Documentation for Mixer, etc

Hello,

jrpavel wrote: The Windows Sound applet is straightforward: you select a playback and a recording device and off you go.  It's not quite clear what the "use default devices only" does.

Windows documentation states: "Limits your programs to the selected sound cards. If you use programs that require a specific type of sound card, and that sound card is selected in Default Device, select this check box. Ifyou programs can use any sound card on your computer, clear this check box".

It's a pretty esoteric switch. Best ignored...

jrpavel wrote: The documentation suggests (p18) that I should find LynxTwo Record x and LynxTwo Play y devices, but the Lynx drivers just come up as LynxTwo z.  Some fiddling and searching on the web site, reveals that LynxTwo 4 seems to generate output over SPD/IF and, counterintuitively, LynxTwo 4 is also the SPD/IF input.

The owner's manual refers to our Version 1 driver, which supports ASIO and MME driver models. With the Version 2 driver, the OS and standard multimedia apps use WDM as a driver model. Part of the WDM spec is that play and record devices can't have unique names. Therefore, LynxTWO Device 1 is synonomous with LynxTWO Play 1 and LynxTWO Record 1.  In ASIO applications, the Record and Play devices are named as indicated in the manual.

Keep in mind that SPDIF/AES routing to Device 4 is the default state. This can be user-altered if desired.

jrpavel wrote: My conceptual problem is that there is Record/Play window in the mixer which, confusingly, seems not to map to the Windows Play/Record devices and an Output windows which seems to not quite correspond to the Windows Play device.

Perhaps one important missing piece here is our Mixer Addendum. This is available in addition to the std. User's Manual specifically to explain the functionality of the Mixer. It is on the Install CD, or available online here.

Short version - This is what you can do in the Record/Play Mixer:

* Customize which physical input is routed to which Record device. Most people leave these in their default state, but there are a number of reasons you may want to change it. For instance you may want a stereo input going to several record devices at one time, for recording as separate tracks or in separate programs. Or, if you only use the digital in, never the analog in, you may want to have Record 1 be the digital input, etc.

* View input meter levels

*Apply mute or dither to input signals

* There are some diagnostic tools in the R/P mixer. We can tell if there are underruns (dropouts) recorded by the driver, determine which play and record devices are being accessed by software (the text turns red when a device is being used, blue when not), and see what bit-depth is being requested by software.

This is what you can do in the outputs mixer:

*  Assign monitor sources. Up to four monitor sources can be assigned per output. These can be input sources, or playback streams from software. If, for instance, you want to access the Digital Out as Play/Device 1 (instead of Play 4), you can do that by assigning Play 1 as the monitor source for the Digital Outputs

* Manage output levels

* Mute or dither the outputs.

jrpavel wrote:   What is the correct relationship between the the two Mixer windows and the devices selected in the Windows applet?

The Windows default device applet simply lets you specify which driver device is the default for playback and recording. Applications that don't let you specify which audio device you want to use, will use the defaults. If you keep the Lynx Mixer in it's default state, choosing Device 1 will mean playback goes to the Analog Outputs. If you choose Device 4, they will go to the Digital Output. Likeswise for the default recording device.   

jrpavel wrote: The only way I can rationalise this setup is to think of the Mixer as remapping the Windows Play/Record devices to the selected cable: Windows Play device -> Mixer Play (for monitoring) -> Output (selects from the Mixer Play devices and routes them to an output cable) Windows Record device -> Mixer Record (for monitoring) -> Output (selects from the Mixer Record devices and routes and mixes up to 4 of them to an output cable) Is this right?

Not quite. The Lynx Mixer allows you to define what physical I/O is associated with what play and record devices. The Windows sound settings merely allow you to identify which of these devices will be the default, for the benefit of applications that don't let you specifically choose an audio device. 

jrpavel wrote: What happens to the devices that are not selected in the Windows applet?

They are still available to any applications that allow you to choose an audio input or output. Almost all audio applications have this capability.

jrpavel wrote: To simplify things (and make them less error-prone) it would be nice to have a "straight passthough" button which takes the devices selected in the Windows applet and passes them to/from to the corresponding cable without any mixing, muting everything else (leaving just the adapter settings to play with).  The "restore defaults" is close, but probably does not take account of the Windows applet settings.

It's a chicken before the egg thing... Windows is only accessing devices that we define. The same result would be had by just keeping everything in it's default state after installation. Windows sends audio to the analog output,and there is no levels alteration or change to the signal whatsoever.

jrpavel wrote: Loopback with the jumpers is another thing that could be better explained...

