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Using Guitar Amp Simulators 101, Part 3

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This post is part of a series called Using Guitar Amp Simulators 101.
Using Guitar Amp Simulators 101, Part 2

In the second part of Guitar Amp Simulators 101, we looked ways of using different amplifier, cabinet and microphone models, as well as some of the more advanced amplifier settings, to achieve specific goals in designing a guitar sound. In this third part, I’m going to guide you through some slightly more complex virtual guitar rigs, focussing on blending sounds and using more advanced cabinet and speaker modelling to achieve more realistic sounds.

As before, the focus is on Native Instruments’ Guitar Rig though, this time, I’ll include some 3rd party cabinet and microphone models, too. So grab your guitar, fire up your DAW, and let’s dive in!


Depth and Texture

It’s probably fair to say that most rock and pop recordings make use of multiple, distinct guitar sounds, whether discretely and in specific applications, for example, producing distorted sounds with a big 50 Watt half-stack and clean sounds with a vintage Vox AC30, or by blending tones throughout all or part of a song. Of course, in bands with two or more guitarists (or, at least, arrange songs for two distinct guitar parts), this blending happens naturally, though even there, there is potential to blend sounds by using multiple cabinets and microphones for each guitar.

The point being that, unless you’re aiming for a very raw, uncomplicated sound, you’re almost certainly going to achieve better results by blending multiple tones.

As we saw in the last part of this series, cabinets and microphones can have as much or even more to do with the overall sound than the amplifier itself. You’ll remember that we blended the warm, rich tones of a Marshall Plexi model with a brighter sounding 2x12 Fender style cabinet model, and further tweaked the tone by blending two distinct microphone sounds. By extending this principle to encompass blending whole, distinct set-ups, we can achieve the rich, thick textures and vibrant sounds we hear in professional recordings.

To hear this principle in practice, try listening to some of your favourite recordings while rolling the balance control between hard left and right. As you do this, you should be able to pick out multiple distinct guitar tones. It’s not uncommon, especially with hard rock and metal, to be able to discern that the overall guitar sound is actually a blend of two or more sounds which, on their own, sound too extreme – too bright, dark, distorted, clean, etc. – but the sum of them is just right, and much richer and more interesting than anything you could produce with only one tone.

These are the principles that this tutorial is based on, so let’s work through them one at a time.


Horses for Courses

The most basic application of our basic idea is using distinct amplifier models for specific tasks. We could roughly divide common guitar applications into the following, potentially overlapping categories:

  • Clean
  • Overdriven
  • Distorted
  • Rhythm
  • Lead

So far so obvious, but the point is that each is an individual job and may best be served by different tools. Since, with modelling software, we have near limitless options, there’s no reason to make the sort of compromises that most of us have to make in a live situation, so we can go ahead and use as many amps as we like to get a rich complement of sounds.

The key thing is that, to achieve this, in most cases you’re going to need to set up multiple guitar channels in your DAW – an obvious point for more experienced users, but maybe not so obvious for our newcomers – and, ideally, pan them around the stereo field to present a realistic, interesting sonic picture.

That last part, incidentally, is referred to as “sound-staging”. In essence, this means placing sounds in the stereo field to make the listener’s brain believe that it’s hearing real people playing music in a real space. So, for example, you’d typically hear a drum kit and vocals more or less in the middle, with guitars at one or both sides.


Special Blend

We can make our guitar tones richer still by using a more sophisticated arrangement of cabinets, microphones and even amplifiers within each individual guitar track.

Amplifiers

We can run a single guitar signal through two completely different amplifier models by using the Split Mix tool in Guitar Rig. As the name suggests, this allows us to take the guitar signal and split it out to two separate signal chains, before mixing the results back together.

For example, let’s say that we want the brightness of the Marshall JCM800 model and the fatness of a Mesa model. Starting with an empty signal chain, select Split Mix from the Tools panel and drag it into the signal chain. Then drag one amplifier and insert it under Split A (above Split B), and drag the other amplifier under Split B (above Split Mix). Using Split Mix, we can now pan each amplifier in the stereo field and use the crossfade slider to determine how much of each we hear.

