We all know the card doesn't have bass managment (crossover for subwoofer) the only alternative was using the windows bass managment which after testing for a little while I found it was awfull, it does some heavy processing on the audio in general and delivers a horrible quality audio. In my case for movies I use an ASIO plugin on MPC-BE and for music a bass plugin for Foobar2000 (until I found Apo) but what about general audio or spotify/youtube... that's where APO Equalizer (Is not just an equalizer) comes in.
 

https://sourceforge.net/projects/equalizerapo/

 
What can you do with Apo? Downmix, upmix, copy channels, apply filtering, increase/decrease db on channels, combine settings, etc... but we are focusing only on Bass here, and I'm just going to share my config and findings, started using the program yesterday so... no expert at all and it was all try and error based on examples and the confusing documentation.
 
a) If you have the Nahimic installed then you need to uninstall everything, reboot and reinstall without nahimic and reboot again. (To enable Audio Enhancements that Apo needs)
b) Install Apo Eq, open it and it will tell you it needs to install something and reboot, do it.
 
We need to do two things, an option to redirect any audio (crossover) to the subwoofer (1) and (optional) apply a little more bass to the L R channels (2).
 
 
 
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1) Bass Redirect: Send the low freq. to the subwoofer, in my case I chosed to send only the audio from the L R channels and apply a crossover of 60hz or 80hz or 120hz. Usually a crossover gets applied to the audio we are playing on the speakers altering the original audio but Apo let us copy those L R channels on other virtual channels and there apply the crossover and sent it to the subwoofer leaving the L R channels untouched. The scripts does that and also apply a -10dB to the bass signal to lower the volume a little.
 
Apo lets you see how the 'code' written looks like:

 
You need to create a .txt file with this settings:
 

Copy: BASS=L+R
Channel: BASS
Filter: ON LP Fc 80 Hz
Copy: LFE=LFE+-10.0dB*BASS

 
That's it, you can change on the txt file "80 Hz" for any freq. you want and the output volume.
 
Then on the Apo interface remove everything with the - symbol and add new entries with the + -> Control -> include to load the txt files.
 

 
At first i found it confusing when is ON and when is OFF?, if the square is blue is ON.
 

 
 
 
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2) Bass boost: I like unaltered audio but sometimes we want a little more bass for the speakers, thanks to this guide for that!

https://inspiringheadphones.com/equalizer-apo-quick-and-easy-guide-to-more-bass/

 
The Peace Equalizer interface is a lot better to work with if you want to test and manage different presets with the equalizer-only.
 
I increased +3dB on the 120hz freq. and lowered the general volume to -3dB to avoid any possible clipping, keeping the general volume at 0dB all in one script, I chose to apply this increase on all channels except the Central and Subwoofer channels.
 

Preamp: -3 dB
Channel: L R RL RR SL SR
GraphicEQ: 120 3

 

 
If you only want for the front speakers, just delete RL RR SL SR.
 
 
 
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3) Surround Replica: Copy L R to all speakers:
 

 

Copy: C=L+R RL=L RR=R

 
For a 5.0 configuration, copying both L+R on the center channel and just L for RL and R for RR, you can adjust the gain on the Nu Audio interface for each speaker or with Apo.
 
 
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 Note #1: The filters will be applied in order, i found that the order is inverted... the first one is actually the last one... why? i don't know, for example:
 

[1] -3dB

[2] Surround Replica

In this order we would assume first is going to apply -3db to L R and then replicate that change to all speakers but it doesn't :s

 

[1] Surround Replica

[2] -3dB

This way, first it does the [2] and then the [1].

 

Note #2: After pressing ON you can close the program, and even reboot, the setting will still be applied you don't need to open the program again.
 
UPDATE: Finally got a response from EVGA support, the official word is that this card will NOT have a native crossover. If you are reading this and don't have the card yet, don't buy it, don't support this kind of BS.