The weird thing that I experienced with my Alpair 7.3 is that I realized that it is a very neutral speaker.
Since it has a metal cone composite material, it doesn't literally need tweeters anymore, the highs are all there, yes for me up to 20khz range (when I connected it to my APPJ mini tube amp before). So some would think that it is a slightly bright sounding speaker. For me, it is not, but rather because it is a very detailed driver.
When I installed it in the dashboard of my car, it sounded like a British speaker: rich, warm, and very inviting, but with naturally recessed highs, I wondered why. I realized now that it was just revealing the sonic signature of my Alpine amp, which is known to produce warm sounding signature. Yun lang nga medyo nagroll-off ang highs, which is lacking for my personal taste. For a metal-cone driver, it is sure warm sounding when connected to a certain "warm" amp.
Now either to experiment with a different car amp, or use the Alpair7 for home use and make another DIY box hahaha. Huwag na muna :p