MFJ-616 Speech Intelligibility Enhancer
TM
Instruction
Manual
5
1. Initial Set-Up Levels:
Begin by setting the
Speech Intelligibility Enhancer
TM
controls as
follows:
Volume:
10:00 position (about 1/3 up).
Balance:
12:00 position (mid-scale).
Frequency Controls:
Set all four for 12:00 position (mid-scale).
Bypass: Speech Intelligibility Enhancer
TM
On (switch in)
Input A/B:
A (out)
Speaker:
On (in)
Power:
On (in)
2. Radio Levels:
Adjust the volume control on the
A-Input
radio for a comfortable listening
level in the monitor speakers. Next, press the
Input
switch to select the
B-Input
Radio. Set the
B-Input
radio's volume control for a comfortable listening level.
3. Set Balance:
Sitting at the microphone location, adjust the
Balance
control so sound appears
to come from the center of the console in front of you.
4. Set Speech Intelligibility Enhancer
TM
:
Adjust all four frequency settings (300, 600, 1200,
2400) to preference. Use the
Bypass
switch to gauge the effectiveness of each control as you
adjust it.
5. Headphones:
Plug in a stereo headset and turn the
Speaker
switch off (out). The speakers
should silence and the phones should work normally.
Some Results of Research on Speech Intelligibility in hearing English Words:
• The frequencies important for speech intelligibility are the consonant sounds from 500 to
4000 Hz. They contribute 83 % of word intelligibility.
• Frequencies from 500 to 1000 Hz contributes 35% of word intelligibility and 35 % of sound
energy.
• Frequencies from 1000 to 4000 Hz contribute 48% of intelligibility but has only 4% of sound
energy.
• In contrast, frequencies form 125 to 500 Hz contributes 55 % of sound energy but only 4 % to
word intelligibility.
• In other words, nearly half the speech intelligibility is contained in 1000 to 4000 Hz frequency
range with only 4 % of the speech sound energy.
• On the other hand, the low frequencies 125 to 500 Hz have most of the speech energy but
contribute very little to intelligibility.