Audioscan Verifit 2 - Manual (Page 150)

Verifit ® User's Guide Version 4.2 © June 2015
REUR, Real-ear Unaided Response, SPL (or BSPL), as a function of frequency, at a specified measurement
point in the ear canal, for a specified sound field, with the ear canal unoccluded (ANSI S3.46).
Reference microphone, microphone used to measure the stimulus level in the measurement process or to
control it in the equalization process.
Release Time, the time required for HA output to fall to within +/-4dB of its steady-state level for an input step
from 90 to 55dB SPL. (ANSI S3.22)
REM, Real-ear Measurement.
RTG, Reference Test Gain, the HFA gain for a 60 dB input SPL with the gain control at RTS (ANSI S3.22).
Reference, Sound-field, the calibration point of a sound-field measurement.
RSETS, Relative Simulated Equivalent Telephone Sensitivity, difference in dB between the HFA-SPLITS
(SPA-SPLITS) and the RTG plus 60 in the "M" (microphone) mode. RSETS = HFA-SPLITS - (RTG+60)
RTS, Reference Test Setting of the gain control, for a 60 dB input SPL, the setting of the gain control required
to produce an HFA gain within 1.5 dB of the HFA-OSPL90 minus 17 dB. If the full-on HFA gain is less than the
HFA-OSPL90 minus 17 dB, the RTS is the full-on setting of the gain control (ANSI S3.22).
Saturation, in a hearing aid, the limiting of output caused by the output circuitry and transducer reaching their
maximum capability.
SPA, Special Purpose Average, the average of values in dB at three third octave frequencies separated by 2/3
of an octave (ANSI S3.22). See also HFA.
Spectrum, the BSPL as a function of frequency for a broad-band signal.
Speechmap, a trademarked hearing instrument fitting environment introduced by Audioscan in 1992. It presents
hearing threshold, UCL and amplified speech spectra as SPL in the ear canal. The fitting goal is to make
amplified speech audible and comfortable while avoiding discomfort for loud sounds. Originally speech was
simulated using amplitude-modulated tonal signals. The Verifit replaces these simulated speech signals with real
speech, both recorded and live. For details of the test signals and analysis methods, see Speechmap Technical
Details.
SII, Speech Intelligibility Index, a quantity calculated from measures of speech, noise and hearing threshold
that is highly correlated with the intelligibility of speech (ANSI S3.5).
Speech Region, a statistical range of short-term spectra present in a speech passage. The short-term spectra are
typically 120 - 130 millisecond averages in 1/3 octaves. The statistical range is typically from the 70th to the
99th percentile.
SPL, Sound Pressure Level, rms sound pressure relative to 20 uPa, expressed in decibels. SPL = 20log10 (rms
sound pressure / 20uPa).
SPLITS, coupler SPL for an inductive telephone simulator, SPL developed in a 2cc coupler by a hearing aid
with the gain control at the RTS when the input is the magnetic field generated by a TMFS (ANSI S3.22).
TMFS, Telephone magnetic-field simulator, a device for producing a magnetic field of consistent level and
geometric shape when driven by a specified current (ANSI S3.22).
THD, Total Harmonic Distortion, the power in all harmonic components as a percentage of the power in the
fundamental. If less than 20%, the power of the total signal may be used instead of the fundamental. For most
hearing aids, the inclusion of harmonics above the third will not significantly alter the THD (ANSI S3.22).
Transducer, a device which transforms energy from one form to another. For example, a microphone or
earphone.
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