Pre-filter in Tool Interface Panel

[Gritgy]

I have a question about Pre-filter in Tool Interface Panel. There is the option to choose pre-filter setting from 0-8. I'd like to know a bit more detail about this pre-filter.
What is the different between each steps of prefilter starting from 0-8?
What should we select?
What factors need to be concerned to select the correct pre-filter setting? Cable lenght?

[Jerry]

It is NOT from 0 to 8. It is only 0 and 8. Any other number will open the circuit so that you will not receive any sonic signal. The purpose of is to insert a capacitor into a filer to bring the sonic baseline back to 0.0 volts before the first arrival. In doing so it also attenuates and phase shifts the signal a bit. It is recommended that this setting be left at 0 unless you need it when the first arrival is coming in before the signal gets back to 0 volts, then set it to 8.

[Gritgy]

Thanks a lot Jerry. It is clear now.