Flip between mixes and the music never stops.

MixStack is a free A/B tool built around one thing: seamless, gapless, timecode-synced switching. Load your mix revisions, tap another, and it carries on from the exact same moment in the song. No silence, no restart, no lost place. You hear the difference between the mixes and not the switch.

★ SEAMLESS, GAPLESS, TIMECODE-SYNCED
Every mix in the group is locked to one timecode, and each switch is sample-accurate. Flip mid-chorus, mid-snare, mid-reverb tail, and the playhead never moves. That's what makes a small change in a vocal, a kick or a bus compressor audible: the only thing that changed is the mix.

★ ONE TAP TO THE RECORD YOU'RE CHASING
Keep reference tracks beside your mixes and jump between the two groups with a single key. Each group remembers where you were, so you can step out to the reference and come straight back.

★ LEVEL-MATCHED, SO LOUDER DOESN'T WIN
Volume Match evens out the loudness of every track, so you judge the mix and not the level. Switch it off whenever you want the raw files.

★ HEAR IT SOMEWHERE ELSE
Preview a mix through a Car, Room or Arena speaker simulation, built from real impulse responses, and check it in mono or isolate the sides.

★ SEE WHAT YOU'RE HEARING
A live spectrum scope and a per-track EQ show where a mix is carrying its weight. Bypass the EQ to compare before and after.

★ NOTES STAMPED TO THE SECOND
Type a note at the exact moment you hear a problem. Notes pin to the waveform, and you can save them as text or email them to yourself or the mixer.

★ PRIVATE BY DESIGN
No account, no sign-up, no tracking. MixStack works offline, and your audio is processed on the device. It never touches a server.

★ WORKS WITH THE FILES YOU ALREADY HAVE
WAV, FLAC, AIFF, MP3, M4A, OGG and Opus, including high sample rates such as 96 and 192 kHz. Bounce a revision from your session, open it from your files, and it plays. There is no conversion step.

★ KEYS THAT FEEL LIKE KEYS
Hardware-style keys with a distinct click for each kind of button. It uses your phone's own touch feedback setting, so switch Touch feedback (Touch interactions on Samsung) on in system settings to feel it.

Free, with no ads, no accounts and nothing to unlock. Also on iPhone, iPad, Mac and Windows. Learn more at hornsupaudio.com/mixstack.

From HornsUP Audio.