Before starting to build a soundsystem for my bicycle I would like to ask where I can be redirected or provided info for a) a ready-made solution, b) a set of clear instructions on how to make one.

My requirements are:

  • It has to fit somewhere on the frame or the rack (maybe pannier style) - a trolley is not an option as I do not have space to store it.
  • The battery has to last a minimum of 5 to 6 hrs
  • It has to be loud enough for a city Critical Mass ride (many cyclists circulating together)

Thanks in advance!

  • 12
    I hope I don't live anywhere near where you will be riding when you get this built.
    – David D
    Apr 8, 2019 at 13:48
  • 1
    Cheers for bringing sound to Critical Mass rides! It makes the rides so much more enjoyable. On our rides here there are usually people with compact PAs on cargo bikes.
    – gschenk
    Apr 8, 2019 at 15:48
  • 2
    @David D. In my experience music does not annoy bystanders. It underlines that the people taking part at the ride have a good time and are happy. The rides are on major roads where the noise pollution by cars is high in the first place. We cyclist may even bring noise down, since we prevent cars and lorries from going past at speed. There are people who are annoyed, because they have to stand (in their enormous tins) while we ride. I don't mind if the music and the joyfull atmosphere rubs it in. We cannot convince these guys anyway.
    – gschenk
    Apr 8, 2019 at 17:19
  • 3
    So to clarify - this is for events, not for daily riding ?
    – Criggie
    Apr 8, 2019 at 20:05
  • 5
    @gschenk I really don't think that annoying motorists is an effective way to make the roads safer. Please don't do that. Apr 9, 2019 at 7:42

2 Answers 2


I have seen numerous people riding down the path with a sound system on their bicycle. Without exception they use the simplest and most portable solution: a bluetooth speaker. This meets all of the requirements of outdoor usage:

  • Self Contained
  • Waterproof
  • Long Battery Life
  • No wires to run
  • Lightweight and portable
  • Inexpensive

Source: https://www.amazon.com/JBL-JBLCHARGE3BLKAM-Waterproof-Portable-Bluetooth/dp/B01F24RHF4/ref=sr_1_10?keywords=bluetooth+speaker&qid=1563418742&s=gateway&sr=8-10

Tie it to your bike rack and pair it with your phone. I've done it myself once, but be warned, you will need a louder one outside (especially at a critical mass ride). So you may have to invest in one of the larger models.


Some design considerations - your plan will be customised to your bike, but in general you'll need three parts.

  1. Batteries Depending on budget, you may end up having to use some car batteries. That would be the older way of powering your rig, but they've heavy and relatively fragile. More modern batteries would be smaller and lighter but cost more.
    You'll also need some way to charge them safely beforehand.
    There are modern "powerbanks" that can provide USB levels of voltage at 5V or some that will provide 12V, which might be ideal.

  2. Sound source You might want to use a phone via a wire or bluetooth, but a dedicated source would be better. Imagine getting a phone call while the music is playing.
    A 12V device is perfect, because 12V batteries are common. And a common 12V sound source is a car stereo. A modern car stereo can play MP3 from a SD card or USB drive. And if there's no tape or CD mechanism then they're really quite shallow depth, which helps with your physical build. You can wire a car stereo straight to your 12V battery with nothing more than wire and joiners.
    Downside, car stereos are not particularly waterproof, so you would want to put it under some sort of cover. enter image description here

    1. Speakers Gotta get the sound out somehow, and speakers (more accurately Drivers/cones) are the only way to do that. You could salvage speakers from an old hifi speaker cabinet. This has the added advantage of providing big and small speakers plus whatever crossover circuit is in the cabinet.
      If cost isn't an issue, then "outdoor-rated patio speakers" would be a good choice.

    2. Enclosure This is where it gets hard. You want some kind of way to mount your stuff on your bike so it can still be ridden, but also to support and protect the components. Generally speaker boxes are made from reasonably thick plywood/customwood/chipboard. And you don't want to add silly amounts of wood to your bike.
      So work on paper and see where you need to leave clear for your legs and arms, and clearance areas for turning. Upshot - there's some space in the main triangle, but the larger areas are on a rear rack and over a front rack. That would be an excellent starting point.
      Do make sure your stuff isn't loose - it must not fall off at any point for any reason. Use saddle clamps screwed into the wood, and not cable ties or bungees or springs.

      • Combine 3 and 4 by simply reusing some old speaker boxes from a defunct stereo, and strapping them over your rear rack.

enter image description here

This might be getting a bit too much - look at that poor rear tyre, and that they've had to weld on outrigger wheels.

Other considerations for you to be aware of

  • Copyright and rebroadcasting - Music isn't free. The music you might hear on the radio is paid for on a per-play basis to the copyright holder. Its conceivable that you might get asked for your "rebroadcasting licence"
  • Being antisocial - Critical Mass gets a bad reputation sometimes for being a disturbance. Consider that you want to avoid a Noise Control or "Breach of the Peace" notice.
  • Fellow Riders - Riders next to you don't want to be deafened - Be aware of the maximum sound output of your rig.
  • Waterproofness and crashworthyness. Bikes get bumped about, and sometimes its not fine and sunny. Consider what needs to be dry or protected.
  • Taste - There could be families with kids on the ride, so consider the lyrics and appropriateness. Sing-a-long type songs might be a bigger hit than "judas megaslaughter" Use good judgement - perhaps even have a set of USB drives with different genres/playlists pre-prepared.


  • Don't bother with stereo - sound quality and imaging is not going to happen. So use mono only.

Links: https://www.instructables.com/id/Bike-Party-Sound-System-Basic-Rear-Rack-Style/

  • 1
    You’re a Judas Megaslaughter fan too!?🤪
    – Swifty
    Apr 12, 2019 at 5:25
  • @Swifty nah its a totally made-up name. I was thinking about the playlist on my commute, and basically the playlist should be songs that people know and would sing along to. "Mahna Mahna" by the Muppets, "Meet the Flintstones" theme, "Bicycle race" or "we are the champions" by Queen, most anything from Phineas and Ferb, The point is it should be "recognisable/approachable/acceptable" by a large part of the audience.
    – Criggie
    Apr 12, 2019 at 6:54
  • 1
    I know, and I think you’re spot on. I just thought it was the best made up band name for a good while. Perfectly evocative, yet over the top silly. It helps make the point🎶
    – Swifty
    Apr 12, 2019 at 6:59
  • 3
    I also think some of the commenters are going to lose their minds when they find out that cars... have... stereos lol ;) mine even goes past eleven, that’s pretty loud as we all know. I like that you answered the q and tempered it with sensible advice on how to not be antisocial that leaves OP to make their own mind
    – Swifty
    Apr 12, 2019 at 7:03
  • @Swifty almost a whoops - metal-archives.com/bands/mega_slaughter/4288 Naturally, they're Swedish.
    – Criggie
    Apr 12, 2019 at 7:06

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