Introduction
The Pyramids of Power, despite their developmental shortcomings, met most of their design goals.
- Bold/interesting design
- High fidelity
- Low cost (<$300)
- High SPL
- Simple crossovers
- Acoustic suspension
- No parallel sides
- Good dispersion/wide sweet spot
- Experiment with alternative driver configurations
One of the motivating factors in building the pyramids was the availability of a speaker kit. Mr Fletter, the Industrial Arts teacher at Forest Hills Central High School, offered students a car speaker kit. This was meant to be built as a single box for installing in a hatchback. The kit comprised of speakers and crossovers for a 3-way stereo setup and instructions for building a hatchback box. Mr. Fletter had two kits in hand that prior students had decided not to use. The total cost was under $250. The speakers and crossovers were not anything awesome, but they were no worse than any other consumer loudspeaker available from a big box shop.
I had been considering the pyramid shape for some time. It took away the problem of parallel sides, as I was concerned about standing waves. I didn't actually calculate at the time what frequency those standing waves would be at. This also satisfied the uniqueness requirement. Since I had two sets of speakers and I wanted the finished product to be grand but not behemoth, I chose to configure the woofers in an isobaric acoustic suspension.
Although I didn't do any formal acoustic design or modeling, I did get a chance to draw the speakers up in a CAD program. Mr Fletter was impressed with the design but at first very reluctant to approve the project as he felt the actual construction would be very hard. He was right, but the end result was worth it, especially as the speakers slowly formed and the rest of class realized I sort of knew what I was doing.