Does this filter exist?

Discussion in 'Effects [BG]' started by superbassman2000, Feb 5, 2006.

  1. maybe this can't even be done, but i was wondering if there was a filter out there (made for musical instruments or not) that could take a signal (aka bass) and filter out all the harmonic content of a note, leaving just the pure tone, aka the fundamental.
    so for example, I play an open A, which should (if i tune it correctly) generate a tone composed of several sinusoidal waves with harmonic frequencies, the strongest wave being 440 Hz, which is the fundamental ...what i want is a filter that will filter out all those extra harmonics, but still leave that 440 Hz fundamental sine wave.

    does anything like that exist?
  2. Perhaps the first step is to clearly define your cutoff point. You could hook your rig up with a 31 band graphic EQ, and start taking away treble until you have the sound you want.

    Then, you could make a 3rd order low pass filter to give you a sharp rolloff without lugging around a rack mounted EQ.

    Or, just get a synth!:bassist:
  3. WalterBush


    Feb 27, 2005
    Yuma, Az
    There are lots of keyboards that will happily give you a pure sine wave, and if you slap a MIDI pickup on your bass, you could probably use the bass to control said keyboard.

    I'm not sure that filtering your bass tone will give you a simple sine wave, though. I think it would take a small music store's worth of electronics controlled by a computer to remove all but the fundamental of a note from your bass's tone.
  4. Toasted


    May 26, 2003
    Leeds, UK
    I suspect, but do not know for sure, that you could do this with a v-bass.
  5. Samurai


    Sep 13, 2003
    I agree that a keyboard can do it no problem, and that's probably all that you get to get.
  6. i was suspecting both of those points...
  7. Seems to me like if you take only one frequency, the fundamental, of you bass signal you get a pure sine wave...
    A SB1 might be able to get you there...
  8. Toasted


    May 26, 2003
    Leeds, UK
    Deep Impact doesn't do it.
  9. bassman314

    bassman314 I seem to be a verb, an evolutionary process... Gold Supporting Member

    Mar 13, 2005
    Bay Area, CA
    I don't think the way you are describing it, it is possible...

    however, the V-bass, or GK system, or something similar can do it, and you'd use a simple Sine-wave voicing in teh processor.
  10. i know that i am probably not saying it the best way, but i was just watching this video -> and that sounds as much as a sine wave as i have ever heard it...the pedal costs 250 dollars, which is much more than i can really spend, but i was wondering if anyone knew of any other pedals that could make a similar sound!

    I know that its just an octave pedal, but that is not how any of the octave dividers i've ever owned/played sounded!
  11. mactac

    mactac Supporting Member

    Nov 28, 2005
    Victoria, BC, Canada
    this is totally my domain - i'm really into this stuff...

    yes, it's easy. there are many ways to do it one way is to do it with modular stuff.

    take the signal out of your bass into a pitch->CV converter. plug the output of this into the CV input on a lowpass filter.

    from here, there are 2 ways to do it:

    1. set the filter cv so it tracks the fundamental of your bass. set the lowpass filter to have a resonance of zero, and adjust the fil;ter so it filters out everything above the fundamental. you'll need a lowpass filter with a really steep rolloff to do this.


    2. (better). set the filter cv so it tracks your bass properly. turn the resonance all the way up into self-oscillation, turn off the sound of the bass itself. what you'll have here is a pure sine wave (provided by the self-oscillation of the filter) that tracks the pitch of your bass

    i've used both of thesemethods quite a few times for various applications... it's works very well
  12. Mr_Dave


    Mar 11, 2005
    Melbourne, Australia
    Employee - Basscentre Melbourne

    this is not what you want but might sound close to the effect you trying to create. boss oc2 octave pedal, just octave 1 on, not clean signal... just a thought you might be able to try
  13. zombywoof5050


    Dec 20, 2001
    440hz is not the fundamental frequency of an A on a bass, it's like 3 octaves higher.