Forums > MaxMSP

Build Own EQ

October 23, 2008 | 8:38 am

Hello all,

Just a question that has baffled me a little bit.

I am looking to build my own parametric eq for my patch that i am building, just to make it even more weirder than it is. I aslo plan to even stick some extras on to it, so it ends up being more than a eq. But that is later.

My question is just, where to start. Maybe what object to start from.I dont want to use any 3rd party externals, because i would like it if it was built by me.

I have thought of filtergraph~, but feel there could be a better way than that.

That was about it…


October 23, 2008 | 10:14 am

I would use [filtercoeff~] and [biquad~]. Have a look in the [filtercoeff~] help file. It works pretty much the same as [filtergraph~] but without the gui. Then you are free to use dials/sliders/numberboxes/whatever to control the settings.

If you would like I can post some abstractions I’ve made for dealing with filters. I’ve got one for bandwidth to quality (Q) factor conversion and vice versa and one for scaling MIDI values to the audio frequency range (and back again) so that setting the centre frequency can be done without having to scroll for ages at higher frequencies due to the logarithmic nature of frequency.

lh


October 23, 2008 | 10:20 am

great, cheers for your help.

That would be great for you to put the abstractions up


October 23, 2008 | 10:58 am

Bandwidth to quality factor:

– Pasted Max Patch, click to expand. –

Quality factor to bandwidth:

– Pasted Max Patch, click to expand. –

Audio frequencies to MIDI:

– Pasted Max Patch, click to expand. –

MIDI to audio frequencies:

– Pasted Max Patch, click to expand. –

Let me know if they’re useful or not, they should all work properly but I’m currently in the process of tidying up many of my abstractions so I can put them online to share with everyone and sometimes I take bits apart and forget to put them back together.

lh


October 23, 2008 | 11:00 am

great, thanks a bundle man. Very much appreciated ;)


October 24, 2008 | 7:31 am

Lewis G. Edwards schrieb:
> great, thanks a bundle man. Very much appreciated ;)

I do all my conversions of this sort with atodb, dbtoa, mtof and ftom…


Stefan Tiedje————x——-
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October 26, 2008 | 4:25 am

yea, i was going to say "frequencies to midi/midi to frequencies = [ftom]/[mtof]."

take a look at the cascade~ object. You can get cascade~ to be displayed on the filtergraph, so you have a visual representation of your cascaded filters. I believe Darwin Grosse does this in the Expanding Your Guitar tutorials.


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