Optical audio how does it work

Join , subscribers and get a daily digest of news, geek trivia, and our feature articles. By submitting your email, you agree to the Terms of Use and Privacy Policy. That little oft-neglected port can be a real life saver, though. Be it analog or digital, the signal is sent as an electrical impulse over conductive wire.

Unlike other cabling standards, the optical audio system uses fiber optic cables and laser light to transmit digital audio signals between devices. The standard was introduced way back in by Toshiba, and was originally intended for use with their fledgling Compact Disc players. Even more distinctive than shape is the fact that when the device is powered on, you can see a faint glow of red laser light around the port door.

See the photo at the top of this article. Although the standard is over thirty years old now, it has been refined quite a bit, and modern TOSLINK connections are as useful as ever. So why is the lonely optical cable so underutilized? If all your devices and everything is functioning just the way you want, then by all means carry on. You have a wonderful and high-quality older media receiver that has every port under the sun except HDMI inputs.

You can pipe the HDMI video from the source say your cable box into your TV, then turn right back around and pipe the optical audio out to your receiver and speaker system. If you have any reason at all to isolate the audio signal from a digital source it is almost always, without a doubt, easiest to do so via TOSLINK cables. What if you want to use a pair of analog headphones with your TV, but your spouse wants to use the speakers so they can listen at a different volume? Many television sets and receivers have a plain old headphone jack, but most of them kill the audio to the speakers when a headphone cable is plugged in.

Ground loops are, from an electrical engineering standpoint, a fairly complex subject. One of the most common causes of a ground loop in home media gear is poorly grounded cable TV equipment. In this situation, your power outlets and the connected media equipment are on one ground hopefully, if your house is up to code, the main earth-ground spike outside but the coax cable is grounded to another ground often a water-pipe ground if there is a water pipe or spigot near where the cable enters the home.

This disparity between the placement, capacity, and total potential energy of the two different grounding locations causes, in a manner of speaking, congestion in the electrical system. At best, this ground conflict does nothing and you never even notice. Sometimes, though, it can cause humming over your speakers and even potentially damage your equipment. In such cases, you can often completely eliminate annoying ground loop humming from your audio system by isolating the offending device with a TOSLINK cable.

Remember, TOSLINK cables are fiber optic, and because the cables are either entirely plastic or plastic and glass, there is no electrical conductivity to transfer the ground loop noise. Image Credits: Hustvedt , Michael Gaida. Browse All iPhone Articles Browse All Mac Articles Do I need one? Browse All Android Articles Many don't accept those formats at all. The cables are cheap , and having just one wire simplifies setup.

If you can't, optical is fine. If your gear doesn't have HDMI, it can't take advantage of the high-resolution audio formats from Blu-ray anyway unless you connect with analog, and decode from your Blu-ray player. Got a question for Geoff? Still have a question? Tweet at him TechWriterGeoff then check out his travel photography on Instagram.

He also thinks you should check out his sci-fi novel and its sequel. Be respectful, keep it civil and stay on topic. We delete comments that violate our policy , which we encourage you to read. Discussion threads can be closed at any time at our discretion.

HDMI vs. Geoffrey Morrison. March 13, a. Glass fibers can transmit such "lossless" signals over great distances without needing a power boost [sources: Encyclopaedia Britannica ; Wood ]. By the same token, optical audio delivers higher-quality sound than older copper-wire connectors by converting electrical signals to light and piping them through optical fiber.

The age of optical audio dawned in the s, when Toshiba created Toslink , the first optical audio cable. The Japanese electronics company had developed its own compact disc player and was looking for a way to output the improved digital audio quality to speakers and headphones.

In an optical audio setup, the digital electrical signal from the source -- say, a DVD player -- is converted into light by a device called a transmission module.

In Toslink, this module consists of an LED, or light-emitting diode, and a drive circuit, usually sent through plastic fiber, whereas ST Fiber Optic uses glass fiber and a red laser light at a nanometer-wavelength [sources: Modern Home Theater; Toshiba ]. The signal then speeds along the optical cable to the destination device, usually a television or audio receiver, where a light reception module converts it back into a digital electrical signal. From there, the device transmits it to your speakers or headphones.

Because it sends only sound, an optical audio cable is usually used with a video-only cable, such as DVI Digital Visual Interface or S-video. So, what's the catch? Well, optical cables tend to be somewhat brittle, and the plastic ones are not as lossless as their glass counterparts. The reconversion of light into an electrical signal has been known to introduce errors.

More to the point, however, some argue that HDMI see sidebar has rendered the format moot [source: Johnson ]. Optical audio's chief competition and the current reigning champion of AV cables, HDMI high-definition multimedia interface transmits an uncompressed p video signal and up to eight channels of digital audio [source: Derene ].

Optical cable interfaces can handle digital audio 6. Plus, it's an all-in-one cable, so you can just plug and play and get on with your life. What does optical bring to the party? Optical's main advantage over HDMI used to be price but as of , low-end HDMI cable costs have come down to competitive levels high-end cables are another story. After years of feeling lost in the formats, I tackled this article with a combination of excitement and trepidation.

On the one hand, I hoped that, at long last, I might decode the alphabet soup, untangle the mass of cables and reel in the rhetoric to discover just what all those jacks were for. On the other hand, my previous forays into the field hinted that my hopes for clarity might end up squelched.

It's not that I'm a technophobe -- quite the opposite. I can upgrade my own computer although, admittedly, that used to be a lot easier and, in college, I helped my mom program her VCR so many times that I could talk her through it blindly over the phone, like a tower jockey walking a non-pilot through landing a It's just that, somewhere along the line, a few cables became many, the color codes ceased to mean what I thought they meant and the number of prongs stopped corresponding to the number of jacks.

More than that, though, it was that no one could give me a straight answer as to which solution was the best. There's a reason for that, and it's the chief stumbling block to writing an article about consumer electronics: The world of audio is steeped more in lore than in hard facts; there's as much snake oil in those wires as sound.

I did my best to steer clear of the hype and to stick to the facts.