How to use the command 'sox' (with examples)

The command sox stands for Sound eXchange. It is a versatile command-line tool that allows you to play, record, and convert audio files. It supports a wide range of audio formats, which are identified by their file extensions. By using sox, you can perform various operations on audio files, including merging, trimming, normalizing, reversing, and printing statistical data.

Use case 1: Merge two audio files into one

Code:

sox -m input_audiofile1 input_audiofile2 output_audiofile

Motivation: This use case is useful when you want to combine two separate audio files into a single file. For example, if you have separate audio tracks for vocals and instruments, you can merge them to create a complete song.

Explanation:

• input_audiofile1 and input_audiofile2 are the paths to the two audio files that you want to merge.
• output_audiofile is the path to the output audio file that will contain the merged audio.

Example output: The two input audio files are combined into a single audio file, which is saved at the specified output path.

Use case 2: Trim an audio file to the specified times

Code:

sox input_audiofile output_audiofile trim start end

Motivation: You may need to trim an audio file to remove unwanted portions or extract specific segments. For instance, you can use this command to extract a specific part of a song or remove gaps at the beginning or end of a recording.

Explanation:

• input_audiofile is the path to the input audio file that you want to trim.
• output_audiofile is the path to the output audio file that will contain the trimmed audio.
• start is the starting time of the segment to be trimmed. It can be specified in seconds or using the HH:MM:SS.sss format.
• end is the ending time of the segment to be trimmed. It can also be specified in seconds or using the HH:MM:SS.sss format.

Example output: The specified portion of the input audio file is extracted and saved as a separate audio file.

Use case 3: Normalize an audio file

Code:

sox --norm input_audiofile output_audiofile

Motivation: Normalizing an audio file adjusts the volume to the maximum peak level without causing any clipping. This is useful when you want to ensure consistent volume levels across multiple audio files or prevent distortion in audio recordings.

Explanation:

• input_audiofile is the path to the input audio file that you want to normalize.
• output_audiofile is the path to the output audio file that will contain the normalized audio.

Example output: The volume levels of the input audio file are adjusted to the maximum peak level and saved as a new audio file.

Use case 4: Reverse and save an audio file

Code:

sox input_audiofile output_audiofile reverse

Motivation: Reversing an audio file can be useful for creative purposes or for analyzing audio content. For example, you might want to add a reversed effect to a song or study the waveform in reverse.

Explanation:

• input_audiofile is the path to the input audio file that you want to reverse.
• output_audiofile is the path to the output audio file where the reversed audio will be saved.

Example output: The input audio file is reversed, and the reversed version is saved as a separate audio file.

Use case 5: Print statistical data of an audio file

Code:

sox input_audiofile -n stat

Motivation: Printing statistical data of an audio file can provide valuable information about its characteristics, such as duration, sample rate, channel count, and more. This can be helpful for analysis and understanding the properties of the audio file.

Explanation:

• input_audiofile is the path to the input audio file for which you want to print statistical data.
• -n is an option that tells sox to perform operations without writing any audio file.
• stat is the parameter that instructs sox to print the statistical information of the audio file.

Example output: The command displays various statistical information about the input audio file, including its duration, sample rate, channel count, peak amplitude, and more.

Use case 6: Increase the volume of an audio file by 2x

Code:

sox -v 2.0 input_audiofile output_audiofile

Motivation: Increasing the volume of an audio file can be necessary when the original recording is too low in volume. By amplifying the volume, you can enhance the audibility and overall listening experience.

Explanation:

• -v 2.0 is the option that instructs sox to increase the volume by a factor of 2.0.
• input_audiofile is the path to the input audio file that you want to amplify.
• output_audiofile is the path to the output audio file where the amplified audio will be saved.

Example output: The volume of the input audio file is increased by 2x, and the amplified audio is saved as a new file.

Conclusion:

The sox command is a powerful tool for manipulating audio files. It allows you to perform various operations, such as merging, trimming, normalizing, reversing, and extracting statistical information. By understanding these use cases and the corresponding command syntax, you can effectively work with audio files and achieve your desired audio processing tasks.