calculate_loudness_cpp

Native C++ port of the bramslow2004 canonical engine, corrected per
AMToolbox 1.6.0 reference with noted simplifications.

Calculates the American National Standards Institute (ANSI) S3.5-1997
Speech Intelligibility Index (SII) (ANSI 1997,
(ANSI, 1997)), a standard
method for computing the intelligibility of speech from acoustical
measurements of speech, noise, and hearing thresholds. This package
includes data frames corresponding to Tables 1 - 4 in the ANSI standard as
well as functions utilizing these tables and user-provided hearing
threshold and noise level measurements to compute the SII score. The
methods implemented here extend the standard computations to allow
calculation of SII when the measured frequencies do not match those
required by the standard by applying interpolation. Furthermore, the
package now includes a native, highly optimized C++ implementation of the
canonical Moore & Glasberg (2004) specific loudness model for impaired
hearing, which structurally mirrors the bramslow2004 implementation from
the Auditory Modeling Toolbox (AMT) to calculate loudness in perceptual
sones. It also includes advanced methods to predict aided SII based on
hearing aid prescriptive rationales, introducing Open-NL (Open Non-Linear),
a novel theoretical optimization framework. Open-NL utilizes a Nelder-Mead
simplex algorithm to maximize the ANSI SII metric, subject to computational
physiological loudness penalties and simulated hardware Maximum Power
Output (MPO) constraints, to derive theoretical gain targets. The package
also provides functions to calculate real-ear insertion gains, estimate
maximum power output (SSPL90), and prescribe dynamic range compression.
NOTE: This package is explicitly flagged as a non-clinical academic tool
designed exclusively for theoretical modeling and simulation. It has not
undergone clinical validation and is strictly contraindicated for general
clinical fitting. Unapproved use for direct patient care is prohibited. Any
application of this tool to human subjects must occur exclusively within
the strictly controlled context of Institutional Review Board (IRB)
approved research studies. Development of this package was originally
funded by the Center for Bioscience Education and Technology (CBET) of the
Rochester Institute of Technology (RIT).

Mark Shaver

Calculate ANSI/ASA S3.5-1997 (R2024) Speech Intelligibility
Index

calculate_loudness_cpp function

<dl><dt>inputF</dt>
<dd>Vector of input frequencies (Hz)</dd>
<dt>inputLdB</dt>
<dd>Vector of input spectrum levels (dB/Hz, free field)</dd>
<dt>HLcf</dt>
<dd>Audiogram frequencies (Hz)</dd>
<dt>HLohcdB0</dt>
<dd>OHC loss at audiogram frequencies (dB)</dd>
<dt>HLihcdB0</dt>
<dd>IHC loss at audiogram frequencies (dB)</dd>
<dt>NoChan</dt>
<dd>Number of ERB channels (default 30)</dd>
<dt>E_Beg</dt>
<dd>Lowest ERB rate (default 3.0)</dd>
<dt>E_End</dt>
<dd>Highest ERB rate (default 32.0)</dd>
<dt>Binaural</dt>
<dd>Integer indicating whether to compute binaural loudness (default 0L)</dd></dl>

Arguments

Calculate Canonical Loudness (Native C++ Engine) — calculate_loudness_cpp

<dl>

<dt>inputF</dt>
<dd>Vector of input frequencies (Hz)</dd>


<dt>inputLdB</dt>
<dd>Vector of input spectrum levels (dB/Hz, free field)</dd>


<dt>HLcf</dt>
<dd>Audiogram frequencies (Hz)</dd>


<dt>HLohcdB0</dt>
<dd>OHC loss at audiogram frequencies (dB)</dd>


<dt>HLihcdB0</dt>
<dd>IHC loss at audiogram frequencies (dB)</dd>


<dt>NoChan</dt>
<dd>Number of ERB channels (default 30)</dd>


<dt>E_Beg</dt>
<dd>Lowest ERB rate (default 3.0)</dd>


<dt>E_End</dt>
<dd>Highest ERB rate (default 32.0)</dd>


<dt>Binaural</dt>
<dd>Integer indicating whether to compute binaural loudness (default 0L)</dd>

</dl>

calculate_loudness_cpp: Calculate Canonical Loudness (Native C++ Engine)

Description

Usage

Value

Arguments