The Chainlink

Hey you sound geeks, I'm looking to build a new Boom Bike and would like to run all this past you. Please comment and help me out. : )


Goal: A compact, well balanced, light weight, energy efficient sound bike with stable well made components that can take the road. Cost? No expense limit but less is always best.


  • Produce massive sounds approximately as good as Todd's sound bike. :)
  • Use of a microphone and at least two other independent audio devices.
  • Performance at peak volume for six to eight hours.
  • Ability to circumvent DC power batteries and directly power device through AC external power source.
    • If possible charge batteries while plugged in. (Not a requirement.)
  • When plugged in (or not) needs to power additional devices like a DJ laptop. Loss in peak performance during this time is acceptable.
  • Future requirement: Electric assist "push" so that others who are not as strong can still use it. Loss in peak performance time during assist acceptable.

Shopping List So Far:


AOSOM Cargo Bicycle Motorcycle Trailer - Red and Black(L)

Price: $119

Folding FrameCubage about. 140 Liter.Specially strengthen Bottom.Trailer Weight: 35lbsMax loading : 180lbSize: 31.5x24x14inch (LxWxH)The size of the tires are 20"(Diameter) x 2.125"Length with drawbar is about: 54inchPackage Size:  28x22x14inch (LxWxH).


(2) Peavey PR-15-NEO 15In 400W 2-Way Speaker Neo +

Price: $219 each

Weight Unpacked: 31.31 lb(14.2 kg), Width: 21-1/2", Height: 28-3/4", Depth: 17"

Specs: Two-way sound reinforcement enclosure 400 watts program, 800 watts peak 8 Ohm One 15inch woofer with 2.375inch VC and lightweight neodymium magnet RX14 compression driver with a 1.4 inch titanium diaphragm 1 inch exit 90 x 40 degree constant directivity horn Tweeter protection Heavy-duty crossover Lightweight molded polypropylene enclosure Molded-in pole mounts system Heavy-duty metal grille.


(2) Sure 2x100W @ 4 Ohm TK2050 Class-D Audio Amplifier Board

Price: $44.00 each

2x 100 watt amplifier board integrates Tripath's high performance TC2000 and TP2050 chips. Powered by any DC voltage from 10V to 32V, this high efficiency design is capable of driving 4 ohm or 8 ohm speakers with up to 100 watts per channel. Volume control can be implemented via on-board DIP switches. An auto fan control function optimizes thermal management.


Possible Efficiency Modification: Is to remove the crossover in the Peavey PA speakers and install the Sure amp as instructed here. This may be a later project if I find I am loosing a lot of power. So it's possible I will only be using on Sure amp during initial phase.


The best 800w amp I have found may or may not a be a digital amp it's rated Class FD which I assume means it's a push pull digital amp. But I don't really know. It seems to be efficient and I would totally go this route if it meant I could push the power I needed. 

Pioneer GM-D9500F Car Amplifier - 75 W RMS - 800 W PMPO - 4 Channel...


Boss PH3KD Phantom 3000 Watt Class D Monoblock Amplifier with Remote

Two of these look like they could push the power I need. Any thoughts?


Behringer XENYX502 5-Channel Mixer

Price:  $43.40

130 dB dynamic range, bandwidth ranging from below 10 Hz to over 200 kHz and up to 60 dB of gain and a +48 volt phantom power supply.



Batteries, I really honestly cannot make up my mind. Again cost is not an issue only capacity, weight and how many I need to buy to get the amount of power I am requiring. When I do the crude math I think the Shorai $176's are the best option but I am not sure.


Power supply, again totally cannot make up my mind. In fact I am sorta at a loss how I would have both AC/DC power... All the inverters and supplies I have found don't seem to offer this option. Any thoughts?



And finally, how the hell am I going to fit all of this on the trailer? It's possible this is such a large setup that it would be unstable if I tried to modify the trailer design of the AOSOM. This may require me to build my own trailer but I have no metal working skills so I would have to outsource this. Anyone know of a good, and not busy as hell, metal worker?


Here is my rough sketch of what the trailer will have to have...