In my example, I want the same noise reduction and reverb effects applied to each side of the split, so I place these modules outside of the split system, i.e., noise reduction before Split A and reverb after the Split Mix.


Of course, if you wanted to have an effect apply only to one half of the split, you would simply place the module within the appropriate section – say, a flanger under Split A, and a thick, nasty octave pitch shift under Split B – allowing a huge range of creative options.


Cabinets

A common practice in professional recording situations is to record the guitar sound from multiple microphones positioned around the cabinet, or even multiple cabinets.

In Guitar Rig, we can begin by taking out the basic Matched Cabinet module and replacing it with the Cabinets and Mics module. This tool allows us to achieve a number of things:

  • Apply multiple, separate cabinet models to a single amplifier model
  • Access more microphone models, with the ability to add a different microphone to each cabinet
  • Utilise more sophisticated microphone placement techniques
  • Use individual bass and treble EQ on each cabinet/microphone combination

That’s a lot of flexibility! To illustrate the possibilities, here’s a sample set-up:

Here, I’ve got a Marshall style 4x12 with an off-axis dynamic microphone placed close to the speaker (using the Distance control), a little air, and panned slightly to the right, giving a thing, bright sound. With it, and panned to the opposite side, I have an Orange style 4x12 going into a condenser microphone, placed a little further away at the edge of the cone, with more air, giving a fat, bassy sound.

You’ll also notice that, using the slider controls under the cabinet icon, we can even alter the “size” of the cabinet, allowing us to get a thinner or fatter sound.


If terminology like “off-axis” and “dynamic microphone” is new to you, this may seem a little baffling at first glance. There’s lots of good information on AudioTuts and elsewhere that can help you to understand what all of these things mean but, as with anything in music, your ears are your best guide. The main thing to understand is that each has its own, unique sonic properties and, as we’ve seen previously, that means these parameters are a great way to tailor your sound without reaching for the EQ.

If you’re using Guitar Rig 4, incidentally, you’ve got another, similar set of options in the form of the Control Room module. The only drawback is that Control Room limits you to one cabinet, so you can’t blend different models together. Of course, we’ve just covered an idea that will solve that problem: employ the Split Mix tool, just as we did to blend two amps!


Stereo Positioning

Not only do the Cabinets and Mics and Control Room modules open up a lot of tonal options, they allows us a good deal of flexibility in how we arrange our guitar sound in the stereo field.

While traditionally you would arrange your tracks in the stereo field using your DAW’s panning controls, we can make use of all these options to create much more elaborate arrangements. For example, in your DAW, you could pan your guitar tracks dead center, and use only the cabinet panning within these modules to position your cabinet or cabinets around the sound-stage (being sure to set your guitar track to stereo in your DAW, of course).

Using this method, you could create a whole wall of guitar with just one track in your DAW, or separate out multiple microphones and/or cabinets on each track of a multiple-guitar arrangement.


3rd Party Impulse

You might already have heard of cabinet impulses. In fact, John Boswell wrote a great introduction to using them for Audiotuts+ March 2009, which I strongly recommend you read for a more detailed background.

Briefly, a cabinet impulse is a recording of the acoustic response of a real guitar cabinet and a real microphone in a real room. For example, someone could record the acoustic properties of, say, an Orange 4x12 with a Shure SM57 in their bedroom, and you could then take the resulting impulse file and apply it to a guitar signal, either from a modelled amplifier or even from a real amplifier, to reproduce that sound.

Many cabinet impulses are available to download for free and, increasingly, very comprehensive packages of professionally recorded impulses are available to buy from companies like RedWirez and Recabinet.

To apply the impulse to your guitar signal, you’ll need a plugin to run the impulse file. While some amp simulator plugins, like Peavey’s ReValver, will do it natively, most don’t, so you’ll need an additional plugin. Lots of 3rd party plugins are available, and many of them are free, for example LAConvolver for Mac and LeCab for Windows.

