REAPER Audio Workflows

How to batch convert and normalize a folder of audio files in REAPER

By StudioRescue Editorial

Published October 3, 2026

This is the job nobody plans for. You end up with forty interview clips at the wrong sample rate, or sixty sound effects recorded at wildly different levels, or a folder of WAVs that someone needs as MP3s by this afternoon. Doing that one file at a time is miserable, and it is also where mistakes creep in.

REAPER's batch converter is a separate window from the normal render dialog, and plenty of people who have used REAPER for years have never opened it. Here is where it is, what each control actually does, and the things it will not do for you.

Where the batch converter lives

Open File, Batch File/Item Converter. The REAPER User Guide describes it as the tool for converting files or media items to a different format, bit depth or sample rate in one pass.

The Add button does two different things. It adds files from disk, and it adds selected media items from the current project, which is handy if you have already trimmed clips on a timeline and want them exported individually. Once items are in the list, REAPER shows you their channel count, sample rate and bit depth, so you can see at a glance which files are the odd ones out. Remove and Clear take things back out, you can drag rows to reorder them, and clicking a column header sorts the list.

If you do this job regularly, use Presets. Output settings can be saved as a preset, which turns a ten-click setup into one click next time.

Decide where the files go and what they are called

By default the converter writes to the same directory as the input files. You can also Browse or Open to pick a different folder, and there is an option to mirror the source directory structure if your files are spread across subfolders.

The File name field accepts wildcards. The default is $source-converted, which keeps the original name and appends the word "converted", so Vox 1.wav becomes Vox 1-converted.flac. Click the Wildcards button to see the rest, including $project for the project name and $length for the length of the file.

The right-click context menu in the file list has three options worth knowing: Add output files to current project, Replace input file with output file in current project, and Open output file in Media Explorer. The first one saves a round trip if you are converting files you are about to use anyway.

Format, sample rate and channels

Pick the destination format from the Output format dropdown. The settings underneath it change depending on what you choose, so a FLAC output shows encoding depth and compression level while an MP3 output shows bitrate options.

Sample rate and Channels both default to matching the source, so a 48 kHz mono file stays a 48 kHz mono file unless you say otherwise. Choosing a specific rate from the dropdown converts everything in the list to it, which is the fast way to clean up a folder where some files were recorded at the wrong sample rate.

Channels are worth a moment because the behaviour is not obvious. Leaving it on source preserves the structure of each file. Beyond that, REAPER can explode and implode:

• A mono file rendered to stereo produces a two channel file with the same material on both channels.
• A stereo file rendered to mono produces one mono file.
• A stereo file exploded produces two separate mono files.
• A six channel surround file exploded produces six individual mono files, one per channel.

There is also a Resample mode dropdown. The User Guide is blunt about this one: resampling can affect pitch, length or tempo, and it should only be changed if you are confident about what you are doing. The default is a sensible place to stay.

Dither and Noise shaping sit next to those controls. They only matter when you are reducing bit depth, for example 24 bit down to 16 bit. If you are staying at the same depth or going up, leave them alone.

Normalizing, trimming and fading the whole batch

This is the part people usually come looking for. The Normalize/trim/fade button opens a set of post-process render options, and the checkbox beside it switches all of those options on or off in one go.

Inside, you can normalize peaks using peak levels or using loudness-based measurements, including true peak and LUFS targets. You can apply brickwall limiting with a specified dB ceiling for peaks or true peaks. You can trim leading silence and trailing silence, pad the start or end with silence, and choose the fade in and fade out curves.

Which target you pick depends entirely on where the files are going, so treat any number you read online as a starting point rather than a rule. A spoken-word episode heading to podcast apps is commonly delivered around -16 LUFS integrated for stereo, which is a widely used convention rather than a universal specification, and we go through that properly in the guide to hitting -16 LUFS in REAPER. Sound effects and sample libraries are usually normalized to a peak target instead, often somewhere around -1 to -3 dBFS, because what matters there is headroom rather than perceived loudness.

Applying an FX chain to every file

The Use FX option lets you build an FX chain that gets applied as each file is processed. There is also an FX tail field in milliseconds, which matters if your chain includes anything with a decay, such as reverb or a delay, so the tail is not cut off at the end of the file.

This is where the batch converter stops being a file converter and becomes a genuine time saver. Build and audition the chain on a single track first, save it, and reuse it here. If you have not saved a chain before, saving and reusing FX chains in REAPER covers the mechanics.

Two practical notes. First, a chain that was tuned on one voice in one room will not suit every file in a mixed folder, so batch FX works best on material that is genuinely similar. Second, anything that adapts to the input, such as a compressor set by ear on one take, will behave differently on a quieter or louder file.

Speed and metadata

There is a Use CPU cores setting, which defaults to All. More cores means faster processing, and there is rarely a reason to reduce it unless you need the machine for something else while the batch runs.

For metadata you get two options: preserve the existing metadata where possible, and add new metadata. If you are delivering files to someone else's system, check what they expect before you strip anything.

What the batch converter will not do

It is a converter and a post-processor, not an editor. Being clear about the line saves a lot of frustration.

• It will not edit inside a file. It can trim silence from the start and the end, but it cannot find and remove a cough in the middle, or cut out a flubbed line. That is manual work, and removing a one-off noise from a take is a different job.
• Normalizing is not levelling. It sets the overall level of each file against a target. It does not even out a performance that swings from a whisper to a shout within the same file. That needs compression, and compression on a batch is a blunt instrument.
• It will not repair damage that is already recorded. Clipping, distortion and heavy background noise survive conversion intact.
• Lossy to lossy loses more. Converting MP3 files to another lossy format re-encodes them. Go back to the original WAV if you still have it.
• It is not free software. REAPER costs $60 for the discounted license, which covers personal use and small businesses, or $225 commercial, with a 60 day full-function evaluation. If all you need is format conversion, the free command line tools ffmpeg and SoX do that job well and cost nothing.

If you came here because Audacity lost its Macros

A lot of people hit this problem in 2026 for a specific reason. Audacity 4.0 shipped without Macros, which was the free one-click way many people ran batch conversions and normalization. On the official Audacity forum in September 2026, a thread titled "No Batch MP3 conversion feature?" got the plain answer that macros are not part of Audacity 4 yet, and a separate thread confirmed that macros are not in Audacity 4.0 and may be added in a future version. Staying on Audacity 3.x is the workaround people are using.

If you are considering REAPER's converter as a replacement, set expectations accurately. It is not a Macros equivalent. Macros replay an arbitrary sequence of editing commands; REAPER's batch converter converts, post-processes and optionally runs an FX chain. For the specific job of converting and normalizing a folder, it does that well. For reproducing a long custom editing recipe, it does not.