Redoing port soon and need advice. Sub is a Fi Q18, 6 spoke basket, SPL audio recone, on under 1k. Port is 12" plastic pipe. I want it tuned at 29 and I can get there 2 ways. 1. 34" of pipe internal and 2" external giving me 8.08 cubes. And 2. 28" internal and 6" ext. giving me 8.48. How much would the extra .5 cube affect the sub. (Fi recommends up to 10 cubes for 1 Q18)

Redoing port soon and need advice. Sub is a Fi Q18, 6 spoke basket, SPL audio recone, on under 1k. Port is 12" plastic pipe. I want it tuned at 29 and I can get there 2 ways. 1. 34" of pipe internal and 2" external giving me 8.08 cubes. And 2. 28" internal and 6" ext. giving me 8.48. How much would the extra .5 cube affect the sub. (Fi recommends up to 10 cubes for 1 Q18)

Without knowing the TSP of the new abomination of a subwoofer you have, there is no way to answer the question and going by Fi's recommendation for the Q series is as arbitrary as simply picking volume and tuning at random. That is the problem with "custom" drivers...

Realistically the difference in .5cuft when we are talking 8cuft is not going to be audible so really its irrelevant. But the only way to "know" the difference is to model it, which you can't do without the thiele small parameters for your driver

yeah i understand. i need ts params but i put the recone in so no one tested the specs. recone built by corey dean at spl audio and he told me the ts params were close to what they were from Fi but thats almost impossible with a different basket and spiders. i just have never ran anything bigger than 6.5 cubes and wondered would it make any sound difference.

Of course there will be a difference, but no one on here nor even Corey or FI could tell you what that would be.  If you really want it right measure the T/S.  It isn't all that hard.

I'm all ears man

http://bfy.tw/2suW

http://bfy.tw/2suW

LMAO....love the link sir!!!

If you have questions regarding the process ask, but that was way easier than typing something up.  Stop by rat shack and grab a resistor and the rest isn't so hard.

 

Do cycle the sub and break in the suspension first though otherwise the T/S will shift once that occurs

Subs been built since January and played so its good n broke in.