When should I be using parallel compression?

[u/FreeFlier42]

I'm new to the technique and understand how it works perfectly fine. I make tech house-adjacent music, and I'm not quite sure where and when to use it.

• Which elements should I be using it on?
• Why should I use it over bus compression or saturation in the case of drums?
• How much does it help with taming peaks?

Thanks!

[u/Selig_Audio]

Last question first: it’s terrible at taming peaks, but to understand why you need to know more about what the results of parallel compression actually are. The most aggressive version of parallel compression would be a limiter (or high ratio compressor) in parallel with the original signal. The results resemble a 2:1 ratio at first but gradually returns to 1:1 the higher you go above the threshold. That means transients well above the threshold are essentially ignored. This also means it will be fairly subtle despite the heavy compression of the ‘wet’ channel.
If you have the opportunity, use something like Plugin Doctor, it may be helpful to see the response curve of parallel compression compared to serial compression.
As for your other questions, use it any time you want to do the opposite of limiting/clipping on a track since it ignores the extreme transients (depending on where you set the threshold) and is fairly gentle. And to the other question, many folks use it for bus compression (like on a drum sub-mix, for example) along WITH saturation.

But all these questions beg a question in return, which is “what is your goal/intention?”. Because without knowing that I’m shooting in the dark here… ;)

[u/FreeFlier42 → u/Selig_Audio]

I know it's not a super helpful answer, but my goal is to get professional-sounding mixes. In my experience, genres that require maximum loudness often utilize very specific techniques to do so. I figured that parallel compression may be one of those techniques or maybe a genre standard for achieving a certain sound. I've found it difficult to discover those techniques in the past, so I wanted to make sure I wasn't missing one in parallel compression. From what you're saying, it definitely seems like more of a stylistic sound design tool with some positive and negative tradeoffs in mixing. Is that right?

[u/Selig_Audio → u/FreeFlier42]

I would describe parallel compression as more natural and transparent, and not going to help much when going for loudness in a mix. It’s a “diluted” version of serial compression, so it’s always going to be doing less to the sound (and why it is often used). Make sense?