The AB:X mixer on MIX, fourteen stems playing, meters lit

Reference Anywhere.
A/B Everything.

The stem mixer for iPhone that answers one question, wherever you listen: is it better?

Launch news only, never shared. Privacy

TUE 11:48 PMPARKED OUTSIDE

CAR TEST · MIX V8

  1. 01kick disappears in here
  2. 02vocal harsh around 3k?
  3. 03is v8 actually better than v7?
  4. 04ref sounds so much wider. why
  5. 05where is everything sitting
  6. 06pick a master before Friday

Every car test ends in a list.

Cross it off
before you drive home.

  1. Mixer with KICK soloed; every other stem's meter is dark
    01

    kick disappears in here

    Up to 32 stems, started together.

    Solo it, mute around it, set it anywhere from −40 to +20 dB. A meter lights only when you can hear its stem.

  2. Lead vocal EQ, band 3 cutting 4.7 dB at 3 kHz over the stem's live spectrum
    02

    vocal harsh around 3k?

    A four-band EQ on every stem.

    Bell, shelf, cut or band pass, drawn over the stem's live spectrum. The edit is ink; the signal is light.

  3. MIXREF
    On MIX: the stems' meters lit
    On REF: the stems go dark while the reference plays
    03

    is v8 actually better than v7?

    One key for A/B.

    MIX ⇄ REF puts your mix against a reference; FX ⇄ RAW puts it against itself without your changes. Both flip while it plays.

  4. The reference stage: REF 1 on its own playhead and loop
    04

    ref sounds so much wider. why

    A reference on its own transport.

    Three slots, each with its own playhead and loop, so your chorus sits against theirs. REF CURVE draws its tonal shape into your Master EQ; MONO and band focus are for listening only.

  5. The Lattice: every stem placed by tone and level, LEAD VOX selected
    05

    where is everything sitting

    The Lattice.

    Every stem placed by where its sound sits and how loud it is. Hold one: up and down is level, sideways is tone.

  6. Version compare with BLIND on: the rows read VERSION A, B and C
    06

    pick a master before Friday

    Version compare, blind.

    Up to eight finished mixes on one transport; switching keeps your place in the song. BLIND hides the names and shuffles the order.

The rest of the kit.

  • Master EQ and limiter

    The same four-band EQ across the whole mix, then a two-stage limiter with a brickwall behind it.

  • Level matching

    Every A/B matched in level, adapting as you work or locked while you listen.

  • Level sources

    One loudness baseline for every stem, without changing the balance you built.

  • Projects and snapshots

    Stems, references and every setting, with autosave, and up to twelve named snapshots.

  • Export

    24-bit WAV or AAC, the whole song or one loop, with a notes file for your DAW.

  • Screen off

    Background playback, with lock screen and AirPods controls.

  • Private

    Every file is copied into the app. Nothing is uploaded; nothing leaves the phone.

  • Your colours

    Stage Dark, Studio Light, ten stem palettes, or one of your own.

Your studio has one room.
Your listeners have all the others

  • The car

    Where every mix gets judged.

  • The couch

    At the volume people actually listen.

  • The train

    On the earbuds your listeners own.

  • The walk

    Screen off, with lock screen and AirPods controls.

  • Direct sun

    Studio Light, built to stay readable outside.

AB:X is coming to iPhone in fall 2026. Join the waitlist for launch news.

Launch news only, never shared. Privacy

The car test,
without the drive back

Without AB:X – bounce and hope1 drive per round

  • mix_v7.wav
  • mix_v7_FINAL.wav
  • mix_v8_FINAL_car.wav
  • mix_v8_FINAL_final.wav
  • Bounce a stereo mix and AirDrop it to your phone.
  • Listen in the car and type notes you can't act on.
  • Juggle two apps to hear a reference.
  • Drive back, recall the session, bounce again.
  • Save it as v9_FINAL_final.
  • Pick a master with the names showing.

With AB:X – stems in your pocket1 sitting

The AB:X mixer in Studio Light
  • Export stems once and open the folder in AB:X.
  • Hear it in the car and fix it there: level, EQ, solo.
  • One key flips between your mix and the reference.
  • Export mix notes with every change, ready for the DAW.
  • Snapshot it, and A/B against an hour ago.
  • Compare versions blind.

Questions & answers

01Is AB:X a DAW?

No. It's a comparison instrument: stems, an EQ on each, and one key to A/B against a reference or an earlier version. You make the mix in your DAW; AB:X is where you find out if it's better, wherever you are.

02How do I get my stems in?

Export them from the same start point and open the folder in AB:X, from Files, iCloud Drive or any provider. Up to 32 files: WAV, AIFF, CAF, FLAC, ALAC, M4A, MP4, MP3 or AAC.

03Can I compare against a commercial track?

Yes. Load up to three references. Each has its own playhead and loop, so you can hold your chorus against theirs, and one key flips between them.

04Can I take my changes back to the studio?

Export writes a 24-bit WAV or AAC with a notes file listing every change, or every setting.

05Does my audio leave my phone?

No. Stems and references are copied into the app's own storage, and nothing is uploaded.

06Does it line my stems up?

It starts them together; it doesn't move them. Export every stem from the same zero.

07Which devices?

iPhone, on iOS 17 or later.

The AB:X mixer in Studio Light, fourteen stems playing

Same car. Better mix.

AB:X is coming to iPhone in fall 2026. Join the waitlist for launch news.

Launch news only, never shared. Privacy