Small desktop system from re-purposed parts and unused stuff

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I hadn't built much of anything for quite a while audio-wise, mostly because I am quite content with the stuff I have and use. I however have been feeling the need to upgrade the quality of my desktop audio at work, without spending too much money on new stuff. Not a tall order seeing how it consists of USB-powered 2.5" drivers in plastic boxes hardly bigger than my fist.

For the speakers, I simply thought I'd use the pair of TB W4-1320SIF I had unused, in their DCR enclosures I built a few years back, but they're a tad large for desktop use at about 16 liters external bulk. I decided to build simple reflex enclosures for them, ~4.25 liters net Vb, for an external bulk of roughly 8 liters. I am in the finishing stages for these and will update the thread with pictures in the coming days hopefully. Ok, here's a teaser shot of the early stages and a new-to-me construction technique:

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As for powering these speakers,, I modified a small amplifier I built a couple of years back. It's a YJ blue/black TPA3116 board that I installed in a small Hammond enclosure that used to house a (now sadly deceased) computer interface for devices at my work. The amp used to have two impedance matching input transformers and no volume control, as it was meant to be used from the headphone output of a phone/tablet/media player, but removed those and added an ALPS Blue Velvet. Here are a couple of shots of it.

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I power it with a 19V brick SMPS and yes, through a ¼" phono jack. At least I labeled it. :)

More to come as I finish the speakers.
 
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A bit tardy, but here's what I built.

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Excuse the grainy pictures, these were taken on cell phone with low-ish light conditions for the front shots.

As mentioned in the first post, it's a pair of Tang Band W4-1320SIF in 4.25 liters reflex. I just decided to go for kerf-cutting ~2" radii to try it. I did not think of the issue that they could easily tip-over forward. I have a small piece of dense rubber-foam under the lower radius keeping them from doing so.

I ended-up tuning them to 75Hz instead of closer to 80Hz like I'd initially thought. The bass is well damped and tight. I'm not using any BSC.

I used Speakon connectors, in part because I like them, but mostly because I had a pair sitting unused.

I wanted to just varnish or oil the BB ply, but I got a bit of cracking on the outside of the bent kerfing, so I decided to paint them. I used latex paint; certainly not the most durable option, but these should not see too much abuse and it was good to minimize the smell as I had to paint in the house. I applied and sanded several coats of BIN primer and am pretty happy with the quality of the finish. There are some rougher spots in the back, but they're pretty flawless in front. The colour does not come out great in the above pics; it's "low-tide" which is a light green, think sea foam.

As always, these drivers sound pretty good to me. They were much more bass heavy in the DCR I had them in, which had more to do with the larger Vb than the extra reflex stages. They extend quite smoothly to 20kHz on-axis, but the treble response falls-off quite fast subjectively when moving from the "sweet-spot", which leads to many describing them as sounding "dark". This surprises me somewhat as I figure the phase plug should help with the off-axis behavior.
 
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The newer models such as W5-2143 look very interesting. I'd buy a pair, but I can't justify the need for it. A whizzer-less 5" might just be the sweet-spot for me. I just hope that it has somewhat better dispersion the W4-1320SIF. I know it's mainly a function of cone diameter and profile and I'm talking about a larger driver here, but the treble power response does fall-off quite steeply on the W4-1320SIF.
 
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