Most home theater devices use HDMI to connect between each other. However, not every TV or AV device has built-in speakers, which is why you cannot play sound via HDMI cable. Or you are an audiophile who would like to use Hi-Fi Stereos and speakers in the home entertainment system. That is where the HDMI to audio extractor comes into place!
SIIG's 4K HDMI 1.4 Audio Extractor & Converter CE-H26Q11-S1 which extracts and converts HDMI digital audio signal to 2-channel analog stereo, 5.1 channel Toslink optical, or coaxial S/PDIF outputs.
You do not need to rely on the poor speaker system inside your TV or monitor (if it has one). You can extract the audio fro.m your incoming HDMI source and convert it to digital optical or analog stereo audio speaker system, such as a sound bar or other external speakers.