SUB_OUT_L, SUB_OUT_R or just a single SUB_OUT
One or more of the SUB connections could appear on the rear of the android headunit.
What is SUB?
SUB is a shortened name of sub-woofer. This is the speaker that produces the very low frequency sounds. The sub-bass from the sub-woofer. It is all about the bass.
Speakers
8x9s or standard factory fitted speakers that can be as small as 5″ in diameter. These small speakers are good for mid range sound production but just don’t have the bulk for a deep bass, the sub bass.
Bring in the SUB
The SUB speaker is often an aftermarket fitment to expand the sound range of the speakers. The SUB is ideally run from it’s own circuit and output on the android headunit. This allows for the greatest level of fine tuning at the headunit end, bass fader or better the EQ. This is why you find that some of the better thought out android headunits have a SUB_OUT connection. Better if they have SUB_OUT_L and a SUB_OUT_R for greater compatibility with the various aftermarket subs available.
SUB_OUT
- SUB_OUT is sub bass output for a sub bass speaker (MONO)
- SUB_OUT_L is sub bass output for a sub bass speaker (LEFT Channel)
- SUB_OUT_R is sub bass output for a sub bass speaker (RIGHT Channel)
Plugs and Sockets
The SUB_OUT (or often shortened to just SUB) on an android headunit will either be a RCA (Phono) socket on the rear panel or it could equally be the same RCA (Phono) socket on a flying lead bundle. It all depends on the manufacturer. The sockets on the rear panel are cheaper to produce and give the lowest level of install flexibility. The flying lead bundle means production costs are higher due to the extra parts, picking and packaging. But the flying lead has the greatest flexibility for installation options.

RCA/Phono SUB connector
SUB connections from the android headunit are usually a RCA (phono) socket and this requires a matching plug. The SUB RCA/Phono plug is shown in the picture below. The RCA phono socket is used on many of the android headunit connections and are easily confused. If the SUB out isn’t working and the app for EQ/Bass fader is set ok, check the SUB out on the android headunit is connected to the SUB_IN of the sub.
Problems
A common problem found when installing a sub to the android headunit and we have a solution to the ‘Android head unit has one sub out but sub has two inputs‘.
