if I have to use granular synthesis such as an max msp patch, how would I go about creating high voltage/arc/tesla sfx...I tried loading different industrial material sounds such as plastic and styrofoam into granular patch...I believe this will get me the texture, what would be your take on this.
Andy Farnell has a fantastic book called Designing Sound, which details theories of designing procedural sound effects, with methods in Pure Data. Here is a great quote from his practical on Electricity:
The sound of a spark in an anechoic chamber is almost an ideal impulse (which is why spark gaps are used to do impulse captures), so the sound of the crackle is influenced greatly by the surrounding material.
The chapter mentions a few key aspects, namely Relaxation of charges (e.g. try LFO modulation of a 50hz Hum), Phasing (due to different spark/arc lengths, especially relative to observation point) and Resonance (see above quote).
From the practical here - "The effect combines humming, phase shifting and synchronised crackles (chirp impulses) for a 50Hz arcing sound." If you choose to download the patches (I presume they're compatible), be sure to download the 4 abstractions that are required. Also it is worthwhile to experiment with an additional delay or reverberation space.
To answer your specific question, it might be worth using a very small 'impulse-like' grain size, and try let it oscillate at a fixed frequency (e.g. 50hz), so it becomes a buzz. If you want to be realistic, you probably won't need to use detailed samples from plastic and metal, since the spectrum of a buzz is very consistent and static. The main variation is found through the above effects, which are essentially byproducts of the initial spark sound.
Any pulse oscillator would be okay, you can use the grain synth as a pulse signal. you work from any electric hum sounds,the oscillator itself is fairly simple the interesting thing is what frequencies to add and substract from the hum, and how to change the sync of the pulse. For example, you can pass the signal through two filters, firstly a high pitch filter to make the most raw sound possible, to work from, and secondly a low filter to make the electric arc movements in a sweeping fasion. it's mostly a variation of phase sync and filter on a pulse osc.
The dynamics of the movement of the arc is that it slowly floats further away from the most stable path, and when it's too far, it snaps fast back towards another stable path, so the LFO to simulate the changes in phase resulting from the sound arriving at the use at different times, can be an slow lfo that is reset in a semi chaotic manner. perhaps add a spike on the filter when the lfo resets because a large arc bangs th more it changes it's course.
The same principle can be added for side arcs, some less loud and faster resetting small arcs added to the first sound.
The grain synthesis can only be used as an oscillator with phase control i think, alot of the sound of the arc must come from how the different pulses bounce in the room and arrive at the user, adding and substracting from each other in a complex frequency and phase variance.