MB-7 Signal Flow?

[cturner]

I guess it’s my week to post in the BC subforum.

I read the overview in the MB-7 manual, but it doesn’t answer my question, which is:

MB-7 has a crossover network at input to create the bands it processes, but at the other end, merging the bands, does it apply the same filtration?

For example, if I insert a plugin on a band that’s limited to 100-1000hz, and that plugin produces harmonics in the 3-5khz region, do these harmonics get merged at full gain, or are they subject to another band limiting stage—high passing at 100hz and low passing at 1000hz—before the merge with the other bands?

Thanks!

[cturner]

To answer my own question, it appears that the MB-7 bands are merged at full bandwidth, so if a plugin creates harmonics for example, at frequencies outside its band, those are simply merged on output. It doesn't appear a band is limited a second time, on output, as it flows through MB-7.

Hope I'm correct. :-)

[rrichard63]

To answer my own question, it appears that the MB-7 bands are merged at full bandwidth, so if a plugin creates harmonics for example, at frequencies outside its band, those are simply merged on output. It doesn't appear a band is limited a second time, on output, as it flows through MB-7.

Hope I'm correct.

That's always been my assumption about all multiband processors. It appears that you have done some testing to confirm this, for which I thank you.

[cturner]

Yes, I made a 500-2000hz band in MB-7 and input a 1khz wave, so it should be fairly band limited. Then added a saturation plug to the MB-7 band, which generated harmonics in the high end that were well above the 2000hz upper limit. I didn't see any appreciable difference on a spectrum analyzer that compared both waveforms, i.e. with and without MB-7.

EDIT: I was interested in 112dB’s Redline Tube Preamp, which seemed to be doing something else than having a 3-band EQ before the saturator. I thinks it’s a crossover network of some sort. A judicious use of my current saturation plugs inside MB-7 seems to get me sonically to the same place, and more.

[Blue Cat Audio]

You are right, ndeed: when merging the bands, no additional filtering is done. The plug-in only applies phase compensation filters to align the phase of all bands (which might be different due to the non linear phase crossovers).

Applying distortion to a specific frequency band will produce harmonics that can be higher than the cutoff frequency. And that's actually what makes multiband distortion particularly interesting!