Re: square waves

[Charles Zwicky <cazwicky@earthlink.net>]

Daryl,
  A chorus effect is nothing more than a short delay (5-20ms) in which 
the delay time is modulated by an LFO.  The LFO in a chorus is 
usually a triangle wave, so that the delay time smoothly changes from 
the shortest to the longest time.


Most 'harmonizer' type effects do not have an LFO, they use a 
different method to produce a steady pitch shift.


The PCM-42 was designed as an early "multi purpose effect" if you 
will.  By setting the delay time very very short (0 to 10ms) and 
modulating it slowly, you will produce flanging effects. A slightly 
longer delay (5-20ms) and a slightly faster modulation produces a 
"Chorus" effect. Most delay effects have some sort of modulation, but 
the PCM-42 was one of the few which has a square wave available in 
the LFO ina ddition to the triangle wave.



>On the old David Torn instructional video, he mentions the 
>oscillator in the machine and demonstrates its effect with some 
>harmonized delays. Forgive my ignorance, but is an LFO present as a 
>controller for any sort of time-based modulation, i.e., the rate 
>control on a simple chorus pedal? Does every harmonizer have an LFO? 
>And do looping machines such as the Repeater which offer some pitch 
>control also have an LFO?  Or is the PCM-42 unique in having this 
>effect available in its delays/loops...?
>
>Daryl Shawn
>www.swanwelder.com
>www.chinapaintingmusic.com
>
>>The PCM-42 delay line has an LFO which is used to modulate the 
>>delay line, it can be used to create flange, chorus or wobbly 
>>echos. It has two waveforms available, triangle and square. If you 
>>use an expanded memory PCM-42 and modulate your loop with the 
>>square wave the effect will be similar to having someone switch the 
>>speed of a tape machine, with dramatic jumps in pitch and speed.


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