CSS voice-balance

The CSS voice-balance property is used in speech media for controlling the balance — or spatial distribution — of the audio output across a lateral sound stage.

The voice-balance property allows you to specify whether the spoken voice comes from the left, the right, or anywhere in between.

Syntax

Possible Values

number: This value can be any valid number between -100 and 100 (inclusive).
left: Same as -100 (the voice sounds like it's coming from the left).
center: Same as 0 (the voice sounds like it's coming from the center).
right: Same as 100 (the voice sounds like it's coming from the right).
leftwards: Moves the sound to the left by subtracting 20 from the inherited voice-balance. It can only go as far as -100. In other words, if the inherited voice-balance value is already less than 20, this keyword will only reduce the value to -100.
rightwards: Moves the sound to the right by adding 20 to the inherited voice-balance. It can only go as far as 100. In other words, if the inherited voice-balance value is already more than 80, this keyword will only increase the value to 100.

In addition, all CSS properties also accept the following CSS-wide keyword values as the sole component of their property value:

initial: Represents the value specified as the property's initial value.
inherit: Represents the computed value of the property on the element's parent.
unset: This value acts as either inherit or initial, depending on whether the property is inherited or not. In other words, it sets all properties to their parent value if they are inheritable or to their initial value if not inheritable.

General Information

Initial Value: center
Applies To: All elements.
Inherited?: Yes
Media: Speech

Example Code

Official Specifications

CSS Speech Module (W3C Candidate Recommendation 20 March 2012)

Vendor Prefixes

For maximum browser compatibility many web developers add browser-specific properties by using extensions such as -webkit- for Safari, Google Chrome, and Opera (newer versions), -ms- for Internet Explorer, -moz- for Firefox, -o- for older versions of Opera etc. As with any CSS property, if a browser doesn't support a proprietary extension, it will simply ignore it.

This practice is not recommended by the W3C, however in many cases, the only way you can test a property is to include the CSS extension that is compatible with your browser.

The major browser manufacturers generally strive to adhere to the W3C specifications, and when they support a non-prefixed property, they typically remove the prefixed version. Also, W3C advises vendors to remove their prefixes for properties that reach Candidate Recommendation status.

Many developers use Autoprefixer, which is a postprocessor for CSS. Autoprefixer automatically adds vendor prefixes to your CSS so that you don't need to. It also removes old, unnecessary prefixes from your CSS.

You can also use Autoprefixer with preprocessors such as Less and Sass.