I am a new player to Diablo 3.
I started by creating a season character, but the Trials of Tempests effects are so loud and flashy that they often ruin the gameplay.
I can’t hear the dialogs and sometimes it looks really disturbing through cutscenes. Is there a way to lower their volume? I already set the effects volume down, and voice up. I can’t enjoy the story like this to the full extent.
I assume this is a bug, right?
No, not a bug. That is season theme.
If you enjoy playing campaign, do it in non-season where the season theme is not activated.
Most of the seasonal objectives have to be done in adventure mode. Only one conquest need to complete the whole campaign in one hour; but everyone will skip all dialogs or cutscenes.
So you are telling me that the extremely loud volume is not a bug? Then this is the quality I can expect from Diablo 3 in general? I’m honestly curious, I mean no offense.
You can change the volume on the game settings. I set it very low and listen MP3 played in the background.
As I said in my opening post, I changed to volume, but it is not a solution to the problem. Listening to music instead of the game is again not a solution. I want to hear the game.
But I guess this is an implicit answer to my question about game quality. Shame. 
Your topic is about the theme sound ruins storyline experience.
I told you to play story in non-season where no season theme. That was my solution for you.
If you are that new to the game where the story is still interesting to you, then the best way to experience it is by playing the campaign in non-season as Maskraider suggested.
None of the seasonal gimmicks are active there, which is the thing that is annoying you.
Thanks, but you both seem to miss the point of my bug report. I’m not bothered by the existence of the buff’s effects, but the volume of it, which is like twice of the other sound effects, completely suppressing everything.
Edit: please stop suggesting unreasonable ideas. I know I can mute the game, change to normal mode or even play something else or whatever.
Then please stop reporting things that are not bugs in the Bug Report forum.
The noisy effects, the darkening of the screen, and so on are part of the Season 21’s theme. Blizzard have already advised that they will be addressing Issues with the theme, which a click on the Blizz Tracker link would have found for you…
Again, this is not a bug.
Well, you just proved that it’s a bug. You linked 2 posts stating that Blizzard knows about it and is working on it.
Thank you. I did not know where to check, I learned that. 
A game bug is an issue where a game feature is not working as intended.
Season 21 Theme IS working as Blizzard intended it to. Therefore, it is NOT a bug.
However, the Trials of the Tempests is so annoying and so offensive that many players are complaining about it. Blizzard has listened to our feedback and is working on changing the Theme so it is less annoying and offensive.
There is no bug and nothing to fix. Only modifying the Theme’s current behavior. (Or so we hope).
Just to add, dev is working on a patch to address “accessibility issues” (no idea what it is) of the seasonal theme; and disable theme in set dungeon (this is a bug fix, but unrelated to this topic). Not much information yet.
To be honest, I’m not that annoyed by the sound effect (even not playing music in the background). A bit annoyed by the visual effect, but not as much as people said in their hate posts. If they’ll tune the contrast down a bit.
If you want to experience the story as a new player, you should play non-season. You benefit nothing from seasons in story-mode.
With that said, had the season buff not been so loud (both audio and visuals), I wouldn’t necessarily give you the above advice, since sometimes it adds a fun twist to the gameplay. This season is not. However, it is not bugged, it is working as the devs intended (except for an unintended effect in group play).
They are looking into some of the complaints about it, so we might get some changes, but I wouldn’t hold my breath.