I used to build loudspeakers in college... Both for fun and because funds were very low
I used to follow plans from a speaker building magazine I kept up with for a few years. I even struck out and built a few of my own... It was a very informative time; I really learned how truly difficult it was to build a world class loudspeaker...
For $1500 you have a fairly wide range of speaker choices, especially if you buy used. New, you could still buy plenty of speakers worth owning.
I would not build a speaker with that kind of money. I don't pretend to think you couldn't get something nice, but there are a few sticking points for me:
1. you will invariably want to move up, and homebuilt loudspeakers have almost no market. You would lose a bundle.
2. cabinet manufacturing and design is paramount to a speaker's resulting sound, IMO. One of the reasons I bought my B&W N805's is they had the least errant color of any speaker I auditioned; they also simply "disappear" into the room with a good playback chain. IMO lots of this has to do with the cabinet design, which no homebuilder could replicate, and I have never seen a kit come close to.
3. crossover design is an art as much as it is a science. Beyond design, different caps, resistors, inductors, etc. have different sonic signatures that cannot be predicted by numbers or cost alone. This is a real difficult area to nail. Good speaker companies spend lots of time here.
That being said, if you want to persue speaker building and you have 24/96 in mind, make sure you build a design that at least goes out to 30-35k (at 6db down) as extended highs really do make 24/96 recordings shine.
24 bit playback... You're going to want a good 24/96 DAC to take advantage of those recordings. A/V receivers, even the top models, don't do as well with 24/96 as a good cd player does with 16/44.1... You need a good 24 bit DAC to make 24 bit playback worth it, IMO.
And that leads to something i was told years ago, forgot for awhile, and relearned multiple times (read: I made mistakes LOL): SOURCE FIRST! Spend as much as you can on the source; it will affect the quality of your playback rig more than any other piece... Even the loudspeakers (where most people put the bulk of their $$)!
Most importantly with speakers, bring 'em home for a home audition if at all possible. Things tend to sound quite different in each person's rig than in a hifi shop!