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[GiAnt]

Dear all, I would like to have your help in order to convolve FIR filters directly in MC. I have build FIR filters with Rephase and put them in a config text file according to the instruction (http://convolver.sourceforge.net/config.html). However, when I try to load the config file invariably receive messages of errors such as "not valid" (in status) and "output is changed from 2 channels to 8 (or 4 or 6). In contrast single FIR files (wav) works perfectly.
In spite of intense investigation on the net, I have not found up now a solution. This is frustrating because MC is really a wonderful software.

[mattkhan]

It's quite difficult to comment without some detail as to what you're doing

Can you post what you have (that isn't working) and what the configuration is intended to do

[GiAnt]

Certainly ...

[mwillems]

Can you take a screencap of the convolution panel during playback, and a screencap of the audio path also during playback?

Sometimes the convolution display shows "not valid" for valid filters when playback is stopped, but actually shows filtering happening during playback.  The audio path will also tell us what's actually happening.

Also: unrelated, but you really shouldn't leave the clip settings set to "flat-line overflows"; it's useful for diagnostics, but it's not a good practice to leave it that way, and potentially poses a risk to your equipment depending on your setup.

[mattkhan]

So this is a stereo 4 way system? What is output format set to? i.e. do you have sufficient output channels in the output format?

does jriver like 2 8 or does it require 8 8? I've always set them to the same value personally as jriver is presenting 6 (or channels to the convolver even if only 2 carry any content.

[GiAnt]

Can you take a screencap of the convolution panel during playback, and a screencap of the audio path also during playback?

Sometimes the convolution display shows "not valid" for valid filters when playback is stopped, but actually shows filtering happening during playback.  The audio path will also tell us what's actually happening.

Also: unrelated, but you really shouldn't leave the clip settings set to "flat-line overflows"; it's useful for diagnostics, but it's not a good practice to leave it that way, and potentially poses a risk to your equipment depending on your setup.

Many thanks for the reply. I will post the screenshots tomorrow (now I stay away from the house where the audio system is located). I'm writing from a laptop not connected to the main sound card (a MOTU 28 channels). However, the snapshot I have shown looks the same of the main PC.

[GiAnt]

So this is a stereo 4 way system? What is output format set to? i.e. do you have sufficient output channels in the output format?

does jriver like 2 8 or does it require 8 8? I've always set them to the same value personally as jriver is presenting 6 (or channels to the convolver even if only 2 carry any content.

Yes, it is a stereo 4 way system. I have tried different output format including 7.1, 10 and 16 channels, but unsuccessfully. I will try to rewright the config text according to your suggestion, it could be this the right way to solve the problem.

PS. unrelated, is it possible to change the default settings of the subwoofer? parametric equalizer 2 is an astounding tool and the possibility to build a crossover for a 4 way system (notwithstanding some restrictions) is very interesting. Unfortunately the presets for the sub channel are tedious and the Low pass filter comes always incorrect ...

[mwillems]

PS. unrelated, is it possible to change the default settings of the subwoofer? parametric equalizer 2 is an astounding tool and the possibility to build a crossover for a 4 way system (notwithstanding some restrictions) is very interesting. Unfortunately the presets for the sub channel are tedious and the Low pass filter comes always incorrect ...

I don't understand what you're asking here.  There are no default subwoofer settings in parametric equalizer?  Do you mean the default subwoofer settings in output format?  If you want to build a custom sub channel, you can do it in parametric equalizer or in convolution (the same way you set up your active speakers, just imagine the sub as a third band).

If you can be more specific about what you're trying to achieve and what issues you're encountering, we can help.

[GiAnt]

I don't understand what you're asking here.  There are no default subwoofer settings in parametric equalizer?  Do you mean the default subwoofer settings in output format?  If you want to build a custom sub channel, you can do it in parametric equalizer or in convolution (the same way you set up your active speakers, just imagine the sub as a third band).

If you can be more specific about what you're trying to achieve and what issues you're encountering, we can help.

