For whatever reason, it seems like aiming my subs straight up makes them quieter than when they are facing right at the rear liftgate. I did not know if this could simply be due to a different perspective, different materials absorbing the sound, or some other mechanical reason. Also, will putting subs that are in the recommended ported enclosure, into the recommended sealed enclosure make them THAT noticeably quieter? I understand that in theory they should not have the same SPL, but better quality, but I was wondering if the SPL/SQ differences are really all that significant.
Noticably quieter... yes, if you really focus on it. But it's certainly not like it's going to go from "loud" to "not loud anymore". It's pretty subtle, actually... especially if you build a sealed enclosure that's about as large as your ported enclosure (ie. increase the efficiency of the sealed enclosure). In fact, the latter is really easy, if you have a ported box now, with round ports... go to Home Depot, plumbing aisle, find the PVC fittings... all the 3" and 4" elbows, receivers, drains, toilet flanges, etc. In that section, they sell things called "test plugs"... they are two thick plastic discs sandwiching a soft rubber disc, with a screw and thumb-nut clamping it together. You can stick this in your PVC port, tighten the thumb-screw, which sandwiches the two plastic discs together, squishing out the rubber disc, and completely sealing the PVC port. ...voila - instant sealed enclosure! B) They only cost a few dollars, also.
The difference in volume when aiming is likely caused by cancellation. When faced to the back and up against the liftgate the waves only travel a few inches before hitting a barrier that reflects them toward your ear. When firing up the waves are radiated upward and then bounced down and out. Plenty of different angles that can cause cancellation. Going from ported to sealed the biggest thing you will notice is the change in low end frequency response. Unless you have a high tuning that is. When porting a lot of the percieved gain in volume is due to the added low end. It gives your FR a higher average volume as well as increasing your volume by the ~3db.
hm... that is interesting Geolemon, I had not thought of that. While I do not have round ports to seal, I am sure that I can think of something that will work, at least something that will work long enough to see if I like the change.
