It was my first time watching the Super Bowl over the air since cutting the cord.
My biggest issue was the audio. I could barely hear any bass from the woofer. The surround sounds were faint too.
A quick Gemini query suggests that the Channels App and/or FireTV stick settings may need to be adjusted.
Any idea how I can go about it?
What did Gemini say'?
Channels just passes along whatever is broadcast. Perhaps you need to adjust the audio settings directly on your tv set first.
Next time, watch it directly live, and play with the tv settings until it sounds like you want. If you need to, go over to Avsforums and ask. Post in whatever forum matches your particular tv set. Or, do a search on your tv's model number. There might already be a post explaining how to set the audio settings. AVS Forum
DD doesnt work in my case on the Channels Fire TV app. Live TV which i know has a DD 2.0 or DD 5.1 audio feed will not decode on my AV amp. Ive tried to get this working numerous times. I have to use Plex for DD decoding.
A bit more info on your setup might be useful - there are multiple factors that could be limiting your audio here.
What was the source - OTA channel on a HDHomeRun or something on TV Everywhere?
For me, the best fire stick settings are simply in Settings > Display & Sounds > Audio > Surround Sound and I chose "Best Available" (as selecting the wrong one here for your receiver can limit it to just 2ch stereo.
If the TV channel is only broadcasting in stereo for some reason, your receiver may have the option ('DSP') to be put into a Dolby Pro Logic II mode. This does wonders of tricking a stereo signal into 5.1. You wouldn't want it on all the time, as it's not a true and accurate surround signal (e.g. for movies etc) but it's a great option for broadcast TV.
Does playback of anything you have with DD decode via an av amp correctly in Channels DVR app for Fire TV? I suspect it doesnt. The fire tv settings im using all work fine with decoding DD from various souces using other apps. Those same sources (local files, streams, live tv...etc) decode fine in Kodi, Plex etc... but will not work when playback is via Channels DVR app. Audio output is always PCM. My friend who also has the same setup as me experiences exactly the same.