In general, "warm" sounding speakers will have frequency responses that are accurate and taper downward after 10kHz. They might also have more bass, which many people feel makes it sound "warmer".
So in general, that usually eliminates DefTech, GoldenEar, Paradigm, B&W, since these usually have a +5dB peak around the 10kHz region.
Try speakers like KEF, RBH, PSB, Revel, Focal, Monitor Audio.
I think a lot of people listen to DefTech/GoldenEar big towers with built-in subs and might think they are not "bright" at all, but it might be because these speakers have a lot of bass, which could make it seem "warm".
But if your hearing is super SENSITIVE, I would audition all speakers as long as possible to be sure.