I want to be able to go in and see how low the overhead clusters can accurately reproduce.
But how would I go about finding the best spot for the xover?
I usually put it in the rack.
It depends on how detailed you want to get. You could measure the existing
system and your subs separately at very low levels, then look at the responses and see where and how they overlap and pick what you think is a good starting
point. Then start there and keep playing with it. Or you could, as Wolf said, look at what the manufacturers recommend and use that as a starting
point.
Two points I'll add here. First, we don't know what your
crossover is or what options it has, so that somewhat limits what we can offer. You may or may not have a choice of filter type, slope, symmetrical or asymmetrical slopes,
etc. Second, an
RTA is only going to show the SPL at the measurement mic, it is not going to let you see what part of what you are seeing may be the room or what is happening at
crossover in regards to
phase. That is where something like
Smaart or EASERA SysTune can be very beneficial. You can certainly setup the
system without such tools but the type of information these programs can provide can be very helpful.
As long as we're discussing xovers, do they usually fall before or after the EQ.
My hope is to run EQ separate for the
house and sub feed. The sub feed will come from a completely separate pre-aux
send so I have complete control over it, among other site-specific reasons.
It depends on the physical devices and what you are trying to do. In my systems EQ is typically both before and after the
crossover, before for general subjective tuning and after for objective
system tuning.
One warning is to keep in mind that both the levels out of the
console and the amp levels can function as part of the EQ and
crossover. The EQ aspect is pretty easy to see, if you turn up the sub via the
console or amp then that's like turning up all the faders for the sub frequencies.
The
crossover effect is a little more indirect but if you think of the fact that a
crossover is a slope, sloping down for the lower frequency
element and up for the higher frequency
element, then you might see how the
level of each
element affects where the two slopes cross. If you turn up the lower frequency
element or
attenuate the higher frequency component, then the frequency where the two slopes cross, the
crossover point, moves up. If you turn down the low frequency component or increase the
level of the high frequency component, then the resulting
crossover point moves down in frequency. So remember that the relative amplitude of the signal components can affect the
crossover and that any changes in those may require changes in the
crossover settings. It may take several iterations of adjusting the
console outputs, amps or powered
speaker levels and the
crossover settings to get where you want.