Square/sine/sawtooth waves?

Discussion in 'Effects [BG]' started by Gyoon, Sep 13, 2006.


  1. Gyoon

    Gyoon

    Joined:
    Nov 12, 2004
    Location:
    Toronto, Ontario
    Is there an ANALOG pedal that can convert a passive bass signal into all of these shapes? I'm getting more and more into synth sounds these days, it seems, but am not quite interested in going digital yet. I'm too brainwashed or something . . .

    Glenn
  2. EricF

    EricF Habitual User

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    Sep 26, 2005
    Location:
    Pasadena, CA
    EHX Bass Micro Synth.

    Digital is not necessarily a bad thing - don't be afraid. As long as the quality of the tone is what you're looking for, why does it matter how you got there?
  3. Gyoon

    Gyoon

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    Nov 12, 2004
    Location:
    Toronto, Ontario
    I looked at the Microsynth . . . It does produce a square wave, but I don't think it can do the other two. The square wave is the one that I'm least interested in, actually. I figure that a Distortion pedal can give you a pretty good version of that.

    As far as Analog V. Digital, I was looking to go with analog because I have a pretty good collection of dedicated pedals. I think the combination of the moogerfooger filter, bassdrive, and EBS octabass can give me a lot of what I need. The flexibility to choose a synthetic wave shape is what I'm looking for. I haven't ruled out the Deep Impact, but am holding out until something similar enters the market/the prices drop.

    Glenn
  4. Tristan

    Tristan

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    Ottawa, Canada
    hmmmmmm... i wonder if something based on a phase locked loop would track fast enough.

    was the korg g5 analog? ive never seen or heard one
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  6. EricF

    EricF Habitual User

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    When you say not digital, are you talking about computer-based effects, or ANYTHING digital including pedals?

    The Boss SYB-5 can do square and sawtooth wave shapes. Since it's a digital pedal, I figured it was out of the picture for you.

    Please correct me if I'm wrong, but isn't a sine wave the shape of a regular (clean) sound wave?
  7. Tristan

    Tristan

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    Sine wave is a pure tone but a bass makes harmonics.
  8. EricF

    EricF Habitual User

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    Got it. Thanks :)
  9. jonly

    jonly

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    Oct 3, 2005
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    Springfield, il
    that would sound awful. Just a sine wave with no tonal characteristics would just be a hum.
  10. Tristan

    Tristan

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    Jan 28, 2001
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    Not awful... not much character though, i guess.

    I had an FM synth and I liked playing with a patch I made called "PureBass" which was just a sine wave. Also high-pitched "rap flute" type souds can be had with just a sine wave.
  11. andrewd

    andrewd

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    Boston, MA
    a sawtooth wave is made up of lots of different sine waves

    i've found that combining sine, square, and saw waves together can yield better results than just one on its own (using softsynths)
  12. MeYHymN

    MeYHymN Habitual User

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    FWIW, the dreaded 60 cycle hum is just a sine wave, it has no harmonics/overtones to give it any "sound" per se.

    What you're looking for appears to be discontinued and that's the Terratec SINE MB 33 II Info here. Manufacter's link gives "page not found" error.
    A moog voyager 2 grand for the cheap one.
    A Zeroscillator for 1400 seems all analog, doesn't specify if it's instrument friendly.
    For what you're wanting, unless money is no object, I'd try the Boss pedal mentioned above or some DSP plugin. There's the EH Bass Micro Synthesizer. Not sure if it's true analog, and it seems to do square only. Keep in mind, all digital circuits are analog at their core. Sorry for piping up here, but your post peaked my interest leading into an hour research session.
  13. lug

    lug

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    Feb 11, 2005
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    League City, Tx
    +1 Some of the big old pipe organs would produce something closer to a pure sine wave.
  14. bongomania

    bongomania Gold Supporting Member

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    ?????
    I guess the word "core" can be interpreted different ways, but I would disgree strongly with this statement. Once you get past the A/D convertor, the signal will typically stay in the digital domain until the final D/A conversion to the output. Of course some IC's can operate in A or D realms, and some such as BBDs are "both", and some circuits contain a mix of A and D elements.

    I think stripping the harmonics from a bass guitar signal would be very challenging even in the digi domain. Your best bet might be a MIDI pickup or a pitch-CV convertor, and then take those outputs to control an analog synth (keys, rack, or modular).
  15. Tristan

    Tristan

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  16. niftydog

    niftydog

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    This is quite difficult to do in analogue. The problem is that a bass' output is unpredictable. It's not sine, square or triangle, it's probably all of the above and some. To identify and strip out what you don't want whilst leaving the fundamental intact is a difficult assignment. Even then, to get a pure sine wave would basically require you to generate it using the bass signal as a reference oscillator. Then, you've gotta adjust and gate the oscillator to represent the note attack, and control the amplitude to represent the decay. etc etc etc. Lots of engineering mountains to climb with a project like that. Analogue? I highly doubt it.

    Digital, yes, but it's all gotta be done in the 10ms or so between when you pluck and when the processing delay is noticeable. The only thing that probably comes close is MIDI equipped.

    The EH BMS does square wave, but it ain't a square wave really. A true square wave sounds hollow and lifeless. There is a DIY circuit called the PWM that gives a true-ish square wave. Take the LFO out of circuit and it makes you sound like a NES game sound track!
  17. niftydog

    niftydog

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    Everything is made of lots of different sine waves. A pure sine wave in the absolute sence is virtually unheard of. There's always some distortion.

    Square waves are ridiculous numbers of sine waves all added together. More harmonics than a harpists convention in heaven.
  18. 8guy

    8guy

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    Jun 19, 2005
    Location:
    Madison WI
    If I remeber right FM synths like the original Yamaha DX 7 Only used sine waves in combinations To mass up to produce the sounds, I tried to program them years ago but it was tricky.
  19. xan

    xan

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    Sep 10, 2004
    Location:
    Perth, Australia
    Dont hold your breath for anything cheap and equivalent to the deep impact any time soon. There are alternatives but I am yet to come across anything that tracks as well as the DI other than the Korg G5.
  20. elros

    elros

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    The EHX bass µ-synth does square, as has been mentioned. But there is no stomp-box (that I'm aware of) that does square, saw and triangle. Saw and tri are quite difficult to produce from a square.
    Some years ago I was working on a circuit that I figured should be able to produce these waveforms. It would work like this. The bass signal goes into a compander circuit. The signal is there divided into harmonics and dynamics. The harmonics goes into a square wave shaper (modified schmitt trigger). From there, it'd go into the mystery circuit that someone else have designed (I forgot who) which will make a saw wave out of a square. This mystery circuit works on the PLL principle, but there is a bit of tracking lag - but this lag only affects the amplitude of the resulting saw (it would be softer or stronger for a while after you change notes) which I figured I'd fix with a heavy compressor. And since the resulting harmonics signal could / would be treated with the expander part of the compander circuit, it'd get back its dynamics.
    I never finished the circuit. The compander section is done, the filter (2-pole state-variable type) is breadboarded and works well, but the other bits are still only on paper.

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