You have a couple options in SignalScope X, depending on what kind of analysis you are trying to perform.
If you are measuring an acoustic response (frequency response or impulse response) with an impact hammer, then the Dual FFT Analyzer tool is what you need (requires Pro Tool Set subscription). The Dual FFT Analyzer includes options specific to impact testing.
If you just need to capture an impulsive sound, then you can do it with the Oscilloscope. For an impact sound that lasts 2-5 ms, you could set the time scale to 0.5 or 1.0 ms/Div and turn on Single-shot triggering for your input(s). You'll need to set a trigger threshold that allows you to capture the impact and reject other lower-amplitude sounds.
The trigger point will be the first input sample that exceeds the threshold with the selected slope (positive or negative). If you need to look at data that precedes the trigger point, you can drag the time axis to the right.
Oscilloscope data can then be saved to a data file (CSV, MAT, or TXT) or an audio file (AIF, CAF, or WAV).
Here's an example of a handclap in a small room with a time scale of 0.5 ms/Div, shifted to the right by 0.5 ms.
