XCON 12" - New spruced up box concern

[8adk1d 0]

Ok basically I had an ok box, performed well'ish, ported 2.4ft3 60sq" port @ 33hz, then I made an adaptor to sit over the front and channel the ported box into the cabin via the skii port.
This worked a treat and made it much cleaner sounding and changed my tuning down to 27hz.

 

Now, I have a new box finished I payed some $$ for and its 2.8ft3 tuned to 32hz with 50" inch of port, the concern is pretty much straight away below 32hz the sub seems to sort of get stuck in and doesnt excurt properly and have stuff all output also, what is this and what can cause it?? I know it could be a lack of backpressure in the box but the new box I thought was a much better design than my old one which could delve from 33 to 28 and still have decent controll and at no frequency did it do this "Stuck in" excursion.

My only hope is that when I make my new adaptor entry to the cabin that it will lower tuning to about 30hz sealed to cabin which is perfect based on 27hz being very nice but perhaps a little too low in response and It will add some back pressure to stop the sub from excurting "In"

 

my old box sealed into the cabin was doing 141@28hz and 138db still at 24hz but the long port of 1.8m was creating ugly port echoes in kick drums or any frequency above 45hz to about 55hz and also excursion went mental at 36hz for some reason like a bad spot and I was hoping this new design would fix all that but now theres a new very ugly problem

 

Old Box:

http://i190.photobucket.com/albums/z68/8adk1d/Car%20Audio/IMG_20140507_193039.jpg

 

http://i190.photobucket.com/albums/z68/8adk1d/Car%20Audio/IMG_20140314_181733.jpg

http://i190.photobucket.com/albums/z68/8adk1d/Car%20Audio/IMG_20140314_181223.jpg

 

http://i190.photobucket.com/albums/z68/8adk1d/Car%20Audio/IMG_20140310_172154.jpg

 

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New Box still making adaptor for that continues a 45* port entry instead of "splat" into the wall of the adaptor:

http://i190.photobucket.com/albums/z68/8adk1d/10717790_785156258210464_1376268556_n.jpg

http://i190.photobucket.com/albums/z68/8adk1d/10726708_787424414650315_540361306_n.jpg

http://i190.photobucket.com/albums/z68/8adk1d/IMG_20141019_191418.jpg



 

[frogcase2002 393]

Looks like your "Kinda" turning it into a 6th order bandpass .. why not have a 4th or 6th order bandpass designed for it if your wanting to fire it into the cabin?

[8adk1d 0]

I'd like to do something like that, a 4th order would be great but probably not really suited to the XCON. A 6th order I don't know what to design and really don't want to blow this thing up, tuning one chamber to the fs and the other an octave or slightly less up is all I could really think of doing, port area and volume sizes for both chambers I do not know.

I just had this box made so I'll see how I go but I thought someone could give me a pointer as to what is this effect of "In" excursion like its getting sucked in, I reduced my port area over my previous box so its not really adding up to me.

BTW how do I change that frickin name in my profile, its 6 years old and I'm wiser.