[MurphyNut]

From a young age I've had a fascination (and still do) with how sound is reproduced through a loudspeaker. I remember as a kid taking apart an old television cabinet, removing the speaker and mounting it in a wooden box and using it to bypass the cheap little speaker in my Phillips cassette player. I was amazed at the improvement in sound and this got me experimenting with other projects.
So I've made all manner of basic "audio things" over the years this speaker has been the most successful, certainly the most involved and challenging I've attempted so far.

The Concept

I wanted to make a Bluetooth speaker that would be stylish and have a strong 1930's Art Deco look about it. Good sound quality was important and it not to be too large (no taller than a foot.) To be battery powered so it could be portable without worrying about plugging it in anywhere.
I'm not a technical person so no plans were drawn up, but I had a clear idea in my head of how it should look and be constructed.

Construction

The main feature is the hexagonal "head" this was a smallish trinket/craft box found at the local car boot for 50p and this was were it started. The main body of the cabinet was made up as a frame and 4 mm plywood panels attached to it. I doubled up the thickness on the sides were the bass drive units were mounted and other areas where I felt more rigidity was needed. The inside was lined with a heavy rubber coated fabric material l had roll of.
Throughout the build I took care to ensure nothing would vibrate and the cabinet should be solid and completely air tight as I was going to incorporate a passive radiator into the design.
The "head" section didn't need to be air tight as it was a separate space to contain the tweeters and Battery pack. I still lined it with damping material to ensure nothing would resonate.
I've ensured the back panel can be removed if I need to get inside for any reason. This is sealed off with a rubber surround.

Style

The whole cabinet was veneered in European walnut at differing angles with a contrasting veneer running along the bottom edge, similar in style to many radios of the 1930's.
I've accumulated quite a lot of veneer over the years for my vintage radio restorations, I usually only use very small bits for localized repairs, it was nice to use larger sections on this project.
Out of my box of spare knobs I found a suitable black Bakelite one to key in with the black elements incorporated in the cabinet design.
The grill was cut from a sheet of mesh (I again picked up at a car boot sale) and sprayed gold. Incidentally this mesh is exactly the same as used on Bush Dac 90a.
Amplifier, drive units and battery
The drive units come from an Altec Lansing ipod dock I bought new about 15 years ago, the dock developed a fault last year and I wasn't able to fix it so I saved the speakers and the rest had to go.
That dock sounded really good and the salvaged speakers are of high quality with huge magnets on the bass units and well made crossovers.
The bought amplifier board (TDA7297) is a little marvel, it's tiny, it delivers 15 watts per channel and runs on 12 volts.
I did some research on this unit and it gets outstanding reviews and glowing forum discussions.
So despite it's size and cheapness I had no worries using it. It isn't Bluetooth (ll'l come that aspect later) but I liked it having a volume control which the Bluetooth boards didn't have.
The battery pack holds 8 AA batteries to give me the 12 volts, then the current ones have run out I'll replace them with rechargeable ones.

Sound Quality

I'm extremely pleased, it certainly sounds much bigger than the cabinet would suggest.
Out of curiosity I did a few listening tests before I had actually finished it. Firstly with the back off, it sounded bass shy and boxy, with the back on a remarkable improvement was heard.
I spent a hour or so trying out some familiar tracks to get an overall feel for the sound, it was quite neutral with no unpleasant coloration detected, vocals sounded particularly pleasant.
Decent volume could be achieved without any distortion or harshness to the sound.
Out of pure coincidence the passive radiator unit I had ordered arrived not long after this, so later that day I had another listening session with it installed.
This really does extend the bass response quite a bit without it sounding overblown.
This speaker isn't strictly a Bluetooth one but I have a clever little receiving device (seen in the rear picture) that easily converts it by plugging into the Aux socket at the rear.

Conclusion

It's been a very enjoyable project, of course it's taken much longer than I anticipated. I've certainly learnt a few new skills and it hasn't cost me much, just my time.