Fyra is an iPhone app for comparing mixes of the same song. Load up to four bounces and tap between them while it plays — the switch is sample-aligned and gapless, so nothing changes but the mix.
ALL FOUR PLAY IN LOCKSTEP — TAP A SLOT. THE PLAYHEAD NEVER FLINCHES.
01 · Sample-aligned
Every loaded mix plays at once, locked to the same clock and the same point on the timeline. You only hear the one you’ve selected.
A tap swaps the audible mix without touching the timeline. Same moment, different mix, seamless.
Drag sideways on any waveform to scrub; the seek commits on release. Transport gives you −5 s and +15 s skips and loops by default, so you can compare mixes by replaying the same bars.
02 · Auto gain
Boost any band and the mix gets louder — and the louder version wins the comparison whether or not it sounds better. Every serious engineer knows this bias; almost no tool defends against it. In a comparison app it would be fatal, so both of Fyra’s EQs are auto-normalizing: every curve is loudness-compensated at the EQ itself.
Fyra measures the overall lift or cut in your curve — the area under it, spread evenly across every octave — and trims the volume by the exact opposite. It’s instant and never pumps or breathes: one steady level change, not a compressor.
A surgical cut touches so little of the spectrum it hardly registers, while a wide shelf moves much more — and the trim scales with it.
Net boosts pad the output down; net cuts earn make-up gain. Boosting stops feeling like a free win, and what’s left is the honest question — does it actually sound better?
The compensation value is always on screen, so you always know exactly how much level Fyra is adding or taking away.
A NET BOOST PADS ITSELF DOWN — IT CAN’T WIN ON LOUDNESS.
03 · Two EQs
8 BANDS · A/B BANKS PER MIX · PAD COMPUTED FROM THE CURVE, ALWAYS SHOWN
Rotate the phone for a full-screen editor: drag color-coded handles for gain and frequency, tap to toggle a band, and shape with high pass, low shelf, bells, high shelf, and low pass. The response curve is drawn live from the same math that computes the pad.
Two independent curves per mix with instant switching. Power is shared across banks, and both banks are loudness-compensated — so A/B always compares curve against curve, never level against level.
Fixed-role bands styled like hardware: bass, mid, and treble knobs in 2 dB detents with haptic clicks, plus low- and high-cut sweeps that switch fully off at their idle ends. It shapes whichever mix is audible — letting you compare your existing mixes and then test master EQ changes to hear where to go with your mix.
04 · Gain staging
The master readout shows fader plus auto-compensation combined — the net gain actually applied to the bus. Nothing moves your level without showing itself.
The whole chain runs in 32-bit float, so the only clip point is the DAC. A peak limiter guards that ceiling: bit-transparent below full scale, graceful above it — and it catches the inter-sample overs that slammed masters reconstruct on conversion.
Peak meters read post-limiter — the true output — and a gain-reduction row computed from pre/post taps shows exactly when the limiter works. If the safety net is catching you, you’ll see it.
player 1 ─ EQ 1 (8-band, A/B) ─┐
player 2 ─ EQ 2 (8-band, A/B) ─┤
player 3 ─ EQ 3 (8-band, A/B) ─┼─ mixer ─ master EQ ─ limiter ─ out
player 4 ─ EQ 4 (8-band, A/B) ─┘ (+ fader) │
meter tapsPOST-LIMITER PEAKS · GAIN REDUCTION METERED, NEVER SILENT
05 · Details
Full Now Playing integration: lock-screen play/pause, ±5/15 s skips, scrubbing, and song + mix metadata. Comparison continues while you drive.
WAV, AIFF, MP3, M4A, FLAC. Imports are copied into the app, and its folder is visible in the Files app — AirDrop a bounce straight in.
The common file-name prefix becomes the song name, and cards show only what differs — “Mix 8”, “Mix 9 less synth” — until you rename by hand.
With no processing engaged, mixes play untouched: EQs bypass at the band level, cut filters default off, and the limiter passes unity below full scale.
Mixes, EQ curves, and banks are saved per song. Pick a comparison back up days later exactly where you left it.
Fyra is Swedish for four — about the most alternatives a person can meaningfully hold in their head. The limit is a feature, not a constraint to engineer away.