Originally Posted by Tack
Well, I was speaking in general terms but you're right about the small PR. A 1 ft³ PR box will be no output monster, but you can have something that's flat to tune in a small box I guess. Depends on your goals.
Yes you can, above tune. There's nothing to be done below that.
I'm not trying to correct you, I just don't want anybody to get the wrong idea and sack their driver. " Dood I got 124db at 10hz from my PB12!"
Speaking of DSP, I always wondered why JL kills the output on the Fathom at around 20hz. They have a good amount of amp and a beefy driver and they pretty much cut the legs out from under it.
Well sure box size is always the trade off vs either SPL or extension, Hoffman's Iron Law at work and all. The benefit to this route over a sealed EQ'd box is there is no compression of the low frequency signal. For example, If I have a 1000 watt amp on my tiny sealed sub, and I'm boosting below 30hz by 6 db, the sub will only be linear for the first 250 watts of output, as in the SPL achieved at 50 hz from a 250 watts is pulling 1000 watts from the amp where that 6 db of boost is applied. After that point you will no longer increase SPL throughout the boosted range of response, while the higher frequencies continue to get louder. Compression is occurring. This will not happen if a PR reflex design is used, and the fact that JL cuts the response below 20hz anyway removes one of the main perks of a sealed design, making it even more questionable (its about the $$).
Just so I dont come across as completely talking out of my a$$
This PR with 750g mass added
In a 14" cube with 800 watts
Not saying this would specifically be better then the JL, just that subs like this are completely possible. You can see the price of the PR, and why they are not used