I was wanting to do some rough frequency response characterization of some microphone / preamp / soundcard combinations. I am not worried about phase at all just relative frequency responses. Ideally I want to characterize it between 5Khz and 24Khz, but would be happy with 10K to 20K. I plan on getting a speaker with a relatively flat response from 10K to 20K playing white noise, measure the frequency response using REW RTA with a UMM-6 microphone. I would then repeat this process with a microphone on a sound card, take the difference (division?) of the results using REW and have a frequency response curve. I expect it will have some wild results at the very top end, but will this work? Is there a better way to do this? Should I be using stepped sine instead?