That's a bit of exaggeration. Unless you're trying to do something unusual building your own speakers doesn't require a degree in anything. You do have to be willing to do some research and have some basic woodworking tools and skills. If you're going to build something requiring a crossover then you'll need to understand schematic symbols. There are many free designs available on the web. If you're under the impression that you can just throw some parts in a box and get good results then don't bother. One thing you can't do and that is be in a hurry. Check out the link that Stone provided.
I agree with Timn8ter completely. If your goal is simply to get more value for your money, a pre designed kit, or one of the hundreds of designs available online will provide you with a speaker that will compare favorably to considerably more expensive commercial offerings.
For example, the Proac Response 2.5 is a highly regarded 2-way costing approximately $4,000. You can build it yourself for around $500-600. Wayne J's Eros is considered to be a very good sounding speaker and falls right into the same price range. I'm hoping to build a clone of the Usher CP-737 soon. The Usher sells for around $2000 and is considered a "steal" and is said to compare to other brands costing double. My cost to build the pair, minus cabinet costs, will be $544.
There are many levels of "DIY". To design your own speakers does require reasonable talent, as well as considerable practice, and in most cases, some level of testing equipment. But, to build a pre-existing design requires nothing except some moderate woodworking skills, soldering skills, and the ability to follow somebody elses notes.
OK I'd like to build something like the bose cubes,except better for surround sound for my Kenwood 100 Watt per channel receiver.Five boxes with two 5" midrange speakers in each box.I want each of these boxes to handle 100W at 8 ohms.I need to know how to wire these and need to know whether or not I need a tweeter in each box(or will the 5" speakers provide enough highs?).But if so, does this affect the 8 ohm impedance.What kind of a crossover unit do I need?Does a crossover also affect the impedance??Help me please.Thank you,email@example.com