Force Mono WSAPI / wdm?

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Adger
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Force Mono WSAPI / wdm?

Post by Adger » 26 Jul 2012 21:22

When using an external Soundcard, hooked up via USB2, I can not enforce "mono" in the mic settings panel when using WSAPI drivers. Using WDM works - but only for Mic Input channel 1. When trying to enforce mono for Mic. Input 2 the whole input fails. This is PFOA-related, since the input by itself works (i can see the windows "meters" flicker). What could I do to make enforce mono work? Avid/m-audio says in their FAQ that the audio-software needs to handle the mono-setting so I guess I am doing something wrong. Help please?

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radio42
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Re: Force Mono WSAPI / wdm?

Post by radio42 » 26 Jul 2012 21:22

I guess I might add an extra 'Mono' DSP function for input channels to the next version of PF.
That will at least solve your WASAPI device driver issue as explained above under Option 1 (so that no extra VST DSP is needed).

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Re: Force Mono WSAPI / wdm?

Post by radio42 » 26 Jul 2012 22:59

That sounds strange, as the 'Mono' option in the mixer-input-channel explicitly uses only a 1-channel (mono) for its recording and provides an appropriate mono-to-stereo upmix internally.
I am not sure, what Avid/M-Audio means by saying, that the audio-software needs to handle the mono-setting - as this is the only effective option you might use.
But what you explain more sounds like, that the audio device doesn't support 1-channel (mono) recording, but only a 2-channel (stereo) recording.
What happens, if you do NOT select the 'Mono' option in PF?
Is in such case only the Left-Channel used?

But note, that when using WASAPI in shared-mode, the real channel setting (stereo or mono) is defined in the Windows Sound control settings.
E.g. you MUST select an appropriate '1-channel/Mono' option in the Windows Sound control settings of that input device - if that is available.
If not, this would again be an indication, that the device doesn't support native 1-channel (mono) recording.

So, if that is not available, you might try WASAPI in exclusive-mode (which typically offers some more recording modes).
But if even that fails and the device doesn't support mono (1-channel) recording, I also wouldn't know what to do.

Maybe you can ask Avid/M-Audio, if your audio device supports real mono (1-channel) recording?
Or what they mean by, that the audio-software needs to handle the mono-setting...may be they mean something like: uhhh, just record stereo with our device and throw away the right-channel and clone and audio signal in the left.-channel to the right-channel to make it sounds like mono?
If that's the case, I could only say: nope, that is something PF doesn't offer today - but I guess there are some VST DSPs available doing such funny things.

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Adger
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Re: Force Mono WSAPI / wdm?

Post by Adger » 26 Jul 2012 23:57

according to their FAQ http://www.m-audio.com/index.php?do=sup ... ee1f1eae16:

Code: Select all

 Audio only records and plays back on 1 side; how do I make it stereo?
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Q: I’ve plugged my guitar or microphone into my M-Audio interface, and when I try to record the signal it’s only recording to one channel of the stereo pair.  How do I get my input signal to be stereo?

A:  This is happening because a mono input source (such as a guitar or microphone) is being fed to a track in your recording software that is setup to receive a stereo signal.

Guitars, Basses, and most all professional microphones are monophonic (aka "mono") devices, meaning they do not output a stereo (2-channel, left and right) signal.  Since most every form of recorded music is released in a stereo format in this day and age, it's quite natural for those new to audio recording to (incorrectly) assume that the average pop album is composed of several stereo recordings layered together.  The reality is, however, that modern stereo pop recordings are most commonly composed of several mono instrument and vocal tracks being panned and mixed together to create a sense of stereo separation in the final mix*.  The only typical situation where input from a guitar or microphone would be recorded in stereo would be a situaiton where those devices where being passed through a stereo effects processor before being plugged into your M-Audio recording interface.

If you are feeding your recording software mono input from a guitar or microphone (remember, the human voice is also a mono instrument), you will need to make sure you are recording to a track in your recording application that is setup to record in mono.  The most important step in capturing a mono recording is to make sure that, in your recording application, you have selected the proper input channel from your M-Audio interface.  By default, many recording applications will pair the mono inputs on your recording hardware into stereo pairs, so that input 1 and input 2 show up as “input 1/2”, inputs 3 and 4 (if you have that many inputs) show up as “input 3/4”, etc.

When recording a mono source, you want to record a single input from your audio interface, not a stereo “x/x” pair.  Please refer to the documentation for your DAW/recording software for specific information on how to select the proper recording input from your M-Audio interface.  On some DAW/recording applications, it is also necessary to first insert/add a “mono” audio track (instead of a "stereo" audio track) before selecting a mono input for recording.  Please see your software’s documentation for more details.

Also see these Software Configuration Guides for many popular software applications.

Once you’ve recorded your mono sources as mono tracks, you can begin the process of mixing and panning them into a stereo mix, adding stereo effects and mixing them with natively-stereo recordings from stereo keyboards, samplers, etc. 

Setting up your recording software to record a mono signal into both sides of a stereo track is never advisable, as this is a waste of disk space with no practical benefits to your final mix-down results.

*Note: in the context of classical music, recording a single instrument in stereo (by using mulitple mono microphone pairs at once) is a common practice.  This practice of recording in stereo is usually not the most suitable approach when recording tracks in a pop, rock, hiphop, country, etc context.

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Adger
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Re: Force Mono WSAPI / wdm?

Post by Adger » 27 Jul 2012 00:01

I have checked each and every possible location within windows, PFOA, and the panel for the soundcard. there is no "make this mono" setting - except for PFOA in its "mic" setup.

