i3 - November/December 2017 - 16

Tech

By Dave Wilson

PIPE LINE

Over-the-Counter
Hearing Aids and
CTA's New Standard

s announced in the last edition of i3, President Trump
recently signed into law a requirement that hearing
aids be made available over-the-counter. Bringing
over-the-counter hearing aids to consumers is a top priority
for CTA, and the successful navigation of the legislative process
was an important element in CTA's effort. The other element
was the creation of a voluntary industry standard describing
minimum performance criteria for these devices. That standard was published this year along with a new logo to help
consumers identify products that comply with it.

ANSI/CTA-2051, Personal
Sound Amplification Performance
Criteria, covers a range of operating parameters for devices that
assist with hearing but have not
gone through the U.S. government
approval process to become prescribed hearing aids. ANSI/CTA-2051
addresses a range of operating
characteristics including things like
frequency response, maximum
acoustic output, distortion control,
high-frequency gain, latency and
battery life, just to name a few.

The CTA standard organizes device
operating parameters into three categories. Category 1 parameters must be
within a defined range, and must be
tested using the methods described in
the standard. Category 2 parameters
do not have to be within a defined
range, but they must be measured and
reported using the procedures described
in the standard. Category 3 parameters
do not have to be within a defined
range and do not have to be measured,
but the existence of the device capability
or feature needs to be reported.

CATEGORY 1: CTA PERFORMANCE CRITERIA FOR PSAPS
Parameter

Requirement

FREQUENCY RESPONSE
BANDWIDTH

Standard band: 250 Hz - 5 kHz | Wide band: 250 Hz - 10 kHz

FREQUENCY RESPONSE
SMOOTHNESS

No single peak in the ⅓ octave frequency response shall exceed 12 dB relative to
the average levels of the ⅓ octave bands ⅔ octave above and below the peak.

MAXIMUM
ACOUSTIC OUTPUT

The maximum output sound pressure level shall not exceed 120 dB SPL measured in a 2cc
coupler. Note: This is equivalent to a level of roughly 115 dBA referred to the sound field.

INPUT DISTORTION

THD+N = 5% or less with 500 Hz tone applied to microphone at 100 dB SPL

OUTPUT DISTORTION

THD+N = 5% or less at 70 and 100 dB SPL output with 500 Hz input

SELF-GENERATED NOISE

No more than 32 dBA (equivalent SPL) referred to the input

NOVEMBER/DECEMBER 2017

ANSI/CTA-2051
Logo Program
A new logo program was established to
help consumers recognize devices that
comply with ANSI/CTA-2051. This logo
indicates the device was tested using the
methods described in ANSI/CTA-2051 and
found to comply with all relevant performance requirements in the standard.
The standard was developed by
CTA's Portable, Handheld and
In-Vehicle Electronics Committee,
which is working on a number of
other standards related to health,
fitness and wellness through its Health,
Fitness and Wellness Subcommittee.
GO ONLINE: To get involved,
visit standards.CTA.tech.
Companies interested in using
the logo should contact Catrina
Akers (cakers@CTA.tech).

CTA Standards
CATEGORY 1 parameters include
frequency response bandwidth, frequency
response smoothness, maximum acoustic
output, distortion control limits and selfgenerated noise levels. All of these parameters must be measured and fall within
an acceptable range.
CATEGORY 2 parameters include highfrequency gain, battery life, latency and
RF immunity. These parameters must
be measured and reported but do not
have to be within a defined range.
CATEGORY 3 parameters include
tone control, level dependent gain/
compression, signal-to-noise ratio
enhancement, noise reduction, feedback control/cancellation, device personalization, device coupling to the ear,
and wireless connectivity. No measurement methods are defined for these
parameters and there are no defined
limits for compliance, either. The existence of these features in a device
simply needs to be reported.

I T I S I N N O VAT I O N

http://standards.CTA.tech

i3 - November/December 2017

Table of Contents for the Digital Edition of i3 - November/December 2017