Contour Guide Devices Install 中文

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FiiO SnowSky RETRO NANO EQ app for Android

Contour EQ is a free, open-source Android app that reads and writes the parametric EQ stored inside the SnowSky RETRO NANO. SnowSky is a FiiO brand, so you may also see it as the FiiO Retro Nano. The EQ is written into one of the dongle's USER slots, so it works in every app, with no system equaliser.

Stable 1.8.0

Install Contour

What Contour does on the RETRO NANO

Bands Filter typesPKLSHSLPHPBPAP Kept in the DAC DAC settings in the app
10 bands PeakLow shelfHigh shelfLow passHigh pass 3 slots DAC settings: -
Supported sinceContour 1.8.0
USB ID (VID:PID)0A12:4007
Chip / protocolFiiO
EQRead and write to USER1, USER2 and USER3; every send is read back from the DAC. Slot names are kept in the app
Bands10
Filter typesPEAK, LOW SHELF, HIGH SHELF, LOW PASS, HIGH PASS
Gain-12 to +12 dB
Q0.25 to 8
Frequency20 Hz to 20 kHz
Preamp-12 to +12 dB, whole dB
Where the EQ is keptIn the USER slot you pick, USER1, USER2 or USER3, which becomes the active one. The EQ and the preamp stay after unplugging.
TestedBy the developer on hardware and on a test rig, November 2026. Contour cannot read this DAC's firmware version.

Using Contour with the RETRO NANO

  • Use the RETRO NANO in one of its USB modes. In Bluetooth mode it leaves USB, and Contour does not see it.
  • Pick USER1, USER2 or USER3 above HOLD TO SEND. Contour writes the profile to that slot, reads every band back and makes it the active one. A shorter profile is filled up with flat bands, because the RETRO NANO always holds ten.
  • If the RETRO NANO is on Close EQ when you plug it in, Contour shows that no EQ is active. The first send switches it to the USER slot you picked.
  • Android may ask again for permission to use the RETRO NANO after you unplug it and plug it back in. Allow it, and Contour reads the DAC.

Everything else works the same on every DAC: How to use Contour.

Contour EQ and FiiO Control

FiiO's own tools for the RETRO NANO are the FiiO Control app and FiiO's web page for USB. FiiO Control lists 10 bands, all seven filter types, Q 0.25 to 8, USER1 to USER3 and the stock voicings. Contour offers the five filter types that played as drawn on a test rig and leaves out the two that did not. FiiO Control also works over Bluetooth, which Contour does not. Contour runs on the Android phone the dongle is plugged into, keeps your profiles in a library on the phone and needs no internet or account.

Questions about the RETRO NANO

Is there an EQ app for the SnowSky RETRO NANO on Android?

Yes. Contour EQ reads and writes the RETRO NANO's 10-band EQ and preamp in its USER slots from an Android phone over USB. It is free and open source (Apache 2.0). FiiO's own tools for this DAC are the FiiO Control app and FiiO's web page.

Does the EQ work on a PC or an iPhone?

Yes. The EQ is stored in the RETRO NANO's USER slot, so it plays on every device you plug it into. You need an Android phone only to change it with Contour.

Can Contour update the RETRO NANO's firmware?

No. Contour does not update firmware. It reads and writes the EQ and the preamp in USER1 to USER3.

Do I need a driver or root?

No. Android supports USB audio dongles out of the box, and Contour talks to the RETRO NANO over USB after you allow it in Android's permission prompt. No root, no extra driver.

Other DACs Contour supports

Same chip / protocol: FiiO

Other chips

All supported devices