I'm interested in building a portable bluetooth boombox, but I don't really know anything about audio. I am going to follow this forum (http://techtalk.parts-express.com/forum/speaker-project-gallery/62234-1st-boombox-project-the-madeleine?242898-1st-Boombox-Project-The-Madeleine=) for the build, which I can easily follow except for one part.

The guide gets kind of vague when he starts to talk about the audio crossover design, but there are some pictures he includes of the PCB and parts.

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PCB assembled

My question is: Is my below schematic correct? The connections in red are directly from the first picture of the physical PCB, but the blue connections are what I'm unsure of.

Schematic If you need any additional information like speaker frequencies or PCB component values please let me know. Thank you.

UPDATE: I've found a picture of the bottom after scouring online for a while. I've posted an updated schematic with what I think is accurate based on the pictures. Do you think this is indeed a correct schematic?

PCB top PCB bottom New schematic

  • 3
    \$\begingroup\$ Reverse Engineers would include the P/N of each cap and confirm if non-polarized with LCR readings with a schematic using proper symbols. \$\endgroup\$ – Tony Stewart EE75 Sep 24 '17 at 16:52
  • \$\begingroup\$ Redraw your schematic properly with all part numbers and values shown. The connections to Tweet- and Tweet+ appear to be reversed (R1 and R2 go to J1 pin 6, not pin 5). \$\endgroup\$ – Bruce Abbott Sep 24 '17 at 19:33
  • \$\begingroup\$ My apologies, I've updated the schematic :) \$\endgroup\$ – Owen Sep 24 '17 at 20:05
  • \$\begingroup\$ Okay, to the best of my knowledge, my most recent schematic is the proper layout (unless someone objects of course :) ). \$\endgroup\$ – Owen Sep 25 '17 at 0:02
  • \$\begingroup\$ I beleive this is not "reverse engineerng"... but I might be wrong... still, this is an interesting post! \$\endgroup\$ – scjorge Aug 2 '19 at 8:07

I checked your link, but stopped reading when I reached a picture of the bass reflex vents. They are way too long. Also the drivers look very expensive. But it will sound like crap because the vents are way too long, so they will resonate like organ pipes. This hints at the designer having no clue what he's doing.

I'd advise building the classic:


  • \$\begingroup\$ They'd be quite useful for storing pencils in though. \$\endgroup\$ – Ian Bland Sep 24 '17 at 23:35
  • \$\begingroup\$ Wow, very active forum post! Thanks! I'll definitely be looking into this... \$\endgroup\$ – Owen Sep 25 '17 at 0:00

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