Wassup Audio Community!
Hey guys, i've been loving 123Toid's videos and I found this community and i'm loving all the cool builds and info out there! My friend has a woodworking company and he asked me to build the component side for his wooden boomboxes. I've been doing a ton of research, but I quickly learned that audio engineering is a hugely complicated endeavor 😛 I'm hoping this community wouldn't mind helping me along! I'm looking at using 2x Tang Band W5-2143 5" Paper Cone Full Range Driver 8 Ohm, and powering it with a Sure Electronics AA-AB31511 1x500W Class D Audio Amplifier Board. I'll build a beefy 102Ah battery pack with a decent BMS and i'm looking into bluetooth 5.0 too. Alright, tear me apart lol.
Seems like a nice project but you could always use a stereo amp so you have a stereo output instead of mono through both speakers, he might appreciate that consideration. You will also want to make sure he makes the box the right size for what drivers he is using (whether ported or sealed), as for the electronic that looks bang on, just add a bluetooth module with a voltage regulation circuit or an amp with bluetooth built in already and you are done (apart from switches and so on of course). Any help needed we will be here to get you through to the end of your projects. 🙂
Whats up Elliott thanks for the input 🙂 I was under the impression that a stereo setup isn't worth it in a boombox because the speakers are so close together you don't get a stereo affect anyways. Is that true? The voltage regulation circuit seems intimidating, if i could find a board with bluetooth 5.0 and had plenty of drivers i would choose that, but I looked and i came up short.
Welcome! We are happy to have you. I am glad you found the videos helpful and we will try to help you along with your project.
That is a good question and one that will never be answered to anyone's liking, lol. It is true, there won't be much stereo separation. I know, I have created many boomboxes with shared enclosure. It simplifies the build, and it isn't always worth the hassle and added weight of adding the divider. However, there are some benefits to separating it. But really it comes down to your goals for the build.
Have you decided if you want to port it or keep it sealed?
It really depends on how directional the drivers are because if they were very directional you might want to think about toeing them out slightly (pointing away from each other) and using a stereo signal (this will make it more pronounced). You can notice the stereo separation if done right, it is just whether you feel it to be worth it. As Toid said it also depends on whether you are doing ported or not because if you are porting you can't easily separate the drivers needed for stereo as you then need an enclosure 2x bigger than if it was vented mono as you would need two ports.
So it really can be said to be a choice from:
Stereo - Sealed (pointed away from each other or not)
Mono - Sealed
Mono - Vented
I'm not sure how to make the decision of sealed/ ported so i'll talk about the goals for the build and maybe that'll answer the question of whether i should port and whether i should go stereo. Especially for the first model we make, my goal is to create an audiophile level enthusiast grade boombox that can fill a large outdoor space such as a backyard or a tailgate while still having the ability to sound like a top of the line home speaker when it's brought indoors. I don't want it any bigger than 45 x 28 x 30cm L x W x H, so those limits on the air volume could answer the sealed vs vented question. I'm guessing i should add a DSP to the amplifier board to fine tune it for its application too. The component cost for the first one isn't too important, but i would keep it under 500. The goal is to create a boombox that is as beautiful to listen to as it is to look at, so I want to blow him away.
That's actually a pretty small box to achieve true stereo separation. You could spend a lot on DSP board, or if you are handy with schematics and a soldering iron, you could build a stereo expander. A decent article can be found at Elliot Sound Products (ESP), and searching for "Stereo Width Controller". A quick search of the TL082 is $0.35 on Digikey, and you'd need 3 total for the "Deluxe" version. You could perfboard, stripboard, or etch a board. I have a whole playlist of videos that can guide you in doing the last one.
Yeah I do think it will be difficult to achieve stereo separation, the woodworker told me he can angle his cuts to give it maybe up to 15 degrees of toe out per speaker. What I really need help with at this stage is figuring out the enclosure volumes and whether it should be ported or sealed. What kind of port(s) should i use, should i separate the speaker air spaces inside the boombox? Here is a list of parts that I ordered already.
2x Tang Band W6-2313 6-1/2" Coaxial Full-Range Woofer
1x Sure Electronics AA-AB32195 2x300W Class D Audio Amplifier Board (T-Amp Technology)
1x Sure Electronics AA-AB41136 Bluetooth 4.0 Audio Receiver Board aptX +EDR 12 VDC
1x Sure Electronics AA-AB41147 Digitally Controlled Stereo Electronic Audio Volume Control Board
1x Mean Well MW SE-600-48 48V 12.5A 600W Regulated Power Supply AC Adapter
The power supply should allow me to test the performance at different levels, which will help with final battery design. I ended up going with the bigger, nicer speakers which I hope wasn't a mistake. I know the box solution will limit the speakers from reaching their true performance, but hopefully yall can help me make the best boombox possible for the size. I also went with a stereo board, but depending on testing i'll probably end up going mono since I think chasing stereo separation might be out of reach. So can anyone help me design a box that is around 45 x 28 x 30cm L x W x H??