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Author Topic: JRSS Mixing and some sound card questions  (Read 9163 times)

JRU

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JRSS Mixing and some sound card questions
« on: April 20, 2014, 12:40:25 pm »

Hello,

I was wondering if someone could explain how JRSS mixing works? I could not find a page detailing how it handles the mixing. Particularly down mixing a 5.1 or 7.1 stream to 2.0. Does it mix the center/sub/side/rear channels into the front L/R or does it discard them?

I have a RME AES card and the only way I can get more than 2 channels in JRiver is with the ASIO option. In MPC or KMP the ASIO option does not show up and I can't get more than 2 channel output. Further when I do get 8 channel output in JRiver via ASIO then the "subwoofer" channel is -10db from the rest on output 4 in the RME software. If I replace the sub channel with the right channel or add 10db to the sub channel in the EQ section then I can get the same output level from all channels. I tested this using the inbuilt audio calibration tones with 7.1 channels and 44.1khz. Everything is -20db but the sub channel is -30db. If I don't touch any of the settings with JRSS off (no upmixing or downmixing) and EQ off and switch between 4 channels, 7.1 and 10 channels in output format I get -10db on output 4 with 7.1 and 10 channels in JRiver but with 4 channel output in JRiver all 4 outputs are -20db. All readings are taken from RME's software that came with the card.

I know I can just add 10db to the EQ section and solve the issue, but I am curious why the issue exists, I also would like to be able to use other methods besides ASIO like WASAPI.

Any help would be very much appreciated. I am stuck on what to do.

Thank you!

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6233638

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Re: JRSS Mixing and some sound card questions
« Reply #1 on: April 20, 2014, 12:51:28 pm »

I was wondering if someone could explain how JRSS mixing works? I could not find a page detailing how it handles the mixing. Particularly down mixing a 5.1 or 7.1 stream to 2.0. Does it mix the center/sub/side/rear channels into the front L/R or does it discard them?
All channels are included in the downmix.

Further when I do get 8 channel output in JRiver via ASIO then the "subwoofer" channel is -10db from the rest on output 4 in the RME software.
LFE signals are intentionally encoded at -10dB and it is assumed that there will be 10dB added further down the chain. (e.g. in the amplifier)
 
 
I'm not sure what you are actually trying to achieve here though.
If it's simply a stereo downmix, what JRSS does should be correct.
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mwillems

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Re: JRSS Mixing and some sound card questions
« Reply #2 on: April 20, 2014, 12:59:52 pm »

Hello,

I was wondering if someone could explain how JRSS mixing works? I could not find a page detailing how it handles the mixing. Particularly down mixing a 5.1 or 7.1 stream to 2.0. Does it mix the center/sub/side/rear channels into the front L/R or does it discard them?

It does not discard them, it folds them into the L and R channels.  I don't think the actual matrix is public (but there are some hints around on the forums).

Quote
I have a RME AES card and the only way I can get more than 2 channels in JRiver is with the ASIO option. In MPC or KMP the ASIO option does not show up and I can't get more than 2 channel output. Further when I do get 8 channel output in JRiver via ASIO then the "subwoofer" channel is -10db from the rest on output 4 in the RME software. If I replace the sub channel with the right channel or add 10db to the sub channel in the EQ section then I can get the same output level from all channels. I tested this using the inbuilt audio calibration tones with 7.1 channels and 44.1khz. Everything is -20db but the sub channel is -30db. If I don't touch any of the settings with JRSS off (no upmixing or downmixing) and EQ off and switch between 4 channels, 7.1 and 10 channels in output format I get -10db on output 4 with 7.1 and 10 channels in JRiver but with 4 channel output in JRiver all 4 outputs are -20db. All readings are taken from RME's software that came with the card.

I know I can just add 10db to the EQ section and solve the issue, but I am curious why the issue exists, I also would like to be able to use other methods besides ASIO like WASAPI.

Any help would be very much appreciated. I am stuck on what to do.

Thank you!

In 5.1 and 7.1 systems the sub is supposed to be calibrated 10dB louder than the other channels.  The JRiver test tone for the sub output is deliberately 10 dB lower than the other channels, so that if you measure the actual sound output in your system, a correctly calibrated sub (+10dB) will play back at the same volume as the other channels.  The actual JRiver output on the sub channel shouldn't be attenuated during playback (I don't think), just the test clip.  

4 Channel output doesn't have an LFE channel (the .1 in 5.1) so that's why you're not seeing it in 4 channel.

I wouldn't recommend adding 10dB in the PEQ section as you might drive JRiver's output into clipping.  Better to adjust the volume on your actual sub (if it has a volume control) to achieve the correct calibration, or (barring that) use the level settings in the room correction module as it will automatically offset boost to avoid clipping.

Check out this thread for more info: http://yabb.jriver.com/interact/index.php?topic=88345.msg605503#msg605503
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JRU

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Re: JRSS Mixing and some sound card questions
« Reply #3 on: April 20, 2014, 01:39:34 pm »

Thanks guys.

I think I understand about the -10db part, not sure how to test it in playback though. Is there someway to test it?

Thanks for letting me know about the mixing, I'm glad to know that the channels are not discarded and are indeed mixed into the L/R signal. I want to clarify, I would need to select 2 channel output and select JRSS mixing to achieve this?

Could anyone shed light on why I am only able to get multiple channel output through ASIO and not other methods? I really am stuck on this, help please!
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mwillems

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Re: JRSS Mixing and some sound card questions
« Reply #4 on: April 20, 2014, 03:33:01 pm »

Thanks guys.

I think I understand about the -10db part, not sure how to test it in playback though. Is there someway to test it?

Do you have an SPL meter?  If so, just download some audio calibration clips that aren't built into JRiver, play them in JRiver like a normal file and measure the output.  Or if you have a way of seeing the output in the RME mixer, you can skip the SPL meter.

