Hi all 🙂 I don't post often here but lurk a lot and on other audio forums - I'd just like to share some details of a project I've been working on:
Nothing concrete to show right now besides some pretty renderings, I have a rough prototype built that I'm working with now to test driver suitability - it's 2.5" with a shallow profile so the overall depth of the unit should be around 35mm total and the remaining dimensions around the same as an average to large smartphone. I have a little shower radio of around the same dimensions and can confirm it's comfortable to carry around in a jeans pocket if necessary - enough to forget it's there anyway. Jacket pockets no problem.
Total enclosure volume is only about 0.2 litres giving little below 150Hz, but the driver has an unusually high xmax for the size, going right to around 3mm (and on many tracks even at this level it still sounds great), which couples with the psychoacoustic principle of the missing fundamental to give a deceptively powerful bass response. Very hifi too - listening to a prototype now and it is fantastic.
With a TPA3132 amp and a 3 cell (true 12 volts) lipo it could theoretically be run up to 35 'real' (~0.2% THD) Watts with a maximum SPL of 101.5dB at one metre.
The plan is to eventually go fully open source with this, and to be as non commercial as possible, but as there are a lot of custom moulded parts involved and a lot of hard grind design work to do before it's ready, it'll need quite a large Kickstarter campaign if it's going to happen at all. To keep things simple it'll be distributed in kit form (just screw + glue enclosure, no soldering) at first with more or less a costs + handling price point.
I don't really want to make a business out of this, but I do want to see it happen, and want it to be amazing - I'm experimenting with ways to circumvent the corporate process altogether that would involve some form of decentralised costs + donations based payment system.
Lots still to determine and a long development path ahead. Right now it's just me doing the general design and trying to fumble my way through parts engineering (and praying it's all practically possible in terms of machine tolerances etc as far as it seems to be to me), and another forum member (who made these very tiny amps http://www.diyaudio.com/forums/class-d/264517-really-really-small-tpa3132-amp-7.html) doing board layout/programming, I've got a lot to learn before this is anywhere near real but also have full commitment to seeing this through, as it's been in mind in one way or other since around 2009 (though only really in development for a few months now)
An externally hosted image should be here but it was not working when we last tested it.
Nothing concrete to show right now besides some pretty renderings, I have a rough prototype built that I'm working with now to test driver suitability - it's 2.5" with a shallow profile so the overall depth of the unit should be around 35mm total and the remaining dimensions around the same as an average to large smartphone. I have a little shower radio of around the same dimensions and can confirm it's comfortable to carry around in a jeans pocket if necessary - enough to forget it's there anyway. Jacket pockets no problem.
Total enclosure volume is only about 0.2 litres giving little below 150Hz, but the driver has an unusually high xmax for the size, going right to around 3mm (and on many tracks even at this level it still sounds great), which couples with the psychoacoustic principle of the missing fundamental to give a deceptively powerful bass response. Very hifi too - listening to a prototype now and it is fantastic.
With a TPA3132 amp and a 3 cell (true 12 volts) lipo it could theoretically be run up to 35 'real' (~0.2% THD) Watts with a maximum SPL of 101.5dB at one metre.
The plan is to eventually go fully open source with this, and to be as non commercial as possible, but as there are a lot of custom moulded parts involved and a lot of hard grind design work to do before it's ready, it'll need quite a large Kickstarter campaign if it's going to happen at all. To keep things simple it'll be distributed in kit form (just screw + glue enclosure, no soldering) at first with more or less a costs + handling price point.
I don't really want to make a business out of this, but I do want to see it happen, and want it to be amazing - I'm experimenting with ways to circumvent the corporate process altogether that would involve some form of decentralised costs + donations based payment system.
Lots still to determine and a long development path ahead. Right now it's just me doing the general design and trying to fumble my way through parts engineering (and praying it's all practically possible in terms of machine tolerances etc as far as it seems to be to me), and another forum member (who made these very tiny amps http://www.diyaudio.com/forums/class-d/264517-really-really-small-tpa3132-amp-7.html) doing board layout/programming, I've got a lot to learn before this is anywhere near real but also have full commitment to seeing this through, as it's been in mind in one way or other since around 2009 (though only really in development for a few months now)
I was going to comment on speakerplans that I think it's a really bad choice of name for an otherwise cool project. Everything has to be pod these days... but a pod you pee in? No thanks. That's the unfortunately word association I and I suspect many others get.
