Old Production Takes From an Old Guy

Parallel Compression Pt. 1

I’ve been posting on Twitter the last few weekends about my use of parallel compression and that’s generated quite a few inquiries asking to explain it. Having messed around with the process for the last 6-8 months, and really getting into it since we got the SD8, I’m seeing some real advantages to it. This turned out to be a really long post so I’m breaking it up into two parts. First, let me give you a little history and explain some terms. Later this week, I’ll show you what I’m doing. I’ll be the first to say I’m not yet an expert on this subject, but it’s been a lot of fun learning the technique and playing with variations of it.

A Brief History of Comps

There is some debate over where this technique originated. It’s often known as “New York Compression” as it was used heavily in the NY mixing scene during the ’70s and ’80s. Others say the ttechnique is over 40 years old, having been employed in Motown to help vocals stand out over the much more complex musical background of that style of music. If you listen to earlier samples of music (think Frank Sinatra), you’ll hear the vocals way out in front and a sparse musical landscape way in the back. When the much busier style of Motown music came along, it was hard to get the vocals to sit out front; they were getting lost in the mix. Parallel compression was employed to fix that. That’s basically how I use it today. You can read more about the Motown history of parallel compression in this great article (props to Jeremy Carter for digging this article up). Either way, it’s a greatly useful technique for enhancing your mix.

Defining Terms

We throw around a bunch of terms when we’re talking about parallel compression—double patching, double bussing, smashing, spanking, bus with a comp—so let me see if I can clear some of those up.

This is a greatly simplified version of double patching.Double Patching is how we achieve parallel compression. Basically, we patch the same mic into two channels and process them differently. On an analog board, this can be done with a simple Y-cable. On a digital board, you just patch the same input into two channels. In either case, one channel gets a heavier comp, the other is processed normally.

Again, a greatly simplified version of double bussing.Double Bussing is used if you’re working with multiple inputs that you want to parallel compress, you bus them the two separate groups; again, one is normal, one gets the comp treatment. I’ll talk about why you might want to do either method in a moment.

Smashing is a colloquial term for parallel compression. When someone has a vocal smash channel, it’s typically created with parallel compression. Because we typically employ pretty significant amounts of gain reduction to the channel (10-15 dB of gain reduction), it is said to be “smashed.”

Spanking I consider spanked a milder form of smashing. On some level, I’m making up definitions of terms here, and others may define them differently. But for our purposes, spanking is like a smash, only with less gain reduction, perhaps 6-9 dB.

Bus with a Comp I learned of this variation from my friend Dave Stagl. In this variant, a group of channels is sent to one bus with little or no processing, and another one with a comp inserted. This is perhaps the most mild form of parallel compression, as when Dave says “a bus with a comp” he’s only doing 4-6 dB of gain reduction (maybe less). It’s a pretty subtle effect at that point. Thus, it’s not really a smash, it’s a bus with a comp.

All clear now? OK, let’s move on to one variation of the technique.

Input Parallel Compression

If you only have one channel that you want to enhance with this technique, and you have an extra channel to use, this is a great way to get it done. As mentioned earlier, you simply double patch your mic (let’s say the worship leader’s vocal) into two channels, say 25 & 26. Channel 25 is your “normal” channel. You may have a comp on it, and you may be doing some mild compression there. You also probably have EQ and other stuff going on; it’s what you normally use. On Channel 26, you insert a compressor and dial it down so you’re achieving a pretty significant level of gain reduction. How much will depend on the effect you are going for. I’ve played with settings ranging from 4-6 dB of reduction to 12-15 dB. I’ve been using less lately, and been happier with the results.

Next time, I’ll talk about Output Parallel Compression and show you some examples of how I’m using it in our setting.

9 Comments

  1. craig.coia@yahoo.com

    I recently got this working with an analog board, a spare effect/aux bus output, and a stash of TS-TS cables (and a compressor).

    Instead of using an insert and two precious channels on a 16ch board, the [whatever] gets sent thru the Efx1 output, post-fader, into the comp and returns to a ‘Efx Rtn’ intended for patching in reverbs etc.
    Now I get the added benefit of having the vocal level still controlled by one fader; and the ability to switch the mix going to the comp with one row of dials. Nowhere like an SD8 but in smalltime analog world, it’s cool.

    Also, I’ve heard this called “upward compression” because… (and this is how I think of it)
    Adding your smash channel in gives you a +3dB boost to that voice (assuming the faders are the same) plus any makeup gain. If we call it +8dB including makeup gain, just by having the smash by default the whole voice is louder. As the comp kicks in, the smash channel is gain reduced and +8 becomes +4 or -2dB depending on the degree of ‘smashuration’, meaning that the loudest parts of the track become closer to ‘regular’ level, while the quiet phrases are pushed up.

    Also I think a lot of the effect (and difference from regular compression) comes as the smash is reduced, so the relative level of smash to original changes. The original comes through stronger, still with feeling as it’s not being squashed; then as the track gets quieter, the ‘smash’ simply adds more of the same.

    Not that I want to take away from your explanation, Mike; but I realised more about the goal of parallel compression after thinking about it this way.

  2. craig.coia@yahoo.com

    I recently got this working with an analog board, a spare effect/aux bus output, and a stash of TS-TS cables (and a compressor).

