sub sonic filter tunning

[audiohz 2]

Ok so I'm running two sundown sa12's vented at 38hz 2.0 cb per sub on a saz 1200d whats probably the lowest I could safely run my ssf?

[Julian 641]

3-5hz below your tuning. 

[audiohz 2]

Ok one more thing the box was built very strong but was built for the smaller sundown sub e12 now that I have swapped subs to the much larger sa 12 would the displacement of the sa now changer my port tuning any?

[///M5 2,833]

Sure, but it will do it by changing the overall volume of the box. If the sub is .05cuft larger you just lost that space, but unless the box is uber small the difference will be pretty negligible.

[altoncustomtech 773]

Yes it will, everything like that affects the tuning but it this particular thing won't have a huge affect.  If the design said you were tuned to 38hz with E12's then you might be up as high as 40hz but I doubt it.  Even the 38hz is way above where I would want it though.

[garychurch84 127]

Alton explains here. http://www.soundsolutionsaudio.com/forum/topic/61253-ssf-and-lpf-on-the-cresendo-bc2000d/

[audiohz 2]

Sure, but it will do it by changing the overall volume of the box. If the sub is .05cuft larger you just lost that space, but unless the box is uber small the difference will be pretty negligible.

ok I may be wrong but I thought adding more mass inside the box ie larger sub mass would lower the ports Hz not increase the Hz

[Sencheezy 689]

It will depend on how much power, and the subwoofer capability. Trust me, it will tell you when it is set too low. You will only be able to find out once it's in and playing. 

[Impious 1,476]

Sure, but it will do it by changing the overall volume of the box. If the sub is .05cuft larger you just lost that space, but unless the box is uber small the difference will be pretty negligible.

ok I may be wrong but I thought adding more mass inside the box ie larger sub mass would lower the ports Hz not increase the Hz

Enclosure tuning will increase as enclosure volume decreases for a given port length and cross-sectional area. So if the new subs take up slightly more volume, then the enclosure tuning will increases slightly. The difference in your case is small enough it will not make an audible difference however.

[audiohz 2]

So does anyone know of a way to lower it from 38hz to say 34hz?

[lithium 358]

make the port longer. if its a slot port i guess you could build something from mdf to extend the port externally. otherwise just build a new box. 

[Impious 1,476]

So does anyone know of a way to lower it from 38hz to say 34hz?

Model it. I wouldn't be surprised if the differences were small enough to be virtually inaudible.