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3000-person Pedal Powered concert system fits in briefcase. Rock The Bike’s biggest custom build to date.

Demolding montage
Demolding wave guides. Each of the slots is at a slightly different angle, allowing the 6 tweeters to reach different parts of the crowd.  Photo: Mike Cobb.

1/9/15 Update! The Russian Dolls / BRX system is in use! Check out the photos and blog post about the 9/21/14 People’s Climate Rally in Oakland.


It’s always exciting when you move from the brainstorming and drawing phases of a custom project into the hands-on, smelly, goopy, dusty build phase. That’s happening right now for a project that could hopefully have a big impact on how we do our largest Pedal Powered concerts. It doesn’t have a concise name at the moment, so I’ll call it the 3000-person Pedal Powered Concert System that Fits into a Briefcase. Another name I’m considering is “America’s Concert” in honor of the AC72 America’s Cup boats that partially inspired it. It’s also inspired by Fukishima & Global Warming, Bike Party, James Bond, and Rube Goldberg.

It’s a new way to reduce the volume and weight of our 12-speaker concert PA system, using ultralight materials and a stacking / nesting / Russian Dolls redesign of the loudspeaker cabinets.

Loudspeakers contain lots of air. Air is what allows them to reproduce low frequencies like bass notes and the beat of dance music.  But it means that they take up lots of space.

This is particularly an issue if you want to move your sound system from one place to another, as we often do at Rock The Bike, since we don’t have a venue of our own but work with events and in parks to put on our shows.

When an event is scheduled to take place in another city, the problem of moving air gets more pronounced, because we have to ship our gear using the trucking system. This 1000-pound pallet was shipped to Chicago in order to do an 8-bike system last spring. The cost was about $800 each direction. What’s worst is that the money goes to support the trucking and fossil fuel empires, which we are ultimately trying to challenge with our work on bicycle transport and human power.

What’s more striking is that we are now comfortable producing events with 20+ pedalers and a much larger sound system than what we shipped on this pallet. So, if we want to share this experience in other cities, we’ll be looking at more pallets, more truckloads, or perhaps buying our own vehicle. By that point the message and the methods are contradicting each other pretty strongly. Sigh.
But next summer will be festival season. And we will want to showcase Pedal Power to the fullest. We want to help festivals provide an experience for their fans that allows for real connection with the musicians and each other, great sound, and the unforgettable experience of using their own bodies to accomplish something that was previously done for them. Not only do we want these festivals to be bold and provide this alternative, we think fans will demand it. A growing number of people are putting the pieces together — or as says, ‘Doing the Math’ — and linking our fossil fuel dependency with Climate Chaos. These people are going to find it harder and harder to enjoy music festivals powered by diesel, amplifying bands flown in from far away. Sooner or later the way we celebrate will have to sync up with peoples’ attitudes and concerns. It doesn’t mean that we won’t want to enjoy music, but that we’ll want the experience of it to be more consistent with our values.

Here are our first steps:

What you’re looking at is a casting of one half of a 3-way tweeter waveguide manufactured by JBL for their VRX 932LAP line array speaker. It’s a speaker we’ve owned for less than a year, and it has made a big impact on our ability to do larger shows, where the audience may be spread out across a bigger meadow or amphitheater.

Here’s the demolded ‘plug’ of the JBL wave guide, that allow us to make fiberglass reproductions of the original waveguide in the material of our choice: fiberglass. Fiberglass is relatively light, plenty strong, and capable of beautiful lighting effects.

Here are a couple pictures of the fiberglass wave guides in progress.

Here’s a picture of the VRX932LAPs in use at the 2013 San Francisco Bicycle Music Festival:
Photo: Erin Sanchez
And another shot in use at Ecochella. The curved gap on the right side of the speakers is the wave guide reproduced in fiberglass above. As you can see, the two speakers on the top could possibly fit into the subwoofer on the bottom. In our new system, they will.

Fiberglass is lighter and stronger than the ABS plastic and plywood used by most speakers. It’s also translucent, allowing beautiful lighting effects for night time events:

shown above: El Arbol, the Bike Tree. The new PA system will have similar internal lighting.
In addition to our rebuild of our 4 VRX 932LAPs, which is now in progress, we’ll also be rebuilding all 4 of our PRX 618XLF subwoofers, and 4 of our PRX 612m monitors. Twelve speakers in all! That’s why it’s Rock The Bike’s biggest custom build to date.
Thanks to the unique design of the as yet unpublished stacking / nesting / Russian Dolls design of the new system, and the inherent properties of fiberglass aluminum honeycomb, the overall space and weight savings will be significant. I anticipate that our new PA will pack into 40% of the volume that it currently does, and it will weigh about 33% less. So perhaps we’ll still ship 1000 pounds of gear to Chicago, but we’ll be able to do a 3000-person show instead of a 500-person show with that 1000 pound pallet.

Spreading the bike-powered concert is a big mission for Rock The Bike. After 8 years of R&D that began in our humble shop with a beautiful intention of capturing People Power, and lots of great events, mostly here in the San Francisco Bay Area, we want to share this work at a bigger scale. We find ourselves head to head with a Goliath of a concert industry. Concerts have become a huge expression of power. Production companies with box trucks haul in tons of gear, erect trusswork towers and backdrops to create a sensation of star worship, and then turn up the volume. The sound and lighting and transportation require lots of fuel. All of this fuel is ratcheting up the power consumption of our celebrations. But deep down we know it’s not necessary. Check out this awesome run-down of a 3000-person Beatles concert from 1964, which had a sound system much smaller than what we use for the same size audience, but which was a smashing success in terms of audience response.

In other words, it’s time to stop using raw Wattage to try to create what the Beatles had with their talent and charm. It’s obvious that the number or ratings of the loudspeakers isn’t a predictor of the effect a concert can have. If we want concerts to have an effect of creating togetherness, inspiration, beauty, Wattage isn’t the way to do it. Content is.

Our fullest bike powered system can be hauled by bike, set up without forklifts, and weighs about 1000 pounds. It has successfully been used in spaces that can hold 3000 people. With the current re-build, we’ll be able to share it in other places with less transport cost.

In coming weeks I’ll post more progress showing how we are rebuilding our concert PA to use ultralight materials and a beautiful new design. Thanks for reading!