Box tuned at 35hz ssf?

[audiohz 2]

Sub is a Sundown sa 12 in a 1.75 cu box at 35hz where would the subsonic filter be good to set at?

[jcarter1885 995]

30-33hz should be fine, hard to pick this number on an amp so anywhere in that range will due.

[audiohz 2]

30-33hz should be fine, hard to pick this number on an amp so anywhere in that range will due.

my co worker has a cc1. He telling me to set it at 28hz but that sounds to low.. I'm putting 750 rms on the sub also.

[altoncustomtech 773]

You typically want to set the SSF 3-5hz below the tuning frequency of the enclosure.  However, just because someone tells you the enclosure is tuned to 35hz, or that's what the calculator said when you designed it, doesn't mean that's exactly what it's tuned to.  There's a simple way to set the SSF using some test tones, and not that retarded CC1, that will be far more accurate.

 

First off, get yourself a set of test tones that covers your target tuning frequency +/- 15hz at least, a full set is handy to have on hand period.  Those or a tone generator on your phone, tablet, or as a piece of test equipment.  Before you start, turn your SSF all the way down so it's not interfering with this procedure.  Start with a tone that's about 10hz higher than your target tuning frequency and turn it up enough to get the sub moving very noticeably.  Now, start changing frequencies one at a time down toward your target tuning frequency and watch the cone movement on the sub.  Watch for the sub to move the least amount and then start moving more again and at that point you've actually gone below your tuning frequency.  Back up and go back and forth a few hz until you're sure which frequency the sub was moving the least amount.  THAT frequency is the REAL tuning frequency of your enclosure.  If it happens to match the target frequency then great, if it doesn't don't be surprised.  Lots of things that get missed in calculations, cuts, and construction can affect the final tuning frequency, it's no big deal.  Now, change to a frequency that is 3hz to 5hz lower than the real tuning frequency of your enclosure and turn it up enough to really (and safely) get the sub cone moving good so it's easy to see.  All you have to do now is turn your SSF dial up until the sub cone is moving about half as much as it was when you started and your SSF is set PROPERLY.

 

 

That's all there is to it AND you have the added benefit of knowing exactly what your tuning frequency is.