Voiceover File Formats and Delivery: A Quick Guide

You nailed the read. The client loved the audition, the session went smoothly, and now all that's left is sending the files. Then the email arrives: "Please deliver as 48k/24-bit WAV, mono, with files named per the attached spec." If that sentence makes your stomach drop, this guide is for you. Technical delivery trips up more new voice actors than performance does, and the good news is that none of it is hard once someone explains it plainly.

WAV vs MP3: Which Voiceover File Format to Send

The short version: deliver WAV unless the client specifically asks for MP3.

A WAV file is uncompressed audio. It contains everything your microphone captured, which is exactly what a client's audio engineer wants. They may be mixing your voice under music, running it through processing, or cutting it into a video timeline, and every one of those steps benefits from starting with full-quality audio.

An MP3 is compressed audio. The encoder throws away data to shrink the file size, and once that data is gone, you cannot get it back. That trade-off is fine for auditions, where casting directors are listening for performance and want small files that load fast. It is usually the wrong choice for finished work.

Here is how I break it down for my students:

• Auditions: MP3, typically 192kbps or higher. Most casting sites specify this anyway.
• Final delivery: WAV, unless the client requests otherwise.
• IVR and phone systems: Sometimes these need specific formats like 8kHz u-law files. Ask the client, because phone systems are their own strange world.
• Podcasts and radio: Often WAV for production, but some clients want broadcast-ready MP3s. Again, ask.

One thing I see constantly with newer talent: never convert an MP3 back into a WAV and deliver it as a WAV. The lost quality does not come back, and an engineer can spot it. If your session was recorded as a WAV, deliver that original file.

Sample Rate and Bit Depth Explained in Plain English

These two numbers describe how your audio is captured, and they show up in nearly every voiceover delivery requirement.

Sample rate is how many times per second your interface measures the audio signal. The two rates you will actually encounter are 44.1kHz and 48kHz. Music traditionally lives at 44.1kHz, while video and broadcast live at 48kHz. Since most VO ends up attached to video, 48kHz has become the working standard for voice over. When in doubt, record at 48kHz.

Bit depth is how precisely each of those measurements is stored. Your two options are 16-bit and 24-bit. Record at 24-bit. It gives you more headroom and a lower noise floor, which means quiet passages stay clean and you have more room for error with your recording levels.

So the default spec you should set in your recording software today is 48kHz, 24-bit WAV. In Reaper, that lives in your project settings, and I recommend saving it as your default project template so you never have to think about it again. If a client asks for 44.1kHz/16-bit, you can convert down from your higher-quality original with no problem. Converting up from a lower-quality file does nothing useful.

One more setting worth checking: record and deliver in mono unless told otherwise. Your voice comes from one microphone. A stereo file of a mono source doubles the file size for zero benefit, and some production workflows will flag it.

File Naming: The Unglamorous Skill That Gets You Rehired

Nothing about file naming is exciting, and that is exactly why doing it well makes you stand out. Producers deal with dozens of talent files, and the person whose files drop cleanly into their project gets remembered.

If the client gives you a naming convention, follow it exactly. Capitalization, underscores, numbering, all of it. A spec that says "ACME_Spot01_TalentName_v1.wav" means precisely that, not your creative interpretation of it.

If no convention is given, use a format like this:

• ClientName_ProjectName_YourName_Take1.wav

A few rules that apply no matter what:

• No spaces in filenames. Use underscores or hyphens instead, since spaces can break links in some upload systems.
• Never send a file called "Untitled.wav" or "audition_final_FINAL2.wav." It looks careless because it is.
• Include your name. Casting directors download stacks of auditions, and a file with no name attached is a file that gets skipped.
• If you deliver revisions, add a version number. "v2" tells everyone instantly which file is current.

How to Actually Deliver the Files

Email attachments cap out quickly, and WAV files are big. A minute of 48kHz/24-bit mono audio runs around 8 to 9 megabytes, so a long narration project will blow past email limits fast.

Your realistic options:

• Client portals: Voices.com, Voice123, and similar platforms have built-in delivery. Use them when the job came through the platform, since delivery through the site also protects you in disputes.
• File transfer services: WeTransfer and similar tools work well for one-off deliveries. Send the link in a short, professional email.
• Cloud storage: Dropbox and Google Drive links are the workhorses for ongoing clients. Keep a tidy folder per client and double-check your sharing permissions before sending, because a link the client cannot open makes a bad impression.
• The client's system: Larger production houses may hand you an upload link or FTP details. Follow their instructions and confirm the upload went through.

Whatever method you use, send a brief note listing what you delivered: how many files, the naming used, and an invitation to request adjustments. Clear communication around delivery is part of the product.

Build a Delivery Checklist and Stop Worrying

Every technical mistake in this article is preventable with a checklist you run before hitting send. Mine looks like this:

1. Correct format? (WAV unless specified)
2. Correct sample rate and bit depth? (48kHz/24-bit unless specified)
3. Mono, not stereo?
4. Files named per the client's spec, or per my standard convention?
5. Audio checked top to bottom for noises, mouth clicks, and missed lines?
6. Delivery method confirmed and links tested?

Run that list every time and technical delivery stops being a source of anxiety. It becomes a two-minute routine.

If you are still building confidence on the technical side of voice over, this is exactly the kind of thing I work through with students in 1-on-1 coaching, from session setup to final delivery. And if your recordings themselves need work before delivery specs even matter, take a look at my gear guides and courses here on VO Trainer. Get the fundamentals locked in, and clients will notice that your files are as professional as your reads.