- Discover what a “glue” compressor is and why it’s helpful in mixing
- Learn the applications for different types of compressors
- Find out how to dial in a compressor to glue tracks together
If you’ve been around the music production sphere for a while, then you’ll have likely come across the term “glue” being used in conjunction with mixing.
But what does this exactly mean?
From the context, you can infer they mean that they use these specific dynamic processors to create cohesion within the mix. This takes them from separate multitracks to sounding like a professional, finished production.
Glue Compressor vs Compressor: What’s The Difference?
Here’s a little secret…the compressors mix engineers use to “glue” tracks together…are the same ones they use in other areas of the recording process! Sure, there are a few that might be reserved for mixing. Usually, engineers go with something that adds its own flavor, but in certain genres, a transparent compressor might be the best choice.
But overall, they’re the same models used for serial compression.
The clincher? Certain models just work better on a bus or track group – whether it’s a track group or the stereo master bus. These include software or hardware versions of compressors from companies like the SSL, Fairchild, Slate, Crane Song, and Great River – to name a few.
This digital handbook takes this exact approach, breaking down compression theory into bite-sized actionable chunks to help you master the tool and make intelligent mix decisions. By the end of the read, your tracks will stand louder and prouder, and be full of energy.
Bus Compressor or Compressor?
So which do you choose? You’ve certainly seen plugin and hardware compressors labeled specifically as bus compressors. What makes these different? Let’s quickly run down what a bus is.
A bus is simply a track that is receiving signal from other tracks. Think about recording drums. In a multi-mic kit scenario, you usually have (at least) microphones on the kick drum, snare, and two overheads. Each microphone is going to its own channel. But you then send all of these elements to another stereo channel to mix an overall kit balance while dialing in the close mics on their individual channels.
The easiest explanation is that some compressors are meant to work on single-channel sources, and some are designed for stereo sources. This is certainly true regarding hardware, but advancements in plugins have made it so that you can use compressor plugins on mono or stereo sources. It’s important to note this isn’t true for every plugin, so read up on whichever model you’re using before you disappoint yourself.
Don’t forget to check out Parallel Compression Explained (Best Practices & Mistakes)
Dial It In
When it comes to using compression to glue your tracks together, settings are everything. Bus compression is a totally different mindset than compressing a single track. When adding inline compression on a single track, you’ll generally be more liberal with your settings. This includes a higher ratio with more gain reduction.
But that’s not the case when you’re trying to glue elements together.
Attack and release settings are one of the most critical regarding compression. This is true whether you’re working on single tracks or groups. The time constant is one of multiple controls that determines how the compressor reacts to the signal.
For glue compression, most of the time, you’ll go for a slow attack and fast release. You don’t want to kill the transients, and you don’t want the compressor to hold on for too long.
It can seem confusing at first, but it’s pretty simple. Attack determines when the compressor starts reacting to the signal, and release determines when it lets go. That’s it! In conjunction with other controls like threshold and ratio, you form the overall compression characteristic.
You’ll dial in attack and release differently when trying to add cohesion to tracks. When you’re compressing something like a vocal or guitar, you’ll generally want a medium attack and faster release – depending on other factors. You don’t want to totally destroy the transients and kill the dynamics. But with bus compression, you want to barely move the needle.
You’ll be working with lower ratios, usually something like 1:5:1 or 2:1. You’ll also aim for lower gain reduction levels like 1dB or 2dB. Remember, bus compression isn’t necessarily about adding “excitement” to your mix. When done right, you shouldn’t really notice the compressor doing its job, but you’ll definitely miss it when you mute it.
Struggling with compression settings? Take a look at our free compression cheat sheet!
What’s Your Flavor?
When it comes to choosing a compressor for gluing your tracks together – whether you’re working with a group or on the stereo master – flavor is the name of the game. Glue compressors usually add their own sound to the tracks, and they’re often meant to be used conservatively as far as settings go.
That doesn’t mean that a totally transparent compressor isn’t called for now and then. It’s all about finding the right tool for the job.
FAQ
What is compression glue?
This is a recording term for using compression to help your tracks work better in the context of the overall mix. Often there will be multiple stages of “glue” compression, from the vocal and drum groups to something more broad covering the master stereo fader.
Using compression in this way isn’t necessarily about adding a noticeable amount of gain reduction. Many engineers dial it in so that it’s just “kissing the needle,” usually between <1dB gain reduction to a few dBs.
What’s the difference between a glue compressor and a standard compressor?
Both terms refer to a compression plugin or hardware unit. The biggest difference is that compressors used to glue tracks together often impart their own sonic qualities on the audio<span style=”font-weight: 400;”>. This is in contrast to other compressors that are designed to sound as clean as possible without coloring the audio at all.
Compressors used on groups and buses are generally designed to work with stereo audio. This is similar, but not the same, as dual mono. This is especially true for hardware, but as plugin technology has gotten better and better, a lot of software compressors can be used on mono or stereo source material.
Regardless of which you choose, you can get quality results that add unity to your tracks and give you a more professional sound overall.
Conclusion
Compression is one of the best ways to add cohesion to your tracks. Whether using it on instrument groups or the stereo master channel, it can add sonic symmetry and smooth everything out.
Some compressors are meant to add “color,” and some are meant to be as transparent as possible. Regardless of the sound you’re going for – experimentation is key. Luckily with modern digital audio, it’s never been easier.
Most compressor plugins work with all types of signals, so you’re not as boxed in as you used to be in choosing a specific bus compressor. Follow your ears, try out a new compressor, and have fun!
For more helpful guides on compression check out: