4-channel Montage Output Effect Problem

Recently I have been processing my files using a particular sequence of effects in the Master Section.

Today I tried placing the first effect in the Montage Output section, so that it gets saved with the montage with no fuss. Unfortunately the output from the effect is now entirely different (and I cannot immediately analyse what the difference is). This behaviour is the same in 9.1 and 9.5.

The situation is as follows:
I have an Ambisonic A-format set of channels placed in a 4-channel montage on four tracks, the four signals being routed to Lf, Rf, Ls, Rs in order. To convert this to Ambisonic B-format (which is also four channels) I use a special 4-in, 4-out VST which also applies microphone calibrations: VVEncode. This may be followed by additional processing, such as Peak Master. I then place a decoder in the playback processing slot which converts the B-format into signals matching my loudspeaker layout (normally four speakers in a square).

This all works fine until I move VVEncode to the montage output. The effect then is as if the wrong A-format signals are being sent to the plugin inputs; but without generating a series of artificial test signals it is virtually impossible for me to add any precision to that description.


I think I can reproduce this. If I make a 4 channel montage, DVD compatible Lf Rf Ls Rs, and place a multichannel plugin like Steinberg EQ or Voxengo Curve in the Montage Output, the plugins aren’t routing correctly. But the same plugins route ok for 4 Channel Lf Rf Ls Rs if placed in the Master Section instead.

But if after making the 4 channel montage and trying this with Montage Output plugin, you switch the montage to 6 channel 5.1 Lf Rf Ls Rs C LFE (enable additional to get this configuration) in the lower right pulldown and play, then switch it back to 4 channel Lf Rf Ls Rs montage, it seems to make the plugins in the Montage Output route correctly.

It definitely seems like there’s something wrong going on there, but that could be a temporary fix I think.

I also think it retains the fix after you save the montage and reopen it later.

Thanks for that! I’ll try it.

It never occurred to me that the channel naming might affect the routing within WaveLab. I’ve always thought of it simply as naming at the documentation level, which would only have an effect when written into the output file. Since WaveLab’s channel naming doesn’t match what my signals mean - and indeed, the function of this plugin is to change their meanings to another set of meanings, also unknown to WaveLab - I have no reason to think about anything other than four channels in the correct order with no meaning outside my head and the programming of plugins I use.

In my setup, the channels only correspond to speakers at all after processing by a plugin in the monitoring slot. It is a matter of luck that the three channel configurations involved all have the same number of channels at present, or I couldn’t get away with using WaveLab at all. But I am currently awaiting delivery of a third-order microphone which will have 19 A-format (capsule) outputs, which will then be processed to 16 Ambisonic B-format outputs, and then to however many speaker outputs are required (I will probably be trying a mere six). So I shall have to be using Reaper for that.

The problem is that assigning meanings to channels within WaveLab has introduced a rigidity (and probably complexity) in configuration. I can see how it came about; but it needs to break away from this rigidity - which must be in the way of enabling it to handle more channels and multi-channel files - and just leave the users to specify where the outputs go at the last moment (by connecting their speakers right, and specifying the channel mapping mask in the output file at the file-writing stage).


Because I didn’t mention it before, I think the original problem was that the Steinberg and Voxengo plugins were only seeing channel 1 and 2 when first inserted in the Montage Output of the 4 channel montage, which is definitely wrong and should be fixed in Wavelab.

If you don’t need or want channel naming in this case, I wonder if the 8 channel standalone configurations route as expected. I didn’t try that.

I finally got around to revisiting this.

Quite simply, for me montage output effects don’t work in multichannel montages. At all. I’ve tried with a number of plugins, and inserting them and turning them on and off has no effect on the output. A good one to test with - because it has 4-in, 4-out and so won’t cause any other problems - is the AMBEO A-B Converter linked on this page (it’s free, so no problem getting it for testing). It has meters on its inputs and outputs, and you will see that no input signal is being reported when it is used in the output of a four-channel montage, not even on the first two channels. The signals are shown as expected when it is placed in the master section.

I tried bob99’s tweak, but it made no difference for me.


I will check this for 9.5.30