I tried my hands on the measurement after lots of presuasion from fellow forumers. Of course also there is a need to reconfirm and reassure myself on the soundness of my design and execution.
The software used in the measurement attempt - ETF.
You can read all the marketing stuff on this software from its official website. In short, I installed the software on my laptop and I setup the soundcard connection as per the help file. The difference is that I use the microphone jack directly to the mic instead of the mic to a pre-amp and pre-amp to the line-in.
There seems to be 3 point of resonancem ~19Hz, 32Hz and 45Hz. If the above is to be trusted, low freq performance is excellent - in fact better than theorectical. The high output below 20Hz is unrealistic since measurement charts from the manufacturer show almost 0 output at this freq. Thus, there is much doubt in this result.
Though a lot more spikes than the low-freq chart, the variance is excellent, less than +-2dB from the mean.
Output is an almost perfectly flat with variance of only 1dB between the peak and valley!
I will ask around to find out on how to get a more meaningful result from this software.
#1 The sluggishness of the bass reduced tremendously. I think the fibrous material slows down the air inside the box thus the muffled and sloppy effect.
#2 As far as my memory can recall. Such impressions are largely subjective and likely being influence by emotional needs. In this case, could it be my desire 'to believe' that the two box sound the same or they do really sound similar? At that time it is diff to do an A/B as it entail moving the drivers across from one box to the other. Thus time blurrs.