Yes using LFE, as for me thinking a lower setting for crossover, it’s not that I thought it would be good I’m just blindly trying random combinations. I literally do not know anything about how it works. No experience with crossover or gain or setting up systems. Nada. You could probably tell me any nonsensical thing you wanted to, and I would believe it because I just don’t know.
Confusion over subwoofer settings is common so don't be afraid to ask. There are two sources of bass in the receiver. One is the bass (lower frequency) portion of music and video content that is part of the stereo sound mix (or multi-channel sound mix with movies). The subwoofer crossover setting in your audio video receiver (AVR) determines the crossover point for sending that material to the subwoofer. As mentioned, most people start at 80Hz and you can experiment from there. Your Atoms do not produce any deep bass so I would not go below 80Hz. My Studio 20's are rated down to 54Hz but I still use a crossover of 80Hz and would not go below 60Hz.
The other source of bass is the LFE, or low frequency effects track, in movies. This is the .1 in 5.1. The LFE track only gets sent to the subwoofer pre-amp out on your AVR and is not normally fed to your main speakers (there are ways around this but I will keep this simple). The LFE channel can have content from 0 to 120Hz. Most AVRs will have separate settings for subwoofer crossover and the LFE channel. To make sure you get all of the LFE content, most people set the LFE channel to 120Hz within the AVR setup menu. The AVR then blends the LFE channel and bass content below the crossover setting and sends it to the subwoofer pre-amp out connection.
Your subwoofer also has a crossover dial. This is for people that are sending a full range signal to the sub. The subwoofer will filter out material above it's crossover settings. Since your AVR is already performing the filtering, you do not want to filter twice, so you set the subwoofer crossover to maximum. (If the AVR crossover was set to 100Hz and the subwoofer crossover was set to 80Hz, then you would end up filtering out all material from 80Hz to 100Hz which would make a royal mess of things.)
The level control on the sub is for level matching. If you have a setup microphone for setting speaker levels in your AVR, you typically start at the middle setting on the sub and let the AVR calibrate the speakers. You can then fine tune the level to your liking. If you can't auto-calibrate the speakers, then start in the middle and experiment with different movie tracks until you find the right balance.
For accurate level matching you can purchase a measurement microphone and use Room EQ Wizard (REW) software to measure each speaker, but that's a more complex discussion. For level matching, find material that you know has bass content below 80Hz. The opening race scene in Ready Player One for example has loads of bass effects. Classic rock and pop can actually be a little thin below 60Hz so you can look for tracks that have deep bass synth or a bass player using a 5 string and playing that open B string. Classical music can have deep bass content as well if you know what to listen for.