Cool site and help requested

Found a discussion about this site at DIY audio. Very cool I never used any kind of circuit simulation software and I was up and running in 10 minutes. The link below is to a hp filter as used in Altec circuits. I?m sure it could be done better with a more precise electrical approximation of the driver but I was still able to play around with values to see what the various parts did. You should be able to play with it without signing up. Open it in the editor and select simulate and then frequency domain and then run frequency domain simulation. Now for the help part?. Does anyone know how to make the shelf in the transfer function wider?

https://www.circuitlab.com/circuit/3...m19-hp-filter/