DIY Bluetooth Speakers

[TimC]

I'm going to document a speaker enclosure that I have recently finished for my son's teardrop. His is finished. I had so much fun with it I'm making two more for my other kids and then I will rebuild my original enclosure that I want to do over because it doesn't offer the stereo separation I want. Here's Andy's version followed by my own from a year or so ago.

No protective grill. I think I will leave it as is since the grill will detract from the look. This is powered via 12v from the teardrop or a wall wart.


My first attempt with battery pack. This is powered via a battery pack mounted on the rear. It sounds good but just doesn't pack the punch I like with better stereo separation.


More to come...

[Sparksalot]

What did you use as a receiver in the speakers?

The pair with the wood rounds is cool!

[TimC]

This shows a little bit of how I epoxied the front panel. Surrounded it by wax papered plywood to box it in. You really have to seal the seams as the epoxy will just run out any cracks. It takes a full hour for it to thicken enough to stop flowing out any cracks. And the bubbles in the epoxy are a challenge.

To reduce the bubbles I used clear spray sealer on the surface to seal the wood discs prior to the epoxy flood. This helped, but, bubbles still appear as the epoxy works its way into pores. For the most part blowing on the bubbles (or using a hair dryer) as they surface causes them to pop leaving a nice smooth surface. However, on a highly textured surface such as this there will be some bubbles in the end. The areas that are not flooded will be cut out for the speaker. They are just built up so I didn't waste epoxy.





More to come as I continue building...

[TimC]

What did you use as a receiver in the speakers?

The pair with the wood rounds is cool!

I used a TDA7492p 2x50w amp in one enclosure and the other is a slave. There is a speaker wire running from the powered enclosure to the slave. Yes, that amp is not the highest quality. Sounds good to me though.

The right speaker is the powered one with the amp inside. The left is the slave. The two silver push buttons on the top of the right speaker are the volume up/down buttons (or can be controlled by your BT device). Then a power input for 12v and a simple on - off switch.

[TimC]

My last set of fronts were a better attempt to reduce epoxy waste with a plug cut approximately the size of the speaker hole and trimmed to fit around the end grain discs. This photo might give a better example of what the goal is.

[Sparksalot]

What did you use as a receiver in the speakers?

The pair with the wood rounds is cool!

I used a TDA7492p 2x50w amp in one enclosure and the other is a slave. There is a speaker wire running from the powered enclosure to the slave. Yes, that amp is not the highest quality. Sounds good to me though.

The right speaker is the powered one with the amp inside. The left is the slave. The two silver push buttons on the top of the right speaker are the volume up/down buttons (or can be controlled by your BT device). Then a power input for 12v and a simple on - off switch.

That’s cool. I bet it was completely satisfying as a project in several ways. Are you getting true left//right stereo from them, or are the speakers in parallel?

[TimC]

That’s cool. I bet it was completely satisfying as a project in several ways. Are you getting true left//right stereo from them, or are the speakers in parallel?

Well, I'm not much of an audiophile so I don't know what you mean by true, but I hear very separated stereo. Listening to Steve Miller Band "fly like and eagle". Yeah, separation. These little bluetooth amps are amazing when they work. I've bought four of them so far. One was faulty (bad channel with noise and no signal) and I got a replacement from the seller. So it's hit and miss a bit. I think I just got a bad batch once. Overall very pleased with performance. A true audiophile will probably scoff at that statement though...

The hiss on low volume or no signal is a little irritating. But if I turn them up to "normal" listening volume I can't hear any noise.

Tim

[Sparksalot]

Sounds like you got the stereo part. Sweet. I have a couple of sets of nice bookshelf speakers that might make good candidates for the BT treatment. Hmmmm.

[TimC]

Sounds like you got the stereo part. Sweet. I have a couple of sets of nice bookshelf speakers that might make good candidates for the BT treatment. Hmmmm.

Be sure to match your speaker max wattage to the amp that is pushing them. I used a 2x50w amp with 30 amp max speakers. OK if I don't drive them at max volume. Nice thing about these particular amps is they default to about 75% volume when power is cut. As long as we never boost the phone to max and then increase the volume on the enclosure to max it'll be ok.

[bdosborn]

No speaker building thread is complete without a link to Parts Express, for all you speaker building parts:

https://www.parts-express.com/

Bruce

[TimC]

Yup. I'm using their 3 1/2" Tectonic 8 ohm full range jobbies. They are a quick source and reasonable shipping charges. Had my last order in three days.

Parts-Express has everything you need to build almost any speaker. Just add your creative wood case and build away.

[TimC]

The enclosure side assemblies were not photographed in process. Pretty self explanatory I think. They are 1/2" baltic birch.

Shave a smidge of epoxy off the sides/ends and fit in speaker boxes. They fit before pouring, but a little leakage is guaranteed.


Caulk inside to eliminate air leakage


Machine back panel for inputs and outputs


Layout. Amp will mount inside a case in the right speaker with Vol + & - buttons (not yet drilled). The left speaker is the slave and only requires an input. I would have liked smaller speaker wire inputs, but, this is what I found.

[TimC]

Cutting speaker hole. Even on a drill press using hole saws over two inches is a scary task.



Two sets cut out.

[TimC]

Soldering remote switches on these amps is real fiddly. I just rendered two amps inoperable as far as mounting remote Vol +/- buttons in the enclosures. So waiting for replacements. I'll use those amps on other projects.