ANSI CTA 2051 pdf free download
ANSI CTA 2051 pdf free download.Personal Sound Amplification Performance Criteria.
Category 2: The description of a hearing device performance parameter which must include the value measured per the specified testing method. Category 2 requirements do not include a threshold or acceptable range for the parameter measured.
Category 3: Presence of the technological capability or feature shall be reported in the device description. The specific value/metric for measurement of this value is not within the scope of the standard.
Measurements in this standard specify the use of tones (sine waves) as a stimulus signal. It is recognized that many devices will include non-linear audio processing (DSP) (for example, noise suppression, band equalization) that may cause unexpected test results when tones are used as test stimulus signals. Therefore, when performing measurements using tones as specified in Section 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, and 4.7, any non-linear signal processing should be disabled.
Alternatively, if using tones is not appropriate for testing a specific device, for example, due to the inability to disable non-linear processing, alternative test signals such as real speech and 113rd octave pulsed noise signals may be used. If an alternate test signal is used, 1/3d octave analysis should be performed to obtain individual frequency based test results, similar to what would have been obtained if tone-based measurements were performed.
As in ANSI S3.22-2014, Section 5.2.5, controls of the device under test shall be set for the widest available frequency response range, e.g., tone control typically set for minimum effect.
As in ANSI S3.22-2014, Section 4.1, test signal(s) shall exceed background noise by at least 10 dB, and unwanted stimuli shall be sufficiently low so as not to affect the test results by more than 1 dB.
In addition to the tests included in this standard, it is recommended that informal listening tests be performed during both product development and final evaluation to ensure that there are no undesirable effects present that are not revealed by objective testing.
Category 1
4.1 Frequency Response Bandwidth (Category 1)
Frequency Response Bandwidth of a sound reproduction system relates to the portion of the input acoustic spectrum that the device can provide to a user. A consistent methodology for measurement (relative to a common reference) and assessment of the spectrum width provides the consumer a means to compare and evaluate competing systems. The upper and lower cut off frequencies are defined as the frequencies at which the estimated insertion response falls 10 dB relative to the average level of the insertion gain in the one-third octave bands from 500 to 3150 Hz. The low frequency cut off for all devices shall extend to 250 Hz or below. Devices labeled as “Standard Band” shall have an upper cut off frequency of 5 kHz or greater. Devices labeled as Wide Band shall have an upper cut off frequency of 10 kHz or greater. Frequency response bandwidth shall be reported and labeled on the packaging. Method: Frequency response is measured in a coupler according to ANSI S3.22-2014 using an 80 dB SPL input signal. The one-third-octave insertion gain response shall be calculated from the values of the pressure response measured in a 2cc coupler or an occluded ear-simulator coupler (as specified in IEC 60318-4, commonly called a “711” coupler).ANSI CTA 2051 pdf download.
