The OP asked me to do a comparison of my specs and the 2.5 box. I used 33hz for the 2.5, and mine is not figured using a tuning factor, just proper alignment. This is how close the two are in response:
Here is the anechoic responses
Here is the response with an example vehicle gain
This shows that both of them are pretty identical, with mine not focusing on tuning, but proper loading and coupling. The difference is, my enclosure exhibits a shallower delay from 30-60Hz, resulting in a quicker response time for multiple tones within a certain period. This means, the tones are separated by the ear better and not blended from delay time. Also, it is more in phase from 31-90hz, vs the 2.5 which has a 90degree in phase response from 35-95Hz. What does this tell you? That from 35hz and below, my specifications will also result in more direct output for the previously mentioned less delay time. Hence, more accurate output.
One more thing is that the optimal loading frequency, though it will not show up in the response, for my design is at 37Hz, and for the 2.5 design is higher at 42Hz. This is the result in higher +3dB output shown in the graphs from 32Hz and below, though at those frequencies, that is nothing audible, but mentioned because it is related to the loading of the design, showing that mine has a lower frequency loading capability for higher efficiency. Not by much at all, very close, but the point is, my design was not based on tuning, but loading. And it compared quite well with minor/better results in quality.
I had to show this because the OP requested this in a PM and I wanted to post it here so people will see that a bigger box is not always better. In fact, in this case, it is very close to what my recommendations are, so I give much credit to JL for having those specs...which proves again why some of you say they are very well specifications. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
It also must be noted that my recommended port area was used for both designs. And any smaller port area would result in the JL 2.5cft box to have a drop in response quite a bit for nearly the entire usable range, but will give better quality and a smoother phase than before. So, it is a compromise as always. Hope this helps for those who questioned my recommendations.
