Parallel Compression on Vocals

Whether you are a recording engineer or in the process of learning to become one, chances are you have probably heard of the drum mix technique called ‘parallel compression.’ If you haven’t, let me quickly explain. This is when the recording engineer sends the drum mix out through a stereo buss to a compressor and mixes that signal back into the original stereo mix of the song. The method of ‘parallel compression’ can either be used in an extremely subtle or overt manner by modifying the extent and character of the compression and how much of that compressed signal is sent through the stereo buss. I have found that by using this technique the drive of the drum track performance really comes alive in the mix, even during quieter passages. It gives the drums that ‘in your face’ kind of sound while still retaining a smooth listenable quality.

The results vary from just compressing the tracks because at a low level you get both retained transients and an extra sense of loudness from the compression. When the song starts to get louder, the effect of the compression applied to the bussed signal will become less prominent due to the uncompressed track’s dynamic swells that can tend to dominate the mix.

However, the technique of ‘parallel compression’ doesn’t have to be used just on drums. I discovered a similar technique for myself many years ago for vocals, only to learn that other recording engineers before me used this technique too. The reason why I decided to use ‘parallel compression’ on the vocal was I wanted the lead vocal track of the song to be articulate at lower levels while still retaining a listenable quality at higher levels. In essence, what I had created was my own form of dynamic equalization.

So, I wanted my lead vocal track to be brighter at low levels to help it slice through the mix. However, I knew adding top end would only cause the vocal to be really harsh at higher levels. Adding compression to the vocal really didn’t create the sound I was looking for, it just sounded like I was sitting in the vocalist’s mouth. A little to intimate for what was needed in the mix of the song. Also, the amalgamation of compression and high frequency boost caused the vocal track to become really sibilant, which is usually not a good thing when it comes to lead vocals. Moving the compressor to the front of the vocal chain helped a little bit, but it still didn’t provide that magical sound I was looking for.


I wanted my vocal to be brighter at low levels to help it cut through a mix, but just EQ’ing it caused it to be too harsh at higher levels. Adding a compressor to the vocal did not create the sound I had in my head. It was still to harsh at high levels and the EQ caused the compressor to react in ways that I felt were inappropriate. The combination of high frequency EQ boost and compression often causes a well recorded voice track to become sibilant. Not a good thing. Placing the compressor in front of the vocal signal chain helped, but still did not deliver the “magic” I was looking for.

The solution to my problem presented itself after a few hours of mad science and experimentation. Since I work primarily on a DAW, I decided to duplicate the lead vocal track to a second track, so in essence, there were now two lead vocal tracks. On the duplicate lead vocal track, I first Eq’d all the bottom end out by running it through a high pass filter. I then boosted the top end of the duplicate lead vocal by about 5 or 6 dbs’s. My goal was to create a vocal track that didn’t have a lot of tone to it or vowel sound, just consonants. I then heavily compressed the duplicate lead vocal track to control and push back any loud passages, allowing for the softer passages to come through. Once this was done, I mixed the duplicate lead vocal track back in with the original lead vocal track. The end result was a lead vocal track that was now easy to understand at low levels because of the extra boost in the highs, while also be pleasant to hear at louder levels because of the reduction of the highs due to the heavy compression.

Now one thing you must pay attention to when using this technique on a DAW is processing delay. It can vary a lot from plug in to plug in. An easy way to correct this problem is by inserting the same plug ins on both the original and duplicate track. You would then set the plug ins on the original track to bypass so they don’t effect the sound of the original track. If your DAW already has delay compensation built into its software, then make sure this feature is engaged.

This technique can also be done using your analog console. Buss your lead vocal to two channels on your console and then assign both of those channels to the stereo buss. Insert a compressor that has both a quick attack and release onto the duplicate or ‘articulation’ vocal track. Insert an EQ or filter on the articulation track that can high pass everything below 3khz. Set your compressor on the articulation channel to an extreme compression setting with the fastest attack and release possible. Listen to how the consonants sound coming from the articulation channel and make sure they are clean and without and tone or vowel sounds. Mix the articulation channel back into the stereo buss mix until you can noticeably hear the articulation come up at lower levels while hearing the tone change to a warmer sound during elevated levels. Mix the articulation signal in to taste.

Equalizing With Your Eyes Instead of Your Ears

So, we’ve all done it at some point or another. Whether it be looking at the transients on waveforms to match tempos, watching the meters too much, or the biggest culprit – watching the graphic display on an EQ, we have all used our eyes way too much when mixing at some point or another…. How can one not with all those pretty graphics and curves.

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Waves Renaissance EQ 6 Parametric EQ

This little black EQ has been a big “go to” of mine for over 10 years now. I would have to say that close to 98% of the time I use this EQ during my mixes.

I’m not going to use this time to diss the Renaissance EQ, it just happens to be one of my main DAW EQ’s of choice. Its simple to use, I’ve always liked the sound and UI on this EQ, as well as the small amount of processing power it uses up. And I’ve always liked to see the results of what turning the knobs will bring. For some reason, I have always loosely correlated that the stranger the graphic display on an EQ looks after I use it, the better job I did at equalizing the sound. This probably stems from watching engineers mix ‘ITB’ back in the early days and noticing that the EQ curves on their graphic displays were always rather strange looking. My brain almost combines the two actions together (listening and looking at the curve)…. probably to my disservice. I found it’s really hard to not look at times. Even though I started my career on analog equipment, I’ve worked the majority of that career on a DAW, Pro Tools more specifically. I’m used to that workflow and have now come to find it familiar and home.

BUT……..

Recently, I was mixing a song for one of my regular clients and the mix just wasn’t coming out the way I hoped it would. The REQ6 has always helped me get that modern vocal sound for hip hop, rap, and trap music, but this project that I’ve been working on isn’t quite that. The approach needed was a more old school approach. The mix needed a warm, personal, underground kind of sound. That’s probably not the best way to describe it, but you get the idea.

To keep the story to the point, my traditional approach wasn’t working. So, I decided to go back to the drawing board. And what does that exactly mean in the world of digital audio engineering??

ZERO OUT THE FADERS AND REMOVE ALL PLUG INS!

So I decided to start the mix over completely from scratch. Over the last 16 years of engineering, I’ve learned that it’s ok to start over sometimes. Starting over allows you to put your head into a different space, try new things, not be so restricted, which is important when mixing a song. Usually when I make this decision, it is the right thing that is needed for the mix. So what was to be my new approach?

Since I decided I wanted to try and go for more of an old school approach to this mix, I needed to try and emulate the same workflow from that time period. So, just like a real analog console, I decided to use the SAME signal chain on every channel, since a real console has the same equalization and dynamics on every channel. My trusty old Waves SSL 4000 Channel Strip seemed like a good fit for this eclectic approach.

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I started the mix over, and after a few hours, it started to sound the way I was hearing it in my head, smooth, fat, and personal. The mix was much warmer and less digital sounding than my first approach. Overall, it was more balanced and sounded pretty analog for a 100% digital ‘ITB’ mix. Because of this approach, I forced myself to really LISTEN, not listen through visual ques and folley. Now just because this approach worked this time around, doesn’t mean it will always work. Each song and genre is different, as well as their requirements for what makes a good mix. What I did learn from this though is that I had become lazy when using equalizers with graphic displays. At times, I found I was using my eyes to eq sounds, and since we can’t listen with our eyes, this was having the occasional adverse effect on my mixes.

So, if you are just starting out your career as a mix engineer, may I highly recommend not getting yourself stuck into the visual part of mixing if you are mixing ‘ITB’. There are times when it is important to see what you are doing, but it is what we hear that makes the overall sound of the mix.

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