Setting up is simple. Put an instance of your amp simulator into a channel in your DAW and, within the amp plugin itself, remove or turn off the speaker and cabinet simulation (according to Native Instruments, Guitar Rig’s amp models are designed to respond to the cabinet model, just as a real amplifier responds to the “load” of its speaker cabinet, so I turn off the cabinet, rather than removing it entirely).

After the amplifier plugin, load an instance of your chosen convolver plugin (LeCab, LAConvolver, etc.) and, in the convolver, load your chosen cabinet impulse file. Depending on what plugin you’re using, you may need to adjust some settings to get the best sound, so refer to the plugin’s documentation for guidance).

Here’s what the basic set up looks like, using Guitar Rig and LAConvolver in Logic Express:

And here’s a sample of Guitar Rig’s Citrus amp with its matching cabinet:


And here’s the same thing with the Guitar Rig cabinet disabled through an Orange 4x12 impulse from RedWirez:


What I notice is this: the output from the RedWirez impulse sounds more realistic, less synthesised and processed, but also less glossy and produced. This is to be expected. I don’t know precisely what goes on inside a Guitar Rig cabinet model, but it’s bound to be tuned to sound as attractive as possible with its matching amp model.

To get the best out of an impulse, we need to employ some slightly more complex routing, akin to what we were doing with the Cabinet and Mics module.


Impulse Deux

As with the Cabinet and Mics method, we can get some great sounds by blending together multiple cabinet/microphone sounds. To achieve that, let’s put an instance of Guitar Rig into a channel which has three auxiliary outputs.

Those Aux channels will host the cabinet impulses, so to make sure I don’t hear the unprocessed amplifier signal, I’ve set the channel output to No Output.

On each of the Aux channels, I’m placing an instance of LAConvolver, into each of which I’ll add a different cabinet impulse. Choosing the impulses to mix is largely a matter of taste, but it’s worth thinking of it in terms of blending individual characteristics to build a cohesive whole.

For example, I’m using three impulses based on the exact same cabinet, but with different microphones placed in different positions. One of them is a “room” microphone – the sound of the cabinet recorded from some distance across the room – which I’m using to give a sense of spatial dimension to the sound, just like the Air control in Guitar Rig. The other two are “close” microphones – positioned more or less right next to the cabinet – but each is a different microphone in a different place. One of them is producing quite a bright, trebly sound; the other is rounder and has more bass. By mixing them together, I’m hoping to achieve a balance of clarity and substance.

Finally, I’m going to pan them out to spread the guitar sound around the virtual room. I’ve put the two close microphones on one side, panned slightly apart, with the room microphone on the opposite side, the idea being to replicate the sound of the guitar amp being to one side of the listener, and the “room sound” coming from the opposite wall. To round it off, I’ve routed all three cabinets to a bus track, on which I’ve got a little bit of compression:


That sounds pretty good. It’s quite raw, but it’s much closer to what I’d expect to hear if I’d put a few microphones up in front of a real amplifier. A little EQ, perhaps a dash of reverb and another, different guitar sound on the other channel and I think we’d have the beginnings of a very good recording.


Denouement

So, there we have it. I hope I’ve introduced you to some new ideas and sparked your creativity. As we’ve seen, amp simulation needn’t be seen as a compromise; there are endless opportunities to achieve high quality, professional sounds, many of which would require many thousands of dollars worth of equipment to achieve in the “real” world.

One final note: Things can get complicated very quickly when exploring these avenues, so my advice is to play around with these techniques outside of your regular projects. I keep a “sandbox” DAW template in which I play around with these ideas, so that I can work with them without the risk of screwing up anything I want to keep. If I hit on something good, wherever possible, I’ll save it as a preset so that I can just drop it into my future projects with a couple of clicks.

While it’s often tempting to use ever more elaborate and sophisticated ways of producing great guitar sounds, it’s important to keep sight of what you’re trying to achieve: good tone. In the end, it’s important to find a balance between complexity, use of system resources, ease of use, reliability and tone: in other words, only make it more complicated if the ends justify the means.

Happy tweaking!

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