Sharp lag with large sound files

After having this issue: Please attach the complete output of the "Game Output (Your Minecraft name) " which can be found on the fourth tab of the launcher.

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[17:35:01] [Client thread/INFO]: Setting user: IntenseArmadillo
[17:35:01] [Client thread/INFO]: (Session ID is myTokenHere)
[17:35:03] [Client thread/INFO]: LWJGL Version: 2.9.2
[17:35:03] [Client thread/INFO]: Reloading ResourceManager: Default, legacy_IntenseArmadillo.zip
[17:35:03] [Sound Library Loader/INFO]: Starting up SoundSystem...
[17:35:04] [Thread-9/INFO]: Initializing LWJGL OpenAL
[17:35:04] [Thread-9/INFO]: (The LWJGL binding of OpenAL.  For more information, see http://www.lwjgl.org)
[17:35:04] [Thread-9/INFO]: OpenAL initialized.
[17:35:04] [Sound Library Loader/INFO]: Sound engine started
[17:35:05] [Twitch authenticator/ERROR]: Given twitch access token is invalid
[17:35:07] [Client thread/INFO]: Created: 512x512 textures-atlas
[17:35:13] [Client thread/INFO]: Connecting to play.smashroyale.com, 25565
[17:35:15] [Client thread/INFO]: [CHAT] [HolographicDisplays] Found an update: v2.1.9. Download:
[17:35:15] [Client thread/INFO]: [CHAT] >> http://dev.bukkit.org/bukkit-plugins/holographic-displays
[17:35:15] [Client thread/INFO]: [CHAT] Vault 15.3 is out! You are running 15.2
[17:35:15] [Client thread/INFO]: [CHAT] Update Vault at: http://dev.bukkit.org/server-mods/vault
[17:35:15] [Client thread/INFO]: [CHAT] You have no new mail.
[17:35:15] [Client thread/INFO]: [CHAT] Set fly mode enabled for IntenseArmadillo.
[17:35:15] [Client thread/INFO]: [CHAT] [AsyncWorldEdit] You have an old version of the plugin. Your version: 2.1.5, available version: 2.2.0
[17:35:15] [Client thread/INFO]: [CHAT] [-]-----------------[+]-----------------[-]
[17:35:15] [Client thread/INFO]: [CHAT] ????????
[17:35:15] [Client thread/INFO]: [CHAT] ????????
[17:35:15] [Client thread/INFO]: [CHAT] ????????  Welcome IntenseArmadillo
[17:35:15] [Client thread/INFO]: [CHAT] ????????  You are at the hub
[17:35:15] [Client thread/INFO]: [CHAT] ????????  Use /server
[17:35:15] [Client thread/INFO]: [CHAT] ????????  NEW try out /vote
[17:35:15] [Client thread/INFO]: [CHAT] ????????  Armadillo out.
[17:35:15] [Client thread/INFO]: [CHAT] ????????
[17:35:15] [Client thread/INFO]: [CHAT] [-]-----------------[+]-----------------[-]
[17:35:39] [Client thread/INFO]: [CHAT] Played sound 'mob.enderdragon.end' to IntenseArmadillo

As soon as the sound plays via the /playsound command, there is a sharp lag. More lag for the bigger the file. This file is 2.8MB, and it's sharp lag spike is about 5 seconds. This happens on all computers, windows/ mac, with multiple people testing (good/ bad computers).

The sound, if possible, needs to load concurrently in the background to allow the user to keep playing whilst the sound is loading.

If you need any more info, let me know.

use

"playsoundname": {
  "category": "category",
  "sounds": [
    {
      "name": "filelocation",
      "stream": true
    }
  ]
}

the "stream": true fixes the lag spike

@FVbico where does that go? In the pack.mcmeta?
Thanks for the help.

just use my setup, also pitch is part of the command, not sounds.json (playsound sound player x y z maxvolume pitch minimumvolume)

I couldn't get yours to work, and I'm only using the pitch to see if it's working.

but pitch isn't part of sounds.json

It still had the same sharp lag spike which suggests it wasn't working. Sorry, but the first time is confusing :/

Got it! Thanks for the help.