April 8, 2026·6 min read

How to Use Your iPhone as a 4-Track Recorder

A 4-track recorder lets you layer up to four separate audio tracks into a single song. With Reel, your iPhone becomes a portable 4-track studio that records in 32-bit float at up to 96kHz, with overdub, loop, and mixing built in.

What is a 4-track recorder?

A 4-track recorder captures up to four independent audio tracks that play back in sync. Each track can hold a different instrument, vocal, or sound, and you mix them together to create a finished song.

Classic 4-track recorders from the 1980s used cassette tape. Modern versions like the Teenage Engineering TP-7 use digital audio. Reel brings this same workflow to your iPhone with no extra hardware needed.

How Reel works

Reel is designed around a single jog wheel and tape-style transport controls. You record on one of four tracks, rewind, and record the next layer while listening to what you already played.

Every recording is saved as a project with all four tracks kept separate. You can solo, mute, adjust levels, pan, and export the full mix or individual stems.

Recording your first track

Open Reel, tap the record button, and start playing. The built-in iPhone microphone captures mono audio at 48kHz, which Reel converts to 32-bit float to match the project. Tap stop when you are done. That first take is now on track 1.

To add a second layer, arm track 2, hit record, and Reel plays track 1 back while recording your new performance in sync.

Using a USB audio interface

Plug a class-compliant USB audio interface into your iPhone with a USB-C cable or Lightning to USB adapter. Reel automatically detects the interface and switches input to it.

With an interface you can record stereo, connect condenser microphones with phantom power, use instrument inputs, and record at 96kHz in 32-bit float. The OP-1 Field works perfectly for this when set to 8ch USB mode.

Overdubbing and punch-in

Overdubbing means adding new material to an existing track. Reel lets you punch in at any point on a track, record your new part, and punch out, keeping everything else intact.

This is how you build a full arrangement one layer at a time: drums first, then bass, then chords, then melody.

Exporting your mix

When your project is done, export as a single stereo mix or as individual track stems. Reel supports WAV, AIFF, and M4A formats. Stems are useful if you want to finish the mix in a desktop DAW.

WAV and AIFF exports are 32-bit float, preserving the full dynamic range of your recording with zero clipping. M4A uses AAC compression for smaller file sizes.

Frequently Asked Questions

Can I record multi-track audio on my iPhone?

Yes. Apps like Reel turn your iPhone into a multi-track recorder. You can record up to 4 independent tracks, overdub layers, and mix them together into a finished song.

What sample rate and bit depth does Reel record at?

Reel records every project in 32-bit float end to end. The built-in iPhone microphone captures at 48kHz mono, and Reel converts it to 32-bit float for the project. With a USB audio interface you can record stereo at up to 96kHz, natively in 32-bit float when the interface supports it.

Do I need a USB audio interface to use Reel?

No. Reel works with the built-in iPhone microphone out of the box. A USB interface adds stereo input, higher sample rates, and professional mic connectivity.

What file formats can I export?

Reel exports to WAV, AIFF, and M4A formats. WAV and AIFF exports are 32-bit float for maximum dynamic range and headroom. M4A uses AAC compression for smaller file sizes.

Can I use Reel with the OP-1 Field?

Yes. Reel supports the Teenage Engineering OP-1 Field over USB. Set the OP-1 Field to 8ch USB mode in its system settings to enable multi-track recording of all four stems.