Convert WAV to M4A
Encode an uncompressed WAV as an M4A, which holds AAC audio. This is the best case for the format: nothing has been discarded before now, so the encoder is working from the original samples rather than from something another encoder already picked over. At the same file size this beats an MP3 made the same way, particularly at lower bitrates.
Use this without the search next time. Prathom Workbench puts Prathom's tools in your toolbar.
Add to Chrome — freeDrop your WAV file here, or click to browse
Up to 50 MB. Deleted automatically after 30 minutes.
What it does
- A first-generation AAC encode from uncompressed audio
- Better than MP3 at the same size
- Plays on every Apple device and modern player
- No watermark and no sign-up
How to use WAV to M4A
- 1
Add the WAV
Drop the file in or choose it from your computer. WAV files are large, so the 50 MB cap arrives quickly.
- 2
Convert
The samples are encoded to AAC and placed in an MP4 container, which is what an M4A is.
- 3
Keep the WAV
The M4A is the listening or delivery copy. The original is the one to work from next time.
The one situation where AAC is at its best
An AAC file made from an MP3 is a second-generation encode. So is one made from an OGG, a WMA, or anything else already compressed. In each case the encoder never sees the recording — it sees what a previous encoder decided to keep, and applies its own different judgments on top.
A WAV has been through nothing. Every sample the microphone produced is still there, at full precision. The AAC encoder therefore gets to make its decisions about the actual audio, which is exactly the situation the codec was designed for.
If you have ever wondered why two AAC files at the same bitrate can sound noticeably different, the number of encoders that have been through the audio is a large part of the answer.
How it works
The WAV's samples are encoded to AAC and written into an MP4 container, which is
what an .m4a file is. The extension exists to mark audio-only MP4 content; the
audio inside is ordinary AAC.
The file typically ends up around a tenth of the WAV, which is compression doing what it does — spending data where the ear notices and skipping where it does not.
AAC or MP3
They are not really competing for the same job any more.
AAC is the better codec and the right choice when you know what will play the file: an Apple device, a modern computer, podcast software, a recent car. At lower bitrates the difference is not subtle.
MP3 is worse and is understood by everything ever built. For a file going to somebody else's equipment, or into a car you have never seen, that is worth more than the codec advantage.
Since both should be encoded from the WAV rather than from each other, there is no reason to treat this as a choice. Make the one you need now, and make the other from the same master when you need it.
Keep the master
The WAV is the copy every future version should come from. Once it is gone, every subsequent conversion starts from something that has already been through an encoder, and that generation is permanent.
Examples
A recording for an iPhone or iPad
Apple devices handle M4A natively and the file is a fraction of the WAV, which matters when a recording has to live on a phone.
A voice-over for a podcast editor
Podcast software works comfortably in AAC, and a first-generation encode from the master is the right thing to hand it.
Frequently asked questions
Is M4A better than MP3?
At the same bitrate, generally yes, and the margin is clearest at lower bitrates. AAC was designed as MP3's successor and does the same job more efficiently. The catch is support: MP3 plays on essentially everything ever made and AAC does not, so an old car stereo or a cheap player may refuse the M4A.
Why is a first-generation encode worth caring about?
Because most AAC files are not one. Converting an MP3 or an OGG to M4A gives a second generation — one encoder's judgments applied on top of another's, which do not agree and cost a little extra. Starting from a WAV means the encoder sees the original recording, which is the situation the codec was designed for and the best it can do.
What is the difference between M4A and AAC?
M4A is an MP4 container holding an AAC track; a bare `.aac` is the same audio with no container around it. The container carries the sample rate, channel count and metadata, so software that expects one handles M4A and sometimes refuses a raw stream. The sound is identical.
Should I make an M4A or an MP3 from my recording?
M4A if you know what will play it — an iPhone, a modern computer, podcast software. MP3 if the destination is unknown or old, because nothing refuses it. Both are lossy, both should be made from the WAV rather than from each other, and there is no reason not to make both.