    Instead of using an insert and two precious channels on a 16ch board, the [whatever] gets sent thru the Efx1 output, post-fader, into the comp and returns to a ‘Efx Rtn’ intended for patching in reverbs etc.
    Now I get the added benefit of having the vocal level still controlled by one fader; and the ability to switch the mix going to the comp with one row of dials. Nowhere like an SD8 but in smalltime analog world, it’s cool.

    Also, I’ve heard this called “upward compression” because… (and this is how I think of it)
    Adding your smash channel in gives you a +3dB boost to that voice (assuming the faders are the same) plus any makeup gain. If we call it +8dB including makeup gain, just by having the smash by default the whole voice is louder. As the comp kicks in, the smash channel is gain reduced and +8 becomes +4 or -2dB depending on the degree of ‘smashuration’, meaning that the loudest parts of the track become closer to ‘regular’ level, while the quiet phrases are pushed up.

    Also I think a lot of the effect (and difference from regular compression) comes as the smash is reduced, so the relative level of smash to original changes. The original comes through stronger, still with feeling as it’s not being squashed; then as the track gets quieter, the ‘smash’ simply adds more of the same.

    Not that I want to take away from your explanation, Mike; but I realised more about the goal of parallel compression after thinking about it this way.

  3. mike@churchtecharts.org

    Craig,
    You are right to mention upward compression. I meant to and forgot. It’s a different way of explaining it that can clarify what we’re doing.

    And I like your idea of using an insert; that’s clever!
    mike

  4. mike@churchtecharts.org

    Craig,
    You are right to mention upward compression. I meant to and forgot. It’s a different way of explaining it that can clarify what we’re doing.

    And I like your idea of using an insert; that’s clever!
    mike

  5. fohdave@goingto11.com

    I want to throw in a couple of quick notes on this:

    1.) Digital console users need to use caution when trying to implement this because depending on how you go about doing it, whenever you start bussing things around and processing them you will induce latency.

    If the combined latency on each of your busses is not equal, you can end up with some really squirelly sounding stuff when you try and combine two busses in your L/R that aren’t in time with each other. It might only be a couple samples, but that’s all it takes for some really nasty phase stuff to happen.

    One of the reasons I like using the VENUE for this is because you can get the console to automatically delay compensate for processing on your output busses ensuring that everything is in phase when it arrives at the L/R no matter if you process each bus differently. You can still do this with other digital desks, though, you just have to be aware and figure out what kind of timing issues you’ll have to deal with and then compensate.

    2.) I try and avoid a post-fade send to a compressor ala an Aux or FX send on a console whenever I can. The issue here is as you adjust your input fader, you are essentially adjusting the threshold on your compressor with it (ex. when you lower your input fader, you lower the signal level into the compressor which in essence raises the compressor’s threshold and changes the compression that’s happening with it).

    Something to bear in mind, too, is that part of the perceived effect of parallel compression is a “sound”. Remember, compressors change tone as well as dynamics. For example, drums can get fatter and punchier when you start compressing them.

    If your compressor starts compressing more or less than where you initially set it, you can end up with a different sound than when you first dialed it in. In practice, this reality doesn’t seem to bother me much with vocals, but it has destroyed my drum sound in the past. Again, this is just another thing to bear in mind when setting this up.

  6. fohdave@goingto11.com

    I want to throw in a couple of quick notes on this:

    1.) Digital console users need to use caution when trying to implement this because depending on how you go about doing it, whenever you start bussing things around and processing them you will induce latency.

    If the combined latency on each of your busses is not equal, you can end up with some really squirelly sounding stuff when you try and combine two busses in your L/R that aren’t in time with each other. It might only be a couple samples, but that’s all it takes for some really nasty phase stuff to happen.

    One of the reasons I like using the VENUE for this is because you can get the console to automatically delay compensate for processing on your output busses ensuring that everything is in phase when it arrives at the L/R no matter if you process each bus differently. You can still do this with other digital desks, though, you just have to be aware and figure out what kind of timing issues you’ll have to deal with and then compensate.

    2.) I try and avoid a post-fade send to a compressor ala an Aux or FX send on a console whenever I can. The issue here is as you adjust your input fader, you are essentially adjusting the threshold on your compressor with it (ex. when you lower your input fader, you lower the signal level into the compressor which in essence raises the compressor’s threshold and changes the compression that’s happening with it).

    Something to bear in mind, too, is that part of the perceived effect of parallel compression is a “sound”. Remember, compressors change tone as well as dynamics. For example, drums can get fatter and punchier when you start compressing them.

    If your compressor starts compressing more or less than where you initially set it, you can end up with a different sound than when you first dialed it in. In practice, this reality doesn’t seem to bother me much with vocals, but it has destroyed my drum sound in the past. Again, this is just another thing to bear in mind when setting this up.

  7. richemery@gmail.com

    Thanks Mike, for another great post I am going to try this out on my lead vocal tomorrow night at our midweek youth service.

    Also I can’t wait to read part 2

    Rich

  8. richemery@gmail.com

    Thanks Mike, for another great post I am going to try this out on my lead vocal tomorrow night at our midweek youth service.

    Also I can’t wait to read part 2

    Rich

  9. ChurchTechArts

    […] ← Parallel Compression Pt. 1 […]

© 2021 ChurchTechArts

Theme by Anders NorenUp ↑