Compact bass boxes for Bike Rave sound system - 12V powered Delta 12LF

I've played around with building portable battery-powered sound systems over the past 10 years, with my focus being on "Bike Raves" recently which combine free party culture with the freedom of cycling
Before I launch in to the new project, I will provide a bit of background and share what I've built previously...

What is a Bike Rave? A party on wheels is a simple description - Dom Whiting's DnB on a Bike is an example, and there are events like that around the world regularly drawing thousands of participants
Down here in Melbourne, 500 would be a big number... and in Sydney even 100 would be considered a decent turnout

Here are some of my video snippets from 2021 and 2023 Melbourne Bike Raves, and if you search insta etc you'll come across great footage of the bigger events elsewhere

My work has previously been fairly rushed and scrappy but it's become more refined with each version of system I build, and I'm hoping to progress further again
I'm about to embark on an ambitiously scaled project - putting as much sound as I can on a DIY Carla Cargo trailer, and yes I'll have to build the trailer too

So why is this in the Subwoofers forum?
Because my focus right now is on squeezing the most I can out of the 12" Eminence drivers I have on hand:
6x Delta 12 LFA, 2x DeltaLite 2512 and 2x OEM sub drivers that measure T/S close enough to the 12LFAs that they'll fit the same boxes.

The limitations of size, weight and amplification available make for an interesting balance of compromises - leaning towards lightweight and efficient with a lot of output 60hz and up
Sticking with the current drivers (it's not economical to try and sell them to buy new ones) also limits my alignment choices too

Calling the intended cabinets "bass boxes" is a way of dodging the fact they won't have much sub as such ;)

I've almost landed on final design for now, and with the above intro out of the way I will share the build details as it soon progresses...
Looking for examples of previous systems, I realised how hopeless I am at documenting the details - either due to rushing through the build, or being too caught up in the moment at an event to not capture it in photos :rolleyes:

Here are the best examples of each version... you can see more pics on instagram

My first bicycle sound system - this was really neat, a compact and stable setup but the trike's shape didn't have any room for expanding:


Wanting to go bigger, I switched to a two wheeled "longtail" cargo bike with 200kg load carrying capacity and built narrow bass boxes to fit on the side racks.
From memory these were ~50L and should've been tuned to 60Hz but I didn't keep any notes or measurements.
This is just a mockup, there was an amp box that sat under the tops:


When I moved cities I scrapped those boxes and built similar version - going bigger and really pushing the limits of what a two wheeled bike can handle
I think these boxes are ~60L and tuned to 60ish again
It's hard to believe, that with 80KG+ load on the back stacked that high that it was still very manageable when rolling along:


I did find the limits of that setup, and really suffered for it... (now have a leg full of titanium) so returned to the idea I'd ignored years ago, to use a trailer
With the trailer taking the bulk and weight, I could downsize to a smaller bike too - this was a test run that gave me confidence:


And where it's at now - adding a third bass box hit the limits of the cheapo trailer but it looks great, is stable to tow and really did whomp out some sound!

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Either Reflex or Bandpass.

Sounds like you got a good idea what is going on.

Thought the same, live sound 12" would be great bass
for bike system. Since the efficiency is good.

and most bass being around 60 to 40 Hz
that makes systems sound impressive

Far as just off the top of head Qts for
eminence line
assume the 2512 would have smaller box
but same similar bass as the others.

interesting that is a lot of sound on a bike
Are you concerned with keeping the weight down or does ease of construction mean more to you? Along those lines:

How much mass in the drivers and how much in the enclosures?

What did you use for enclosure material previously?

Could you handle something like a matrix braced enclosure build?

Or would a light, thin, under-braced, resonating box really make any difference, since it seems like this is more about loud and fun?
I had a little play with some designs using your Eminence drivers & as usual BR actually wins for output vs size.
Where it does not win is output vs power.
I looked at Martinsons designs - Tham and Roar 12 Most were poor matches but given the possible limitations on power it was interesting that the Roar 12 and the Delta 12 LFA gave a reasonable output. Your reflex cabs you said are 60L and the Roar is 180L so might be considered as the same as 3 reflex boxes.
The Black line is one Roar12 4.9V - (nominal 3 watts)- Grey is 3 BR boxes 60L 2.7V each (so again 3 watts)- both approx 180 litres with the delta 12 LFA

Might be worth some conciderationif the Mid tops can be integrated, and you have enough amps & speaker managment!:)


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Thanks for the replies and ideas in a short time!

To run through a few points, without blowing out the post with excess quoting...

Gotta keep the weight down, so using 12mm radiata pine plywood for now. Will need to use a bit of bracing, but really have to be pragmatic and accept that some box resonance and other flaws are part of the compromise for this application

Drivers are 5kg each and I'm hoping to get a BR box built from half a sheet of ply, so that's 10kg in timber
Multiply that by six and we're looking at 100kg already

I intend to use the 2512 in same box as D12LFs, looks like they'll work and being half the weigh is desirable too

For size limitations, the trailer I am building is a Carla Cargo variant but this will be a few months off...
The bed will measure 650 wide, and ~1600 long, have a look at DubTrain One for inspiration

Power is from a 12V 100AH LiFePO4 battery, using class-d car amps I have four mono units that'll each output 200W in to 8r (35V), and two 4 channel that'll output 35W (17V) a channel or bridge two channels for 100W (28V)


Won't need them all just yet, and will probably need a second battery eventually. Currently have one Thomann 2 in / 4 out DSP and will look to get another one when required. Also have a few old MaxxBass 103 units for some fake bass, though don't know how necessary they'd be with modern music production already pumping up the harmonics
Tops in use right now are four Klipsch KI-102 with 8" woofer and 1" driver (only used two at a time so far though), I have a pair of big 45cm wide horns (JBL 2380 copies at a guess) and 2" P.Audio compression drivers in storage that I'd like to use eventually

I'm about to commit pencil to paper to draw up final details before making sawdust tomorrow, for four bass reflex boxes to start with
Dimensions will be 50W x 55D x 37.5H, so four wide / three tall is 1.5M either way
Ports will be 4x Penn 3" tube and with about ~65L net internal volume I'm expecting them to be ~57Hz boxes

I like the idea of exploring what output I can get with 35V in to the Delta 12LF, unfortunately the ROAR12 is too deep for a 65cm wide trailer. Bandpass or TH/Hybrid will be looked at in the near future
As the rig grows, the current BR boxes could be low/mids run as part of 3 way system since I do have 10 drivers to use. Will just take it a small step at a time, and try to capture details and measurements for a change...