A laptop may not be equipped for sound on its HDMI port.
Because of their compact nature, laptop computers can't possibly have all the options that desktops have. With space at a premium, manufacturers may only include necessary components and connectors for the basic applications for the laptop's intended use. Just because a laptop has an HDMI connection port doesn't mean it's equipped or set up to support all HDMI functions. A common laptop HDMI question asks why there is no sound connection.
HDMI
An HDMI connection uses a 19-pin port that carries digital high-definition video and up to eight channels of audio over a single cable for connections within a home entertainment system. But since HDMI's development in 2002, upgrades and additional features have made it attractive to more users. As of version 1.4 of 2009, HDMI includes an Ethernet channel to connect any HDMI component in a home entertainment system to the Internet for support. An HDMI port on a laptop could be set up for only such a connection.
Graphics Card Doesn't Support Sound
An HDMI port on a computer could be set up as an auxiliary output for an additional monitor. Since laptop screens are limited in size, many graphics applications would be greatly enhanced by the use of a larger screen. The video card in this case may support elaborate video functions, but not have an option for sound. A DVD player installed in this laptop may work well to install programs or play movies on the screen with sound on the internal speakers. But connecting the laptop to an HDTV with an HDMI cable would not play sound from the DVD.
Incompatible Audio Card
An audio card in a laptop may support sound for the internal speakers, and send an output signal to external speakers or headphones. But since the audio card doesn't support digital sound, there's no way to route it to the HDMI port. The HDMI port may send the video to a projection screen for training or sales presentations, but in these situations, the person doing the presentation speaks and doesn't need sound. Again, the DVD player in this laptop would not send sound to the HDMI port.
Programming
If a laptop has a video and audio card compatible with HDMI, it still may not be set up to send sound. It may have been previously set up for graphics only or a presentation to a projection screen. Because there is such a wide selection of video and audio cards, and such a wide range of programming options, setting up a laptop to route the sound onto the HDMI port may have only one small step omitted that keeps the sound turned off. First check sound and video card HDMI compatibility, and then check all setup options.
Tags: HDMI port, audio card, entertainment system, HDMI connection, home entertainment, home entertainment system