Each season in Destiny 2, there will be weapons that standout as just being a bit more useful than others. The Deafening Whisper is definitely one of them. A Wave Frame Grenade Launcher, rounds fired by this weapon will cause a long trail of elemental damage to explode outward in the direction the round was heading when it detonated.
This elemental based fire will absolutely nuke mobs, clearing far more enemies than you may have thought possible. Why is this a good thing? It’s a low ammo method of mass mob control, and a quick way to clear out massive groups of enemies.
To get the Deafening Whisper, you will need to get involved with the Season of Hunt’s main activity, Wrathborn Hunts. These involve chasing down particularly dangerous enemies for The Spider, and you will need to get a Cryptolith Lure from the Crow.
After that, you need to get lucky. The available Wrathborn that you can chase down will have a rotating pool of rewards, so check each of the Pre Mods to see what that particular boss is dropping. If you see the Deafening Whisper, slot that Mod into the Cryptolith lure. You will need a full charge to start a hunt, and this can be done by playing Strikes, Crucible, or Gambit.
After that, it’s a pretty simple process of taking the lure to a Cryptolith, beating the midboss, and then following the trail of greenslime to the next location. When you get there, finish off the midboss and then take out the main boss to get your loot.