On Halloween 2007, the bands Ginger Ninjas and Shake Your Peace! launched The Pleasant Revolution Bicycle Music Tour in North San Juan, California. From the Sierra Nevada mountains through southern California, into Baja and eventually Mexico City, the team has played shows, recorded music with local musicians, and advocated a leapfrog-style transition to sustainable transportation.
During shows, two guitars, two vocal microphones and the bass are amplified through the portable audio system, which includes two JBL PRX512M loudspeakers halfway between the drummer and the two singers up front. To power the system itself, four Xtracycle bikes (elongated bicycles for extra carrying capacity) are set up in the air on kickstands, allowing the wheels to spin freely and turn a generator (a small DC motor run in reverse). The generator in turn goes into a capacitor to control the voltage. An indicator on the handlebars tells the 'riders' (always volunteers from the audience) whether to pedal harder, cruise, or stop. The four capacitors feed a high-quality inverter, into which an eight-channel mixer and the two PRX512M loudspeakers are plugged, creating a 1,000-watt, portable, human-powered sound system.
The entire system is packed onto the Xtracycles for transportation between shows, a task that requires an optimal combination of power and light weight from the audio components. "When you are a traveling bike band, you also want music on the road," said Kipchoge Spencer, lead singer of the Ginger Ninjas, co-founder of Xtracycle and organizer of The Pleasant Revolution Bicycle Music Tour. "So I'm carrying one of the PRX512M speakers on the rear deck of my Xtracycle. With an iPod and a lightweight lithium phosphate battery [charged by a 26-watt folding Brunton solar panel], we have a 500-watt 'soul cycle' with amazing thump and brilliant attitude."
Although Spencer did not anticipate audiences to be larger than 300 people, crowd sizes have often reached 500. "The tour has been amazing so far, so much so that we extended it for a few more months," Spencer said. "We've been playing some really great shows, some planned but many just impromptu in the town plazas."
According to Spencer, the power efficiency of the PRX512M loudspeakers has contributed significantly to the success of the tour. "The PRX loudspeakers are the only speakers in the world that I'm aware of that could make this system possible," Spencer added. "Not only are they light, but the built-in amplification is efficient enough to make good use of our limited amount of human power. And they sound amazing. The hyper-efficient digital amplifier puts them in a class by themselves when it comes to ecological amplification. Whether or not you're a self-propelled bicycle road show, you should be using these speakers if you care about saving energy."
(Jim Evans)
