I've been working on a project for the past 6 months to build a tiny performance desktop speaker. The concept was to make it look like a traditional BBC design that had been miniaturized by a shrink-ray, but use the best modern bits inside to produce a great sound. I'm calling it the 'LBM' or Little British Monitor.
I'm 28 years old, a sole trader and build everything in my workshop here in Kent, UK. I want to turn this into a product and to keep the price down I need to build the LBM in quantity. So for this reason I have launched a Kickstarter project to help me get funding. The address: http://kck.st/1KbfIyJ
Please help support me!
You might actually win a pair if you comment and like my facebook post here - http://on.fb.me/1fTl9bJ
I'm making these available as a DIY kit, as well as a pre-made product. So I hope you will find this interesting! They are tiny so can be put together on a table top and the circuit is pre-assembled so just needs wiring up. I have a CNC machine that I built so I will provide the pre-cut birch ply panels and they need some sanding and glueing, finishing etc... It would be a great fun project for anyone I think.
Real American Black Walnut Veneer
Assembling
Glueing
Wife helping out 😉
My PCB Prototypes
Populating the PCB.
Frequency response of LBM
I'm 28 years old, a sole trader and build everything in my workshop here in Kent, UK. I want to turn this into a product and to keep the price down I need to build the LBM in quantity. So for this reason I have launched a Kickstarter project to help me get funding. The address: http://kck.st/1KbfIyJ
Please help support me!
You might actually win a pair if you comment and like my facebook post here - http://on.fb.me/1fTl9bJ
I'm making these available as a DIY kit, as well as a pre-made product. So I hope you will find this interesting! They are tiny so can be put together on a table top and the circuit is pre-assembled so just needs wiring up. I have a CNC machine that I built so I will provide the pre-cut birch ply panels and they need some sanding and glueing, finishing etc... It would be a great fun project for anyone I think.
Real American Black Walnut Veneer
An externally hosted image should be here but it was not working when we last tested it.
Assembling
An externally hosted image should be here but it was not working when we last tested it.
Glueing
An externally hosted image should be here but it was not working when we last tested it.
Wife helping out 😉
An externally hosted image should be here but it was not working when we last tested it.
My PCB Prototypes
An externally hosted image should be here but it was not working when we last tested it.
Populating the PCB.
An externally hosted image should be here but it was not working when we last tested it.
Frequency response of LBM
An externally hosted image should be here but it was not working when we last tested it.
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I'm not sure if the last two photos showed.
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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That would require us to have a FB account. 🙂
Nice looking project. Tell us what the circuit board does. It is active XO and amp and are you doing via DSP or traditional analog op amps?
What are the specs? Power of amps, what drivers are you using, etc.
You do realize the competition here is ferocious. It will be tough to beat a commercial speaker like a JBL LSR305. That has a 40w/ch class D, DSP XO and EQ built into amp chip. Balanced XLR input. A M2 style waveguide that is one of the best I have measured. Oh, and they cost $225/pair.
These are smaller though and the box looks really nice.
Nice looking project. Tell us what the circuit board does. It is active XO and amp and are you doing via DSP or traditional analog op amps?
What are the specs? Power of amps, what drivers are you using, etc.
You do realize the competition here is ferocious. It will be tough to beat a commercial speaker like a JBL LSR305. That has a 40w/ch class D, DSP XO and EQ built into amp chip. Balanced XLR input. A M2 style waveguide that is one of the best I have measured. Oh, and they cost $225/pair.
These are smaller though and the box looks really nice.
Hi,
The circuit is using analog active filters based around TL074 (though you could swap in OPA devices). It is configured as 2-way stereo by default but a quick drill and wire link on some vias will convert it to 3-way mono.
Amps are 2x TDA7264, giving 4 channels of 25watts rms Class-A/B. I tested some Class-D amp ICs (TDA7492, TPA3116, IRS2092) and they all had a lot of midrange distortion making good drivers totally pointless. Good for bass though.
The idea of offering the circuit as a reward is that DIYers can select their own filter components to make designs the way they want, the amps suit high-end speakers, and it's compact.
My PCB also includes a rail splitter on-board, so you can choose to power it either with a single-rail supply or dual rail. Everything on one compact PCB.
Regarding the competition, there is not a lot in this size range which is as good. Although most are a bit less expensive too. The LBM have a cabinet volume of 2.6L; the JBL you mention are nearly 14L so a totally different fish. 🙂
The circuit is using analog active filters based around TL074 (though you could swap in OPA devices). It is configured as 2-way stereo by default but a quick drill and wire link on some vias will convert it to 3-way mono.
Amps are 2x TDA7264, giving 4 channels of 25watts rms Class-A/B. I tested some Class-D amp ICs (TDA7492, TPA3116, IRS2092) and they all had a lot of midrange distortion making good drivers totally pointless. Good for bass though.
The idea of offering the circuit as a reward is that DIYers can select their own filter components to make designs the way they want, the amps suit high-end speakers, and it's compact.
My PCB also includes a rail splitter on-board, so you can choose to power it either with a single-rail supply or dual rail. Everything on one compact PCB.
Regarding the competition, there is not a lot in this size range which is as good. Although most are a bit less expensive too. The LBM have a cabinet volume of 2.6L; the JBL you mention are nearly 14L so a totally different fish. 🙂
Why is that a dubious option. My understanding is that it's only necessarily dubious if you've been smoking a doobie while designing it.
It's a very interesting way to get a project to market. The Bluetooth facility is a particularly good idea.
Good luck with it.
Good luck with it.
Thank you. It took a lot of work to get the bluetooth working really well. The modules put horrible switching noise on the power lines which baffled me for weeks. Eventually I got a neat solution which works wonderfully. I've even heard this switching noise on commercial products that IMO should do better.
The only thing I found that fixed the noise was an isolated DC to DC converter to get the 5v from the amp main power supply.
It's lossy as it uses compression and digital transmit. BT 3.0 birate 24Mbps which should technically be fast enough for any kind of lossless audio but it is probably implemented similarly to 320kbps mp3. 320kbps sounds quite good and is what I use for my Blind Subjective sound tests. Also quality of DAC in BT module also limits SQ. To be fair, the BT connection in my car stereo when connected to my phone sounds fantastic. No noise, plenty of dynamic range.
320kbps MP3 or better, I.e. Lossless wmv, wav etc would be ideal (not an apple user)
Woah!!! Hang on a sec. £499 a pair? How much are Sonos? I certainly wouldn't pay that price, though it doesn't mean others wouldn't stump that kind of cash. Entered the comp anyway. Good luck though I think the price is steep.
What wattage did you measure the frequency response curve at? ~95dB at 60Hz....from an Aura 3"/4"? (Well guessing at the driver here but) Seriously??? Or is there some error here? (be that my error or yours 🙂)
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