Forums > MaxMSP

narrow band graphic eq

January 23, 2014 | 6:19 am

Hello all,

I’ve been trying to find a way of modifying the max example of the 1/3 octave graphic eq to reduce the bandwidth of each filter, maybe suffering like 1/6 or 1/9 octave wide.

Does anybody know if this is possible or am I wasting my time?


January 24, 2014 | 12:24 am

I’ve made a bit of headway with this – using several fffb~ objects (as the maximum number of filters per object is 50).

The only thing that I am struggling with now is the filter frequency ratio – I notice that the 1/3 octave eq quotes this as "A third-octave equalizer has a frequency ratio of the cube root of 2, i.e. 1.259921…"

I’m not sure as to where this number comes from – or the calculation to find the ratio for narrower bandwidths.

Any ideas?


January 24, 2014 | 7:12 pm

You can get this using mtof. For third of an octave, just increment the pitch value going into mtof by 4.

January 24, 2014 | 8:09 pm

the calculation is always the same for no matter how many keys per octave. like peter suggests, mtof, which performs the math, can also take float, and lets you do any number per octave you want.

April 8, 2015 | 12:15 pm

The best narrow eq i have used is reapers ‘rea eq’ you can select an individual frequency from a noisy sound file. its pretty incredible.

it’s free. States : "Freely usable". 32 bit and 64bit available. win and mac too I believe, but may need to download reaper for mac? needs some googling.

I am wondering, does "free to use" mean one can incorporate the eq in their patch vst~ and distribute on line as a free to download standalone? I ask this, as I am after a narrow eq for my patch too. Hence I found this thread. I just wonder about legal issues with ReaEQ..

But yes, ReaEQ is simply awesome. : )

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Forums > MaxMSP