# Audio Overlay Overlay one audio track on top of another at a specific time > Canonical page: https://elysiatools.com/en/tools/audio-overlay - **Category:** Media - **Keywords:** audio, overlay, mix, delay ## Overview The Audio Overlay tool lets you mix two audio tracks by overlaying one on top of another at a specific time. It's designed for adding background music, sound effects, or voiceovers to existing audio files with precise timing and volume control. ## Inputs - **Base Audio** (file): Select the base audio file - **Overlay Audio** (file): Select the overlay audio file - **Overlay Offset (seconds or hh:mm:ss\[.ms\])** (text): e.g., 5 or 00:00:05 - **Overlay Volume (1.0 = original)** (text): e.g., 0.8 ## When to use - When you need to add a sound effect or music track to an existing audio file at a specific moment. - When synchronizing voiceovers or commentary with background audio for podcasts or videos. - When creating layered audio compositions for presentations, audiobooks, or multimedia projects. ## How it works - Upload the base audio file that will serve as the main track. - Upload the overlay audio file to be mixed in. - Optionally, set the offset time to delay the overlay start and adjust the overlay volume using decimal values. - Process the files to generate a new audio file with the overlay applied at the specified time. ## Use cases - Adding intro or outro music to podcast episodes without manual editing. - Overlaying sound effects at specific timestamps in video audio tracks for enhanced production. - Mixing voice narration with background ambiance in audiobooks or educational content. ## Frequently asked questions ### What audio formats are supported? The tool supports common audio formats like MP3, WAV, and others as indicated by the file input options. ### Is there a file size limit for uploads? Yes, each audio file must be under 200 MB, as specified by the file limit in the tool settings. ### How do I specify the overlay offset time? You can enter the offset in seconds (e.g., 5) or in hh:mm:ss.ms format (e.g., 00:00:05) for precise timing. ### Can I adjust the volume of the overlay audio? Yes, you can set the overlay volume using a decimal value where 1.0 represents the original volume, such as 0.8 for reduced volume. ### What happens if I don't set an offset or volume? If no offset is specified, the overlay audio starts from the beginning of the base audio. If no volume is set, the overlay uses its original volume. ## Related tools - [Audio Band-Reject Filter](https://elysiatools.com/en/tools/audio-band-reject-filter): Remove a specific band of frequencies - [Audio Insert Silence](https://elysiatools.com/en/tools/audio-insert-silence): Insert silence at a specific timestamp in an audio file - [Audio Punch In/Out](https://elysiatools.com/en/tools/audio-punch-in-out): Replace a segment of audio with another clip - [Audio Split at Timestamps](https://elysiatools.com/en/tools/audio-split-at-timestamps): Split audio at a list of specified timestamps - [Audio Channel Swap](https://elysiatools.com/en/tools/audio-channel-swap): Swap the left and right channels of a stereo file - [Audio Crossfade](https://elysiatools.com/en/tools/audio-crossfade): Apply a crossfade between two audio files - [Audio Delay](https://elysiatools.com/en/tools/audio-delay): Add a delay effect - [Audio Interview Level Matcher](https://elysiatools.com/en/tools/audio-interview-level-matcher): Match loudness between a host and a guest track (or any two voice takes) while preserving natural dynamics. ## Samples - [Copyright-Free FLAC Audio Samples](https://elysiatools.com/en/samples/flac-samples): Lossless FLAC audio samples for testing and development, mirrored from MP3 set with nature sounds and meditation music - [Copyright-Free MP3 Audio Samples](https://elysiatools.com/en/samples/mp3-samples): Collection of royalty-free audio samples for testing and development purposes including nature sounds, meditation music, and ambient audio - [Copyright-Free WAV Audio Samples](https://elysiatools.com/en/samples/wav-samples): Uncompressed PCM WAV audio samples for testing and development, mirrored from MP3 set with nature sounds and meditation music - [Copyright-Free Raw PCM Audio Samples](https://elysiatools.com/en/samples/pcm-samples): Raw PCM s16le audio samples featuring nature ambience and relaxing music for waveform, playback, and conversion workflows ## Related content - [Multitrack Audio Mixing and Overlay](https://elysiatools.com/en/hubs/audio-multitrack-mixing-and-overlay): Balance multiple audio sources, place timed layers, smooth handoffs with crossfades, and verify a clean, non-clipping result by listening and checking peaks.