer
TM
with
headphones. Also try speakers.
For best results, use a pair of high quality bookshelf speakers designed for high-end stereo
systems.