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.

20 Valuable Game Changing Studio Lessons

The understanding of recording, mixing, and mastering hip hop, rap, and other kinds of music is no doubt a talent and an art form. Development of this skill takes time, and requires many mistakes, experiments and life lessons. To truly benefit and prosper in audio engineering, one has to have a hunger to go through and take in the vast amount knowledge out there on recording, mixing, and mastering.

Once you begin sifting through the knowledge and applying it in a real world setting, you will come to find there is a big difference between knowing something and actually getting it. The beautiful thing is, once you finally get something, the ability to master those techniques and others becomes exponentially easier. You will find that recording, mixing, and mastering isn’t really a job anymore, it is just a part of life.

Over the last 16 years, I have had to learn many hard lessons in the world of audio engineering. A lot of times I thought I understood what certain techniques were and how to apply them, but I often was wrong or just partially correct on those techniques. Some of my most memorable times in the studio were when I finally ‘got’ a certain recording or mixing technique. You can say these were my ‘a-ha’ moments.

1. Learning everything there is to possibly know about the hardware and tools I have at my convenience.

2. Compression: Much can be discussed about this subject, but one thing that is so crucially important is getting the attack and release times correct. Compression can really lift up a performance or it can shamefully destroy it.

3. The day I realized that pretty much anything in the studio could be automated in some form or another.

4. Low and High Pass filtering is truly my friend.

5. The first time I turned off my computer screen to listen back to a mix. Blew me away how much easier it was to listen, identify, and make changes to the mix.

6. The first time I recorded and mixed in a professional acoustically treated studio. The amount of detail and separation I could hear in the frequency spectrum almost startled me.

7. How simply cutting out a little 275-375 Hz on most close mic’d tracks can remove boxiness and really bring out detail to things.

8. Getting rid of frequencies, or subtractive equalization, is so much better than additive equalization. Its just easier and more natural to take out what isn’t needed than to artificially add it in.

9. Hearing live drums mic’d through a stereo pair of C12’s and PZM’s. I finally understood where the life and dimension of a recorded drum performance came from.

10. Discovering that the more plugins I use in a mix, the more digital and artificial sounding the mix will become.

11. Distortion is a form of compression and a good way to add harmonics.

12. The first time I threw up a quick mix of raw audio tracks instead of attempting to dial in the perfect sound on every track. It increased the overall quality of the mix while cutting down average mix time.

13. It’s always good to get feedback, even if its from somebody without any musical or audio engineering experience.

14. Getting stuck in a mix, zeroing the faders, trashing all inserts and sends and then pushing the faders back up again. Valuable learning experience and test to the ego.

15. Dynamic Equalization via side chain compression. The bees knees!

16. Realizing that knowing how you want things to sound in your mix is so much more important than just knowing cool mix techniques and tricks. The tricks can sometimes help you get there a little faster though.

17. Musical arrangement is vitally important to the outcome of a mix on a song. It’s where the song can really be made or destroyed.

18. “Fix it in the mix” is a term that doesn’t always apply to every situation. Sometimes it is faster and easier to just re-record something if it is not right.

19. Parallel compression allows for smoother, natural dynamics overall and less aggressive compression individually.

20. When, after what seemed like centuries of recording amateur artists and bands, somebody of superstar status steps up in front of the microphone and shows how it’s really done. Wow!

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