AF’s Weblog

June 1, 2012

How to Get the Pumping Drums Effect with Sidechain Compression

To read the full article see:  Sidechain Compression

Sidechaining has been around for years; this is the process of using one signal to control another. A couple classic examples are using a kick drum to gate a bass part, or doing de-essing – isolating the high sibilant frequencies from a vocal, and using those to trigger compression so that the sibilants come down in volume.

But in the digital age, we can do a lot more with sidechaining. One of the most popular applications is with dance music, where sidechaining can create the “heavy pumping” electronica drum sound used by artists like Eric Prydz and others.

We’ll describe how to do this with Cakewalk Sonar, although the same principle applies to other programs that allow for sidechaining. Sonar allows sidechaining for several effects, including compression, so that one instrument can control the compression characteristics of another instrument. This offers a variety of effects, including a “pumping” drum sound for multitracked drum parts; we’ll do that by setting up the snare to control compression for all drum tracks.

Fig. 1: You’ll need a drum submix bus to create an overall drum sound.

The first step is to create a drum submix bus, and send the drum tracks to it (Fig. 1). We need this submix so the entire drum track can be processed by the sidechained compressor. To create the submix bus, right-click in an empty space in the bus pane and select “Insert Stereo Bus.” To create a send in track view, right-click in a blank space in the track title bar and select “Insert Send.” From the menu that appears, select the send destination. Make sure you feed the bus pre-fader, and turn the individual drum channel faders down so that only the bus contributes the drum sound to the master.

Fig. 2: Assign the Drum Submix out to your main stereo output.

Let’s take a closer look…

….

Create a second pre-fader send in the snare track, and assign its out to the bus feeding the sidechain input.

Fig. 7: We’re almost there – it’s time to adjust the compressor.

To adjust the compressor, start with the compression attack time set to 0 ms; the drum sound will essentially disappear when the snare hits because the gain is being reduced so much. Gradually increase the attack time to let through more of the initial snare hit, and add a fair amount of release (250-500 ms) to increase the apparent amount of pumping.

And there you have it – the pumping drum sound. May it go over well on the dance floor!

To read the full article see:  Sidechain Compression

July 28, 2011

Mysteries of Dynamics Processing Revealed

Filed under: Compressors, Processors, Recording reviews — Tags: , , , , , — audiofanzine @ 7:34 pm

A dynamic processor is something that outputs a signal, where the level of the outgoing signal is based on the level of the incoming signal. In other words, a loud signal coming in will come out differently than a quiet signal coming in.

Basic types of Dynamic Processors

Compressors: The most common – the louder the signal is coming in, the less level it provides going out. In a compressor, a target level is set – called the “threshold” – and any signal coming in that exceeds that level will be reduced. The higher the level is above that threshold, the more reduction will occur. More on this later.

 

Limiters: Limiters are like super compressors. The idea is to ensure that the level does not exceed the threshold. Because this amount of compression is extreme, a limiter relies on certain functions and design that regular compressors do not have.

Expanders: The quieter the signal is coming in, the less level it provides going out. In other words – it makes quiet signals even quieter. Much like a compressor, the threshold is set at a certain level. Any signal that does NOT exceed that threshold is reduced, and the quieter the signal, the more reduction is done.

 

Gates: Gates are like super expanders. Anything that does not exceed the threshold is reduced to inaudible. Again, because gates are extreme, they often require a slightly different design than a regular expander.

 

Now – I’ll focus primarily on Compression, because that’s going to be the most commonly used dynamic processor.

Compression

Every signal you hear is compressed??? Yes, every signal you hear is compressed.

Bare with me. Imagine you have a rapper in front of a microphone. The rapper raps, you record. You play it back. You haven’t used any processing – you’re just playing back the raw vocals.  You are listening to a signal that has gone through at bare minimum 3 stages of compression – and more likely than not – closer to 6.

  • The microphone capsule gains tension as the rappers voice pushes it – in other words – it pushes back. The more the rapper’s voice pushes in – the harder the capsule diaphragm pushes back. In other words, the louder the signal is hitting the capsule, the more reduction the capsule does to the signal. That’s compression! (It’s mild compression, but it’s still compression).
  • Along the way through the microphone, you may hit a tube. Tubes have a non-linear response to voltage – the response is quite curved, and also changes the frequency balance of the signal. This is called saturation – which will tend to “round out” a signal, by reducing the loudest peaks. Compression! And before leaving the microphone, the signal may hit a transformer as well, which will saturate in a similar way… more compression.
  • The preamp is going to have multiple stages of saturation – and often times, the more gain you give something – the deeper that saturation curve goes. In other words, the more you drive the signal at the preamp, the more compression the signal experiences.
  • Then the sound has to actually come out of the speaker cones. Well, those speaker cones are going to build up tension when pushed further. See where this is going? This is called “cone compression”.

