Each of its four bands features switch-selectable frequencies centered on and covering musical-step intervals from 32-Hz “C” to 22.35-kHz “F.” Its four overlapping bands are labeled with note names and frequency allowing for the first time a “translation” between musician-speak and engineer-jargon. The bandwidth control has similar notation with adjustment from 0.2 octave to 4 octaves per band and a boost / cut range of 12 dB.
The low-cut filter is switch selectable from 20-Hz to 150-Hz with slopes of either 12-dB or 24-dB per octave. Like most Crane Song products, IBIS utilizes discrete class-A circuitry and features a truly unique and adjustable “color” function that can be applied to either the entire audio path or to any individual frequency band. A fully stepped mastering version is also available.
The Crane Song Ibis equalizer can do some very different things.
First, each band has 24 frequencies. 12 switch positions and a “+ one step button” this button moves the frequencies up one whole musical step. The high and low bands also can be shelving by pushing the shelving button. The frequency chart showes how each of the bands over lap and how frequencies and musical notes relate. As an example, with the +1 step button pushed in, the frequency moves up two positions on the chart. 32.7 Hz which is the lowest frequency will become 36.7 Hz.
There is a dead zone of about plus and minus .3 db on the “boost / cut” controls where the EQ is flat in response. This allows an easy way to set your bands flat. The range is plus or minus 12 db and is not stepped. The mastering version has a range of 6 db in .5 db steps with a 1 db step between 5 and 6. The Bandwidth is not stepped on the standard version and is steped on the mastering version. the range is from 0.2 Oct to 4 Oct this is at 12 db of boost The low cut is 12 db per octave, but the steep button increases the slope to 24 db per octave.
The filters are of a special type that provide a very clean and smooth sound. To add flexibility to the equalizer a color knob is inculuded. The color knob is an additive second / third harmonic distortion type of process, it can be applied to the full program or any one of the 4 bands. When doing a “cut” it will subtract the harmonic content. The Color Knob is not stepped on the standard version and is stepped on the mastering version.
The use of the color function will allow you to change the equalizer from a very transparent sound to a colored sound. Using it on the low frequencies, band 1, it will add warmth. On band 3 it will add presence and some nice upper midrange detail. On the high frequency band it will add air.