Opitcal Splitter Dilema - Canadian TV, Computing and Home Theatre Forums

aN4rK1 · 2009-01-11, 11:46 PM

Hello All,
here is what Iam trying to achieve:

All of the cables are TOSlink optical cables btw. I bought all the cables and splitters form monoprice and tested them al separately and they seem to work. The problem comes when I go from the 1st tier to 2nd tier of splitters. For some reason the signal isnt going through, and it seems like its losing strength. I dont understand how this can happen as it is optical and fiberoptic. Can anyone shed some light on this situation or possibly provide a solution? Thanks

Also, my friend suggested this idea:

I tried it and it was still the same problem.

Thanks!

mackdaddy0586 · 2009-01-12, 07:43 AM

Every time light passes from one medium to another their is attenuation. In a simple case, the light source originates from a diode, travels through open air for a few milimetres, then to an optical cable (which attenuates the signal slightly as no transmission medium is 100% perfect). It then leaves the optical cable, travels a few milimetres though open air again before passing through the switch. Depending on whether the switches are active versus passive the signal will (former) or will not (latter) be amplified. This cycle will continue to repeat itself depending on exactly how many switches and components you have in series. I would suggest using the shotest optical cables you can find. The problem with active switches though is that the optical signal is proccessed over copper circutry first and is then re transmitted. The problem with this is that latency is ontroduced which will in all likelihood cause audio sync issues. Additionally, I have notice that some devices have a brighter optical sygnal than others. I would suggest a change to your diagram. Put the brightest transmitting devices at the end of the series, and ones that transmit an optical signal less bright at the beginning.

jvincent · 2009-01-12, 08:35 AM

First point, both pictures are the same.

Are the 3-to-1 and 2-to-1 selectors active or passive?

All of the SPDIF outputs I have seen are always active, i.e. there is always light coming out of them, so if they selectors/joiners are passive muxes then the light from one source will interfere with the other.

I think for this to work you need to have a selectable switch. To see if this is the case, keep your existing setup but unplug all of the sources but one and see if it works.

aN4rK1 · 2009-01-12, 11:31 AM

mackdaddy - Thanks, that makes sense and thats what i was thinking as well but I needed some confirmation. I will look at my devices and see if I can arrange the more brighter ones further away.

jvincent - Ah sorry. Didnt realise. Pictures are fixed now. I believe they are active, here is what iam using:

3-to-1: http://www.jex-electronics.com/audio.../jeav08230.jpg
Although not the exact same, its very similar

2-to-1: http://www.supereffort.co.uk/rush/pi...l_TSL257_g.JPG

When iam using one device or the other I make sure, everything else is turned off. As for the switch suggestion, I just recently saw this:

This is powered, and a selector. This I THINK will pretty much solve my problems, but it has 4 inputs and I have 5 devices, I guess I could use a splitter that I have and that SHOULD be ok. What do you guys think? i emailed the seller explaing my situation and now awaiting a response.

This then leaves me with buch of spare cables and splitter but you live you learn i guess

jayoldschool · 2009-01-12, 12:13 PM

Use the splitter in the last post, and eliminate the DVD player. The PS3 will do a better job anyways.

aN4rK1 · 2009-01-12, 12:43 PM

The last post as in the Specialty AV one?
And I would get rid of it but its a really good DVDplayer as it plays a lot of different region dvds and so on, and my mother cant use a ps3 its a bit complicated for her lol.

jvincent · 2009-01-12, 12:50 PM

I just thought of something, is there a digital output from your receiver? You could send that to the headphones.

aN4rK1 · 2009-01-12, 12:51 PM

No sadly, I wish there was. I had thought of that as well.

DJDiggler · 2009-01-16, 03:49 AM

Having used the same switches/splitters before you may be having problems with the cables not engaging properly in the input holes. I had to try a different optical cable and it worked fine.

To use the 2way joiner you must be sure there is no interference. For example, my satellite box always has the optical "light" on, even when power is off.

Use your first diagram and make sure you set the DVD/CABLE selector switch to the "empty" input when your not using either of those components. That will eliminate any chance of interference. check your PS3/XBOX/PC, is the optical active when power is off? (open the little door on the input with a pen if you cant see). You will have to set that switch to an inactive one to use your DVD/CABLE.

If it still wont work try different cables or else the signal loss is to great as suggested.

aN4rK1 · 2009-01-20, 11:54 PM

Just an update on a my solution to this just incase anyone else is having similar issues. I bought the box and it took care of everything. Thanks for all the suggestions guys.

2009-01-11, 11:46 PM	#1
aN4rK1 Rookie Join Date: Jun 2008 Posts: 14	Opitcal Splitter Dilema Hello All, here is what Iam trying to achieve: All of the cables are TOSlink optical cables btw. I bought all the cables and splitters form monoprice and tested them al separately and they seem to work. The problem comes when I go from the 1st tier to 2nd tier of splitters. For some reason the signal isnt going through, and it seems like its losing strength. I dont understand how this can happen as it is optical and fiberoptic. Can anyone shed some light on this situation or possibly provide a solution? Thanks Also, my friend suggested this idea: I tried it and it was still the same problem. Thanks! Last edited by aN4rK1; 2009-01-12 at 09:21 AM.

