Author Topic: Multiple sound cards, selected at random?  (Read 3568 times)

Armor Gnome

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Re: Multiple sound cards, selected at random?
« Reply #30 on: March 05, 2013, 05:52:49 am »
For any audiophiles following this thread:

S/PDIF optical vs coax?  It is my understanding that there is no difference with short cable runs.  That and when using a jumper, there is no need to run the VCC line.

Digital vs. stereo?  Using a single 3.5mm jack is it possible to send a 5.1/7.1/10.2 signal?  Typically when I hear "stereo" I think analog left/right.  Multi-channel audio uses L/R, SL/SR, and C/Sw which again supports thinking that jack can only send analog 2 channel? 

Techie/Audiophile question:  If my assumptions about these signals is incorrect, how does S/PDIF Coax carry a raw digital signal over just 2 wires? 

For my next MD area I am looking to really focus on audio reproduction, so am hoping to learn some and get some recommendations.  Outside of the SB fatality series I wouldn't know where to begin looking.
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phenigma

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Re: Multiple sound cards, selected at random?
« Reply #31 on: March 07, 2013, 05:33:53 am »
Prior to doing any changes today I did a lot of reading so I could get familiar with the terminology.  Mutliple channel audio I understand now as my receiver has inputs for that called conveniently "multi channel."

Multi-channel really refers to any card that can output more than a single mono signal.  This includes stereo as well but often refers to anything that has more than 2 channels.  4/5.1(really 6)/7.1(really 8)

For LMCE any device that has 2 (or more) audio channels *could* be defined with a special "multichannel sound card" device template.  I say *could* because you do not have to define any of these devices, they are usually used to house child devices that are "stereo virtual sound card"s.  This allows us to split card that has 4/6/8 and split it into multiple stereo outputs, each with their own name, very useful for adding squeezeslave devices without adding additional hardware.  Example:  I have a motherboard in an onboard 7.1 analog audio (4x1/8" TRS connectors) and an hdmi output.  I use the hdmi output for the LMCE output and have 4 stereo squeezeslaves setup on my analog onboard sound card.  Each 1/8" jack is now a stereo pair that a squeezeslave outputs on.  I get 4xaudio zones without adding any additional hardware.

 It also allows you to do funky things like combine the output of 4 different channels down to 2.  The key thing to remember here is that you never *need* to define one of these devices unless you wish

J.

phenigma

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Re: Multiple sound cards, selected at random?
« Reply #32 on: March 07, 2013, 05:43:30 am »
S/PDIF optical vs coax?  It is my understanding that there is no difference with short cable runs.  That and when using a jumper, there is no need to run the VCC line.

S/PDIF vs coax.  This is an ongoing debate.  I find optical cables to be inexpensive and easy to run.  Coax can be a pain if you do not have a crimper and RCA ends to crimp on.  Adapters are usually extremely over priced.  I have used both, I hear no difference.

Digital vs. stereo?  Using a single 3.5mm jack is it possible to send a 5.1/7.1/10.2 signal?  Typically when I hear "stereo" I think analog left/right.  Multi-channel audio uses L/R, SL/SR, and C/Sw which again supports thinking that jack can only send analog 2 channel? 

A single jack can support only 2 channels.  See my earlier post re: multichannel.

Techie/Audiophile question:  If my assumptions about these signals is incorrect, how does S/PDIF Coax carry a raw digital signal over just 2 wires? 

Digital is completely different than analog, rather than a varying voltage/current it is a binary voltage switching consisting of 1s and 0s only.  These bits can be multiplexed together using time division multiplexing.  For example the devices would both conform to a standard method of transmitting/receiving.  A byte of data would be sent for CH1, then a byte for CH2, then CH3... to CH8.  8 bytes have been transmitted and the cycle restarts at CH1.  If additional channels (3-8 or 7-8) do not exist, then blank entries would be transmitted to be consistent.  This is a simplification but essentially how it works.

For my next MD area I am looking to really focus on audio reproduction, so am hoping to learn some and get some recommendations.  Outside of the SB fatality series I wouldn't know where to begin looking.

avrfreaks? perhaps for audio card recommendations.  I used to use high-end turtle beach cards, I don't think they exist anymore.

J.

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Re: Multiple sound cards, selected at random?
« Reply #33 on: March 19, 2013, 04:59:37 pm »
Multi-channel really refers to any card that can output more than a single mono signal.  This includes stereo as well but often refers to anything that has more than 2 channels.  4/5.1(really 6)/7.1(really 8)

For LMCE any device that has 2 (or more) audio channels *could* be defined with a special "multichannel sound card" device template.  I say *could* because you do not have to define any of these devices, they are usually used to house child devices that are "stereo virtual sound card"s.  This allows us to split card that has 4/6/8 and split it into multiple stereo outputs, each with their own name, very useful for adding squeezeslave devices without adding additional hardware.  Example:  I have a motherboard in an onboard 7.1 analog audio (4x1/8" TRS connectors) and an hdmi output.  I use the hdmi output for the LMCE output and have 4 stereo squeezeslaves setup on my analog onboard sound card.  Each 1/8" jack is now a stereo pair that a squeezeslave outputs on.  I get 4xaudio zones without adding any additional hardware.

 It also allows you to do funky things like combine the output of 4 different channels down to 2.  The key thing to remember here is that you never *need* to define one of these devices unless you wish

J.

Yes what you describe works really well...we do this type of config in Dianemo all the time. In fact its a revelation once you start to explore the possibilities and the flexibility this offers. As you point out until the virtualisation of sound cards was implemented a physical 7.1 card was often only used for stereo out and the remaining outputs were inaccessible for any other purposes.

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