Build my own speakers?

You have just discovered one of the surprises in high end audio. Typical high end $5000+ speakers that use $50 woofers and tweeters. Most of what you pay for is woodwork, exotic veneer/finish, shipping and packaging and of course some markup (manufacturers need to live!).

If you care only about sound quality then go either DIY (no resale value) or better to go for pro designs in a low cost finish (limited resale value because of low WAF but you got more high quality sound instead of high quality finish).

I would say that the lowest cost option to ultra high end sound is to buy a high quality pro grade two way active second hand monitor of your choice and build your own subwoofer using this LMS 5400 driver. You can probably achieve similar to $50K sound for around $5K. Of course it won't look anything like $50K but if that concerned you then you probably would not be thinking DIY.

Building your own subwoofer is easy but a speaker is tricky...so definitely go for kit/clones if you want to build a speaker - but even DIY is hard to compete with the cheap speaker imports from China. Many boutique high end speakers are now made in China (Quad etc.)

Radrog,

I am going to design and manufacture the best speaker in the world for under $20,000.

There is plenty of engineering but also a lot of hands on knowledge too. If you are going to design your own "amazing" speaker from a blank piece of paper and theory then I sure hope Richard has got lots of time for you. There is a lot of hands on knowledge in speaker design.