Ok – so this is a bit of a simplification – but there’s a point here. The point is that “compression” is always part of the signal. Some mics have less of it, some have more – same with speakers, tubes, transformers, etc. And they all do it in different ways. With tubes, people will talk about their saturation curves and %THD (total harmonic distortion – or frequency alterations). With mics, people will refer to how it “grabs” a sound – or more specifically – the sound’s shape.

Now let’s take a closer look…

Maximum Punch

There is a thin line between a transient sound, and a sustained sound. A sound that holds for any noticeable amount of time is sustaining. A sound that moves by too quickly to register as it’s own moment is transient. But transients can vary in length. A transient can be half a millisecond or it could also be ten milliseconds; they won’t sound the same. A big factor in punch is how long that transient exists. A quick transient sounds “spikey” – but a long transient sounds “punchy.” You want to find the point that makes the transient exist as long as possible before “flattening out” or becoming a sustained sound. Only your ear can tell you where that point is.

 

Good samples are already shaped to have that kind of impact – and any additional compression may actually soften that. Of course, punch has a lot to do with frequency as well – but that’s for another article.

 

Now what about the release? The release is super elusive. It determines how long it takes for the compressor to let go. If the release is too short for the signal you are going to get a disjointed sounding shape which usually results in distortion. If it’s too long, your signal never really returns to its natural shape, and you generally lose tone (or you just get permanent drive on the compressor’s output, giving the whole signal a new bit of tone). So the idea is to find a point that emphasizes the sustain (which is where most of the signals tone lives) properly.

 

Lastly, when the attack and release are set in a way that seem to argue – the compression can become very audible. You either hear the decent or the ascent of the signal level. This is called pumping. It’s generally annoying, but can sometimes be used an effect. If audibly desired, consider the rhythm of the release time, and ask yourself if it’s groove is complimenting the song.

———————————-

So, rather than thinking of a compressor as something that effects the “level” of a signal. Think of a compressor as something that effects shape. Why? Because level can be controlled with the volume fader more accurately and transparently. A fader doesn’t really control shape, unless you are being extremely meticulous. Conversely, compression will always effect the shape of the sound it is working on.

Once you start hearing shape, you will understand compression.

To read the full detailed article see:  Mysteries of Dynamics Processing Revealed

February 17, 2011

Extreme Drum Processing: Exploring the Art of Filthy Signal Mutation

Filed under: Drums/Percussion, Mixing reviews, Plugin, Software — Tags: , , , , , , , — audiofanzine @ 8:43 am

I like music with a distinctly electronic edge, but also want a human “feel.” Trying to resolve these seemingly contradictory ideals has led to some fun experimentation, but one of the more recent “happy accidents” was finding out what happens when you apply heavy signal processing to multitracked drums played by a human drummer. I ended up with a sound that slid into electronic tracks as easily as a debit card slides into an ATM machine, yet with a totally human feel.

This came about because Discrete Drums, who make rock-oriented sample libraries of multitracked drums (tracks are kick, snare, stereo toms, stereo room mic tracks, and stereo room ambience), received requests for a more extreme library for hip-hop/dance music. I had already started using their CDs for this purpose, and when I played some examples of loops I had done, they asked whether I’d like to do a remixed sample CD with stereo loops. Thus, the “Turbulent Filth Monsters” project was born, which eventually became a sample library (originally distributed by M-Audio, and now by Sonoma Wire Works).

Although I used the Discrete Drums sample library CDs and computer-based plug-ins, the following techniques also apply to hardware processors used in conjunction with drum machines that have individual outs, or multitracked drums recorded on a multitrack recorder (or sample CD tracks bounced over to a multitrack). Try some of these techniques, and you’ll create drum sounds that are as unique as a fingerprint – even if they came from a sample CD.

Effects Automation and Real Time Control

Editing parameters in real time lets you “play” an effect along with the beat. This is a good thing. However, it’s unlikely that you’ll be able to vary several parameters at once while mixing the track down to a loop, so you’ll want to record these changes as automation.

Hardware signal processors can often accept MIDI controllers for automation. If so, you can sync a sequencer up to whatever is playing the tracks. Then, deploy a MIDI control surface (like the Mackie Control, Novation Nocturn, etc.) to record control data into the sequencer. Once in the sequencer, edit the controller data if needed.

If the processor cannot accept control signals, then you’ll need to make these changes in real time. If you can do this as you mix, fine. Otherwise, bounce the processed signal to another track so it contains the changes you want.

Software plug-ins for DAWs are a whole other matter, as there are several possible automation scenarios:

  • Use a MIDI control surface to alter parameters, while recording the data to a MIDI track (hopefully this will drive the effect on playback)
  • Twiddle the plug-in’s virtual knobs in real time, and record those changes within the host program
  • Use non-real time automation envelopes
  • Record data that takes the form of envelopes, which you can then edit
  • Use no automation at all. In this case, you can send the output through a mixer and bounce it to another track while varying the parameter. This can require a little after-the-fact trimming to compensate for latency (i.e., delay caused by going through the mixer then returning back into the computer) issues.