2009-01-16, 03:49 AM	#9
DJDiggler Join Date: Aug 2005 Location: Leduc, AB Posts: 1,104	Having used the same switches/splitters before you may be having problems with the cables not engaging properly in the input holes. I had to try a different optical cable and it worked fine. To use the 2way joiner you must be sure there is no interference. For example, my satellite box always has the optical "light" on, even when power is off. Use your first diagram and make sure you set the DVD/CABLE selector switch to the "empty" input when your not using either of those components. That will eliminate any chance of interference. check your PS3/XBOX/PC, is the optical active when power is off? (open the little door on the input with a pen if you cant see). You will have to set that switch to an inactive one to use your DVD/CABLE. If it still wont work try different cables or else the signal loss is to great as suggested. __________________ Epson EX71, Tosh HD-A2, Denon AVR590, Athena P4100, Infinity P362,C250,P162. RCA L42WD22, Pio VSX1016, Athena LS50

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2009-01-12, 07:43 AM	#2
mackdaddy0586 Join Date: Dec 2007 Posts: 49	Every time light passes from one medium to another their is attenuation. In a simple case, the light source originates from a diode, travels through open air for a few milimetres, then to an optical cable (which attenuates the signal slightly as no transmission medium is 100% perfect). It then leaves the optical cable, travels a few milimetres though open air again before passing through the switch. Depending on whether the switches are active versus passive the signal will (former) or will not (latter) be amplified. This cycle will continue to repeat itself depending on exactly how many switches and components you have in series. I would suggest using the shotest optical cables you can find. The problem with active switches though is that the optical signal is proccessed over copper circutry first and is then re transmitted. The problem with this is that latency is ontroduced which will in all likelihood cause audio sync issues. Additionally, I have notice that some devices have a brighter optical sygnal than others. I would suggest a change to your diagram. Put the brightest transmitting devices at the end of the series, and ones that transmit an optical signal less bright at the beginning.

2009-01-12, 08:35 AM	#3
jvincent Moderator Join Date: Nov 2002 Location: Ottawa Posts: 5,369	First point, both pictures are the same. Are the 3-to-1 and 2-to-1 selectors active or passive? All of the SPDIF outputs I have seen are always active, i.e. there is always light coming out of them, so if they selectors/joiners are passive muxes then the light from one source will interfere with the other. I think for this to work you need to have a selectable switch. To see if this is the case, keep your existing setup but unplug all of the sources but one and see if it works.

2009-01-12, 11:31 AM	#4
aN4rK1 Rookie Join Date: Jun 2008 Posts: 14	mackdaddy - Thanks, that makes sense and thats what i was thinking as well but I needed some confirmation. I will look at my devices and see if I can arrange the more brighter ones further away. jvincent - Ah sorry. Didnt realise. Pictures are fixed now. I believe they are active, here is what iam using: 3-to-1: http://www.jex-electronics.com/audio.../jeav08230.jpg Although not the exact same, its very similar 2-to-1: http://www.supereffort.co.uk/rush/pi...l_TSL257_g.JPG When iam using one device or the other I make sure, everything else is turned off. As for the switch suggestion, I just recently saw this: This is powered, and a selector. This I THINK will pretty much solve my problems, but it has 4 inputs and I have 5 devices, I guess I could use a splitter that I have and that SHOULD be ok. What do you guys think? i emailed the seller explaing my situation and now awaiting a response. This then leaves me with buch of spare cables and splitter but you live you learn i guess

2009-01-12, 12:13 PM	#5
jayoldschool Veteran Join Date: Feb 2007 Posts: 1,746	Use the splitter in the last post, and eliminate the DVD player. The PS3 will do a better job anyways.

2009-01-12, 12:43 PM	#6
aN4rK1 Rookie Join Date: Jun 2008 Posts: 14	The last post as in the Specialty AV one? And I would get rid of it but its a really good DVDplayer as it plays a lot of different region dvds and so on, and my mother cant use a ps3 its a bit complicated for her lol.

2009-01-12, 12:50 PM	#7
jvincent Moderator Join Date: Nov 2002 Location: Ottawa Posts: 5,369	I just thought of something, is there a digital output from your receiver? You could send that to the headphones.

2009-01-12, 12:51 PM	#8
aN4rK1 Rookie Join Date: Jun 2008 Posts: 14	No sadly, I wish there was. I had thought of that as well.

2009-01-20, 11:54 PM	#10
aN4rK1 Rookie Join Date: Jun 2008 Posts: 14	Just an update on a my solution to this just incase anyone else is having similar issues. I bought the box and it took care of everything. Thanks for all the suggestions guys.