Just wanted to share current configuration for my subs with anyone interested in aftermarket subs that are more than 5 inches in depth without modifying seats or anything to that nature. One thing first though, dont judge me hahahaha....I had solid system in my explorer but sold it and got the F150 for work purposes. I had 1 of these 10" subs in a ported box that sat where this one is sitting now but just wasn't as loud as I wanted it to be so decided to double up on them. I have always been a bass enthusiast and a do it yourself kinda guy and chose to build a box instead of going with (shallow'r) pre built boxes i have found on internet that goes under the seat. I drew up 2 different options and chose this one out of the 2 because port is a little bigger, also it faces under seat to kinda keep air circulating under seat around amp. I am going to be pulling this all back out to carpet box and re-do wiring, excuse the mess, and will post pics later if anyone shows interest. overall, very satisfied with sound of the highs and feels of the lows.

Current sound system config:
KW-M150BT JVC head unit
6x8 JBL Club 8620 door speakers in all 4 doors
Pioneer GM-D8701 1600 watt mono amp
2 10" DVC 2 ohm Sundown Audios SA-10D2 wired at amp at 2 ohms


First off, picture of the old box that had the single 10" sub in it...



Box configuration layout 1

Box configuration Layout 2


Biggest difference is the port size and direction of port, I choose to go with layout 2 for above stated reason in introduction and as i said, satisfied with it personally.

A few pics of box I did choose to build


A very tight squeeze indeed



yes, I am aware speakers are screwed in different ways, wasn't sure how I wanted box flipped in there....

....well that's it for now, will do sanding and carpeting on box soon, also, I have detailed schematics for building both layout boxes if anyone is interested, just ask and cant send you more info...think a 4x4 piece of ply will build either or...thanks for checking this out and hope it can help anyone down the road...

 

Considering those are opposing subs, you may want to invert the polarity on one of them so they both move right and both move left (so one moves in as the other moves out but the cones will be moving in the same direction). If you leave them wired with both having the same polarity, Both will move out which means one will move left and one will move right. This could cause cancellation in the frequencies.

This may not work out well, but just a thought.

 

Hey Jdunk....I really appreciate your input and you could totally be right. I do have them wired same polarity at the moment. Reason being, I had looked into a few different style boxes online, sealed, 4 order band pass, 6th order band pass and then some isobaric ones I think they were called...from what I gathered from that was if the speakers where back to back or face to face, I would need to wire one in reverse polarity...wasnt 100% clear on how it would sound like that so I installed a wall in between the 2 speakers as shown below...


the separating wall in between the 2 divides box all the way down through port as shown below


...
I was thinking with the wall, it would be better to wire same polarity so they would push and pull air out at same time together equally and thought wiring one reverse polarity would cause one speaker to push air out the port and other pull in...not to sure how it works scientifically but do you think I should reverse one speaker with wall being there still? Thanks for any and all advice and knowledge

 

I am not 100% sure to be honest.

Really all that means is that, even though the boxes are "together" it is really two separate boxes really close to each other.

With door speakers and raw signals, they do this opposing thing too (one moves to the left and one moves to the right) if no time alignment and just "raw" signal. This would cause heavy cancellation in the center of the audible frequencies. An old trick used to be flipping the polarity on one door to get them to move in the same direction (both cones move left/right together) and helped prior to time alignment capabilities.

Being that these are so close to each other physically but firing opposite directions I'd think you would have similar issues of destructive interference. The left sub is trying to push/compress air to the left while the right sub is trying to do the same to the right and then that air will reflect and come back and meet in the center. I don't know if that would cause constructive or destructive interference issues with sub frequencies or not.

Simple solution: Try it both ways and see which way works better.
If you have a smart phone (or if you have a laptop you could run REW), you can even download a basic RTA app and take some measurements and see which way measures better too.

 

I'm willing to try it out, and I have nooooo idea what you are talking about REW and RTA, but my curiosity is peaking though if you care to give simple info about it....either with explanation of what those are or either with what that stands for and I could google them...always tinkered with systems but never had pro equipment...

 

I added a couple of thoughts in an edit to the post above.

RTA = Real Time Analysis programs to analyze the audio response at listening positions. It basically shows the audbile frequencies and how the audio is responding to it. You can find them for free and paid versions for all devices. Some are better than others. If looking for phone apps, choose one that says something about calibrated for your specific phone. You can even pick up a little mic for phones too: 3.5mm Phone Mic
If you have an iphone this is a great app: https://apps.apple.com/us/app/audiotools/id325307477
Here is more info on it: https://studiosixdigital.com/audiotools-modules-2/

REW = room eq wizard, a free RTA (and A LOT more) for computers. Very powerful free program that you can then use with better microphones: MiniDSP Computer Mic
If you have seen anyone or heard anyone talking about measuring their system or tuning their system, it is usually done with REW and a minidsp or dayton usb microphone.

 

awesome information...ill look into the app and continue doing more research and experiments with it...thanks again for the knowledge and ill post any future conclusions in time

 

Just a follow up. I asked a friend this question (who's job is to work and tune audio systems in varying vehicles) because I was interested, and he said he would probably wire them with the same polarity to have both cones moving out at the same time to pressurize the cabin better.

Not saying opposite polarity isn't a possibility still though. I would still probably test and see.

 

Havent had time past couple of days to tinker with components any more but did read up on RTA and downloaded a couple of apps for polarity and such. (JBL has app with polarity test and few other tools)...work keeps me busy through week but will play with it some this weekend. Any obvious pros or cons with position and placement of subs in which the way they are working? Direction of port? Have a rockford 4 channel high amp I'm going to install on the door speakers, not that I'm really having issues with them, just know they can be louder on amp than headunit

 

All in all, subs are hitting nicely for most part...only getting 400 watts to each sub wired at 2 ohms at amp...amp was really good when i just had one sub wired at 1600 watts at 1 ohm...conclusion being, 2 subs at lower watts hits way harder than 1 sub high watt...eventually gonna get a 3k 2ohm amp