For example, with VST Automation (Fig. 1), a plug-in will have Read and Write Automation buttons.

Ohm Force Predatohm & VST automation

Fig. 1: Click on the Write Automation button with a VST plug-in, and when you play or record, tweaking controls will write automation into your project.

If you click on the Write Automation button, any changes you make to automatable parameters will be written into your project. This happens regardless of whether the DAW is in record or playback mode.

Now let’s take a closer look at some other plug-ins…

So What’s the Payoff?

Drum loops played by a superb human drummer, with all those wonderful little timing nuances that are the reason drum machines have not taken over the world, will give your tracks a “feel” that you just can’t get with drum machines. But if you add on really creative processing, the sounds will be so electronified that they’ll fit in perfectly with more radical instruments synths, highly processed vocals, and technoid guitar effects.

So, get creative – you’ll have a good time doing it, and your recordings won’t sound like million others. What good are all these great new toys if you don’t exploit them?

To read the full detailed article see:  Extreme Drum Processing

February 4, 2011

Dynamics Processing Meets Rock Guitar: How to Compress a Guitar or Bass

Dynamics processing with studio-oriented processors? Been there, done that. But have you re-visited it lately in a guitar context? Dynamics control for vocals or program material is very different compared to guitar. Much of this is because there are many ways to use dynamics processing for guitar (or bass). So, let’s take a look at the different ways to apply dynamics, with examples of suggested settings.

For an introduction to compression, check out the article “Compressors Demystified.” If you’re already up to speed, let’s give a few basics on how to set up studio processors with guitar (however, note that these same basic techniques work with plug-in software compressors as well as hardware).

The Interface Space

“Stomp box” dynamics processors, while designed specifically for guitar, are more limited than rack-mount studio hardware – but the latter have issue levels with guitar. Interfacing involves one of four approaches:

Use the instrument input. If the processor has an “instrument” input, you’re golden. Plug the guitar directly into the processor, then run it into the mixer, amp modeler, guitar amp (assuming you can adjust the output level to avoid total overload), or whatever. Look for an instrument input impedance above 100kilohms, and preferably above 220kilohms, to avoid dulling high frequencies and reducing level. But too high an impedance (in the 5-10Megohm range) reaches a point of diminishing returns, because now the input may be too sensitive and prone to noise pickup. A 1Megohm impedance is a good compromise setting.

Use a preamp or suitable direct box. Adding a preamp or direct box (assuming it has an appropriately high input impedance) before the processor will preserve the guitar signal’s fidelity and allow for best level matching. If you’re driving a guitar amp, you may be able to use the dynamics processor’s output control to add some extra overdrive, but don’t go overboard (or do, if you like really nasty sounds!).

Insert into your guitar amp’s effects loop. If you want to record with your guitar amp but are using a line-level processor, patch it into the guitar amp’s effects loop. The loop should be able to provide line levels for the send (goes into the processor’s input) and return (comes from the processor’s output).

If you’re using a hardware mixer, insert the dynamics processor into your mixer’s channel inserts. This will also match levels properly, although you’ll still have to figure out how to interface the guitar with the mixer. The choices are the same as above: If the mixer has an instrument input, great. If not, use a preamp, direct box, etc. between the guitar and mixer.

Now let’s take a closer look how to really do it…

Double Your Pleasure

Patching two compressors in series, with both set for small amounts of compression, can give a significant amount of compression but sound less obvious than using a single compressor to give the same amount of compression. The first stage essentially “pre-conditions” the signal so that the second compressor doesn’t have to work so hard.

 

If you have a stereo compressor that can be set to dual mono operation, you can patch the two individual compression channels in series. With plug-ins, you can just insert two in series in a track. The drawback is that unlike standard compression, where you have to adjust only one set of controls, an ˆ la carte approach requires adjusting both sets of compressor controls. While this might seem like a disadvantage, most of the time you’ll set them to similar settings anyway.

Window Shopping

To get an idea of what’s out there in compressor-land, visit a few retailers and manufacturers and you’ll see the choices are huge, ranging from under a hundred dollars to thousands (and thousands!) of dollars. But realistically, for the type of application we’re describing here, you don’t need anything too fancy – it’s not like you’re using the compressor to re-master vintage recordings for audiophile releases. Besides, these days technology is at a level where even fairly inexpensive devices can deliver excellent results.

 

In any event, all the above tips are just guidelines. Experiment with your dynamics processor, and you may find yet another way to exploit these perhaps unglamorous, but extremely useful, devices.

To read the full detailed article see:  How to Compress a Guitar or Bass

Blog at WordPress.com.