Step 1: Provide your AMR files using the button above or by toss and let go.
Step 2: Click the 'Convert' button to start the conversion.
Step 3: Fetch your converted M4A files.
AMR to M4A Conversion FAQ
What bitrate does the M4A file end up at?
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A lossy M4A is encoded at 192 kbps by default. The Audio Quality setting also offers 320 kbps for the best quality and 128 kbps for a smaller file. A lossless M4A (WAV, FLAC) ignores the bitrate and keeps every sample.
Is converting AMR to M4A a second round of lossy compression?
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Yes, and it is worth planning around. Both formats are lossy, so the M4A encoder is working from audio that has already been through one psychoacoustic pass, and its own decisions compound the first set. At 192 kbps or above the result is still transparent for most listening. If you have a lossless master anywhere, encoding the M4A from that instead avoids the double pass entirely. AMR is a narrowband speech codec running between 4.75 and 12.2 kbps, modelling the human vocal tract rather than the full audio spectrum. An M4A holds AAC in most cases, or Apple Lossless (ALAC) when it came from a lossless rip.
Can I tag the M4A with artist and album information?
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Yes, and it is a genuine gain over AMR, which has nowhere dependable to store any of it. M4A carries title, artist, album, year, track number and embedded cover art in the container itself, so a music library files it correctly without a manual pass. M4A keeps rich iTunes-style metadata, chapters and artwork intact, and is the native audio format across every Apple device.
Why does music sound so poor in this conversion?
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Because one side of it is a speech codec rather than a music codec. It models the human vocal tract and discards everything outside telephone bandwidth, which is fine for a voice memo and destructive for anything with instruments in it. Converting away from it cannot restore the missing frequencies — they were never encoded in the first place. AMR destroys music: its 8 kHz bandwidth removes everything above telephone frequencies, and no amount of re-encoding brings it back.
Will going from AMR to M4A actually reduce my audio quality?
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If AMR is lossy (MP3, AAC) and M4A is lossless (WAV, FLAC), the M4A is no better than the AMR — you cannot recover information already discarded by the lossy AMR codec. If AMR is lossless and M4A is lossy, expect the M4A encoder to recompress; at 192 kbps the loss is imperceptible to most ears.
Can I batch-convert hundreds of AMR files into M4A?
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Several files in one job need a paid plan. Free use is one file per conversion, one conversion an hour. On a paid plan you can add several files to one job, then download each result on its own or all of them in one ZIP.
Can I normalize loudness in the AMR to M4A step?
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Not in this step. The converter has no loudness setting and leaves the level as it is. To even out the volume, run the finished M4A through a Normalize tool on this site.
Will the M4A play on my car stereo / iPod / Sonos / Bluetooth speaker?
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MP3 plays almost everywhere. AAC plays on Apple devices, most Android phones and Sonos. FLAC plays on Sonos and Android but not on older iPods, and WAV plays on nearly everything but makes large files. There are no device presets on this page, so choose the target format your player supports. M4A hides two very different things behind one extension — lossy AAC and lossless ALAC — and non-Apple hardware support is inconsistent.
Is my AMR file private during conversion?
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Yes. Uploaded AMR files are processed on our own conversion servers, no person reviews them, and they are never shared. The upload and the converted M4A are both deleted automatically about 24 hours after the conversion, which leaves time to download the result. See /privacy/ for the full policy.
