Hi,
I am not technical enough to explain the function of a Parametric EQ but just share with you what I use.
I have been using the Yamaha NE-1 Parametric EQ for many years and I must say that it is a helpful tool to get a good tone on my bass. Once you use it, you will not want to do without it.
Usually a Parametric EQ device consists of 3 main elements: frequency, level and bandwidth.
The above NE-1 is easy to use because I just need to select either Deep or Shallow and adjust the frequency to my liking.
For those who are more technical, you can try out some units with two bands of Parametric EQ which is more precise. Some bass amps and mixing boards have build-in Parametric EQ as well.
You can research further if you are keen to understand the technology.
