It all started innocently enough, I wanted to listen to music as I rode my Salsa Vaya. I know this can be solved with simple earbuds but I’ve never been a fan of them. Cycling is a social activity for me and I think earbuds have an anti-social effect. My first solution was an off-the-shelf one. This was before portable Bluetooth speakers were commonly available. Because of this, almost as soon as it began, my quest to find the best portable audio quickly turned into a DIY Bluetooth speaker build utilizing a circuit board amp.
It all started with a Milwaukee M12 radio
It’s kinda hard to believe now, but back in 2012, options for portable speakers were limited. They were just coming out and the ones that I found were small and not very loud. There was no way I would be able to hear them while I was moving.
I ended up purchasing a little Milwaukee radio since I already owned some of their cordless tools. It had a compartment on the front of it that was sized to fit a phone or mp3 player. This feature was advantageous since it didn’t have Bluetooth. I already had a couple of Milwaukee batteries so to extend the run-time I brought along some extras along.
Around this same time period, I came across someone that had made a portable speaker using a PVC pipe as an enclosure. He used a car audio amp and a small 12v battery to power it. I don’t know if I should thank Casey for exposing me to DIY audio or curse him for setting me on the path that I would soon take. Guns N’ Roses comes to mind – “I used ta do a little but a little wouldn’t do so the little got more and more”.
This weird looking speaker isn’t the best portable audio
Casey had built his enclosure using 6″ PVC pipe and 6″ speakers. It was LOUD, especially if you were right behind it since one speaker was facing the front and the other was facing the back. Being used to having my speaker in front of me, I decided to go with a different design. Wanting something more compact than a 6″ PVC pipe, I went with 2 1/2″ PVC pipe and 2″ speakers instead. Casey was using an Alpine brand amp. It was compact, powerful, and (what I thought at the time) pricey. Searching eBay, I found an inexpensive motorcycle amp and I went with that.
A cheap amp (strike one) pushing small speakers (strike two) in an enclosure with a weird design (strike three) sounds about as good as you would expect – underwhelming. My power solution was the only redeeming feature of my first creation. I had moved on from Milwaukee’s radio but I was still using their batteries. They were lithium batteries and they were awesome. I slotted them into a Milwaukee M12 Power Source. It provided a 12v port (perfect for the small amp) and a USB port (great for my phone). It was back to the drawing board for me but at least I knew what to use for power.
DIY PVC pipe speaker second attempt
For my next design, I went with 3″ PVC pipe and 3″ speakers. Instead of aiming my speakers off at a weird angle, I used 90-degree fittings so that they would face me. I still had my iPod hardwired to the amp but now I had a handlebar-mounted Bluetooth remote for it. The bag on the left contained the amp and iPod and the bag on the right had the battery in it. This time I was using a Milwaukee M18 Power Source. These batteries had more runtime than the M12 ones but were larger.
Moving on from the cheap motorcycle amp, I went with a cheap car amp. Even though Vaya 3.0 sounded way better than the previous version, I still wanted more. I tried another cheap car amp that was physically larger. It claimed to have more power but it didn’t sound any louder. This setup worked for me – at least for a while.
A friend of mine built a system using 6″ PVC pipe and 6″ speakers similar to what Casey had done but he was able to install a battery and an amp inside the tube. What interested me the most was the amp that Rob was using, it was a circuit board amp. The amp didn’t have a metal enclosure around it so it was very compact.
I level up on my quest for the best portable audio
A circuit board amp isn’t limited to 12v like a car amp is. This type of amp is what manufacturers use in their products. . A home stereo receiver is plugged into the wall and, by using internal electronics, delivers the correct voltage to the circuit board amp.
In my search for a circuit board amp to use, I found several options at Parts Express. I was drawn to the Sure Electronics amps in particular. I decided on their 2×100 watt amp and my next hurdle was finding a battery to power it. Its specifications called for 15v to 30v.