Dear  Mwillems, you are right … I will try to explain more in depht what exactly I need for.

I recently built a 4 way stereo active loudspeaker system I initially managed with hardware DSPs such as DCX 2496 (and others). Initially skeptic, more recently I have been positively influenced by the reading of several discussions on the net about the possibility to manage multichannel active loudspeakers entirely via software, particularly by using MC as main software.  Being prevailingly a mac user I admit to ignore (up to some day ago) the capabilities of MC. This was a fault since MC is really an astounding software. I started to build the XO using the tool Parametric equalizer 2, initially setting the output format to 7.1 (and later more channel also). With this setting the sub channel comes with a lower gain (like in HT) that I have increased by using equalizer (+20dB) in order to align the sub channel with the others. Since the global output level was also low I increased the gain too (+15 dB). However looking at the tool "analyzer" to check how the XO worked I noticed a “strange” response of the LowPass filter (see screenshot).

Selecting more channels in the "output format" (e.g. 10 or 16) the tool "order channel" (as well as the  the tool "equalizer") continued to show only the 7.1 channels configuration.

Therefore I tried to take advantage of the integrated convolution capability of MC. I have built a number of FIR filters with RePhase, starting from the IR of my drivers. I inserted according to the instruction found on sourceforge the filters in a config text that at a later stage loaded in MC. Unfortunately this config text doesn’t work, probably  as a consequence of one or more mistakes done by me for incompetence. My request of help posted here is in order to have a serviceable XO (possibly as linear phase FIR filters) in MC.

Thanking you in advance for your patience and attention

[mwillems]

Let's take several points separately:

I started to build the XO using the tool Parametric equalizer 2, initially setting the output format to 7.1 (and later more channel also).

If you are trying to setup a stereo 4-way system, the correct output format setting is "stereo in a 7.1 channel container," not 7.1.  That will allow you to use JRiver's JRSS downmixing successfully.  If you have other speakers, you'll need a different channel setting, but you don't mention any other speakers.

With this setting the sub channel comes with a lower gain (like in HT) that I have increased by using equalizer (+20dB) in order to align the sub channel with the others. Since the global output level was also low I increased the gain too (+15 dB).

If you're talking about trying to add that gain in PEQ (i.e. in software), don't do that!  You'll only force your content into clipping unless you've taken other precautions.  

If you follow my channel output advice above, and do your routing as you showed in your picture of the parametric equalizer there's no reason that content you copy to the sub channel should be quieter.  If it still is, something has gone wrong.

However looking at the tool "analyzer" to check how the XO worked I noticed a “strange” response of the LowPass filter (see screenshot).

I don't recommend using analyzer to confirm that filters are working correctly, it's not designed for that.  Analyzer shows a very, very rough picture of what's happening with DSP, especially towards the bottom of the frequency band, it's not very accurate at all.  You need to actually measure the output to confirm that your filters are working correctly.  I can tell you that JRiver's lowpass filters generally work exactly as expected from my own measurements.  The low-pass filters are fine: it's analyzer that's the problem, not the filters.

Selecting more channels in the "output format" (e.g. 10 or 16) the tool "order channel" (as well as the  the tool "equalizer") continued to show only the 7.1 channels configuration.

That shouldn't be the case, although you may need to assign names to channels higher than ten.  Channel configurations higher than 7.1 will retain a 7.1 mixing target, which is a separate issue, but that shouldn't affect the total number of channels available.  You shouldn't need more than 8 channels unless you have more speakers, in which case we'll need to start back from the top.

Unfortunately this config text doesn’t work,

You'll need to be more specific about what isn't working.  I requested above that you post a screen shot of the convolution panel during playback with your config file, and also the audio path during playback.  If playback fails to start entirely with the config file selected, please post the exact error message MC provides.  

[GiAnt]

Mwillems, I followed your advices and now the system works perfectly .
Even FIR convolution now is OK. In the meanwhile I have done many changes to the config file, probably it was a routing issue.
Many, many thanks