Riaan C wrote: , but I tended to pick up a bit of a rolling feedback from time to time. Muso acquaintance that dropped by had a look and opined it was because I had no crossover.

No! The lack of a frequency divider has no impact on the directionality of the system.

Alan Ratcliffe wrote:

• Crossovers have different roll-offs (how fast they change the level of the frequency after the cutoff point), measured in dBs per octave. Generally, the steeper the roll-off (the higher the number) the better. So 24dB per octave is better than 18dB, 18dB is better than 12.

4th Order slopes introduce more group delay than 1st,2nd and 3rd order so 24dB slopes are not better than 18dB slopes! The slope used will depend on the physical displacement of the two systems and the delay necessary to align them for the intended coverage area.

Alan Ratcliffe wrote: It's an easy calculation to figure out - 1ms per foot or 3ms per metre (the speed of sound).[/li][/list]

The delay needed will depend on the temperature and relative humidity and cannot be assumed. An impulse response of the two signals need to be measured and then aligned accordingly. The calculation will also only work for a single position in space and for someone on the other side of the venue the system might not be perfectly aligned. This is a trade-off and the most important area should have priority...