DiBo

You're looking at the street SPL sa4... The regular sa4 is a lot different lol.

Way nicer sub by far IMO. Never been a fan of SP4's. They're ok but the deaf bonce subs are better IMO. The sa4's are nicer and better IMO than my team 15 v2's. It's all opinion. He went from 156+ to 158 direct swap. Enclosure dependent and variables of course.

My buddy Michael went from sp4 18's in a flat wall to sa4-18's. Way nicer subs. Better lows in his application and more motor force. I like the deaf Bonce cooling also. He's a lot happier with the sa4-18's

U-18 in 4.5 will be louder than Zv5-15. My u series 15 was only 1db less than my zv5-15. The U series are more efficient and you'll have slightly more cone area with the U series. You won't play as low but you'll be a lot more musical.

LTO is safe. It'll fit behind your wall.

What did it meter with the SD 20k? Man I'd be iffy about a high price Taramps amplifier. Wonder what you're clamping with it. You ever consider LTO for reserve? You'll lose hundreds of lbs and gain power.

Don't waste your time with home Depot or Lowe's birch. Find somewhere to get 13ply Baltic Russian Birch

Impressive.

Footy from Sundown show yet?

I'm glad those #'s worked out for you. I'm pretty familiar with bigger Sundown drivers. I own a bunch lol. Good job man

About 30in for that low 31-32hz tuning

Let the have nots reside in loserville...

Saw this in your YouTube channel a few days ago. Crazy lol

I second the U series. Excellent quality and great for hard hitting music setups. Don't need rebassed music to wake them up.