First time posting here, I would like to preface this post with I have looked around and used the search features of the site etc, and have not found the answer to information I am looking for. That being said. I purchased a Dayton Sub-120.

On the back of the sub, there are a couple of settings that I have absolutely zero clue as to what they are for or what setting to adjust them to.

Gain - I guess this is just plain power, and you have to adjust it according to the room or your liking??

Freq - No clue what to set this to.

Phase - REV or NDR??

Any help is appreciated! Thank you in advance.

Gain - I guess this is just plain power, and you have to adjust it according to the room or your liking??

Precisely -- this is basically a volume control. If your AV Receiver has an automatic room setup function, you can usually set this around 1/2 to 3/4 and let the AVR take care of the rest. If not, just set it where you like it.

Freq - No clue what to set this to.

This is the low pass filter (LPF) frequency of your sub -- if you set this to 80 Hz, for instance, the sub will only put out frequencies BELOW 80 Hz, and filter out everything above that. Like the gain control, how you use this depends on the functions of your AVR. If your AVR has the ability to set the subwoofers crossover frequency, then use your AVR to set the frequency and just turn the Freq knob on the SUB-120 as high as it goes (140 Hz is the max on the SUB-120, I think). If your AVR cannot control the frequency, then you need to set this to where it sounds good for you, while taking into account the frequency response of your main speakers -- start at 80 Hz and try different settings from there.

Phase - REV or NDR??

It's actually REV for reverse or NOR for normal. Keep it set to NOR unless you have a reason to change it.

Post the model and specs of your main speakers and AVR for more specific advice...

i have the same sub. anyway. i am searching to find where i should put the phase switch.
i have moved the sub right next to my seat, about 3-4' away to my left. i sit dead center of the speakers and tv. my understanding is that i should set it to REVerce. but idk.