Don't use LiPo batteries for this. Use NMC cells. They're much cheaper, holds more capacity per volume, have much better high current drain properties, and are much safer. Not as safe as or as good high current drain properties as LFP cells but close.
This looks to be a traditional "stomp box" size speaker such as those popular on the 41hz forum for use with the amp32. A stomp box is traditionally a standard industry alu or plastic enclosure in a particular size, usually 121x66x37mm. These can be found in any colour you like for very little cost.
Don't use LiPo batteries for this. Use NMC cells. They're much cheaper, holds more capacity per volume, have much better high current drain properties, and are much safer. Not as safe as or as good high current drain properties as LFP cells but close.
This looks to be a traditional "stomp box" size speaker such as those popular on the 41hz forum for use with the amp32. A stomp box is traditionally a standard industry alu or plastic enclosure in a particular size, usually 121x66x37mm. These can be found in any colour you like for very little cost.
Last edited:
Maybe 😀 Anyways, the name, lipo battery power, and enclosure style are all more or less set.
I thought the same for ages but it grows on you and the stylings make it more clear when you see the rendering in 360, it's one of a line of designs I've got in the works that share the same name and for plenty of good reasons that become more apparent when viewed and used together.
It is so a Peapod though 😀 even if it has to be coloured all shades of green with the word peapod engraved in little metal peas down the side to drive the point home:
If the name and stylings are so objectionable then hopefully the open source nature will bring with it less objectionable alternatives (3D printed case + component kits available opens no end of possibilities)
An externally hosted image should be here but it was not working when we last tested it.
If the name and stylings are so objectionable then hopefully the open source nature will bring with it less objectionable alternatives (3D printed case + component kits available opens no end of possibilities)
An externally hosted image should be here but it was not working when we last tested it.
I know it sounds silly but I do really think it looks like a peapod and it was designed with pure functionality and ergonomics in mind (as large as possible curves in all places for going in a pocket)
Oh and it is waterproof so if you really wanted to you could pee on it. Add some green jack leads - daisy chained it'd be like pods on a vine - and appropriate graphic design in all packaging/website and so on I think people would get it - Unless they're urophiles or something.
Last edited:
Just some thoughts...
- How are you doing battery charging, cell balancing/protection, etc?
- How are you providing waterproofing for the audio/charging inputs?
- Plastic mold design is very expensive, especially what you've got there - I see tons of sliders and at least one overmolding operation. Personally I'd keep this in 3D printed land instead of attempting to go for volume.
- You'll need various industry certifications if you turn this thing into a sellable finished good. Those get expensive too...
- How are you doing battery charging, cell balancing/protection, etc?
- How are you providing waterproofing for the audio/charging inputs?
- Plastic mold design is very expensive, especially what you've got there - I see tons of sliders and at least one overmolding operation. Personally I'd keep this in 3D printed land instead of attempting to go for volume.
- You'll need various industry certifications if you turn this thing into a sellable finished good. Those get expensive too...
Hi Gmarsh,
There are far less parts to it than it seems. I will post the full design details in a few days once I've it's fully rendered internally (just a few details and braces etc to work out now), as it's just far too frustrating to try and and be 'semi-open' with this - May as well do it fully open from the start - or fully closed!
Basically there are two main 'shell' pieces, a grille that snaps on something like the back of a phone case,a rubber part that wraps all around the frame, that could probably be moulded in such a way as to fit a bunch of them in a single piece and break them apart afterwards (the breaks are then covered by another piece) - All the buttons and logo pieces are formed in one continuous piece of cast metal, which, as with the rubber, I'm guessing can be formed as many pieces in one mould, as the breaks are not visible - this then slots inside the rubber piece.
The rubber provides most of the waterproofing and the the necessary 'give' required for the buttons to move.
What part looks like an overmoulding to you?
