True, but of the same importance, the speaker cannot be measured independently of the room in a home setup. You need an anechoic chamber, or at least a large and very quiet space. Even a decent size living room will alter the measurements considerably and of course materials matter too.

I have spent a lot of time measuring rooms and you can't underestimate how they can mess with frequencies, but it's also true that good speakers sound pretty good in almost any room, and bad ones will sound bad.