I use my mobile sound system in many types of venues which I'm sure each need special room EQing etc. I can hear when the system doesn't sound great but often am not sure what the offending frequencies are.
If you are trying to figure out what frequencies are more excitable than others in a certain space, Bink's Audio CD has sine waves that you can play back to find out what "problem" frequencies do not need reinforcement - and heck, that might only be for one or a couple of spots in the venue. It's a starting point...
I want to purchase a mic that can accurately read the system response from the dance floor and then also be able to read the direct output on the mixer and compare them to assist in EQing the system.
The Marketplace has some good deals on used mics. I haven't had the chance to get into system (component) measurement just yet, but I have a decent microphone that will suffice for when I get started. I bought it from the Marketplace from a reputable poster, along with some other items I use currently.
It doesn't need to be in real time, I just want to get an idea of where there are abnormal peaks or dips in response that the mic is receiving and adjust the system EQ accordingly.
What are my options if I'm on a budget but still want accuracy?
Although the real-time aspect of measurement may not be as feasible during the show, BEFORE the show, it can be invaluable to show how microphone placement (in distance from boundaries as well as the source) affects your reading(s).
I've also read that a way to check that different drivers are in phase is by playing a tone that is about directly between their crossover points, then invert one of the drivers and adjust delay until they are silent. Does that sound about right? What's a good way to find or produce different tones?
The Bink Audio CD is a great one for those tones. Void Speakers also has a sine wave tone CD, as well as one with various tracks of band-limited pink noise.
It looks like Bink's website lease has run out - if anyone has a copy of the CD they can post for the OP, it would be helpful.