Stereo signal needed for MIR plugin?

[Talino]

Hi,

I have two mono audio tracks (cello & violin) and one stereo VI (piano), the three going into MIR through the plugin. I was going crazy for half an hour because the audio tracks' positions were not handled properly in MIR — there was some audible frequency changes when moving the instruments around, but no positioning information. I could move the icon hard left and hard right to no effect. The piano icon responded perfectly. Then I tried routing the two mono audio tracks into two stereo groups and inserting the plugin there, and it works just fine. Is MIR averse to mono signals or is there a setting I should tick somewhere?

Thanks.

[Dietz]

You ears weren't deceiving you! ;-)

Internally, MIR always "expects" a two-channel signal (stereo or dual mono). For mono sources, you should either reduce the width of the respective Icon to zero (i.e. mono), too, or you should make sure that the signal is represented on both channels equally before entering MIR.

 

HTH,

[Talino]

I don't understand, if I insert MIR on a mono channel, isn't the signal on both channels identical when entering MIR?

[Dietz]

Oh - it seems as I misunderstood your question. In a mono-to-stereo MIR plug-in, the input signal routed into the Icon will be the same on both sides. The actual stereo imagining depends on the settings done within MIR Pro, of course.

In a mono-to-mono instance, the output will stay mono, too.

[Talino]

Well, I guess I didn't express it properly :)

When the MIR plugin *is* on a mono channel, positioning isn't behaving correctly. The instrument has some width to it in MIR (the default value), but since it's fed a mono signal it gets identical L & R signals, which should work. But it doesn't.

It only behaves correctly when I route the mono channel into a stereo group and insert the plugin there. No pan control is touched anywhere in the Cubase signal path.

[Dietz]

There's nothing MIR can do about: Cubase can't automatically "expand" a mono-track to a stereo path just by inserting a plug-in (like ProTools or Logic would do, for example). The way Cubase and Nuendo "think", you have to put a mono audio file on a stereo track manually to achieve a stereo signal from a mono source.

... I hope this finally answers your question ....? 8-/

[Talino]

Almost :) I just tried routing the mono track directly to MIR and choosing width of zero in MIR, and positioning still doesn't work, so if I understand you correctly, in *all* cases (at least with Cubase) MIR should receive a stereo signal at its input. Right?

[Dietz]

The "problem" is Cubase, really. (... it's not a bug, it's just the way Cubase "thinks".) A mono-track will always stay mono. You will have to route it into a "broader" bus (stereo, LCR, 5.1 ...) to do something with it panning-wise. In other words: Instantiated in mono-track, MIR Pro plug-in will supply proper impulse responses - but in mono (i.e. no L/R information at all).

[Talino]

I think I got it this time... Thanks a lot again Dietz!

[Dietz]

You're welcome!

[Talino]

Another question on the same topic: before using MIR, I had setup my VEP template with the the "Vienna Stereo Pan" on every channel. I reset pan to neutral on every channel (L completely left, R completely right), so that the signal doesn't contain any pan information when going into the stereo Cubase channels (on which I have the MIR plugin inserted). I'm just wondering, should I just remove these Vienna Pan inserts from the VEP channels? Are they doing anything to the signal before it leaves VEP?

Thanks.

[Dietz]

As long as you don't aim for a special effect, MIR Pro should be used instead any other panning device. You should leave VE Pro's panner at neutral position, or you simply remove it.

On rare occasions, it can make sense to use a panning device _before_ sending a signal into MIR Pro, e.g. to get rid of the "built-in" panning of 3rd-party sample instruments, or uncentered audio recordings.

HTH,

[Talino]

OK thanks a lot.