Provided you do not exceed 100 db SPL at 1 meter you should be ok for most well built full size speakers. Remember that the majority of expensive speakers actually use extremely cheap drivers (high quality veneer and woodwork can be very expensive). I run my sweep tests at around 90 db SPL at 12 feet back from the speaker.
The problem with running tests at a very low 75 db SPL is that this is not much above the noise floor - so you won't see nulls and you won't get a usable waterfall plot and RT60 due to background noise (heating/air condition/street noise/wind etc).
The problem with running tests at a very low 75 db SPL is that this is not much above the noise floor - so you won't see nulls and you won't get a usable waterfall plot and RT60 due to background noise (heating/air condition/street noise/wind etc).