Evaluating loudspeakers If you don't have a lot of money to spend but you want to estimate the frequency response of different loudspeaker setups what is the best way to do it?

I bought a very nice microphone and built a box with foam on the inside. My idea is to place the loudspeaker and the mic in the box and measure the power level at different frequencies by playing a sine tone at those frequencies.

Or is it better to have the microphone and loudspeaker in an open space where the mic is 10 inches away from the loudspeaker?

I'm sure neither of the 2 methods above are valid for making such measurements (if so please explain why), but how should I do then? 

Also, should I use sine tones or is it better to use another test signal like an "impulse", "white" noise or a chirp signal? 

Hoping to get some good answers / advice

Thank you!
Not an easy job. A loudspeaker produces a complicated 3 dimensional sound field, which heavily interacts with the environment. Even at a distance of a about 3 feet the reflected energy is significantly bigger than the direct energy at most frequencies. Typical loudspeaker measurements are


On axis response in an anechoic chamber
Full 3D response in an anechoic chamber
Radiated power in the far field in a highly reflective environment.
Room responses taken in "real world" setups, deriving a perceptually relevant spectral metric and averaging over a large number of environments and placements


Each of these measurements require specific measurement methods and techniques which are also not trivial. 

Anything you can do with a single microphone in real room will most likely be either useless and misleading. The box is also not a good idea since any box has very strong internal acoustic modes and what you will be measuring will be dominated by these modes regardless of what the loudspeaker is doing. 

Depending on the physical size of the loudspeaker and the size of your measurement space, you may be able to pull off a near field measurement with careful time gating of the impulse response (loosing a lot of low frequency resolution in the process). Getting this right is a lot of work and in my opinion not worth the bother.