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All basic synthesizers can produce the basic waveforms: sawtooth, square, triangle, and sometimes sine. Does each synthesizer "injects" its own character to the waveform? Are all sawtooths the same, or can there be differences?

For example:

  • Can an unfiltered triangle waveform from synthesizer x sound different from unfiltered triangle waveform from synthesizer y?
  • Can there be difference in the harmonic content of the same waveform when produced by different synths?
  • Can the difference be heard?
  • I would have though sine to be the most common as the others are functions of a sine wave using Fourier... en.wikipedia.org/wiki/Square_wave – Dave Engineer Nov 20 '14 at 16:45
  • I am intrigued by the question and the accepted answer. But I want to know from you what you meant by "Are all saw tooths the same"? That is, what in your mind constitutes a saw tooth? – ggcg Dec 30 '20 at 23:39
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They are not identical. The differences are suble, but often audible. Different implementations of both oscillators and specific waveforms will yield slightly different timbres. The rest of the signal path also plays a role, like amps overdriving, and filters adding character themselves (some filters can't be completely bypassed, even when the knob is turned all the way open!).

Here are some examples of sawtooths from different software synths with the filters completely open or bypassed when possible, and with the signal path as clean as the synth allowed.

Arturia Minimoog:

Arturia Minimoog Sawtooth

NI Absynth:

Absynth Sawtooth

GForce Minimonsta:

Minimonsta Sawtooth

Waves Element:

Element Sawtooth

LennarDigital Sylenth1:

Sylenth Sawtooth

They are all different. Arturia Minimoog and Minimonsta label themselves as "virual analog", and seems that they are using sawtooths similar to what we find in analog synths. According to this article the Minimonsta's sawtooth is almost identical to the Minimoog Voyager's. Waves Element is another virtual analog synth, but it has a different and weird sawtooth, probably modeled around another analog synth.

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    Very nice! Just to be persnickety, "In the digital realm "perfect" waveforms are more common " -- as a pal of mine says, 'the world is analog' . You can create any digital sequence, but that's sampled both in time domain and amplitude, and at some point you have to convert it to analog before hitting the loudspeakers. :-) – Carl Witthoft Nov 18 '14 at 13:35
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    You are going to have to get into the realm of slew rates etc to describe "why" - but that would belong in electronics rather than 'sound'. In sound we're allowed to like it cos it sounds nice, not cos the wave is mathematically perfect.... & mathematically perfect waves sound uninteresting. [+1 for both Q & A, btw] – Tetsujin Nov 18 '14 at 20:16
  • This is interesting but after looking at the pics I would think that only one product produced a saw tooth wave correctly. Is it the case that all are called saw tooth by the vendor or have I misunderstood something? – ggcg Dec 30 '20 at 19:45
  • @ggcg All the samples are from the oscillator or waveform labeled as sawtooth for each synth (or at least the ones used at the date of the post), with the signal path as clean as the synth allowed. 100% clean signal path is not always possible, so we might be seeing some shaping by other processes, but in the end that's how they are presenting their "cleanest" sawtooth. That said, I'm not proficient with all these synths, i tried my best, but I could've messed up. Shouldn't be too complicated to corroborate though, all these have free demos i believe. – Von Huffman Dec 30 '20 at 19:52
  • That is interesting. The way I interpreted the question was if identical waves are emitted by different synths will they sound different. The answer to that, in theory, must be no, or only miniscule diffs. But then again, I didn't really understand – ggcg Dec 30 '20 at 20:43
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Sawtooth waves, triangle waves, sine waves, and square waves, and pulse waves of any particular duty cycle, all have precise mathematical definitions, so a "perfect" generator for any of them should yield equivalent results. In practice, sawtooth waves, pulse waves, and square waves cannot be reproduced quite perfectly because they involve an instantaneous "jump"; for that reason, many generators may replace the "vertical" edges with a ramp whose duration is a fraction of the wavelength. It would be possible to define mathematically a dual-ramp wave or trapezoidal wave (sawtooth or square/pulse wave whose vertical edges are sloped) with a particular rise or fall time, but that kind of "sawtooth" becomes a family of waves which are distinguished by the angle of the steeper slope.

Additionally, some "sawtooth" wave generators don't use a linear slopes but instead use the "sharktooth" ramps generated by resistor-capacitor circuits; these may be characterized by the ratio of the minimum slope to the maximum slope on the shallow side of the ramp, as well as the slope on the steep side. I'm not sure what kind of circuit the minimonsta is using.

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    @JCPedroza: Any device which tries to output a "perfectly" sharp edge is going to end up introducing distortion which will likely be affected by things like operating temperature, the impedance of the load, etc. I'm not sure to what extent analog synthesizers intended for musical use endeavor to make edges have the same slope for all frequencies, or to what extent they try to make the slope be proportional to frequency, since both approaches pose design challenges. BTW, I misread the earlier post as indicating that those traces came from analog synths; they seem curious as waves... – supercat Nov 19 '14 at 16:17
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    ...from software synthesizers. In my own experience with software synthesis around 1990, I found that perfect sawtooth and square waves tend to have objectionable aliasing effects at frequencies anywhere near Nyquist, but even simple linear smoothing helps reduce that considerably. – supercat Nov 19 '14 at 16:20
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Most analog VCOs generate almost perfect mathematical waveforms (almost because of minor instabilities/noise but its usually below -60db). But you don't sample VCO, there are many elements in the signal path.. Like high pass filters used to kill DC, usually after VCO, mixer, filter. What you see is just a high-pass filtered "perfect sawtooth". You can try this in any audio editor, just get a sawtooth wave and apply e.g. 6db high-pass filter at 3-30 Hz.

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For most analog synth, and virtual analog synth reproducing the previous, the waveshape is not perfect, sometime, the wave doesn't look like what we think about the name of the shape. Because how they form the wave is not a perfect mathematic formulas.

The firts waves showed by JCPedroza, use the replication of analog oscillator based on the discharge of a capacitor linked to an alternative signal 0 V / + X V input ( square or rectangle ). The signal can be assymetric ( PW rectangle signal ), like with this saw waves, there is only one charge or discharge phase ( like a 99% PW ) .

the signatures of this : curves of the discharge/ charge of the capacitor.

if the capacitor is not enought fast to charge/discharge, there is an offset when the signal input switch the tension. you can see the last thing with the arturia's picture at the edges.

with this system, by playing with the charge/discharge speed, and the PW, you can create a wide range of waveforms.

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