Open Access

ARTICLE

Machine Learning Model Development for Classification of Audio Commands

Kaveh Heidary^*

Department of Electrical Engineering and Computer Science, Alabama A&M University, Huntsville, AL, USA

* Corresponding Author: Kaveh Heidary. Email:

Journal on Artificial Intelligence 2026, 8, 65-87. https://doi.org/10.32604/jai.2026.072857

Received 05 September 2025; Accepted 18 November 2025; Issue published 13 February 2026

Abstract

This paper presents a comprehensive investigation into the development and evaluation of Convolutional Neural Network (CNN) models for limited-vocabulary spoken word classification, a fundamental component of many voice-controlled systems. Two distinct CNN architectures are examined: a timeseries 1D CNN that operates directly on the temporal waveform samples of the audio signal, and a 2D CNN that leverages the richer time–frequency representation provided by spectrograms. The study systematically analyzes the influence of key architectural and training parameters, including the number of CNN layers, convolution kernel sizes, and the dimensionality of fully connected layers, on classification accuracy. Particular attention is given to the effects of speaker diversity within the training dataset and the number of word recitations per speaker on model performance. In addition, the classification accuracy of the proposed CNN-based models is compared against that of Whisper-AI, a state-of-the-art large language model (LLM) for speech processing. All experiments are conducted using an open-source dataset, ensuring reproducibility and enabling fair comparison across different architectures and parameter configurations. The experimental results demonstrate that the 2D CNN achieved an overall classification accuracy of 98.5%, highlighting its superior capability in capturing discriminative time–frequency features for robust spoken word recognition. These findings offer valuable insights into optimizing CNN-based systems for robust and efficient limited-vocabulary spoken word recognition.

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Keywords

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