Quote
Thanks for letting me know about the mixing, I'm glad to know that the channels are not discarded and are indeed mixed into the L/R signal. I want to clarify, I would need to select 2 channel output and select JRSS mixing to achieve this?

If you want a 2-channel only downmix, yes.  

Quote
Could anyone shed light on why I am only able to get multiple channel output through ASIO and not other methods? I really am stuck on this, help please!

I've never used your specific RME device, but some pro audio interfaces present to windows as a set of disconnected stereo pairs.  For those interfaces, the only way to get access to all channels is to use ASIO.  One easy way to check is to look in the system tray at available audio devices.  If you see 4 or more sets of outputs for your RME that are sequentially numbered, then that's probably the deal.

If, on the other hand, you only see one device for the RME in the windows mixer, another trouble shooting step: if you open up your RME device in the windows mixer, how many channel outputs does it show you?  Can you set a different number of outputs there? (or in the RME mixer panel?)
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JRU

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Re: JRSS Mixing and some sound card questions
« Reply #5 on: April 20, 2014, 03:57:47 pm »

Do you have an SPL meter?  If so, just download some audio calibration clips that aren't built into JRiver, play them in JRiver like a normal file and measure the output.  Or if you have a way of seeing the output in the RME mixer, you can skip the SPL meter.

If you want a 2-channel only downmix, yes.  

I've never used your specific RME device, but some pro audio interfaces present to windows as a set of disconnected stereo pairs.  For those interfaces, the only way to get access to all channels is to use ASIO.  One easy way to check is to look in the system tray at available audio devices.  If you see 4 or more sets of outputs for your RME that are sequentially numbered, then that's probably the deal.

If, on the other hand, you only see one device for the RME in the windows mixer, another trouble shooting step: if you open up your RME device in the windows mixer, how many channel outputs does it show you?  Can you set a different number of outputs there? (or in the RME mixer panel?)

I have not got anything hooked up to the PC yet, just installed the sound card to see if it works.

I thought that since JRiver's test tone is -10db then the only way to test it would be with 8 channel test tones? I can view the output in the RME mixer.

In the Windows control panel when I open the sound panel I see that there are 8 options, one lists the AES card as "speakers" and the others are AES 3+4 or 5+6 and so on until 15+16 for a total of 8 options in the sound panel. This also presents in the volume mixer in the tray. Is this what you meant? If so does that mean I am out of luck and can only use 8 channels on programs that support ASIO?

I do want a 2 channel only downmix as I have only 2 speakers but multiple subs. I will source the sub channel from the combined L/R channels and apply HPF/LPF as necessary.

Thanks for the help! I wasn't getting anywhere with this.



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mwillems

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Re: JRSS Mixing and some sound card questions
« Reply #6 on: April 20, 2014, 04:45:58 pm »

In the Windows control panel when I open the sound panel I see that there are 8 options, one lists the AES card as "speakers" and the others are AES 3+4 or 5+6 and so on until 15+16 for a total of 8 options in the sound panel. This also presents in the volume mixer in the tray. Is this what you meant? If so does that mean I am out of luck and can only use 8 channels on programs that support ASIO?

Maybe; it at minimum means that if you want access to all 8 channels you might need to find and switch some settings in the RME software.  I might mean that you can only get at all the channels through ASIO.  I'd recommend looking carefully through all of the options in the RME control panel.

Quote
I do want a 2 channel only downmix as I have only 2 speakers but multiple subs. I will source the sub channel from the combined L/R channels and apply HPF/LPF as necessary.

For this, you'll want "2 channel in a 7.1 container."  If you just select 2 channel, you'll get the downmix, but JRiver won't give you any additional blank channels.  If you select "2 channel in a 7.1 container" JRiver will still downmix everything to stereo, but will give you six blank channels to work with.
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JRU

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Re: JRSS Mixing and some sound card questions
« Reply #7 on: April 21, 2014, 12:12:35 am »

I did go through the RME options and the manual on their website but I could not find anything useful.

I did find this but I did not fully understand it. "The driver offers a WDM streaming device per stereo pair, like AES (1+2)." I think this is referring to the multiple output devices in the Windows sound panel?

I had read somewhere that there is an option called "Interleaved" that might work but I could not find that option in the RME software. I am not familiar with professional sound cards or their software so it is confusing for me, I have reached out to the people I bought it from for help. Are there any tests I could do to see if the only way to get 8 channel output is via ASIO?
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mwillems

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Re: JRSS Mixing and some sound card questions
« Reply #8 on: April 21, 2014, 05:26:31 pm »

I did go through the RME options and the manual on their website but I could not find anything useful.

I did find this but I did not fully understand it. "The driver offers a WDM streaming device per stereo pair, like AES (1+2)." I think this is referring to the multiple output devices in the Windows sound panel?

That's what I was talking about.  Each pair is a different output as far as windows is concerned

Quote
I had read somewhere that there is an option called "Interleaved" that might work but I could not find that option in the RME software. I am not familiar with professional sound cards or their software so it is confusing for me, I have reached out to the people I bought it from for help. Are there any tests I could do to see if the only way to get 8 channel output is via ASIO?

I pulled the manual on your device and it suggests that you should be able to resolve this by changing settings as follows:
Quote
Multi-Channel using WDM

The WDM Streaming device Loudspeaker (Analog 1+2) of the RME driver can operate as usual stereo device, or as up to 8-channel device. An 8-channel playback using the Windows Media Player requires the speaker setup 7.1 Surround.
Configure as follows:

XP: >Control Panel /Sounds and Multimedia /Audio /Volume /Speaker Settings/Advanced <

Vista/7: >Control Panel /Sound /Playback /Loudspeaker /Configure
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