See: http://www.lynxstudio.com/lstreamloopback.html

Best Regards,

Hello,

jrpavel wrote: So, to sum up, the (simplified) pipeline looks like Sources In cables -> Record \                                     Lynx Mixer -> Outputs (cables) Programs -> Play     /

This is an accurate summary of the monitoring options. Input sources can be recorded without having any relationship to the outputs however.  

jrpavel wrote: I'm not sure where the Windows KMixer fits into this (and how it can be by-passed for bit-perfect output), or monitoring.

KMixer is inevitably involved if the WDM driver model is used. The only ways to avoid this is to use a playback application that uses a different driver model (i.e. ASIO), or use our Version 1 driver which doesn't have a WDM component. However, if you use a playback application that utilizes DirectSound, it is sonically preferable to use the WDM driver. 

jrpavel wrote: If I might say so, the Lstream document to which you refer is, to the new reader, hard to follow because it refers in some cases to LynxTwo-A, in others to "The internal LStream expansion port on the LynxTWO" (is that -A, or any) in general and they key to getting it all to work If I have understood correctly, there seems to be an output LStream and a virtual wire LStream 2 and.

To keep this as clear as possible we should distinguish between LStream and LStream Loopback. LStream is the protocol for adding I/O expansion cards to a LynxTWO, L22 or AES16.

Loopback is a driver feature whereby audio playback streams can be routed within the computer to record devices, without any physical cabling. This allows one to play audio from one program and record it in another. The L22 and LynxTWO-A cards have dedicated loopback channels (Device 2 and 3 for the L22, Device 3 for the LynxTWO-A, again, these are defaults, not hard-wired).

LStream Loopback allows a user to put a pin jumper on the card's internal LStream Pins, to facilitate loopback for up to 16-channels. This works for any LynxTWO, L22 or AES16.

Perhaps it would be helpful to detail how the routing would work to accomplish your goals. What are you wanting to use LStream loopback for?  Please describe how many channels you will be recording, what the play application is and what the record application is - and I will put together a scheme for you to follow.

jrpavel wrote: So, how would you pick up whatever is being sent on the SPD/IF channel, say?

How do you mean? Again, loopback routes audio from one program to another. It wouldn't invole the SPDIF or Analog I/O directly.

Best Regards, 

jrpavel wrote: Input sources can be recorded without having any relationship to the outputs however. Do you mean by this that I can just point an application at an input device and record the signal (eg, pick up SPD/IF from Lynx 4) or have I missed something?

Yes. Your diagram described the relationship of the inputs and playback streams to the outputs for monitoring (i.e. hearing the incoming audio directly through the outputs). As you described in your example above, you can choose record 4 in an application as the signal source, and record audio from the digital input without involving monitoring at all. I just wanted to clarify that point.

jrpavel wrote: What are you wanting to use LStream loopback for? I'm just trying to understand it at this stage.  To keep it simple, suppose I want everything that is played on the SPD/IF out to appear on the SPD/IF in, or vice versa.

That would require physically connecting the digital out to the digital in. OR - you could have the audio streaming to  the digital out ALSO go to a loopback output so you can record it in a separate application. Does that sound like what you'd want to do?

jrpavel wrote: KMixer is inevitably involved if the WDM driver model is used. On which side of the Lynx Mixer does it appear (before or after)?

For playback: before. For recording: after.

Best Regards,

Ok - what we'll do is use Play 4 which is routed to the digital out as a default, to also stream to the first 2 loopback channels.This way,the same audio stream can be received by your SPDIF device, and also be used for loopback.

First jumper the Lstream Expoansion port for LStream Loopback as described here.

Next, open the Lynx Outputs Mixer. We want to add Play 4 as a monitor source for LStream Out 1/2. Click a blank monitor source block in the channel strip for LStream Out 1 and choose Play > Play 4L. Then un-mute this source by clicking the "M" next to the newly created P4L button. Do the same for the LStream Out 2 channel strip, but choose Play 4R. When completed, it should look like this (note: the screen shot shows a TWO-C card):

Now, play audio through Play 4 (Device 4). You should get meter activity in the Outputs Mixer for Digital Out L/R as well as LStream Out 1/2. Open the Record/Play Mixer and you should now also see meters for L2I1 and L2I2 (Record 5). Both mixers should look like this:

If you open up a recording an application and select Record 5 (Device 5) as the signal source, you will be able to record the stream from your playback application. Simultaneously, the audio will be playing out the Digital Output.

Best Regards,