Term
| sound pressure level at the microphone opening of the HA |
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Definition
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Term
| the difference between the output SPL in a coupler and the input SPL (output SPL-input SPL = this) |
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Definition
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Term
| a manual or electronic adjustment for overall gain |
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Definition
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Term
| What are key components of probe-mic equipment? |
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Definition
| Tone/noise generator, amplifier, loudspeakers (generate stimuli), reference mic (monitors the SPL reaching the aid from the loudspeaker & adjusts the sound’s volume if the level is too high or too low). |
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Term
| Where is the reference microphone placed? |
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Definition
| placed next to HA microphone |
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Term
| Describe the importance of calibration |
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Definition
| To check that the correct input levels are generated |
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Term
Describe the importance of electroacoustic analysis:
-What: obtaining various measures of ___ ___ ___ in a test box
-Why: For ___ control; provides a standard way to check hearing aid ___; can compare results to how aid ___ worked
-How: We connect hearing aid to a ___, place it in a small ___, then run a test in the test box. |
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Definition
| hearing aid function; quality; function; originally; coupler; chamber |
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Term
Appropriate settings for electroacoustic analysis:
-___ coupler: small cavity that connects a hearing aid to a measurement microphone
-BTE = use ___ coupler
-ITEs & ITCs = use ___ coupler (attach with putty)
-RIC = use ___. May need to use an “adapter” |
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Definition
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Term
How to set up HA appropriately for EC:
-Plug ___ on faceplate side of aid
-Set aid to ___-directional mode, ___ frequency response, greatest HFA-OSPL90, greatest HFA-FOG.
-Disable ___ features (i.e. noise reduction, feedback suppression).
-All tests performed with AGC set for ___ effect. Except for attack and release time tests and input-output tests.
-There is no standard coupler for ___-fit HAs. Most are specified as BTEs using an earhook. |
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Definition
| vent; omni; widest; adaptive; minimum; open |
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Term
| has several cavities to simulate a real adult’s ear (i.e. to mimic change of impedance as freq changes) |
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Definition
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Term
| What is an example of an ear simulator? |
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Definition
| Zwislocki coupler. Main cavity(0.6cc) is connected to 4 other cavities (0.1 to 0.22 cc) by small tubes & dampers |
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Term
| ANSI specifies measuring HAs in __ ___ and IEC standards specifies measuring HAs in ___ ___ |
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Definition
| 2-cc coupler; ear simulator (but allows coupler) |
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Term
| Name two companies that make test boxes for electrocoustic analyses |
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Definition
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Term
Telecoil:
-An inductive pick-up coil used to sense changing ___ fields
-Converts magnetic energy into ___ energy
-Mic converts acoustic energy to ___ energy |
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Definition
| magnetic; electrical; electrical |
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Term
| generation of an electric current or magnetic state by proximity to a different source of electricity or magnetism |
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Definition
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Term
| conductor wound into a spiral to create a high concentration of material into which current flow is induced when a magnetic field enters its vicinity |
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Definition
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Term
| In a hearing aid, the ___ is the induction coil and the ___ produces the magnetic field |
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Definition
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Term
continuous wire surrounding a room that conducts electrical
energy from an amplifier |
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Definition
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Term
| coupler SPL for an inductive telephone simulator |
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Definition
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Term
| coupler SPL in a vertical magnetic field |
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Definition
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Term
| The average of values at 1000, 1600, and 2500 Hz |
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Definition
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Term
| Coupler SPL as a function of frequency for 90 dB input SPL |
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Definition
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Term
| The maximum value of the OSPL90 curve |
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Definition
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Term
| Average of the OSPL90 values |
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Definition
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Term
| Average of the full on gain at the HFA frequencies |
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Definition
| HFA full-on gain (HFA-FOG); input is 50 dB SPL |
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Term
| What are the tolerances for maximum OSPL90, HFA-OSPL90, HFA full on gain (HFA-FOG), |
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Definition
OSPL90=plus or minus 3
HFA-OSPL90=plus or minus 4
HFA full on gain (HFA-FOG)=plus or minus 5 |
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Term
| gain control (VC or overall gain control) setting to produce an HFA-gain within +/- 1.5 dB of the HFA-OSPL90 minus 77 dB for a 60 dB SPL input |
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Definition
| Reference test setting (RTS) |
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Term
| If HFA FOG for a 60 dB SPL input is less than HFA-OSPL90-77 dB, then RTS is ___-___ ___ of gain control |
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Definition
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Term
| average of the gain at HFA freqs for a 60 dB SPL input, with gain control set at RTS |
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Definition
| Reference test gain (RTG) |
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Term
| range between the lowest & highest freqs. at which the freq. response curve is 20 dB below its HFA value |
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Definition
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Term
| distortion components relative to the total power of the signal (expressed in dB or a percentage) |
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Definition
| Total Harmonic Distortion (THD) |
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Term
| THD is measured by putting a ___ dB SPL pure tone into HA (set to RTS) & analyzing the output waveform |
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Definition
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Term
| quantifies the internal noise of HA |
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Definition
| Equivalent Input Noise (EIN) |
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