Ok so I have a single DD9518 on an AB VFL150.1 in a 02 Ford Explorer. Box is to DD specs off their website. D3100 under the hood with an XP2000 in back. Also I have a little Diamond 300.2 powering my components, 6.5" PG RSDs. 0/1 throughout, Big 3 done. After installing everything and then tuning it for a couple days, I have to say I thought it was going to be way louder. My old system was just a 15" FI BL on a Sundown 1500 and I was very pleased. That was my first system though so maybe I was just expecting this one to be wayyy louder, not sure though.
I had a friend of a friend build my box (yes I know bad idea) and it turned out ok I just have a couple concerns. We went with DD recommended specs except I had him go sub up, port back w/ 45's throughout. The port was supposed to be 5" throughout, however on the outside its exactly 5", but on the inside of the box its 4 1/8".
Could this be my problem? If its not 5" all the way through does not change the tuning or will it just sound like crap? If I need a new box built, should I just go with DDs actual specs with sub/port facing same way?
Each coil on my DD9518 each read 2.4, so at the amp I'm getting a load of 1.4 ohms. Is this rise normal or should it be lower? I'm pretty sure the VFL150.1 does ~2500-2900 @ 1 ohm, so it's probably doing about 2k @ 1.4 ohm? So it also could be a problem of under powering my sub I guess.
I bought the sub used its a g motor with I frame and soft parts. The sticker on the magnet of my sub says DD9518gD4. I'm just confused because its a Dual 2 ohm, why in the serial number does it say D4?
Thank you and sorry for all the noob questions.