Troubleshoot audio equipment and tune instruments using a free online tone testing tool. Generate precise frequencies between 20 Hz and 20 kHz, select four waveform types and adjust the output channel. Presets such as 440 Hz and 1 kHz provide convenient references, while the 15-second sweep can help locate room resonances or frequency peaks and dips in speakers and headphones. https://aitoolspros.com/tools/audio/tone-generator/