Do I need a 7.1 sound card to play 7.1 surround sound

[Gallifreyan]

I'm trying to get 7.1 surround sound on my computer and I've read that I need to get a 7.1 sound card to get it to work. However, the built-in sound device offers a 7.1 speaker configuration yet it has only one stereo output port. Could I build upon this or will I need a sound card?

 

[yoji]

That is illogical...

Can you confirm your motherboard please... make and model...

Thanks

 

[Pyree]

Not virtual 7.1 surround sound (still 2 speaker but some algorithm and makes it sound surround)?

 

[Pinhedd]

Okay this is going to be a bit of a long winded explanation but bare with me and read it through

Most onboard audio DACs support both 7.1 output over 3.5 mm stereo jacks. You will need to use 4 of these plugs for a 7.1 system (Front L/R, Side L/R, Rear L/R, Center / Sub). Alternatively you also have an optical connection. The optical connection conforms to the S/P-DIF specification which means that it can transmit either stereo audio or AC3 (Dolby Digital) or DTS encoded audio. The optical connection cannot be used to transmit 6 or 8 channel LPCM.

In order to use the optical connection you must have an audio source which is encoded in AC3 or DTS. You must also configure the audio filters to pass the encoded audio through without decoding it first. If you do not do this, you will only get stereo.

Difficulty: outside of videos very few PC applications have AC3/DTS encoded audio. Games perform all of their audio rendering uncompressed and don't bother to compress it because it has to be decompressed to be sent to the speakers anyway. When you see the "Dolby Digital" symbol on a game box that usually just indicates that the game has prerendered cutscenes with surround sound. Any cutscenes that use the game engine can simply use the game's audio renderer instead and avoid unnecessary complications.

In order to get arbitrary audio over optical you must buy a sound card which has support for Dolby Digital Live or DTS Live. These are real time encoding methods that will capture the uncompressed audio that would be sent to the PC speakers and encode it into an AC3/DTS bitstream that can be sent across the optical connection to an external receiver. Some motherboards have a Creative Labs sound card built in that supports this but very few do.

If you're not using an external receiver and are only using the 3.5mm jacks for your surround setup then I still recommend that you get a discrete sound card. Discrete cards have a typical Signal to noise ratio of <110dB. Integrated sound typically has a signal to noise ratio of <90dB. This means that onboard sound is immensely more prone to static noise and this becomes more audible as volume increases and lower impedance speakers are used.

There's also the matter of resampling and remixing. Onboard devices do a very poor job of these. The Creative Labs 20K2 DSP (used for most of the Creative Labs X-Fi Titanium cards) was specially designed to do these well

 

[gamerk316]

Okay this is going to be a bit of a long winded explanation but bare with me and read it through

Most onboard audio DACs support both 7.1 output over 3.5 mm stereo jacks. You will need to use 4 of these plugs for a 7.1 system (Front L/R, Side L/R, Rear L/R, Center / Sub). Alternatively you also have an optical connection. The optical connection conforms to the S/P-DIF specification which means that it can transmit either stereo audio or AC3 (Dolby Digital) or DTS encoded audio. The optical connection cannot be used to transmit 6 or 8 channel LPCM.

In order to use the optical connection you must have an audio source which is encoded in AC3 or DTS. You must also configure the audio filters to pass the encoded audio through without decoding it first. If you do not do this, you will only get stereo.

Difficulty: outside of videos very few PC applications have AC3/DTS encoded audio. Games perform all of their audio rendering uncompressed and don't bother to compress it because it has to be decompressed to be sent to the speakers anyway. When you see the "Dolby Digital" symbol on a game box that usually just indicates that the game has prerendered cutscenes with surround sound. Any cutscenes that use the game engine can simply use the game's audio renderer instead and avoid unnecessary complications.

In order to get arbitrary audio over optical you must buy a sound card which has support for Dolby Digital Live or DTS Live. These are real time encoding methods that will capture the uncompressed audio that would be sent to the PC speakers and encode it into an AC3/DTS bitstream that can be sent across the optical connection to an external receiver. Some motherboards have a Creative Labs sound card built in that supports this but very few do.

If you're not using an external receiver and are only using the 3.5mm jacks for your surround setup then I still recommend that you get a discrete sound card. Discrete cards have a typical Signal to noise ratio of <110dB. Integrated sound typically has a signal to noise ratio of <90dB. This means that onboard sound is immensely more prone to static noise and this becomes more audible as volume increases and lower impedance speakers are used.

There's also the matter of resampling and remixing. Onboard devices do a very poor job of these. The Creative Labs 20K2 DSP (used for most of the Creative Labs X-Fi Titanium cards) was specially designed to do these well

^^ This.