MP3, WAV, AIFF, FLAC: which format should DJs use?

The four formats in one table

Sizes are calculated for the median length of a track in the Nocti Pool catalog, which is 4:14.

• MP3: a lossy compressed format. At 320 kbps, its best quality, it takes up about a quarter of the space of a WAV. Below 256 kbps, the loss starts to be audible on a big sound system.
• WAV: audio with no compression at all, in CD quality (16-bit, 44.1 kHz) or higher. It's the biggest format, and the worst at handling tags.
• AIFF: the same quality as WAV, also uncompressed, but with real tag support. That's why many DJs who play on decks prefer it.
• FLAC: a lossless but compressed format, like a zip file for audio. The sound is identical to WAV, at a much smaller size. Older players can't read it.

Can you hear the difference?

On earbuds or a small speaker, an MP3 320 and a WAV are almost impossible to tell apart. On a club sound system, the gap is still small, but a lossless file keeps a little more detail in the highs and a little more space in the mix. An MP3 at 128 or 192 kbps, on the other hand, is audible: dull cymbals, swishy highs.

In practice: if you have the space, play lossless (WAV, AIFF or FLAC). If not, an MP3 320 does the job just fine. Avoid anything below that.

The fake lossless trap

Converting an MP3 to WAV doesn't bring back the lost quality: you get a big file that sounds exactly like the original MP3.

To spot a fake lossless file, look at its spectrum in audio software. An MP3 cuts off the highs sharply, around 16 kHz for a 128 kbps MP3 and around 20 kHz for a 320 kbps MP3. A real lossless file goes higher, with no sharp cutoff.

Tags: the AIFF advantage

Title, artist, BPM, key and artwork are written inside the file itself. MP3, AIFF and FLAC carry them with no trouble. WAV doesn't carry them well: depending on the software or the player, you may only see the file name, with no artwork and no info.

That's the main reason so many DJs convert their WAVs to AIFF: same sound, but a library you can read. WAVs downloaded from Nocti Pool carry their tags in a dedicated block that most DJ software can read.

What club decks will play

MP3, WAV and AIFF play everywhere. FLAC plays on recent players, like the CDJ-2000NXS2 and CDJ-3000, but not on older ones.

Before a gig, ask which decks the club has. If you play FLAC, keep a backup copy in MP3 or AIFF. And format your USB sticks in a file system the gear can read: FAT32 works everywhere, exFAT only on recent players.

How much space does it take?

For 200 tracks a month, count on about 2 GB in MP3 320 and 9 GB in WAV. A 32 GB USB stick holds about 3,140 tracks in MP3 320, or 710 in WAV.

A setup that works: your full library in lossless on a drive, and USB sticks prepped with what you'll actually play. The Organize your DJ library guide explains how to sort it all.

On Nocti Pool

MP3 is included in every plan, WAV in the higher plans. Every file comes with its tags: BPM, Camelot key, energy, genre and artwork. The details are on the pricing page.

Frequently asked questions

Is MP3 320 or WAV better for DJing?

Both work. WAV, or better yet AIFF, keeps a little more detail on a big sound system; MP3 320 takes up a quarter of the space, and the difference is rarely audible. Below 256 kbps, find a different file.

Does FLAC work on CDJs?

On recent models, yes, for example the CDJ-2000NXS2 and CDJ-3000. Older models can't read it: keep a copy in MP3 or AIFF if you don't know the club's gear.

WAV vs AIFF: which is better for DJing?

The sound is identical. AIFF handles tags better (title, artist, artwork, BPM, key), which makes it more practical on decks.

Does converting MP3 to WAV improve the sound quality?

No. The quality lost to MP3 compression doesn't come back: the file gets bigger, but the sound stays the same as the MP3.