I went over to Stevie’s on Monday to look at the counter on his coil winder. As my cab was almost complete he suggested I take it over and he would measure it.
The result was that the response was ruler flat to about 5.5KHz, where there was a slight peak and 7KHz where there was a slight dip. According to Stevie, these could be flattened by tweaking the crossover values and were due to differences in the drivers.
So could you hear them? No compared to a studio monitor, also in the room, you could not tell the two apart.
What this does show is that unless commercial manufacturers individually tune each and every cabinet, there will be differences. This probably applies to active PA cabinets too.