You can also see the crossovers either side for the two-way speakers system (+ subby).
Ahhhh... I was looking at those yellow capacitors and coils and wondering where I'd seen them before - on your speaker build thread!
They've made a real difference in the audio quality. I generally don't design my own, but made an exception here. I was lucky, the sound from the system after installing new crossovers is very pleasing.
They are 2nd order Linkwitz_Riley based, just from an online calculator. I didn't bother with a PCB, just point to point connected the coils and caps on a 3D printed template.
I'm looking forward to getting back to speaker building but I'm fighting the urge to chop and change when I'm so close to finishing this.
I had a good go at my to-do list, as always, everything takes twice as long as I imagine it will

I've re-painted the back-box, applied decal artwork and put it all back together. This was after cutting larger vent holes and fitting new aluminum grills. I didn't like the look of the 3D printed grills I fitted originally. A bit too chunky.
Here's some pics. And since I've been talking about speakers and such, a closer look at how they fit into the cramped space!
Back-box with updated vent grills and a fresh coat of paint.
Here's one of the new tweeters (Dayton ND20FB-4 Rear-Mount 3/4" Neodymium Dome Tweeter 4 Ohm). These replaced the cheap car tweeters I had fitted originally. They have great sound, nice and crisp and more detailed.
I made some adapters for them so they can be mounted into the back-box.
Here's the two speakers mounted in place. The small full range speakers are Dayton ND65-4 2.5". I deliberately split higher frequencies away from these with the crossovers.
For a little cheap speaker they sound surprisingly good. I'd use them again for other projects for sure. Link -
https://www.wagneronline.com.au/2-half-inch-aluminium-cone-full-range-driver/speaker-drivers/audio-speakers-pa/993829/fl/The off-axis arrangement is not ideal, but overall quite satisfactory for this project.
Here's a look into the bottom of the back-box. Access to connectors is OK. The 21.5" NEC monitor gets warm. Air can move freely, both through and behind the monitor and then out the vent.
The finished back-box ready for artwork.
Using my newly learned decal application skills (thank you yootubes) the artwork went on fine.
To round out the speaker overview here's a look at the sub-woofer driver and the underbelly of the cab. Also visible is the volume control.
I opted to control the Windows system audio rather than just the Vpin application audio as this is the recommended approach.
The subby volume has been turned down so it doesn't overpower the other speakers and behave like a beast-boombox!