My Front speakers is 12 ft from the listening position. The subwoofer is 2 feet behind the Listening position. The subwoofer should be delayed by 10 feet (12-2), is this correct? The system is a 2 channel system with a subwoofer.
However, this is only correct if your subwoofer amp has no internal DSP, which will add additional delay. The only way to measure that internal delay is with automated room correction (e.g. Audyssey) or using REW + calibrated mic.