These sleek, geometric audio speakers strike a great balance: the concrete comes off as both modern and rustic, and the wood adds a needed warmth to the mathematical shape. They look amazing: and they were completely made by hand. Tulsa-based collective The Makerage whipped up this pair, and wrote up a tutorial detailing the whole process.
It takes a lot of science and a lot of magic to make a good pair of speakers. From hard calculations with Thiele/Small parameters to ideas like 'transparency' and 'presence,' a lot of decisions make up a good speaker design.
One important factor is the material that you use for your enclosures; concrete has some distinct advantages structurally, acoustically, and aesthetically. It is very stiff and heavy--great for supporting the speaker drivers without changing their vibrational dynamics. It also damps out vibrations well, so it doesn't contribute unwanted rings and unpredictable tones to your sound reproduction. Equally important for something that sits in plain view all the time, it has a unique and interesting visual appeal.
The trick to achieving the looks lies in finding the right molds (the Makerage used a faceted plastic bowl set from a department store) and the right concrete mix, such as the glass-reinforced recipe used here for that extra smooth surface.
Check out the tutorial at Instructables: Conspeakuous: Concrete Speakers