You need to use Trueplay (for which you require an iOS device). The players contain a parametric EQ with a lot more filters than anything a user could readily tweak manually, but it can only be tuned using Trueplay.

I do use trueplay! However I do want to reduce certain frequencies further. 

Which speakers do you have? Mention of sub bass suggests there could be a Sub involved. The level of Sub can of course be configured separately. 

I have an arc, sub, 2 ones as surrounds. I reduced my sub volume so as to reduce bass however it reduces certain frequencies that I don’t want reduced I.e. drum kicks. So my goal would be to keep the drum kicks the same but reduce any frequencies below that 

You don’t get Trueplay with a £699 Sonos AMP which is a disgrace and really needs an update to fix. 

This support page says something slightly different:

Link: https://support.sonos.com/s/article/3222

• Amp and Connect:Amp support Trueplay when powering Sonos In-Wall or In-CeilingArchitectural speakers as a standalone Sonos room. 
• Amp and Connect:Amp also support Trueplay when powering any third-party surround speakers in a Sonos home theater setup.

So it turned out that turning off the loudness setting under eq really helped balance the sound out

Your missing the point, but you already know that.