A few years ago I was looking into buying a new pair of speakers for my stereo. Somewhat disappointed with how much speaker $5k+ buys these days, I walked out of the local high-end audio store and started to do some research on the internet. Eventually I learned that nice speakers can cost as much as a luxury car, yet they often use components readily available to you and me, and at a fraction of the cost of the final speakers. The markup buys you nice cabinets, (hopefully) reasonable crossover networks, and (maybe) a satin brochure detailing the speakers' virtues. But it won't guarantee you sonic bliss.
Meanwhile I've learned a few things. Sonic bliss is hard to find. Crossovers, while mostly invisible to marketing literature, are neither textbook trivial, nor magic witchcraft. Instead, they're more like a blend of science and taste, and while the taste part remains highly individual, the science part is being equalized thanks to the incredible diversity of free-, share-, and payware on the internet, and the sheer power of today's personal computers. Likewise, while cabinetry remains a craft to be learned and practised, the theory thereof is readily available to everybody.
A few years ago, when I walked out of the local high-end audio store, dado tools and rabbets were not even part of my vocabulary, nor were plunge routers and round-over bits. Now these tools are filling up my garage, and I'm learning how to use them, particularly without setting my house on fire. Likewise, while I may have learned about concepts like fourier transforms during various lectures in physics, it's only in the context of speakers for reproduction of music that they're beginning to have a meaning.