Kyle

Probably decent, the Lab 12 has great mms and BL for its size giving it a low Q so it would work well in a horn. I don't see any reason this couldn't.

Looks like a new driver, not half bad on paper. Reasonable BL, not too too high mms. Price is solid too. https://www.parts-express.com/Dayton-Audio-MX12-22-12-Max-X-High-Excursion-DVC-Subwoofer-2-Ohms-Per-Coil-295-166

https://www.digikey.com/en/resources/conversion-calculators/conversion-calculator-parallel-and-series-resistor

The speakerpower can do 2+2 so you'll want to try and land a 2ohm load per channel. Look for a driver with a ~5 to ~6 ohm DCR and if you take 3 of them in parallel you're gonna a be right at a 2 ohm nominal load. Perfect for each side of your amp. Are you set on have 6? 4 21's is still a lot and may be easier to deal with.

The size of the driver does not make it fast or slow. In this case, you have low delay because its a sealed box. The HS-24 would perfectly fine for music, but you do need to couple it with a large box because of its higher Q of about 0.5. A big sealed box would be perfect for this driver. Also, to understand why group delay is a much more apparent with a port / horn (compared to just a driver in a sealed box) because the port, unlike the driver acts like a spring mass system. When you apply a voltage to the driver, its ridge and starts to accelerate more or less as a rigid body. But when you apply a force to a spring-mass, then it acts differently compared to the input signal. I'm honestly not sure how group delay is perceived in terms of subjective sound quality -- I hope some others chime in.

Welcome to the forum. I have not looked at these designs in detail, but my 2cents. If you're using a high sens. pro style driver, I don't really see how the system benefits from putting that kind of driver into a 6th order bandpass because the bottle neck is still the low end and its not lacking in mid-bass punch. Using the same size box, you can make the simple 4th order with a larger port with more headroom. I would be interested to see if anyone has experimented with 6th order and compared it to standard ported boxes (same size) with these type of drivers.

I will agree to pretty much everywhere here. BB is nice for things that get big, even if you don't move it much. When you do need to move it (and you will) you won't regret the BB.

no, thank god! it was just a 12" TC-1000 / Epic. Good little driver, plenty loud for my small loft.

I don't add one on my sealed HT sub, then again, I made a mistake once with the amp maxed out and now I have a voice coil ring dent on my metal dish cone Still works fine tho!

Looks nice! I bet they sound fantastic!

I tend to think its a glue problem, or primer problem.

Hard to tell what that might be, best to return it if you can? The noise may be coming from the motor or voice coil. The phase plug won't likely be making any actual noise itself, but any number of things could be wrong with that driver, its very hard to tell sometimes what exactly it is.

Any small issue with glue or primor can lead to failure. Its a bit tricky and takes precision. Hopefully Eminence can get those fixed for you