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radio42
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Re: Force Mono WSAPI / wdm?

Post by radio42 » 27 Jul 2012 00:20

In PF you can select the 'Mono' option for mixer input channels.
That is exactly doing what they descibe above - it is recording a single mono 1-channel only.
So what is happening, if you select the 'Mono' option and what is exactly happening if you don't do that?

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Adger
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Re: Force Mono WSAPI / wdm?

Post by Adger » 27 Jul 2012 02:17

I would be happy if it would work that way - as I would expect it.

Alas: It is only working with WDM-driver model and only with mic-input chanel 1. It is not working with WDM and the second mic (yes, I am refering to a second microphone, a second physical device.) And it is not working all together with WSAPI. With WSAPI I can not click "mono". PFOA refuses to accept my input. The checkbox is there but any click is discarded. Thats my problem.

Edit: Checking "Exclusive mode" in PFOA and/or Windows does not have any effect.

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Adger
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Re: Force Mono WSAPI / wdm?

Post by Adger » 27 Jul 2012 08:45

Reading those posts again I think I should be a tad more specific.

The sounddevice (c400) is an external USB2 device. I am using latest drivers and no hubs. It is directly wired to the computer.
The c400 has two XLR inputs which I am refering to as "mic input 1" and "mic input 2".
Within PFOA I have got one microphone channel. This would be the "default" MIC1.
Using mic input 1 is interpreted as "left" while using mic input 2 is iterpreted as "right" in PFOA's MIC1.
Using WDM I actually can check "mono" in the settings for MIC1. Signals from mic input 1 would be treated as left and right. Using mic input 2 with "mono" checked would fail completely.
Using WSAPI I cannot tick the mono-checkbox. PFOA would not allow that.

I want to be able to use both mic inputs. I want to use both inputs as "mono". And I don't want to mix drivermodels.

Better understandable?

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Adger
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Re: Force Mono WSAPI / wdm?

Post by Adger » 27 Jul 2012 09:31

Idle paws...

After spending most of the morning with trying to figure out where I am taking the wrong turn I guess I can say the problem is related to WDM/WSAPI. Using ASIO (and telling PFOA to read/send from/to the correct inputs/outputs) works, although the mic inputs are still displayed as "left" or "right" respectively in PFOA's MIC1 (see above). But PFOA is sending the signal as "mono" from the PFOA-internal MIC1-mixer-channel to any other mixer-channel, so this is a rather cosmetical issue I guess. If that's the case how about switching the meter from a two-bar-stereo-indicator to a single-bar-mono-indicator? Helps avoid confusion (consider this being a suggestion for a future update.)

I am not sure wether or not the "mono" problem can be solved, but I think there is something fishy around this topic and wdm/wsapi...

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radio42
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Re: Force Mono WSAPI / wdm?

Post by radio42 » 27 Jul 2012 21:17

a) What ProppFrexx displays as an input device is what the driver reports, so that's nothing ProppFrexx creates - so blame M-Audio for that

b) When using WASAPI - and the 'Mono' option is not acctepted (in either shared and exclusive mode):
ProppFrexx calls the WASAPI (CoreAudio) driver to validate the specific settings, in this case the combo: 1-channel plus samplerate.
The driver reports TRUR or FALSE, if this settings is accepted and supported by the driver.
If the driver reports FALSE, the native Mono recording is NOT supported by the driver.
Again, blaim M-Audio for not supporting native mono recording.

c) WDM and MIC2: Using mic input 2 with "mono" checked would fail completely:
The WDM driver model doesn't offer a 'Check supported Format' functionality like WASAPI (as explained in b).
As such this can only be determined by 'try and error' - and if the driver doesn't support that - it would fail.

What I assume is, that M-Audio did the following internally:
- they only offer effectively stereo channels for input and output (at least for WDM and WASAPI)
- as such the Mic1 and Mic2 input are seen as one internal stereo device with a Left and Right channel (Left=Mic1, Right=Mic2)
- this limits the WDM driver when recording to either using both (stereo, Left and Right, Mic1 and Mic2) OR only using Mic1 stand-alone!
- the same seems to aply to the WASAPI driver, so that when you only connect the Mic1 - it still always records in stereo (and as such Mic1 is only usiong the Left-Channel)!
- pure, native mono (1-channel) recording seems to be NOT supported by the WASAPI driver!

So as a result:
1) Using ASIO has no limitations, as ASIO ALWAYS MUST support single channel recording - so use that (as ASIO is anyhow recommended when available!)
2) Using 1-channel recording with WDM also works, but due to the driver limitation ONLY with Mic1 (meaning in this mode Mic2 is kind of dead)
3) Using 1-channel recording with WASAPI never works due to the driver limitation (only stereo recording with Mic1 and Mic2 is possible)

So as a result only 3) might be tweaked as already explained:

Option 1: Using WASAPI with only Mic1 connected:
As only stereo recording is supported by this driver the Mic1 would only appear in the Left-Channel.
A Mono-to-Stereo VST DSP would help in this case to clone the Left-Channel to the Right-Channel.

Option 2: Using WASAPI with Mic1 and Mic2 connected:
As only stereo recording is supported by this driver Mic1 and Mic2 would appear in the same stereo input device as the Left(Mic1)- and Right(Mic2)-Channel.
A distinct and seperate setup/recording of Mic1 and Mic2 individually is not supported.

I guess that is a pure limitation of the device resp. its drivers.
But as you can always use ASIO with that device I guess there is a clean and even preferred way to overcome these limitations.

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