With box flipped end-for-end and phase reversed on sub ( or door speakers ) should alter sound , noticeably !
With box flipped end-for-end and phase reversed on sub ( or door speakers ) should alter sound , noticeably !
Testing something and fixing something .
We may have used graphs or ears in rudimentary diagnosis .
I see nothing that makes me think cancellation . If you remove towel ( good to go ) and then change two wires around ( phase reversal ) and move port behind driver's side . I think everything will sound as best as it can.
LetMeKnow
I hate to bring up the simple obvious stuff, but in advanced tuning, sometimes we forget the basics. Since your sub won't seem to play above 70Hz, have you made sure all crossovers are off except for the DSP? Not sure on your equipment selection, so I can't comment on the amps directly. I have seen people that are really good at tuning bump amp crossovers on accidentally.
"Everybody is a genius. But if you judge a fish by its ability to climb a tree, it will live its whole life believing that it is stupid."
-Albert Einstein
this of course, should be checked. But, i can say that in my experience this is not uncommon considering the setup he has. As a matter of fact, i'd say he should expect it. This isnt exactly fixable without swapping gear, so we might as well focus on what can be fixed via tuning. There are still some phase issues in the crossover region that can be addressed, but i dont think this sub will ever sound great. Thats okay though. Thats not what they are designed for.
When he mentioned '100% opposite' phase appears to be backwards on something. I thought if the phase was in sync everything would have a peak . The towel was to remove backwave altogether and thus deal with cancellation. With port too close to rear wall our tuning may drop a little. The box being 4' 1" from end-to-end and 16" high , 16" deep is what made me think if he flipped it upside down , that port would move behind driver side and sub ( s) would still fire horizontally , forward into cab .
Definately go thru any settings , check em all , again .
If you are certain that nothing was turned on accidenly , then flip two wires ( reversing phase ) and see if everything sounds better .