That’s the technically correct definition, at least. Setting the attack to 50-100ms shapes the envelope of the bass to give it a bit more transient edge. When you buy products through links across our site, we may earn an affiliate commission. with a hard knee, you get the activity starting right at the threshold level. With a hard knee, the compressor does not apply any compression until the audio signal crosses the threshold. They're different things. I've been having trouble finding clear answers to this: You could for example have a sound that has too little attack, and by delaying the attack. Looking for a buyer's guide? I'd be curious to hear what other uses it has. The compressor’s attack setting controls how quickly the compressor turns the signal down once it has crossed the threshold. That has nothing to do with the knee shape of the compressor, which is more about how the compressor reacts to overall signal level increases at a steady state, rather than under fast, dynamic circumstances. The softer the knee, the more gradual the effect. Thanks! You need an account to post a reply. Attack is how fast the compressor reacts to signal. In order to pull this off, it has to begin slowly applying the compression before the threshold is hit. Usually knee starts about 3dB before the threshold but that can vary from one model/design to another... Let's say you have a 4:1 compression ratio with a knee setting turned on or all the way up and your threshold is -20dBFS... the signal is at a 1:1 ratio when it is below the threshold, BUT... as it starts to approach the threshold the knee setting changes that... at -23dB (3 dB below threshold) maybe the ratio is now 1.2:1... at -22dB maybe the ratio is 2:1, at -21dB the ratio might be 3:1 and finally when you hit -20dB the ratio is at the preset 4:1 that you selected on the compressor. knee is modulating the ratio around the threshold so onset of gain reduction is less noticed. You could for example have a sound that has too little attack, and by delaying the attack of compression, or the "start" of compression, you end up changing the ratio between attack and sustain.In other words the attack of the sound passes through uncompressed and then after the compressor begins compressing the rest of the sound. It allows you to determine how curved the transition from uncompressed- to compressed sound will be. We've got those too - click here to see an ever-growing list of community-voted "top ten" lists. Makeup gain is only really necessary for upward expansion. Attack time is how quickly the compressor engages and reduces the volume of the audio.. Knee sets how the compressor reacts to signals once the threshold is passed. No... with drums for example you are commonly using compressors to make the volume spikes of the drums even more pronounced. It seems that they would be related, since they both have to do with the point at which the compression occurs. attack is NOT linear and is logarithmic in nature and there is a difference between FET / OPTO / VCA in their behavior with respect to attack & release curves. Attack time (when used in the traditional sense, ie a time constant) is the time it takes for the compressor to engage 66%. so attack is the speed of response, which can be tailored to the material to lessen or allow leading transients vs. the following sustain of the sound. We all had to start somewhere! New comments cannot be posted and votes cannot be cast, More posts from the audioengineering community. What is the knee on the Compressor. To add to this, the attack time is the time it takes for the gain reduction to conform to the graph posted above. It’s a measurement of how soon the compressor kicks in. Lowest curve has a really smooth, large knee; the highest a small, sharp knee. Since nobody mentioned it in much detail... Knee is not slower release... knee is essentially a variable ratio based on input level and threshold. If you are indeed new to recording and production, please feel free to post a thread topic here if there is something you are curious about - there are no stupid questions! We see you've found the Newbie subforum! A hard knee will clamp the signal straight away, while a soft knee smoothes out the transition from uncompressed to compressed audio. Just a friendly reminder that political discussion, (including "offhand" and 'sideways' commenting) is. thus, the attack time is dependent on the frequency you are compressing. #2 from Attack conflicts with #1 from Knee, and #2 from knee conflicts with #1 from Attack. I'm going to guess that #1 from Attack and #1 from Knee are most appropriate. You will be surprised how many people think this. I think its worthwhile taking the moment to mention that the attack time isn't a delay before the onset of compression. Think of it more like a synthesiser envelope where longer attack times produce a slower build up to maximum volume, or compression in this case, and faster times have a much quicker build up. The knee is how smoothly the compressor engages at the threshold. So would the knee be a function of the compressor ratio possibly? Once the input goes above ~ -25 dB, the output is reduced. So, the knee has to do with the level at which the compression occurs. Products, practices, and stories about the profession or hobby of recording, editing, and producing audio. Quick question: Is there any difference between the knee setting of a compressor and the attack time?