[music-dsp] Math programs

James Chandler Jr jchandjr at bellsouth.net
Mon Feb 28 16:10:32 EST 2005


----- Original Message ----- 
From: "Nigel Redmon" <earlevel at earlevel.com>


>I think it's a good idea to fiddle with filters in a math program and plot the 
>output. I plot just about everything before I code.

Thanks for the graphic example Nigel. Yer png graph showed up fine in Winders IE 
6.

I should learn a math program. From brief inspection, Octave looks 
labor-intensive. SciLab looks more promising.

To minimize the learning/setup curve-- If money were no object, is matlab the 
way to go?

Reckon learning a math program is roughly equivalent to learning a new 
programming language AND learning a new IDE? Would free programs like scilab 
entail more work, having to search out tools or roll yer own?

How much time does it take a dummy to become moderately proficient in matlab?

=====

I have a long-ago-written audio helper program that reads a command text file 
and processes the list of audio files.

The command text file specifies input/output files (and other conditions). I can 
repeatedly tweak an algorithm, hit run, and quickly see/hear the results in 
CoolEdit. Since the utility program encapsulates the audio in/out, the buffer 
processing function is the only thing I have to write.

The utility program has common audio classes. If I want an RBJ filter in the 
block processing function, something like--

RBJNotchFilt.FilterMonoBuf(InFloatPtr, InFloatPtr, InputNumBytes);
//filter the buffer in-place

Having added a class for Dave's polyphase halfband, it is easy to one-line test 
in the same fashion--

HalfBandFilt.ProcessMonoBuf(InFloatPtr, ResampleDirection, InputNumBytes);

There is a tradeoff between slower development using known tools, against 
possibly faster development after spending some unknown time learning a math 
program.

JCJR 




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