Etymotic The BEAN® Quiet Sound Amplifier® - Manual (Page 2)

English
INTRODUCTION
QSA ® stands for Quiet Sound Amplifier. The QSA is a personal sound
amplifier that automatically enhances soft sounds. Loud sounds
pass through as though nothing is in the ears.
The QSA device provides the highest fidelity sound amplification
available at any cost. The sound quality of QSA devices is superior
to that of all known custom-fitted devices, and is available without
medical referral or prescription.
The circuitry in QSA devices incorporates a patented new
ultra-low-distortion output amplifier, along with all of the important
features and benefits of the original K-AMP ® circuit first described over
30 years ago by Mead Killion, Ph.D., Sc.D.(hon), a well known engineer
and professor of audiology. No circuitry, including digital technology,
has proven superior to the sound quality of K-AMP circuitry –
the engine of QSA devices.
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