# Backing Vocal Width Expander Turn a single vocal into a wide stereo harmony stack of 3, 5, or 7 transposed voices panned across the field. > Canonical page: https://elysiatools.com/en/tools/audio-backing-vocal-width - **Category:** Media - **Keywords:** backing vocals, vocal width, harmony stack, stereo widening, choir effect, vocal ensemble, haas ## Overview Creates a lush, wide backing-vocal stack from a mono or stereo lead vocal. The input is split into 3, 5, or 7 voices, each transposed by a different interval (octave/5th/3rd above and below) and placed at a constant-power pan position across the stereo field, with optional short Haas delays (5–35 ms) on the inner voices to widen the image beyond what panning alone can do. The result is a thick ensemble/choir texture. Pitch shifting uses FFmpeg's rubberband filter with formant preservation when available, falling back to the asetrate resample trick. Optional loudness normalization to streaming levels. ## Inputs - **Lead vocal audio** (file) - **Stack size** (select) - **Spread** (select) - **Haas delay (ms)** (number) - **Include sub-octave** (checkbox) - **Backing level (%)** (number) - **Preserve formant** (checkbox) - **Normalize loudness** (checkbox) - **Output format** (select) ## When to use - Create wide backing vocals from a single lead vocal recording. - Add a dense ensemble or choir texture to a vocal arrangement. - Expand a centered vocal with controlled panning, pitch intervals, and optional Haas widening. ## How it works - Upload an audio file containing the lead vocal. - Choose a 3-, 5-, or 7-voice stack and select a narrow, medium, or wide spread. - Adjust optional Haas delay, sub-octave inclusion, backing level, and formant preservation. - Enable loudness normalization if needed, then export the result as MP3, WAV, FLAC, M4A, or OGG Vorbis. ## Use cases - Pop and electronic vocals that need a wider stereo backing layer. - Rock and indie productions requiring a thick ensemble-style chorus texture. - Demo arrangements where one recorded vocal must suggest multiple harmony parts. ## Frequently asked questions ### What audio can I upload? The tool accepts an audio file through the Lead vocal audio input, including mono or stereo vocal recordings. ### How many voices can the stack contain? You can choose 3 voices for a tight texture, 5 voices for a wide stack, or 7 voices for a dense vocal wall. ### What does the spread setting control? It controls how widely the generated voices are placed across the stereo field: narrow, medium, or wide. ### What is the Haas delay used for? A short Haas delay on inner voices adds width beyond panning alone. The available range is 0 to 35 milliseconds. ### Which output formats are available? The result can be exported as MP3, WAV, FLAC, M4A, or OGG Vorbis. ## Related tools - [Audio Add Silence](https://elysiatools.com/en/tools/audio-add-silence): Add a specified duration of silence to the start or end of an audio file - [Audio Fade In](https://elysiatools.com/en/tools/audio-fade-in): Apply a fade-in effect to the beginning of the audio - [Audio Fade Out](https://elysiatools.com/en/tools/audio-fade-out): Apply a fade-out effect to the end of the audio - [Audio Join Stereo](https://elysiatools.com/en/tools/audio-join-stereo): Join two mono tracks into a single stereo file - [Karaoke Vocal Reducer](https://elysiatools.com/en/tools/audio-karaoke-track): Attempt to remove vocals from a stereo track - [Mid/Side Decode](https://elysiatools.com/en/tools/audio-mid-side-decode): Decode a Mid/Side file back into a stereo file - [Mid/Side Encode](https://elysiatools.com/en/tools/audio-mid-side-encode): Encode a stereo file into Mid/Side channels - [Image Sequence to Video](https://elysiatools.com/en/tools/image-sequence-to-video): Convert uploaded image files or a ZIP archive of frames into a video, sorted naturally by filename ## 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 - [Karaoke, Stem Separation & Vocal Tools](https://elysiatools.com/en/hubs/karaoke-and-stem-separation-tools): Remove vocals for karaoke tracks, split songs into stems, isolate or double vocals, slice beats, and balance your mix with free browser-based audio tools. - [Audio Encoding and Format Conversion Tools](https://elysiatools.com/en/hubs/audio-convert): Compare audio format conversion, bitrate changes, sample-rate conversion, codec swaps, and export tools in one hub for delivery and archive workflows. - [Audio Editing and Cleanup Tools](https://elysiatools.com/en/hubs/audio-utility): Compare audio trimming, silence removal, fades, mixing, and denoise tools in one hub for podcast, voiceover, and music cleanup workflows. - [Audio Preview, Tone, and Effect Generator Tools](https://elysiatools.com/en/hubs/audio-generate): Compare audio preview generation, silence creation, ringtone building, fingerprinting, loudness reports, and effect-style audio generators in one hub.