HPF and LF settings ?

Hi, about the sub:

1) the out/in switch is for polarity (also known as phase on some systems). It allows you to reverse the polarity/phase (in the “in” setting). This is necessary if you have two subs, but the wiring is wrong (for example) and both subs are firing, but effectively cancelling each other out (one speaker cone goes forward while the other makes the exact opposite move) when the soundwaves meet. By flipping this switch on one of the subs you get the to both fire the same direction again. There are a few other instances you could use them, but they are way outside the scope of this forum.

2) If your HPF has a cutoff at 125Hz it means that it will let anything 125Hz and over through to the top end. You can leave your K12’s set to “norm”. The won’t be playing what they are not getting in (i.e. nothing under 125Hz). By the way a cutoff in crossover/hpf is never a hard “break”. There will be a “slope”. The steepness of the slope can be (for example) -6, -12 or -24 dB per octave (these are called “orders” – a 1st order filter has a -6dB slope, a 2nd order -12 and so on). The steeper the slope the “harder” the filter. In reality there will also be a low pass filter in the sub, doing the same thing but for frequencies of 125 and LOWER which are fed to the sub amp.

3) Based on 1) and 2) the correct way to hook this up is:

* Controller/mixer to sub (you have only one right?) with two balanced xlr cables.
* Connect XLRs to subs A and B inputs
* Set sub HPF switch to HPF
* Connect XLRs to subs A and B outputs (they will put out 125Hz and higher only) and run to one K12 each.
* On the K12, connect the XLR from the sub to the “mic/line A in” connector
* On the K12 set the LF switch to “norm” and the HF switch to “flat”
* Set the gain A knob on the K12s to a level where the balance between sub and tops is good

You will now have a stereo signal going into your sub. The 125 and less portion of the sound is played by the sub. The two tops get their signal from the HPF output from the sub (still stereo) and play only the 125Hz and above portion of the sound.

Hope that helps.

Tops:
The LF switch set to extSub will cut the low end with a cutoff frequency of 100Hz, so when set from “norm” to “extSub” you will notice a drop in low frequency response. This will happen if you feed a full range signal into the speakers (like when you are not using a sub). The extSub setting is used when you are using a subwoofer without a high pass filter (one that only has a thru connector for full range signal).

Since your subs DOES have a hpf, you don’t have to change the settings on the tops as they are not getting full range signal, but only the signal ABOVE 125Hz. This only happens when you switch the HPF switch on the sub to (go figure) “hpf” and you run your stereo signal into the sub and then to the tops.

If you want to notice the difference, hook up one top and place it a relatively long way from the sub. Have someone help you.
Stand by the top, have the other person flip the hpf switch back to thru, you should be able to hear more bass come from the top (make sure the LF switch is on norm). If sub and top are close together, it might be much harder to determine if the sub-low/low has moved from tops to sub.

As for the in/out, I would think that OUT means no polarity change, so leave it on out.

Again, this switch should not be very useful if you have only 1 sub (since your top and sub are servicing different frequencies, out-of-phase situation should not be a real issue. If you have two subs (especially if you stack them horizontally or vertically), this switch can become important.