Although a bit late, I want to start a thread to show my build of a new portable speaker/boombox.
I started the build around 2 weeks ago, firstly "recycling" the old speaker I made around 2 years ago. It was a sealed design, and wasn't airtight enough. I also had problems with batteries.
I wanted the new speaker to be about similar size, and using the same components I recycled from the old one, and adding some tweeters, since previous lacked high end. I also wanted it to be bass-reflex design. For that reason I also bought a passive radiator which is preferable since cabinet has no openings. the pictures of the drivers are included below. There will be 2 3" midwoofers and 1 3/4" tweeter per side. Passive radiators have a diameter of 4".
I began the build by measuring all of the drivers using REW's T/S parameter measurement. Here are measurements of one driver: Imgur: The magic of the Internet I measured all 4 and averaged the results to simplify the process.
I then designed the enclosure with WinISD. Both of the sides will be separate so there will be 2 midwoofers and a passive radiator on each side. The enclosure has a volume of about 1-1.1L and I tuned the passive radiator to about 80Hz. The tuning might be a bit high but I don't really need low end extension, and want maximum efficiency.
The only filter used in the speaker is a simple capacitor for the tweeters at about 3kHz. The midwoofers are 8ohm each and tweeter is 4ohm. with all drivers in parallel this makes a 4ohm nominal load on the amplifier.
I recycled the amplifier from previous speaker. Its a small TDA7492P bluetooth board which I measured to output about 15-20W RMS from 16V source.
The enclosure is in the process of making. It is built with 6mm MDF. I sawed all the pieces out and drilled the holes for the drivers on front and back panel. Back panel is sawed out using a small handsaw in order to be able to open the speaker if I need to fix something. It is mounted using M4 screws with threaded inserts. The sides are bent using kerf method and filled with a mixture of wood dust and glue. Pictures of enclosure are below.
I will keep posting my progress in this thread as I keep building.
I started the build around 2 weeks ago, firstly "recycling" the old speaker I made around 2 years ago. It was a sealed design, and wasn't airtight enough. I also had problems with batteries.
I wanted the new speaker to be about similar size, and using the same components I recycled from the old one, and adding some tweeters, since previous lacked high end. I also wanted it to be bass-reflex design. For that reason I also bought a passive radiator which is preferable since cabinet has no openings. the pictures of the drivers are included below. There will be 2 3" midwoofers and 1 3/4" tweeter per side. Passive radiators have a diameter of 4".
I began the build by measuring all of the drivers using REW's T/S parameter measurement. Here are measurements of one driver: Imgur: The magic of the Internet I measured all 4 and averaged the results to simplify the process.
I then designed the enclosure with WinISD. Both of the sides will be separate so there will be 2 midwoofers and a passive radiator on each side. The enclosure has a volume of about 1-1.1L and I tuned the passive radiator to about 80Hz. The tuning might be a bit high but I don't really need low end extension, and want maximum efficiency.
The only filter used in the speaker is a simple capacitor for the tweeters at about 3kHz. The midwoofers are 8ohm each and tweeter is 4ohm. with all drivers in parallel this makes a 4ohm nominal load on the amplifier.
I recycled the amplifier from previous speaker. Its a small TDA7492P bluetooth board which I measured to output about 15-20W RMS from 16V source.
The enclosure is in the process of making. It is built with 6mm MDF. I sawed all the pieces out and drilled the holes for the drivers on front and back panel. Back panel is sawed out using a small handsaw in order to be able to open the speaker if I need to fix something. It is mounted using M4 screws with threaded inserts. The sides are bent using kerf method and filled with a mixture of wood dust and glue. Pictures of enclosure are below.
I will keep posting my progress in this thread as I keep building.
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Since the last post I have basically finished the speaker. I finished gluing everything together, filled the cracks and imperfections with wood filler (not sure this is the right term) and sanded it all smooth. It was then time to paint it. I applied 3 layers of primary and 1 layer of white acrylic paint.
Last step was putting in the drivers. I went the easy route and just used some hotglue all around the drivers and passive radiators. It works and you can't see it anyway so its not a problem. I also glued in the amplifier board and connected everything. The back plate is sealed using foam tape and fastened with screws.
After some testing I can say the speaker sounds good enough for casual listening and gets plenty loud. It will work perfectly form my college dorm for listening to music and occasional get together. Anyway, thanks for reading through my short project. I have included some pictures below.
Last step was putting in the drivers. I went the easy route and just used some hotglue all around the drivers and passive radiators. It works and you can't see it anyway so its not a problem. I also glued in the amplifier board and connected everything. The back plate is sealed using foam tape and fastened with screws.
After some testing I can say the speaker sounds good enough for casual listening and gets plenty loud. It will work perfectly form my college dorm for listening to music and occasional get together. Anyway, thanks for reading through my short project. I have included some pictures below.
Attachments
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the finish looks great, i have been looking into the "portable bluetooth" speakers and i feel like in order to have something that sounds good, it ends up being bigger than one may deem portable. I;m looking at a unit with 3.5inch drivers and needing a ported box of 0.18cu.ft or 5L, which i think is needed to give me some bass and good sound, which really is probably driven more based on my driver selection.
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