The update will bring an audio leveling feature which will set the same playback volume for all music and video tracks in your collection.
This update should also be available to other Nokia Lumia Windows Phone 8 devices on various carriers.
The Lumia 810 features a 4.3 inch WVGA ClearBlack touch display, 8GB of internal storage which can be expanded through microSD, an 8 megapixel camera with Carl Zeiss optics which is capable of 1080p HD video capture, a secondary HD camera for video calls, and is powered by a 1.5GHz dual-core Snapdragon S4 Plus processor.
The audio settings on your Lumia 810 allows you to select from a selection of equalizer presets or manually set a preset you suite your need. In order to access this settings you have to connect a wired headphone to your device as it wont be accessible with wireless headphones.
You can download the update by heading over to your Windows Phone Store and checking for updates.