Now, the Waldorf Pulse: attack 0 means 1.9ms. 1.9ms is equal to around 523 Hz with this simple calculation: 1 divided by seconds = Hz So: 1 / 0.0019 is around 523 Hz. This in turn means: you can hear a click in the attack phase that has a maximum frequency of 523Hz which is already easily noticable. When you now turn the amp attack rate to 1, you have 2 x 1.9ms = 3.8ms = 261Hz. Ah, that’s hollower. But still too bright when you play a low and hollow bass sound. When you e.g. play a hollow bass sound with around 80Hz base frequency, you have to make sure that the attack envelope is no shorter than 12.5ms to prevent *any* click. And this is an amp attack value of around 6 on the Pulse!!

Waldorf Tricks – Synthesizer Wiki.