The charging input is a barrel connector that is waterproof by default and either pressed hard into a taper or possibly glued in place (I don't see much that would call for ever replacing a barrel jack - they're sturdy enough) the audio jack connectors are pressed hard - not glued - against the inner edge with a rubber gasket over the round part and if a non-leaky connector can't be sourced (still looking!) a small blob of glue over the leaky part will fix it well enough.
I haven't gone over all the required industry certs you mentioned yet - Something to consider but I can't see it being a show stopper.
Edit: About the charging/balancing/protection, there is a circuit that accounts for this and it's considered in the design.. I'd need to check over the details as I don't have all the electronics information at the top of my head right now! It's a USB slow charger.
Last edited:
I think it's better to make it 'weatherproof', claiming that it's waterproof has all kinds of things sticking to it.
Making the enclosure 3D printable takes a load (money and effort) of your shoulders. You'll reduce your market, but at the same time you lose the people that aren't technical at all, which will decrease your returns.
Gmarsh why are sliders expensive?
What about liability of certain parts, especially the lithium battery. You don't want all kinds of lawsuits thrown at you because a lithium cell exploded.
If you buy them bulk from, let's say, Batteryspace, can you rely on their testing and 'blame' it on them when something happens?
Making the enclosure 3D printable takes a load (money and effort) of your shoulders. You'll reduce your market, but at the same time you lose the people that aren't technical at all, which will decrease your returns.
Gmarsh why are sliders expensive?
What about liability of certain parts, especially the lithium battery. You don't want all kinds of lawsuits thrown at you because a lithium cell exploded.
If you buy them bulk from, let's say, Batteryspace, can you rely on their testing and 'blame' it on them when something happens?
Last edited:
Not submersible for sure. No reason at all for it to not be 3D printable. Lots of things still to consider. As I said pretty much I'm in this one for the long haul so..whatever it takes. Many reasons to be excited about this I didn't mention yet but I'm glad I didn't, better to focus on the basics as it obviously it needs to be torn apart every which way for oversights/issues, and they'll be worked out somehow! Whatever way makes most sense.
Love the name, a product is production that looks like a peapod with several speaker units that look like individual peas.
Hmmm - now you say it that way, I can see the system you're describing, and it sounds cool but it's not this one :/ Perhaps it could be named more aptly after all. Any suggestions?
Pocketbasstard. 😀
Btw. Are you using some kind of DSP in that project to overcome all the disadvantages resulting from size/design? I've seen/heard alot of "speakers" in that size and there all where horrible when not using some advanced psychoaccousticals tricks. But even then, 101dB without "real bass" isnt a pleasure to me, especially outdoors.
Btw. Are you using some kind of DSP in that project to overcome all the disadvantages resulting from size/design? I've seen/heard alot of "speakers" in that size and there all where horrible when not using some advanced psychoaccousticals tricks. But even then, 101dB without "real bass" isnt a pleasure to me, especially outdoors.
Last edited:
I like it 😀 something with the word pocket in it is probably a lot more sensible as it's probably the more unusual/appealing among it's features.
The plan is to use DSP yes - pending what impact that will have on cost and battery life - testing a board in a few days. I've been 'road' testing extensively with the driver on it's own and depending on the genre of music it's fine, the lack of the lower register seems to prevent the driver bottoming out in an unpleasant way at high excursions and the mids and highs remain clean.
An external sub is also an option as the design is meant to 'stack', and the high SPL would really come into it's own then, as with 4 you could get 113db, (119dB for 8) - If the price can be kept low that would make it a real practical option for PA usage as well as personal, and I hope that aspect will help broaden the appeal, as would be needed for any real volume production.
Last edited:
I think a great name for it would be Pokemon - short for Pocket Monitor but I think I've seen that somewhere before. Either that or Pocket Monitor System or..PMS? Right..back to the drawing board 😛
Last edited:
Good luck with the SEO for that name ^^ And the copyright claims. Maybe Pocketmon?
For the DSP you van use the intergrated Kalimba DSP of the Bluecore BT chips.
I used to think so too but turns out that DSP is actually busy running DSP on the radio signal input. Otherwise it would not be nearly as efficient as it is (sort of like how bluetooth was previously).
- Status
- Not open for further replies.