Wow…just Wow! So very cool retro look! The fabrication on these look outstanding. I would love to own a pair of these!

Thanks for the comments, guys… I was a little surprised at the lack of volume. I think the issue is, this amplifier board isn’t putting out near 50wpc. The Lithium ion battery boards are only at ~11V fully charged, and this amp is rated for around double that I think. I wanted the safe and easy charging capabilities that the boards support, so I’m guessing it’s closer to 20Wpc or perhaps less. These are the 8 ohm version of the ND-91, and they are wired in parallel, 2 drivers per channel, of course, for a net of 4 ohm per channel. I accidentally hooked them up in series the first time around, and that was way quieter. The sound quality is good and doesn’t distort much when cranked, but they definitely need more amp. That was apparent the first time I used them in another project as well.

Awesome build! I really like the retro look as well. I am shocked, you are not getting the volume out of it. You should be. I am assuming you are wiring them in parallel to get them down to 4 ohms? If you wired them in series, you would be getting 16 ohms and your speakers would not get loud at all. However, this really isn’t why I wanted to comment. I think your design is great, but you could really use a baffle step circuit to bring out that bass. Without it, the ND91’s lack a lot of low end. Something like a 0.6 solid core inductor and a 4 ohm resistor should do the trick would work for those speakers wired in parallel. Solder the inductor and resistor together (parallel) and in series with your positive wire that goes to your first woofer from the amp. It should really open up your low end.

I love the non traditional Metal cabinets. I am a metal worker as well and have built some enclosures out of metal. Great job!!!