"server script that plays sound id 1845554017 at vol 0.4"

To play a sound with the specified sound ID and volume on the server, you'll need to create a Sound object and set its properties accordingly. Below is a Roblox server script that demonstrates how to do this:

```lua
-- Server script to play a sound with a specific sound ID and volume

-- Create a new Sound object
local sound = Instance.new("Sound")

-- Set the Sound object's properties
sound.SoundId = "rbxassetid://1845554017" -- Replace with your sound ID
sound.Volume = 0.4 -- Set the volume to 0.4
sound.Looped = false -- Set to true if you want the sound to loop

-- Parent the Sound object to the Workspace or another suitable location
sound.Parent = game.Workspace

-- Play the sound
sound:Play()

-- Optionally, if you want to play the sound at a specific position, you can parent it to a Part
-- and set the Sound object's Positional property to true.
```

Make sure to replace `"rbxassetid://YourAnimationIDHere"` with the actual asset ID of your custom jump animation in the animation script section. Also, ensure that the sound is parented to a suitable location in the game, such as the Workspace or a part, depending on where you want the sound to be heard from.

Keep in mind that the script above will play the sound immediately when the server starts or when the script runs. If you want to trigger the sound at a specific event, you'll need to wrap the `sound:Play()` call within a function and connect it to the desired event.