AirEQ’s Bell Filters have a particular behavior regarding the Q and Gain adjustment. The Gain and Q values are interdependent and react accordingly to our hearing sensation.
This allows for a natural equalization process, where the Gain doesn’t need to be readjusted after a change in the Q, and where the Gain adjustment gives a regular loudness sensation across the whole gain range.
While adjusting the Q factor of most equalizers, the gain remains constant.
The problem with this behaviour is that the loudness of the equalized sound varies when adjusting the Q-factor, and thus what you hear is not only the result of the Q-factor adjustment, but also the loudness variation.
With AirEQ, the gain is automatically adjusted in concert with the Q-factor.
The steeper the Q-factor, the more the gain is increased. The audible effect of this is that when you sweep the Q-factor, you hear very few variations in loudness, and thus you can truly hear the effect of the Q-factor adjustment.
Why is this important?
We feel that when you adjust a parameter, it must be coherent with what you hear, and not with "how many dBs the filter adds to the center frequency.”
When tuning the Q-factor, it is better to hear the real effect of the Q-factor, not the effect of the Q-factor plus the loudness variation it produces. You also don't have to change the gain each time you adjust the Q-factor knob.
It is more musical, natural, and intuitive.
For example, if you take a 1kHz bell boost, and set the gain to +3dB and that you sweep the Q-factor, you will hear that for narrow values, the boost can not be easily heard. In many cases, you have to raise the gain for a narrow Q (to add impact to a kick drum, remove voice strong resonances or extra sibilance, add pitch to toms or snare, etc..), and to lower the gain for wide a Q (to gently change the character of an instrument or a song, for many mastering purposes, etc.).
There a dilemma here: generally speaking, you need more (real absolute gain) precision and lower gains for wide Q-factors; less (real absolute) gain precision and higher gains for narrow Q-factors.
You have to familiarize yourself with this kind of behaviour before taking all the advantages from it.
We can consider that the gain display in AirEQ shows the musical units of the gain, i.e. the perceived loudness that you add to the sound, rather than mathematical units.