Views: 384

Replies to This Discussion

I'm a ham radio buff with a pretty good grounding (ha ha) in electronics and I don't even fully understand this audio stuff.  Sometimes I think some of the specifications are outright fabrications or at least misrepresentations of nominal ratings.  The figures are never hard numbers you can actually crunch and come out with answers that mean anything.
James, so true. It's almost like specifications are just another part of the product marketing cycle. It's damned annoying. Do you know if I can even get 800watts using any of the batteries I've listed? The watts to mAh calculations are also very confusing and seem to change depending where you go on the Intersquids. Seems like the only real concrete way is to buy the battery and run a test.
Voltage X The Amps = Watts
Easy as P=IE

Okay, so I won't get too anal about specs. Except for one more time. :)


The Shorai batteries you listed. One has "a" polarity and the other "l" polarity. I have no idea what this means, but I imagine that since Shorai offers two different batteries with identical specs except for the polarity of each of their models, it must matter somehow. Can someone shed light? 

I'm pretty sure that is how the battery terminals are situated.  "L" polarity is the negative on the left while "A" polarity is negative on the right.  On a home-built set-up it isn't that big of a deal but if you are trying to fit the battery into a factory-built enclosure the polarity of the battery might make the difference of it fitting or not if you need to cross the wires and they are not long enough.
Cell logs is a programmable voltage monitor...
I still need to build the trailer. Everything else is secured.

Didn't get it finished for Mass?


I didn't see a single trailer sound system last night.  I saw the one guy on the yellow trike and the farmer pants who is always there, and a guy with a backpack system that was all distortion and a few other smaller units strapped on here and there.


Come to think of it, I don't think I many trailers at the mass at all.  The one dude with the black & white dog.  Not many at all. 

I was too busy for  a while to follow this thread but I'll try to quickly answer several past comments.


First, I'm not running my whole system off a single 2 channel amp, except when I only go out with 2 speakers.  I typically use a 1 channel per speaker unless I'm playing at a lower volume on an all day ride, in which case I'll parallel speakers and use fewer amps.


Second, you don't want to push a Sure amp real hard.  They are very clean at 10 watts RMS per channel, decent at 25 and really start to suck as you go over 50.   One of mine is an older kit model that I populated with better quality components and the distortion doesn't ramp up so quickly.


As for comparing ratings, yes some manufacturers just outright lie.  But mostly they mislead.  A car amp might indicate 1200 watts in the model name, but when you dig deeper you find that is the maximum input wattage, not the output.  Or it might be the peak momentarily survivable output wattage.  Even if it is the RMS output wattage it might be at a godawful distortion level.


There are some very high quality class D amps with high power ratings.  But they are expensive.  And the high power class D board amps tend to have awkward power requirements, such as +75, -75 and +5 voltage supplies (often referred to as rails).

I thought the briefcase system was pretty cool-- did you see it?

He seemed to get a lot of sound out of a fairly small package.


I don't see how it would be possible to keep up with a trailer anymore.  About 1/3 into the ride the pace picked up and it was hard to keep up without a trailer.


James Baum said:

Didn't get it finished for Mass?


I didn't see a single trailer sound system last night.  I saw the one guy on the yellow trike and the farmer pants who is always there, and a guy with a backpack system that was all distortion and a few other smaller units strapped on here and there.


Come to think of it, I don't think I many trailers at the mass at all.  The one dude with the black & white dog.  Not many at all. 

I must have missed the briefcase system. I like to move around and see all the bikes and equipment out there.  I often start at the front and cork at least once just to see everyone, but this month I started in the back and tried to move to the front of the pack but met a situation once where I really needed to help cork as someone was having a difficult time with an asshat.  Then I needed to stop and adjust something on Logan and try and call my wife to come out and wave as we went by the house which blew some time.  So I cut the clusterfrak that happened on Kedzie when the group tried to go through that tight street (Albany maybe?) and tied to get up to the front but the cops up there were being total asshats pushing the leaders to ride too fast and not letting them stop and mass up.  So when everyone cut off the head of the ride by going through the park I doubled back.  


There might have been a few bikes I missed.


I saw one girl with a small ipod dock radio clipped through her backpack with the ipod dangling out of it.  Don't know what kept the ipod in the dock without falling out.  



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