Having recently learned how to build lithium batteries, I decided to assemble a 21.6v one. I didn’t want to exceed 30v and since a 21.6v battery charges at 25.2v, that’s what I went with. Using two dozen 18650 cells, I assembled a 250wh battery – in comparison, the Milwaukee M18 batteries that I had been using were 54wh.
A circuit board amp and a DIY lithium battery
I assembled a module using the battery pack at its core. Then, I added support plates on each side, a circuit board amp on the top, and a Bluetooth board on the front. The integrated antenna on the board provided poor range. I was a little disappointed, but I finally had Bluetooth! I put this module in a trunk bag (frunk bag?) and definitely ruined the manufacturer’s warranty on the bag.
My design involved cutting the top flap off of both of the front panniers. I was no longer sensitive to pricing concerns (you may have already noticed), so that’s what I did. The reason I did this is that a 6″ PVC pipe fits in the bag perfectly. A 6 1/2″ marine speaker was installed on the top of each pipe, with a plywood plug on the bottom. I had to turn the volume down when I was riding since a pair of 6 1/2 speakers were blasting right up at me. This was something that I hadn’t had to do before.
Since I housed the electronics in the bag above the front tire and always packed a rain cover for it. The bag wasn’t rainproof to start with and cutting holes in it didn’t help. To take advantage of the Bluetooth, I put a phone mount on my handlebars for easy access to my phone. It took a couple of tries to find a really good phone mount. I’m now a big fan of Quad Lock mounts.
I finally had a DIY Bluetooth speaker that rocked
I finally had something that I was proud of but soon I wanted more. I decided it was time to upgrade to component speakers but that wasn’t enough. The next step involved getting an amp with more power. I found a higher powered Sure amp at Parts Express. Remember how I had built a lithium battery specifically for the previous amp? Well, this new amp needed a new battery. The amp was a 2×300 watt one with a voltage specification of 25v to 50v.
To reach it’s rated power the amp needed 48v. I already had a 50.4v-58.8v e-bike battery but I would need to bring the voltage down to 48v. To do this I used an adjustable DC buck converter. I installed it in my frunk bag along with the amp and a Bluetooth adapter that had really great range.
This set-up sounded fantastic! The only hiccup was that if I hit a large bump the buck converter would stop working for a second. This didn’t happen often and it wasn’t an issue when parked and playing music but it was really annoying when it happened while riding. I should have been content. But there’s always room for improvement, right?
An Icarus moment in my quest to find the best portable audio
Vaya 4.5 sounded amazing with the component speakers and a powerful amp. But – I decided it needed more bass. I should have focused on the buck converter issue. Instead, I went to the Parts Express website and purchased a low-profile 6 1/2″ sub. I chose it because it was lightweight (a good attribute when you are hauling it around on a bicycle) not because it was low-profile.
I got out my utility knife again and cut the bottom off both of my panniers. Next, on each side, I removed the plywood plug that I had installed and replaced it with a sub. I had two options on how to wire the speakers to the amp. The safe way would cut the power output of the amp in half but the risky way wouldn’t. By now I’m sure that you can guess which option I chose.
The subs added quite a bit of bass but not as much as I was hoping for. It was definitely noticeable though, especially when parked on a wooden bridge. Also, it was kind of amusing not to be able to see where the bass was coming from. The fun was short-lived though. One of my tweeters failed and both of the subs failed. Did you guess the risky wiring method?
The rise of the Big Boom Bagger
The failure of Vaya 4.5 discouraged me from continuing the Vaya audio project and it was a setback in my quest to find the best portable audio. I had another bike in my stable and I continued my goal with it. Around the same time that Vaya 3.0 was taking shape, I had another audio project that was in the works.
It was mounted on a Yuba Mundo. The Mundo is a cargo bike with an extended wheelbase that has a substantial cargo-carrying ability. It was an e-bike so it already had a battery on it. It was perfect for an audio project. The Yuba Mundo was eventually nicknamed the “Big Boom Bagger”. My quest for the best portable audio continues on it.
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