General Question On Box Tuning....

[ptcary]

If a sealed box has a F3 of 46 hz, that means it rolls off -3db at 46 hz?

...and a ported box with a F3 of 39 hz and an Fb of 40 hz, peaks at 40 hz???

Working on plans for a ported wall, and am curious about how it will sound. I have the sealed box above, and really like it's sound, but want to know how much deeper sounding the ported will go 46 hz vs 39 hz rolloff???

[SPL2K]

I have the sealed box above, and really like it's sound, but want to know how much deeper sounding the ported will go 46 hz vs 39 hz rolloff???

Is your box now a wall?

[ptcary]

Is your box now a wall?

No,- 5 cu ft sealed , 4 Hifonics 12"s, 2 up and 2 back, in the hatch. It got a lot louder than I thought it would when I discovered some music here on SMD, so now I want 4 more 12"s, ported wall.

If I stick with Hifonics specs, I only have enough airspace to tune them to Fb of 40 hz, but that is still a rollof that is about 6 db lower than my current sealed box, but it uses the shape of the hatch really well to support the sound.

I guess I just want to know if you think that a ported wall tuned to 40 hz (vs the ideal 33) will still be able to get lower than my current sealed box without giving up too much punch that the smaller 12" subs can do.

This will all be with low power - probably 1K to 1500 watts for 8 12's.

[SPL2K]

No. If your subs are in the back cargo area now and you go to a wall, it will never play as low as it does now regardless of tuning.

Are you doing a wall in the back or right behind the front seats?

[ptcary]

No. If your subs are in the back cargo area now and you go to a wall, it will never play as low as it does now regardless of tuning.

Are you doing a wall in the back or right behind the front seats?

Right behind the front seats, prefer something like the infamous Escalade, but with 8 12s, 1.75 cu ft each sub is all I have available in the car if I design like that, and is Hifonics minimum ported spec. I can also keep them sealed if that would help any.

I am REALLY in love with the looks of how Steve did the Escalade enclosure, there is an advantage to the subs being in an inner chamber like that for me as they will be protected form the Texas sun, and are a little bit less visible when compared to a wall with all subs forward.

My PT will never be in a db competition, so I can sacrifice some sound for looks, but don't want to build if you guys see a problem in advance.

Current box really doesn't get low by SMD standards, rolls off at 46 hz, but really got much louder than I expected from a sealed box. I previously ran one Kicker 15 in a sealed downfire box, so getting used to 4 12"s has been interesting. After I get the new enclosure done, I will have to consider another amp, or replacing my sub amp with a more powerful version.

This is not my first wall, but I have learned so many new ideas from this site, that I have to try it again. I am inherently limited by my electrical system and power, and am pretty partial to Hifonics equipment. Other than that I can build enclosures pretty well, and have a lto of fun doing them.

SPL2K, Thanks for the posts.