I was bored so i decided to take some measurements.
Sub is an adire brahma 12.
Box is .66 cft
The blue line is no poly
the black line is with poly
What caught me off guard is the poly made the sub LOUDER
I expected the increase in lower end performance but not the volume increase.
pay attention to this part.
The blue line was measured with a fixed mic position and the radio volume at 28.
The black line was measured with identical mic position(mic was not moved during the addition of the poly) and the radio volume at 26! 2 clicks DOWN, which equals about 3 db in my truck.
I reduced the radio volume 2 clicks to make the measurement amplitude align better. I am seeing a pretty substantial increase in volume and extended low and upper bass.
Both measurements were taken with identical mic position.
I did the swap with the sub facing up and did not move the box at all. I simply removed the sub, added poly then remeasured. After seeing the increase in over all volume I turned the radio down 2 clicks so that the graphs would line up better.
I had an almost 6 db gain at 30hz!
If i didnt have thta room mode at around 88hz i have no doubt that area would have gained amplitude as well.
Im familiar with poly and have used it often but actually measuring the results has me shocked at the added performance. I would have never guessed it would add volume through the entire sub range.
I was looking at a video online and it seemed inconclusive. This seems pretty darned conclusive to me.
For anyone interested, I used the blackhole "STUFF". Thats literally the name. The rep got all huffy when i called it shredded denham lol and started ranting about acoustical this, acoustical that.
Have you guys ever seen poly add this much performance?