sorry if stupid question but i am a newbe. is drop D tuning (for example to play a few rage songs) simply tuning the E string to a D ? would be very grateful for reply.thanks for the website by the way!

Yes, you are correct. Tuning the low E string down to a pedal note for specific keys is fun. On the upright bass, a I use a low C extension with chromatic keys from E to C. On the electric there is something called the dropshot that does something similar that can be attached to the bass.