Audio from a PC to a AV Reciver?

grimed

Member
Sep 28, 2013
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If I use the optical audio out from my pc or sound card to a AV reciver will I get a signal that will work or will i have to use somthing else.

I will be seting up as a 5.1.

I will be using this fro game and movies

Thanks
 

BrightCandle

Diamond Member
Mar 15, 2007
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Optical 5.1 requires Dolby digital live or DTS live which enables on the fly encoding so that 5.1 can be sent. Otherwise its limited to 2 channels with PCM.

Even if that works one thing to be aware of is that while many sound cards do support this (soundblaster Z, soundblaster xfi, all the Xonar cards and most cmedia cards) some of them introduce upwards of 100ms of latency to do it, so they can be really bad for gaming.

Conversely using HDMI and splitting the sound and video there can allow 5.1 with PCM or DD or DTS but at the same time it will add latency to the video , typically at least 16ms depending on your receiver. So its a tough trade off choosing between HDMI and optical output for 5.1 with receiver driven speakers for gamers at least.
 

cmdrdredd

Lifer
Dec 12, 2001
27,052
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Optical 5.1 requires Dolby digital live or DTS live which enables on the fly encoding so that 5.1 can be sent. Otherwise its limited to 2 channels with PCM.

Even if that works one thing to be aware of is that while many sound cards do support this (soundblaster Z, soundblaster xfi, all the Xonar cards and most cmedia cards) some of them introduce upwards of 100ms of latency to do it, so they can be really bad for gaming.

Conversely using HDMI and splitting the sound and video there can allow 5.1 with PCM or DD or DTS but at the same time it will add latency to the video , typically at least 16ms depending on your receiver. So its a tough trade off choosing between HDMI and optical output for 5.1 with receiver driven speakers for gamers at least.

There shouldn't be any added latency through the use of HDMI from your PC any more than you'd get from a PS4 hooked up to the same TV and through the same receiver.
 
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BrightCandle

Diamond Member
Mar 15, 2007
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There shouldn't be any added latency through the use of HDMI from your PC any more than you'd get from a PS4 hooked up to the same TV and through the same receiver.

Its because with HDMI you are putting both the audio and video through the AV receiver, which does add latency in the grand majority of receivers. They are designed for movies not really gaming unfortunately.

Of course if you are watching a DD or DTS source then there is no encoding delay. So the impact really depends on your source material. Are we talking about gaming, movies or music?
 

Anarchist420

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Feb 13, 2010
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Its because with HDMI you are putting both the audio and video through the AV receiver, which does add latency in the grand majority of receivers. They are designed for movies not really gaming unfortunately.
i wish i hadnt read that. thanks for telling me a truth that i hadnt thought of though.

unhappy because 2 channel uncompressed sounds damn good on my HK3490 and S/PDIF still has the bandwidth to do 5.1 uncompressed at 16b 44.1Khz with no input impedance, no processing lag, and no DPM.
 

cmdrdredd

Lifer
Dec 12, 2001
27,052
357
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Its because with HDMI you are putting both the audio and video through the AV receiver, which does add latency in the grand majority of receivers. They are designed for movies not really gaming unfortunately.

Of course if you are watching a DD or DTS source then there is no encoding delay. So the impact really depends on your source material. Are we talking about gaming, movies or music?

If you aren't upscaling the content and do no processing it shouldn't be anything you can measure by feel. Think about all the people playing competitive online games through a receiver.

I am not saying there is zero added delay or latency but it is so small that you wouldn't notice unless you had proper measurement equipment. I know when I run my pc through my receiver when my tv is in game mode it does not feel different from on my monitor through dvi. The input lag is not significantly different. I dont run vsync on most games because of input lag.
 
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BrightCandle

Diamond Member
Mar 15, 2007
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On mine (Onkyo) I do notice there is about a frame worth of lag added. Its not such a big deal for the console I have it hooked up to but its unfortunate.

All of this depends on the soundcard and the receiver. The soundblaster Z has 100ms extra latency for DD live encoding but the current consensus on head-fi is the cmedia's don't seem to. Various receivers are going to do this differently and no one really does reviews, so it might be worth asking the manufacturer before you go with a HDMI plan.

I wish this was simpiler, its kind of annoying so few companies seem concerned with latency and its impact on gamers. Most TVs are dreadful latency wise, sound gets latency added in the receiver, video gets delay, re-encoding takes significant time etc etc. Its a minefield of complexity.