Balance controls are really tricky to implement, but valuable if done right. Tricky as they can cause degradation of the sound the way a volume control can (loss of detail and bandwidth are the 2 big issues).
OTOH if you don't have one, recordings that are poorly mastered or any weird imbalances in your system including room anomalies will not image right. Generally you only need a few db, but IME those that have really highly resolved systems may only need 1/4 of a db of adjustment, while those with poorly set up systems might need considerably more. So the balance control has to be continuously variable and have a little range, yet somehow not affect the sound.
Our solution was to create a control that varies the *gain* of the circuit rather than the level of the signal going to it. This keeps the control out of the signal path. It also limits the range of the control to about 8db, but allows for the micro adjustments that can really make the difference.
OTOH if you don't have one, recordings that are poorly mastered or any weird imbalances in your system including room anomalies will not image right. Generally you only need a few db, but IME those that have really highly resolved systems may only need 1/4 of a db of adjustment, while those with poorly set up systems might need considerably more. So the balance control has to be continuously variable and have a little range, yet somehow not affect the sound.
Our solution was to create a control that varies the *gain* of the circuit rather than the level of the signal going to it. This keeps the control out of the signal path. It also limits the range of the control to about 8db, but allows for the micro adjustments that can really make the difference.