Optical Audio cable quality degradation

[New-Blu-Blood]

Hey Guys,

I was on Monoprice and discovered a 75-foot optical audio cable for sale. This would be perfect for my HT setup but i am concerned that the long length will result in signal loss. I read that at around lengths between 5-10 meters, the optical audio cable tends to lose signal quality. Below is a link to the page that has the optical cable.

http://www.monoprice.com/products/pr...seq=1&format=2

Thank you,
Brian

[MacDaddyOJack]

It's digital so it's gonna be tough to lose any 1's or 0's. Plus it's fiberoptic, that's one of the best transports we have right now. Besides, if you need a cable that long then there's not much you can do about it, right?

Signal degeredation is not very prevalent in digital signals but I would still stick to the shortest lenght possible.

[Johnny Vinyl]

I agree. If it's the only option you have, then your really don't have much choice.

John

[Arcam_or_bust]

Move your source. Thats what remotes are for.

You should try to keep it closer anyway, 1.5 meters preferably.

How come you would need a long one anyway?

[Clark Kent]

If you go with the Toslink connection at that distance, I would pick the highest quality cable I could find and make sure no kinks are in the run.

[New-Blu-Blood]

Hey guys,

thanks again for all the replies and info. I decided to actually go with a length of 35 feet instead of 75. I thought about getting the 75 footer for future use in a different home theater setup but decided to save up and just go full HD audio.

[crackinhedz]

....at $20, couldn't hurt to try it out.

[typ44q]

From what I understand lengths that long will be more dependent on your equipment than the cable itself. Some newer devices can be run at lengths of over 100 feet without problems but the original spec for Toslink was only 10 meters (33 feet).
Remember this is not the same stuff that the phone company uses which uses a laser to transmit the data. Audio equipment uses an LED and has a very short range (and very low bandwidth) compared to typical single and multi mode fiber which can go over 60 miles! without additional processing.

I would say if at all possible try to move your equipment closer, if thats not possible then you really do not have a choice but to get the 75' cable and see if it works.
also the monoprice cable is a plastic core which is more sensitive to longer runs compared to glass and despite what some people think you can have signal loss/degradation with digital cable weather its HDMI, optical, CAT 5 etc and unlike with a computer where the data rate slows down (because lost packets have to be resent) with A/V you get drop outs that are audible and visually noticeable.

[Big Daddy]

Originally Posted by New-Blu-Blood

Hey Guys,

I was on Monoprice and discovered a 75-foot optical audio cable for sale. This would be perfect for my HT setup but i am concerned that the long length will result in signal loss. I read that at around lengths between 5-10 meters, the optical audio cable tends to lose signal quality. Below is a link to the page that has the optical cable.

http://www.monoprice.com/products/pr...seq=1&format=2

Thank you,
Brian

With long lengths of Optical cables, you have to worry about not bending it. Signal degradation is not the major problem.

Can you use a Digital Coaxial cable?

Read A Guide to Optical, Coaxial, & Speaker Cables.

[New-Blu-Blood]

Thanks for the replies guys. Yes I think I could hook up a coaxial cable but I have heard that optical cables deliver a higher quality form of sound. When you say "bend" do you mean bent in half or slightly bent. It seems pretty difficult not to bend a cable when you hook it up to a blu-ray player or receiver.


-Thanks

[rlf3911]

Yep just get the toslink cable. The length wont affect sound quality. Digital coaxial offers the exact same specs, but fiber optic is just way cooler.

Note that they both only support 2 channel HD audio.

Edit: Straight from the FAQ posted above:

13. For very long distances (e.g., 50 to 100 ft), optical is preferred. However, as was mentioned before, care must be taken to make sure the optical cable is not bent. If it is not possible to keep the cable straight, then a coaxial cable should be used.

[Big Daddy]

Originally Posted by New-Blu-Blood

Thanks for the replies guys. Yes I think I could hook up a coaxial cable but I have heard that optical cables deliver a higher quality form of sound. When you say "bend" do you mean bent in half or slightly bent. It seems pretty difficult not to bend a cable when you hook it up to a blu-ray player or receiver.


-Thanks

For short distances in a home theater room, there is no difference between Optical and Digital Coaxial cable. However, for very long runs such as used by telephone companies, Optical is preferred.

This is also from the FAQ of the above link:

Q. Why can't we bend Optical (Toslink) cables?
A. Optical cables work by sending light signals through a plastic or glass tube rather than electrical pulses down a wire. Digital signals are converted to light and then back to digital. As light travels through different mediums, it can bend. In optical material (plastic or glass), there is an angle of refraction, which when increased to a certain amount, the light instead of going through the material, gets reflected back. Some light still escapes, but most gets reflected internally. By bending an optical cable, two things may occur:

1. The internal plastic (or glass) may snap and break.
2. Even if the cable does not snap, it has a limit of how much you can bend it. The limit is when you bend the cable enough so that the angle of refraction is no longer sufficient for the light to go through.

[Hammie]

I had an optical cable (Toslink) on a D-Link DSM-320 but it would not pass the Internet Radio stations across it. I had to go to Digital Coax (S/PDIF). This was a limitation of the way D-Link deployed the device.