Hello,

You have indeed to consider if the sound you will be recording is about to reach that level, but there is another thing also to check to make your decision:

What is the output signal delivered by your mic at thoses high levels? (you can calculate that by looking to the sensitivity rating of your mic) It might be possible that at high SPL level, the output of your microphone might be clean, but so hot that your preamp can't handle it. In that case also the -10 dB can help.
(a quick rough calculation, might be wrong because it's a long time I didn't do this... so correct me in that case: AT4033 sensitivity:
25.1 mV re 1V at 1Pa (94dBSPL). So at 145 dBSPL the mike will output: 145-94=51; 51/6=8.5; 2^8.5=360; 0.0251*360=9V which mean a 9v RMS output... can your preamp handle this?)

So I suppose vocals aren't really going to go 155dB SPL (?), so I would NOT engage the -10dB pad? is this correct?

Voice can be very loud, (opera singers for instance), and normal SPL measurement are done or recalculated to 1 meter, and are approximately RMS (correct me here, as my way of putting it is quite bad). So if your mic is very close of a sound source, it can receive a SPL much more high than "book described" SPL (which are meant "at one meter").

So I don't have a definite answer on this, from the theory point of view, exept that it will be easy by listening to hear if it's better to use that -10 pad.

Best regards,

Laurent.

Realistically, you will more than likely not need to pad the mic for a vocalist. That isn't absolute, as there are some real screamers out there. But 155 dB is a real high SPL. As for the plosives, they are better controlled by the 80 Hz. highpass filter (and a "popper-stopper"). Great mic...enjoy!