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6
Step 2a: Check the MPO Level
The fitting software will always prescribe an MPO based upon the hearing threshold and the age of the
wearer. Despite this, due to the restricted dynamic range associated with severe to profound hearing losses,
it is very important to begin the fitting session by checking that the MPO is set correctly.
A too high level of the UCL (MPO) control may cause the client to decrease the VC, and thereby reduce the
audibility of speech. Alternatively, setting the UCL control too low may produce complaints of poor sound
quality of own voice and reduced speech intelligibility.
To test the UCL control setting the following procedure can be followed:
• Start talking loudly in front of the client.
• Then talk closer and closer to the ear.
You should always start carefully so you do not cause unnecessary discomfort.
Try to distinguish between a loud sound as being indeed too loud or being uncomfortably loud.
• If the sound is not uncomfortably loud, increase the UCL control and test again.
• If the sound is found to be uncomfortably loud, decrease the UCL control and test again.
The client should also talk and listen to their own voice to evaluate their own voice quality.
Fitting tip:
If the preferred MPO setting is not
at the maximum setting, a 5dB
damped hook should be considered.
This will enable the level of low-
frequency output to be increased,
which may be preferred by users who
need increased low-frequency amplifi-
cation (e.g. left-corner audiogram).
MPO Level
UCL (dB HL)
Adjusts the maximum power
output (MPO) according to the
user's uncomfortable level (UCL).