To determine UCL using an insert earphone and set SSPL90 of a hearing aid accordingly.

Case:

Mr. Jones is having his first HAE and you are assigned to measure UCL. You are skeptical regarding the need for insert phones and also measure UCL with TDH phones. You look at the results and conclude which transducer is most appropriate.

Procedure:

Measure UCL for speech and 2000 and 4000 Hz frequencies using Hawkins' recommended procedure with an insert earphone and with a TDH phone for one person. Determine the HL to SPL relationship at UCL for each transducer by noting the dial on the audiometer and by using the appropriate coupler and measuring system.

Writeup:

1. Compare and explain the differences between the HL and SPL values for each of the transducers.

2. Determine which value should be used for setting the SSPL90 of the hearing aid. Select specifications for a mild-gain (20-40 dB full-on-gain) aid that has appropriate SSPL90. Copy the spec sheet and mark the curve in red.

3. Predict what error might occur should the other values be used.