Another (small) Boombox Build

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21l sealed enclosure, separate compartments for mid/bass & other components. If I were to cut enough holes in the divider/brace could I theoretically reduce the space between the divider & the mid/bass? Make the entire thing less wide.

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An externally hosted image should be here but it was not working when we last tested it.
 
Here's what I meant about cutting holes in the divider. Is it as simple as calculating the volume of the entire shape minus the SLA/SMPS/tweeter/brace, or are there other concerns? It's 27 litres before taking away the occupied space.

An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.
 
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Ack, I presumed that would've been taken into account by the figures published by the manufacturer.

This one is 22.5802 litres after taking away the SLA/SMPS/horn/tweeter but before taking away the mid/bass driver, so it should be roughly 20 litres which would be Q=1.216 for fb=102.89Hz. I was rounding up on everything & guessed the conical dimension for the horn so it'd probably be pretty close to Q=1.2.

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What's the consensus on the best type of wood to use for a boombox? I've modeled it with 12mm simply because the Boominator was made with 12mm birch ply. I'm guessing that whatever I use I'll have to paint/treat/seal to make sure it doesn't warp if it sits on damp ground?

I'm going to have to find a local joiner or a mail-order CNC place I guess, no way I can machine 12mm with a Dremel.

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It seems that the TDA892* family don't play well with 12v (the spec actually quotes +12.5v to +30v as the working supply) so a single NP7-12 won't be a good idea. I'm considering using 2x UL3.4-12 in series to give +24v 3.4Ah in virtually the same volume (~10% larger) & almost exactly the same weight (50g heavier). Would runtime on +24v 3.4Ah be similar or better than +12v 7Ah? My understanding is that the amp might actually be more efficient with higher voltage, so the current draw may actually be less than half of what it would be on +12v?
 
I built a boombox 2 summers ago by simply cramming a pair of 2-way 6.5" car speakers into a flight case along with a Sure amp, 7Ah SLA & 40W SMPS.

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The result works fine, it plays loud & long, it can take a serious beating because of how strong the flightcase is, however no thought whatsoever went into the size/shape of the enclosure for the speakers, I simply found a case that was deep enough & a convenient size to carry.

So this summer I want to build a new boombox but this time do it properly & actually design it before I start building & actually use the best drivers for the price rather than the cheapest car speakers on ebay.

The Boominator is far too big & heavy - I want something in a similar form factor to my current boombox. Most importantly it must be quite 'slim' so that it can be carried on a shoulder strap like a messenger bag. My current boombox is perfect for this, the Boominator's depth isn't.

I'm interested in this project...but I don't understand the PS part...can you post me a scheme? How you charge the battery?
 
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