Three Beginner Questions

Mar 15, 2009 at 11:12pm

Three Beginner Questions

Hi, so I am not a very experienced programmer, but have been learning to develop Max externals in a course I am taking. There’s a few things I am trying to figure out in writing my own externals that I hoped the people on this forum could help me with:

1. In one object I am building, I have separate clocks for each outlet. When calling the clock_function, how can I specify which clock/outlet to call? I have tried putting that information into a variable in my object’s struct, but prolems arise when multiple clock_functions are modifying that variable at the same time.

2. How do I create anti-aliased wavetables for saw, square and triangle waveforms? I have tried creating them by running each value in the wavetable through a two pole, two zero low pass filter at 20 kHz (coefficents determined through the [filtergraph~] object), with no luck. I also tried implementing the mathematic formulas found here:


only up to the kth partial (where k * f < Nyquist frequency). Also no luck.

3. How do I link an array of values to a [buffer~] object?

Thanks for any help. I look forward to your replies.

Mar 16, 2009 at 11:13am

Hi CiC,

It seems to me that your second question doesn’t necessarily relate to max external development but to dsp programming in general, which usually takes a lot of time to get into. http://www.musicdsp.org/ might be of some help there.


Mar 16, 2009 at 4:14pm

thanks matt, that seems like a valuable resource.

i should elaborate on my first question: basically, i ahve X number of inlets, and X number of outlets. When a bang is received in an inlet, a variable number of bangs are output the corresponding outlet. However, when multiple bangs are received in multiple inlets at the same time, the variable in my main object’s struct where i store the inlet number (my clock function then uses this to determine what outlet to output bangs from) gets overwritten so only the last value received gets output. what can i do to prevent this?

Mar 17, 2009 at 2:17am

i found out the answer to my first question: I needed to create a separate struct for a clock/outlet pair, then create an array of these structs within my main struct.


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