Bike/wagon/vehicle -sound Opensource project

Hello Friends

I've been playing around with this project for quite a while, here in DK we have quite a few soundbikes made from cargo bikes.
I want to help people making better ones by doing one myself & sharing knowledge:

Idea:
The idea is to make 1-3 standard configurations for the most common bikes, all designs can be re-calculated to fit other bikes.
Low-to-ground
kick in the middle
tops on wind-up

Specs:
I want to release specifications like the ones for a PA-speaker, this means freq-range & dispertion, most bikes are a mess seen from a PA-perspective.

Bass / WEIGHTLESS BASS:)
I've been playing around in hornresp speaker wizard and I've managed to load the air underneath & around the bike as a part of the horn, this means massive WEIGHTLESS lowend extension.

Parts:
Lightweight is essential, we start big first, so we need a lot of power.
I want to use Lithium batteries & class d amplification.

Problems:
Biggest problem at the moment is getting the right supply voltage for the digital modules, a 48V litium boost out 55V when fully charged, that's not good for my modules, for high power I need 90-100V, 110V will make it shot down!

I've been looking at 12V car amplifiers, but they must be made for boneheads, specs are PEAK POWER @ 1ohm, LOL! I always thought car owners were stupid, but well I've had a van for 10 years now:)

Simulations & drawings:
Are to come, if there's anyone interested here?


Edited by tv00 - 12 April 2015 at 9:52pm

what modules you got up there?
some class d amps like sure electronics are quite happy on 24-36volts  and you can get it easily from lead acid batteries in series...

use high efficiency speaker drivers, should be loud enough...

Interesting idea using sonotube, I didn't think about that, making it a horn or tapped horn not only uses the air below the wagon, but also all the way around it!

I won't use acid batteries, but Lithium, that's lightweight!
For this project we're loading quite massive drivers & need quite some effect for full power, lighter versions on the sketch-board too, but customer wants the biggest!

I'll update with pics & sims during the week...

Blimey! What power does 300w / side take? How many ah do you run that at?

Edited by Sapro2 - 14 April 2015 at 12:08am

I've been looking at 12V car amplifiers, but they must be made for boneheads

Their intended use is blasting 140dB @ 0.25m into the ears of the driver of a potentially lethal road vehicle, what do you expect?

I also think using the ground as part of the horn path may not be ideal for a couple of reasons - The ground surface would need to be solid and non-resonant, so many outdoor applications where that extra output is most needed wouldn't be able to use it, and the whole structure of the bike probably wouldn't be well protected from vibration.