Quote:
Originally Posted by nutrinoland
So in this article
http://hyperphysics.phy-astr.gsu.edu...subton.html#c2
it says that any 2 tones of different frequencies, will interact and produce a third , beat frequency, which is the difference between the two frequencies. Also harmonics within one Tone, such as a saw wave, interact to re-enforce the fundamental frequency, as the difference between the successive harmonics is equal to the Fundamental frequency.
SO WHat would happen to a Square wave though, which has a series of Odd Harmonics ? would it not start to become a Saw wave as its harmonics, created a beat frequency not equal to the Fundamental ? also as the different harmonics (sine waves) interact with each other, wouldn't We have beat frequencies at the full harmonic series ?..A saw Wave ... right ? Yet That is not what happens...cause clearly its still a square wave... ?? whats going on ?
PLs read the article to better understand My question.
Thanks |
best advice to get your mind around this whole thing is to get an oscilloscope:
http://bedroomproducersblog.com/2011...vstau-plugins/
I use the s(M)exoscope myself! also load a spectrum analyser plug-in (such as voxengo's span, which is also free btw) and see the impact a given waveform ('cause the sum of two waveforms is also a waveform in itself, altough a moving one if there's no phase retrigger going on, like on analogue oscillators/free running). it's not such a big deal, it's good to have a good grasp on the theory, but once you put it into practice, combining waveforms is about getting a certain timbre more then anything else, and you begin to get a sense of how that's going to impact the spectrum. all that knownledge can be applied promptly on an instrument such as Zebra, that allows you do draw your own waveforms or wavetables (a number of waveforms you can scan and/or modulate). also worth seeing with the oscilloscope is the impact that certain waveshapers/saturation/distortion has on the waveform and how that translates in terms of the volume on the harmonics produced.
the thing with two free running waveforms is that there's always a certain amount of phasing between them. as the cycles of the two waves don't quite match, you can ear how the cycles approach, when they meet and when they drift apart again, that's beating. the larger the difference in frequency between the two signals, the more apparent this beating becomes. as soon as you phase retrig these waves or hard sync them, that's gone. but beating is more a psychoaccoustic thing then something you can measure. a sawtooth and a square wave will never result in a sawtooth, but some mix of these two waves together, and that will be visible in the shape and spectrum. and yes, you combine two fundamental tones, one with even and the later with odd harmonics. plus, due to the notes starting at different phase positions of the waveforms per each note, the waveform and the spectrum will also be changing a bit. for example: if you have one oscillator tuned to 0 and the other one octave higher (+12 semitones), if they share the same waveform, the first will take two times the amount of time of the second to conclude a full waveform cycle. this catching up and growing appart between the two cycles is what's refered to as being "beating".