See those are things I know how to do. Even I can copy a schematic and make it work but that does little to teach. I want to learn circuitry, not just copy what works. I can easily sell small specialty speaker systems I'd I'd be happy doing it but of course I'd prefer to do more. Also I have contemplated the PC speaker system amp in wood but that would be a more personal project. Not sure if there a market. Though true about quality. Cost rarely represent's quality. That part I'll have trouble with, figuring out how and for how much to sell any of it for. I suspect doing any of it just to prove it can be done is a start. Even if I don't perfect it then surely another can.Providing a good quality product, not just a bunch of features, will usually sell if it satisfies a requirement that people have. In general, quality is not something that can be patented, it has to be designed in and then built in. Unfortunately many confuse quality with features, and when I ask about product quality they start to recite a list of features, and then when I ask about how long a product will last they want to tell me all about their service plans. BlueTooth speakers, amps, and wood enclosures could probably sell for even more in some venues. I do not recall ever seeing computer speakers in wood boxes, nor with higher powered amplifiers.