Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.
The red & green graph show multiple options overlaid, with combinations of bass and treble each at minimum and maximum.
For any one set of values, there will only be one amplitude at any one frequency - a single-line plot.
Your test circuit appears to have bass at minimum and treble at maximum, so you get the lower left segment and upper right segment.
Set bass to max & treble to min, then you should get the upper left to lower right sections.
Overlay the two plots and it should like something like the double line one.
Below is the simulation for the example circuit values (in png picture) with the pots set to the 0%, 25%, 50%(flat response), 75%, and 100%.
The plot values at 0% and 100% is essentially the same as the example.
I had to increase the value of C1 since it was rolling off the bass frequencies.
(Why did you pick such a small value of 0.047uF for that?)
Suraj143, if you don't have the pot model, I can post the files for you.