10” subs for my 2019 RAM under seat box


CarAudio.com Newbie
May 24, 2020
First post here and I’m looking for some expert advice.

I’ve designed an enclosure to fit under the rear seats in my 2019 RAM crew cab, now I need to figure out which subs will work for me. I’m an SQ guy. What I really like is flat frequency response that extends low but remains even not “boomy”.

The external enclosure measures 40” wide, 12” deep (this is the speaker mounting surface) and 7” tall using 3/4” MDF. It’s designed to be downfiring but could be turned upside down for upfiring. Box calculator says 1.287 cu ft before sub and brace displacement.

I was originally planning on 2-10” with about .6 cu ft each. After running some graphs in SpeakerBoxLite the sub that seems to get the lowest is the Dayton Ultimax UM10-22.

Here’s my question: Should I go with 2-10” Ultimax sealed or one 10” sub ported for my goals of flat frequency response that reaches down to 30Hz? What other subs should I look at for deep bass in this install? It is possible that I could modify the design to fit 1-12”My budget for sub(s) is $350.

I will buy the sub amp to match the install so power won’t be a problem.

Any suggestions are appreciated!! Does anyone else have an underseat crew cab install? What are you using? I have included some pics of my cardboard prototype enclosure.


Last edited:


10+ year member
Oct 15, 2005
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