The click~ object and band limited impulses...


    Oct 10 2007 | 6:14 pm
    I'm a complete beginner when it comes to this area so please bear with me on this one.
    I understand that the click~ object is an impulse generator.
    So...
    Are impulses related to band limited impulses and how would I go about creating a band limited impulse using the click object if this were the case?
    Many thanks,
    Rhys

    • Oct 10 2007 | 9:39 pm
      ok.... what are you trying to do?. It depends what you mean by an impulse. It is a generic term that can be used to describe an extremely short burst of sound or an acoustic signature of a an architectural space (and more) which you can use to re-create its reverberant qualities.
      Historically, an Impulse generator could be seen as one of the first microsonic (Microsound by Curtis Roads) generators. The generator creates sounds of very short duration which because of their short duration generate a wide spectrum, which can then be filtered to create a variety of timbres.
      It might be worth looking at a electro-acoustic primer or something like the "Microsound" Book by Curtis Roads, which is a great read. If it is about convolution then it might be worth experimenting with some of the convolving reverbs around. I remember an msp object which did this (?).
      P
      On 10/10/2007, Rhys Perkins wrote: > > I'm a complete beginner when it comes to this area so please bear with me on this one. > > I understand that the click~ object is an impulse generator. > > So... > > Are impulses related to band limited impulses and how would I go about creating a band limited impulse using the click object if this were the case? > > Many thanks, > > Rhys >
      -- Pere Josep Villez Creative and Computational Sound Department of Creative Technologies University of Portsmouth 36-40 Middle Street Portsmouth PO5 Tel 00 44 23 9284 8484
      www.centuryofnoise.com www.perevillez.com
    • Oct 10 2007 | 10:00 pm
      If I understand your question (or, perhaps, the intent behind it) a 'perfect' impulse would theoretically contain equal energy across the frequency spectrum of human hearing. A band-limited impulse is simply an impulse which has some portion (often the high end) of its frequency spectrum attenuated or eliminated altogether. In a digital system a single-sample at full amplitude is the closest you can get to the 'perfect' impulse - this is essentially what [click~] produces by default. You can be creative about how you limit/modify the bandwidth using any of the array of available filters on the output of [click~].
      For some relevant reading, check out some of the following:
      On Oct 10, 2007, at 12:14 PM, Rhys Perkins wrote:
      > > I'm a complete beginner when it comes to this area so please bear > with me on this one. > > I understand that the click~ object is an impulse generator. > > So... > > Are impulses related to band limited impulses and how would I go > about creating a band limited impulse using the click object if > this were the case? >
      ---- Steven M. Miller Professor, Contemporary Music Program College of Santa Fe
      Home SFIFEM Atrium Sound Space OVOS CMP
    • Oct 10 2007 | 10:02 pm
      This is more correctly referred to as the 'impulse response' of the room (or algorithm, or circuit, or...), not the impulse itself.
      On Oct 10, 2007, at 3:39 PM, Pere Josep Villez wrote:
      > or an acoustic signature of a an > architectural space (and more) which you can use to re-create its > reverberant qualities.
      ---- Steven M. Miller Professor, Contemporary Music Program College of Santa Fe
      Home SFIFEM Atrium Sound Space OVOS CMP
    • Oct 11 2007 | 11:25 am
      Where did the links go?
      > For some relevant reading, check out some of the following:
      Thanks
      Rhys
    • Oct 11 2007 | 6:20 pm
      On Oct 11, 2007, at 5:25 AM, Rhys Perkins wrote:
      > > Where did the links go? > >> For some relevant reading, check out some of the following: > > Thanks > > Rhys
      ---- Steven M. Miller Professor, Contemporary Music Program College of Santa Fe
      Home SFIFEM Atrium Sound Space OVOS CMP
    • Oct 12 2007 | 1:59 pm
      ---------------------------------------------------- > You can be creative about how you limit/modify the > bandwidth using any of the array of available filters on the output > of [click~].
      how do you bandlimit a spike? that is always an interesting question.
      well, lets say someone has a wavetable synth or an impulse train he needs to bandlimit ... i am tempted to say such a wave can be bandlimited the same way than you would do it to any other wave.
      for a synthesizer oscillator you have several options of course, normally you would try to calculate harmonic waves already bandlimited, and not filter your audio when its already there.
      but the most simple way for already given waves (please correct me if thats wrong) would be a sample interpolation filter with exponential interpolation such as [slide~ 2.0001 2.0001].
      of course the slide filter would hav to be "tuned" in case we are talking about a pulse train "oscillator" ... "2.0" only works for the "base note" ...
      otoh, as son as you know how a bandlimted spike looks, you can use the [click~] object to output that directly; its perfect for such things.