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DUO/DUO SE Tips for Use

Earphones don’t connect to device, or earphones are not detected by device

  • Make sure you turn on both earphones by putting your fingers right on the earphones' Touch Sensor, which is located near the rear top surface just below the MMCX connector, and hold there for 3 seconds until your hear an engine-start sound with voice prompt "power on"

  • If using the Duo with a new device, check if the earphones are still connected to a previous device. If so disconnect them from the device first, then wait for at least 20 seconds. Your Duo should now appear on new device's bluetooth list. Select and connect as normal

Only one earphone has sound

Your left and right earphones are paired at the factory so there is no pairing to be done at user level. When only one earphone has sound, it could be because:

  • one of the earphones is not powered on: make sure you switch on the one that has no sound by pressing and holding the centre for 3 seconds until you hear an engine start sound with voice prompt "power on"

  • one of the earphones has run out of battery: charge it and try connect again

  • your earphones are in Mono Mode, to change it back to Stereo Mode, switch on the one that's not On, within a few seconds both L/R earphones should connect and play in Stereo

Why does sometimes the R earphone appear on the BT Pairing List, sometimes the L?

Your Duo has the latest in bluetooth technology that provides maximum power efficiency by automatically connecting to the receiving earphone with the highest battery level. This can be Left or Right and is the reason why they don't seem consistent. The earphone will automatically suggest the best one to pair "FL Duo L" or "FL Duo R". Just select whichever shows up on the screen

When re-connecting to a previously used device, the re-connection is fully automatic so you don't need to make the above decision

Sound is poor

Make sure you choose the right ear tips for best sound quality. This means the largest possible size that will fit your ears, because if you choose ear tips that are too small, sound leakage will occur resulting in poor sound with loss in bass and punch.


Unstable or bad wireless connection

Make sure the earphones and your mobile phones are not operating in an area with crowded or strong 2.4GHz signals, such as microwave, other bluetooth devices and wifi routers


In places where persistent interference occurs, for example at a particular treadmill in the gym, it could be because there is a strong wifi router nearby. Try to move to another treadmill or location away from where you experienced the persistent interference. You may also try put the phone closer to the earphones for example on the table instead of in your jacket, to maximise reception


Bluetooth signals travel in straight line and do not go through walls and solid surfaces. If you are experiencing bad connections please try to make sure the device is the line of sight, or if that is not possible, position your device closer to your earphones such as placing it on the same side as the master/right earphone

Cannot manually switch off earphones

Manual switching off is activated by pressing and holding the right earphone for 5 seconds or more FROM PAUSE MODE. If you are playing music and do the above, it will activate Volume up/down instead. Make sure you first press the left or right earphone once to pause the music, then press and hold the right earphone for 5 seconds until you hear a car door closing sound. Both earphones are now switched off

Factory Reset

In normal use there should be no need for the user to perform this function, which is designed mostly for re-pairing of left and earphones for example if you lose one earphone and get a replacement, and need to pair it with the other remaining earphones. For some issues a Factory Reset may help resolved. If you have run out of options you may do a Factory Reset. Please follow these steps: (Note: it must be done in Power On condition, and both L/R earphones must be present)

– If earphones are off, power on first

– From On position, press both earphones for 5s to power off - keep both hands on L/R and continue to hold for a further 15s

– You will hear "Please restart your headset”

– Hold L/R for 3 seconds to restart, you will hear engine sound + Power On

– Release/remove both earphones, you will see Blue LED on BOTH L/R flashing rapidly, this indicates both L and R are establishing a new link between themselves

– After a few seconds, the rapid flashing will stop, and the LEFT earphone’s LED will change to Red/Blue alternate flashing to indicate it’s entering BT search mode

– You should see FL Duo L on your device list

– Select “FL Duo L” and you will see another message “Bluetooth Pairing Request” (on iOS, on Android a similar message will appear), select “Pair”

– If you see “connection unsuccessful” message, just ignore it by pressing OK (on iOS devices)

– You Duo is now reset to factory default, paired to your phone and are ready to use

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