coef_hlshelf2~ double shelving boost /cut filter This abstraction is designed to calculate coefficients for biquad~ which create a double shelving boost /cut filter. It does not contain a biquad~ and must therefore be connected to one. Connecting it to any other object is meaningless. This filter is a combination of a high and a low shelf filter. All in all, this abstraction creates the parameters for three shelves, low mid-range and high, which can be attenuated or boosted independently. The two transitions between the three shelves can also be finetuned by defining their transition width in Hertz. The cut or boost for the three segments (low, middle, high) is defined in decibels (positive for a boost/gain, and negative for a cut/attenuation). Remember that a signal’s amplitude is doubled when it is boosted by 6dB and halved when it is attenuated by 6dB.

from the library : Jimmies Format : Abstraction Environment : max / msp commercial Max 3.x / 4.x http://forumnet.ircam.fr//rubrique.php3?id_rubrique=65