What Are the Audio Inputs on DVD Players?
- Most DVD players sold still include composite audio inputs, which are one of the oldest forms of audio connections. Sometimes called RCA inputs, each composite input can transmit one channel of audio. The red one usually transmits the right stereo track, while a white or black input transmits the left stereo track. Combined, the two create two-channel stereo sound. On some higher-end DVD players, there might be additional composite audio inputs that can be used to create surround sound. One pair of inputs provide the left and right audio tracks for the front audio, while another pair is used for rear audio. While composite audio is very common, it suffers from many limitations. Each cable can only transmit a single audio source, so many cables are needed for true surround sound. Also, the cables are prone to electrical interference, which can degrade audio quality. Furthermore, they are incompatible with many new audio formats found on Blu-ray discs.
- Optical audio is a newer audio format that is superior to traditional composite audio. While composite audio transmits via electrical impulses, optical audio transmits via pulses of light. This eliminates the problem of electrical interference entirely. Another advantage that optical audio cables have over their composite counterparts is that a complete 5.1 channel signal can be transmitted via a single cable, unlike the single channel of audio that composite supports. However, optical audio is not without its own limitations. It cannot transmit a signal greater than 5.1, so it too is incompatible with newer audio formats. Also, it is not very common. While some DVD players may include optical audio inputs, they are not the standard.
- Coaxial audio cables look almost identical to composite audio cables, but the similarities end there. They are a digital connection, capable of transmitting up to 5.1 channels of audio, and they are also less prone to electrical interference. The audio from a coaxial connection will usually sound better as well. It can transmit a wider range of frequencies than standard composite cables can. However, just like optical audio, coaxial audio is not altogether common, and many DVD players do not have coaxial audio inputs.
- HDMI stands for "high-definition multimedia interface." As that name suggests, HDMI can transmit more than just audio. HDMI inputs are typically used to transmit both audio and video, and can usually do both better than dedicated audio or video cables. HDMI is less prone to interference than other audio connections, and is the only audio connection that can transmit uncompressed audio found on many new Blu-rays. Although the HD video and audio capabilities of HDMI are typically overkill for DVD players, since DVDs themselves cannot hold HD video or high-quality audio, most new DVD players sold include HDMI inputs. While DVD players do not benefit from many of the benefits that HDMI provides, many have the connections for convenience, since HDMI eliminates the need for additional audio cables. Unlike other DVD player inputs, HDMI inputs are not circular, they are thin rectangular slots.
