File Delivery Formats for Voice Over

Practical guide to audio file formats. Learn which format to use for your specific platform or purpose. Understand MP3, WAV, AAC, FLAC, and why format choice matters for audio quality and platform compatibility.

By Joel De Las Heras Beán — Audio engineer with +5 years of technical production experience Published: July 20, 2026 · Read time: 8 minutes

The Core Question: Compressed vs. Uncompressed

All audio formats fit into two categories: Compressed (smaller files, quality loss) and Uncompressed (larger files, no quality loss).

Most voice-over workflows use compressed formats for delivery but should be mixed/mastered in uncompressed format for maximum quality.

The Standard Formats: When to Use Each

MP3 (MPEG-3)

When to use: Streaming, podcasts, web delivery, client preview

• Most compatible format across all platforms
• Smallest file size (good for web distribution)
• Mild quality loss but acceptable for voice-only content

Specifications: 128 kbps–320 kbps bitrate (192 kbps is standard for voice-over)

File size example: 2-minute voice clip = 3–5 MB

WAV (Waveform Audio)

When to use: Production, editing, archival, professional workflows

• Uncompressed (highest quality)
• Industry standard for professional audio work
• Larger files (not ideal for web)

Specifications: 44.1 kHz or 48 kHz sample rate, 16-bit or 24-bit depth (24-bit is professional standard)

File size example: 2-minute voice clip at 24-bit/48kHz = 55–75 MB

AAC (Advanced Audio Codec)

When to use: Apple platforms, YouTube, modern streaming services

• More efficient compression than MP3 (better quality at same file size)
• Standard for Apple products (iTunes, Apple Music)
• YouTube preferred format

Specifications: 128 kbps–256 kbps bitrate (192 kbps for voice)

File size example: 2-minute voice clip = 2–4 MB

FLAC (Free Lossless Audio Codec)

When to use: Archival, lossless distribution, audiophile platforms

• Lossless compression (no quality loss, but compressed)
• Supported by podcasting platforms and specialty distributors
• Larger than MP3/AAC but smaller than WAV

Specifications: 24-bit, 44.1–48 kHz

File size example: 2-minute voice clip = 8–12 MB

Sample Rate & Bit Depth: What These Mean

Sample Rate (measured in kHz): How many times per second the audio is digitally captured. Higher = more detail, larger file.

• 44.1 kHz = CD quality (good for music)
• 48 kHz = Professional/broadcast standard (best for voice)
• 96 kHz = High-resolution (rarely needed for voice-only)

Bit Depth (measured in bits): How much information is captured in each sample. Higher = more dynamic range, larger file.

• 16-bit = CD quality (adequate)
• 24-bit = Professional standard (preferred for production)
• 32-bit = Floating-point (specialized uses)

For voice-over: 48 kHz, 24-bit is the professional standard. It captures all the nuance needed for broadcast and production.

Format Recommendations by Platform

What Professional Voice Actors Should Deliver

When you hire a professional voice actor, they should provide:

• Master WAV file (24-bit, 48 kHz uncompressed) — Your archival copy
• MP3 version (192 kbps) — For general distribution and preview
• AAC version (192 kbps) — For Apple platforms and YouTube
• Alternative formats on request (FLAC, specific bitrates)
• Multiple takes/versions labeled clearly (if applicable)

Any professional voice actor should be able to deliver across formats without additional charges. Format conversion is a technical step, not creative work.

File Size vs. Quality: The Tradeoff

For voice-over specifically (not music), the quality difference between formats becomes negligible for end users:

• 128 kbps MP3 vs. 192 kbps MP3: Most listeners can't hear the difference
• 192 kbps AAC vs. WAV: Professional equipment might detect difference; average listener won't
• 192 kbps MP3 vs. uncompressed WAV: Imperceptible difference for voice-only content

This is why MP3 became the standard for web distribution — quality is acceptable for voice, file sizes are tiny.

Common Mistake: File Format vs. Container

A ".mp3 file" is actually two things: the codec (MP3) and the container (file wrapper with metadata).

You might receive: "MP3 inside an M4A container" or "AAC inside an MP4 container."

For your purposes, this usually doesn't matter. What matters is whether the file plays on your target platform. If you're unsure, ask the voice actor to clarify: "Can I use this directly on YouTube?" or "Will this work in my editing software?"