Difference Between Howler and Howl in howler.js

This article explains the key differences between the global Howler object and individual Howl objects within the howler.js JavaScript audio library. While both are essential components of the library, they serve distinct purposes: Howler acts as the global controller for your application’s entire audio environment, whereas Howl instances represent and control individual sound files or audio sprites.

The Global Howler Object

The Howler object is a global controller that is automatically instantiated when you load the howler.js library. It is a singleton, meaning there is only ever one instance of it in your application.

The primary purpose of Howler is to configure global audio states and query the capabilities of the user’s browser. When you call a method on the Howler object, it affects every sound currently playing or loaded in your application.

Key Features of the Howler Object:

• Global Volume Control: You can mute, unmute, or adjust the volume of all sounds simultaneously using Howler.volume() or Howler.mute().
• Global Unloading: To clean up memory, Howler.unload() stops and unloads all currently active Howl instances.
• Audio Context Access: It provides direct access to the underlying Web Audio API AudioContext via Howler.ctx.
• Codec Support Detection: It allows you to check if the browser supports specific audio formats using Howler.codecs('mp3').

The Howl Object

A Howl object is a constructor used to create individual sound instances. Every time you want to load and play a new audio file or a group of audio sprites, you must instantiate a new Howl object using the new keyword.

Each Howl instance manages its own state, source files, playback controls, and properties independently of other sounds.

Key Features of a Howl Object:

• Individual Playback Control: You can play, pause, stop, seek, and loop a specific audio file using methods like sound.play(), sound.pause(), and sound.seek().
• Local Properties: You can set the volume, rate (pitch/speed), and stereo panning for that specific sound instance without affecting other audio.
• Audio Sprites: Howl allows you to define segments of a single audio file (sprites) to play specific sound effects from a single sprite sheet.
• Event Listeners: You can bind events directly to a sound instance, such as triggers for when the sound finishes playing (onend), loads (onload), or encounters an error (onloaderror).

Key Differences at a Glance