Onethumb.
Your EQ lives in the dongle.
Contour sets the parametric EQ of the CrinEar Protocol Micro, Protocol Max and FiiO KA15 from an Android phone. For the Protocol dongles that used to take a computer and a desktop-browser tool, because phone browsers lack the WebHID it needs. The dongle keeps the EQ, so it works with every app and every device you plug it into.
Drag.
This is the app's own EQ maths, live - drag a dot, then hold. Everything stays inside the dongle's limits, so what you see is what it plays: 8 bands, PEAK, LOW SHELF and HIGH SHELF, gain from -10 to +10 dB. The demo uses the Protocol Micro's limits; the Protocol Max has 10 bands, the KA15 10 bands and -12 to +12 dB.
With PREAMP on AUTO, Contour lowers it just enough to stop your boosts from clipping. Tap any number to type it exactly.
Hold.
HOLD TO SEND is the only button that writes to the dongle. Contour writes every band and the preamp, reads them back, and stores them only if everything matches. Unplug it and use it anywhere.
ON DAC means the profile is in the dongle's memory, so you always know what it holds.
Keep.
One profile per pair of headphones, named after them, stored on the phone. Start FLAT, PASTE Equalizer APO text from AutoEQ, Squiglink or EQ by Ear, or save what the dongle holds right now with FROM DAC.
SHARE sends a profile out as plain text. Keep a copy: profiles live only on your phone.
Undo.
A/B switches the curve off and keeps the preamp, so you hear the difference at the same volume (Protocol Micro only for now). Undo works like Ctrl+Z: one touch is one step, up to 100 steps per profile, and CLEAR EQ is a step like any other.
LAST SENT appears whenever the profile differs from the dongle. Tap it to go back to the version the dongle holds.
Watch.
The app in a minute and a half.
The full guide: every function, step by step, in six minutes.
Free andopen source.
Android 9 or newer with USB OTG, and a Protocol Micro, Protocol Max or FiiO KA15. Android asks for USB access when you plug the dongle in.
No internet permission, no accounts, no analytics - nothing leaves the phone.