I've modulated the threshold in this example to better illustrate the use of "hold", which sets the minimum amount of time the gate must remain open. the timer starts as soon as the signal leaves the lotr™. see how in the first peak the amplitude follows it's unprocessed path even as it crosses into the threshold? that's because the gate needs to wait 40 (that's 4 ticks in our scale) before it's allowed to act. in contrast, the second peak enters the lotr™ after this appointed time and hence is acted upon immediately.

hold is really useful if you have really sporadic audio. imagine this scenario - you've recorded an interview and the mic was really noisy. so you have white noise throughout the tape that you want removed and you're going with the gate instead of taking it out by hand - good choice. but human speech naturally fluctuates in amplitude and you don't want the gate closing rapidly in between words - it will sound like your audio is glitching. raising hold to an appropriate time will keep the amplitude consistent between words but still allow for the gate to close during longer passages between sentences.