There are several free audio software options available for noise removal that you can consider:
Audacity: Audacity is a popular and widely used open-source audio editing software. It offers a variety of features, including noise removal tools. You can use Audacity's Noise Reduction effect to reduce background noise and improve the overall audio quality.
Ocenaudio: Ocenaudio is another free audio editing software that provides noise reduction capabilities. It offers a user-friendly interface and allows you to select and remove specific background noise from your recordings.
Krisp: Krisp is a noise suppression software that works as a standalone application or as a plugin for popular communication apps like Zoom, Skype, and more. While it's primarily designed for real-time noise suppression during online calls, it can also be used for post-processing recorded audio.
WavePad: WavePad is a free audio editing software that offers noise reduction tools. It allows you to visually select and remove specific noise elements from your audio recordings.
It's worth noting that while these software options provide free versions with noise removal features, they may also offer premium or paid versions with additional functionality. The effectiveness of noise removal tools can vary depending on the specific audio recording and the quality of the noise you're trying to remove. Experimenting with different software and settings will help you find the one that works best for your needs.