Hello,
I have a decent working knowledge of audio installs but, I have a lot to learn. I’ve put together quite a few multi amp systems in cars and boats in the past 35 years. I owned a small home theater install business in Nashville for 5 years until the crash of 08 killed our business. I am building a new system in my boat and yes, I know this is a car audio forum.

I am all set with mids and highs and associated Amps.

My questions revolve around the Sealed Subwoofer Enclosure and which amp you guys recommend. Although it is in a boat it is dry stored and in an always dry compartment. Before I get blasted I understand “marine rated” gear etc..

The subwoofer specs are 15” dual 2 Ohm to run at 1 Ohm. RE specs the optimal sealed box at 2.1 ft3 and it just seems too small. I have read so many forums and posts including SMD regarding acoustic suspension and not to exceed Qms (3.62). But, the Vas is 207 L (7.31ft3), I have some space but not refrigerator size space. I have been leaning toward a 3.5 to 3.75 ft3 box as the sub displacement is .27 ft3 rated at 2000 watts. I have read about rolloff associated with a larger box, softer, less punchy bass and using Polyfill to reduce some wave issues and to trick the speaker. My brain hurts...

I prefer the sound of a sealed box over a ported box.

I like good hard bass and primarily listen to rock, country and occasionally a little rap ish music. I like it Low but I also want it loud and punchy. I do not have a PC to run Winisd or any of the other programs, only an iPad and a MacBook.

The space is vented into the cockpit area. It is a wakeboard boat and we rock pretty hard at times but, clearly it is not a competition setup like a lot of the systems you guys are running. We will rock pretty hard at times but usually it isn’t for an extended time.

It is getting an upgraded alternator, Big 3 and at least a third Group 27 Battery if not a fourth. It goes on a trickle charge after use.

So finally my first question is how big should I make the box for a good tight, punchy, hopefully reasonably low Bass?

Second part (sorry for the long post) I am trying to decide between 3 Amps.
Sundown SCV-3000 which has plenty of positive reviews.
Soundqubed 4500.1. Limited reviews
CT Sounds 4000.1 also limited reviews
I like the dual power and ground inputs on the last 2 amps. I ran dual 2/0 power and ground from the number 2 battery bank.

I have looked at a ton of Monoblock and these seem to be pretty good Amps and in the price range I am willing to spend, roughly $800.

I would really appreciate some Pro advice.

Thank you, I have been using the 12volt calculator to design the box. I was only needing some F3 numbers on different sizes. I just wanted to make sure it didn’t change much with different size sealed boxes. I was able to receive some help on a different forum.
Thank you for taking the time to try and help me!

BTW, RE gives compact and optimal size recommendations, I just didn’t trust they were correct.
Thanks again!