Audioscan Verifit 2 Bedienungsanleitung PDF herunterladen (Seite 136)

Verifit

User's Guide Version 4.2 © June 2015

Inconsistent levels in speech stimulus

The speech stimulus changes in level and/or spectrum from loop to loop during the test.

• The level and spectrum of the Speechmap stimulus presented is controlled by the on-ear reference

microphone. Any extraneous sound reaching this reference microphone during testing will cause the Verifit

to lower the level of the stimulus, or lower the level of certain frequencies. Subsequent loops of the

stimulus will sound either too quiet, muddy-sounding, or tinny-sounding.

• Keep test room as quiet as possible, watching for nearby computer fans, HVAC vents, or other sources of

noise.

• Limit movement of personnel in the room while testing is taking place.

Test box high distortion or noise

High distortion and/or noise numbers in an ANSI test

• There may be a leak between the hearing instrument under test and the coupler it is connected to. For BTE

type instruments, check the integrity of the tubing at the end of the coupler where it joins with the ear

hook. Look for cracks. ITE type instruments need to have a good seal between the hearing instrument and

the coupler. In addition, all vents need to be closed from the faceplate side of the hearing instrument.

• Ambient room noise may be leaking into the test chamber. Air conditioners, computer fans and similar

noisemakers can yield artificially high noise figures. Check the sealing of the test chamber. Try turning off

suspected noise sources to identify the cause.

• Vibration may be coupled into the test chamber from other equipment on the same table or wooden floor.

Computers, fans and air conditioners may be the source of the vibration. Try turning off suspected sources

to identify the cause. Relocate the source or the Verifit test chamber or mount the test chamber on a foam

pad.

Test box curves inconsistent

The test box curves keep changing from test to test.

• The battery may be close to end of life or starved for air (zinc-air cells) because of a tight seal on the

battery compartment. Try using a fresh battery.

• The test box reference microphone is incorrectly positioned. In order to control sound pressure levels

precisely at the microphone inlet of the hearing instrument, the test box reference microphone must be

positioned as close as possible to the hearing instrument’s microphone without actually touching it.

• The noise or feedback reduction features are attempting to reject the test signal. These need to be disabled

prior to tests with tones or noise.

• The instrument is on the verge of feedback due to a poor seal to the coupler, unplugged vent or a crack in

the tubing on the BTE coupler.

Test box curves differ from specifications

The OSPL90 and response curves don’t look like the manufacturer’s.

• Check that all controls or program settings are the same as those used by the manufacturer.

• Check that vents on earmolds or ITE instruments are plugged at the faceplate.

• Check that ITE instruments are well sealed to the coupler.

• When puttying a hearing instrument into the ITE coupler, be sure to keep the canal portion of the

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Audioscan Verifit 2 Bedienungsanleitung Seite 136