balance
Stereo balance: -1 is hard left, 0 is centre, 1 is hard right.
An ATTENUATION of the channel being turned away from, never a boost of the other one. A balance that amplified could push material already at full scale past it, and there is no limiter on this side of the ring to catch that.
Only the first two channels move. Panning a centre or a surround channel is a different feature with a different name, and doing it quietly here would surprise anyone who asked for what the word means.
A change is heard after the audio already buffered has drained, which is the ring's depth: at least 200 ms, and longer on Android where the device's own buffer sets it. That is the cost of applying it on the way IN, and it is the right trade here because a balance is set once and left, unlike the volume, which lives on the ring's read side precisely so that it is heard within one device period.