M3 Portable Speaker Project - with bluetooth and DTA-2

[marlowe]

I have recently finished a project that turned out decent. I purchased the drivers and other items several years ago, when the drives were on clearance for pretty cheap. If I keep up this pace, I will clear out my driver stash by the time I'm 75 (I have a problem with impulse purchasing from PE).







Write up here (pdf)

[Wolf]

Re: M3 Portable Speaker Project - with bluetooth and DTA-2

I have recently finished a project that turned out decent. I purchased the drivers and other items several years ago, when the drives were on clearance for pretty cheap. If I keep up this pace, I will clear out my driver stash by the time I'm 75 (I have a problem with impulse purchasing from PE).

[ATTACH=CONFIG]46263[/ATTACH]

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Write up here (pdf)

HiVi B3A-B aka RS90. Those ought to sound pretty good!!

I see I have given you some advice too. Glad it worked or you!
Wolf

[jared]

Re: M3 Portable Speaker Project - with bluetooth and DTA-2

Looks great!!! I've been thinking of building something like this to stick in the kitchen.

Any pics of the internals? Any problems with noise from the bluetooth module? I'm particularly interested in seeing what you did with the power supply (12v for the amp, 5v for the bluetooth, right?)

[marlowe]

Re: M3 Portable Speaker Project - with bluetooth and DTA-2

Yes, thanks for the advice Wolf! Those B3A-B are really nice looking and sound pretty good too. I don't have any measuring gear, so I can't show you any fancy graphs. Most of the people who have heard them comment that they are surprised at how nice they sound for such a small speaker. But no one has commented on the great bass.

Here is some other basic info:
Name selection: I'm not good at coming up with fancy or catchy names. I was trying to figure out a name (since that's what the cool people here do) and was drawing a blank. Then I noticed the abundance of M's - Marlowe, Maple, and Mahogany in this project. So it is M3, or M cubed.

The indicator LED turned out great - when it is off, it is completely invisible, when it turns on, the blue light shines through a very thin layer of maple and the clear satin finish. The photos don't really do it justice.

It is assembled using a combination of dado, rabbet, and Kreg micro pocket holes.

I had a slight incident cutting the dado slots in the legs. The blade caught and threw the piece of mahogany at me. My left ring finger was in the way and ended up broken along with some other minor cuts and bruising on my fingers and stomach. It's always good to be reminded of the importance of safety, I thought I was doing things carefully, but obviously I had gotten a bit too comfortable and careless. Fortunately, I didn't loose any digits.

The finish is a satin waterborne lacquer by General Finishes, HVLP spray formulated. I love this finish on maple, it keeps the maple nice and clear, shows the grain without any yellowing. However, the water finish concealed most of the figure in the mahogany that an oil based finish would have brought out.

[marlowe]

Re: M3 Portable Speaker Project - with bluetooth and DTA-2

Hello Jared,

The pdf link in the first post contains several pictures of the internals and a link to instructions for a 5 volt regulator circuit that I used to drop the voltage from 12 to 5 for the bluetooth. The reason I built this was to have something in the kitchen, or patio, etc. A 12 volt battery would make it really portable.

If you have trouble with the pdf, let me know and I'll post the internal pictures here.

The bluetooth works well, has good connection time and distance, but there is a noticeable static. I'm not sure it's from my wiring or from the bluetooth unit. It's not noticeable unless you're close by and the volume is low. Overall, a nice feature for $20 bluetooth and about $10 for the regulator circuit.

Have you checked out Paul Carmody's Sprite? I would do that if I was starting today. https://sites.google.com/site/undefinition/sprite

[jared]

Re: M3 Portable Speaker Project - with bluetooth and DTA-2

Ah yes, didn't see the link at first.

Great work! I think you could even use a car 12v->USB adapter to get the step down to 5v (they have those everywhere, even at dollar stores) - although I don't know if the cheap components would have an impact on sound quality.

I think I'll do the Sprite version this summer, and add a small battery so it could be taken outside.

[asmd]

Re: M3 Portable Speaker Project - with bluetooth and DTA-2

lovely project!
i like the bit about the audiophile grade double sided tape.

I love building tabletop speakers... have got several under my belt, and several more in the works, trying to up my game on the next iteration fixing any flaws on previous version.


regards,
asmd.

[lowpolyjoe]

Re: M3 Portable Speaker Project - with bluetooth and DTA-2

Great looking project!