Originally Posted by
Justin Zazzi
Hello mauian, and you're welcome!
Thank you for the question.
An RTA that uses pink noise will not capture any time-related information such as phase, impulse response, group delay, waterfall, and so on. Time information adds another layer of complexity to what you're doing, but also another layer of information you can use to your advantage. The thing I use time information for the most is setting time delays and polarity and ensure each speaker is summing together correctly.
You can use an RTA to see phase interaction near a crossover point but you can only see if two speakers sum together nicely or if they fight eachother. If they fight eachother, you cannot see which one has a phase response you prefer so you don't know which one to try and adjust.
Time information can be acquired using the acoustic timing reference in REW if you have a USB microphone, however I do not have much experience with that technique. I prefer to use a two-channel sound card with a loop-back cable for the timing reference which seems more reliable. You'll need to use the "measure" button to do a sweep to get time information.
A relatively new feature in REW is the ability to vector-average measurements to reduce the influence of reflections and background noise. This method requires phase/timing information so you must use the measure/sweep method with some kind of timing reference, and that could be more challenging with a USB mic.
Something else you miss out on with a simple USB mic is tons of headache trying to connect everything and settings that are initially confusing and you generally not being productive for a while. The learning curve is steeper, but it comes with more potential benefits too. Very double-edged sword kind of thing.