Saturday, April 30, 2016
Friday, April 29, 2016
Steinberg Cubase Tips & TechniquesTechnique : Cubase Notes
In VariAudio, Cubase 5 users have a sophisticated pitch‑correction tool.
Oops! This recording of someone whistling a series of short notes has been poorly detected by VariAudio probably due to a poor signal level, too many plosives (breaths at the start of each note) and not enough clear pitch information.Oops! This recording of someone whistling a series of short notes has been poorly detected by VariAudio probably due to a poor signal level, too many plosives (breaths at the start of each note) and not enough clear pitch information.
VariAudio is one of the headline features of Cubase 5, but you really need some experience with it to get the best results. Steinberg included a short series of tutorials on VariAudio in Cubase 5's Getting Started manual (based around some sample projects on the install DVD), and these offer a good introduction, so in this column I'll focus on additional tips to improve your VariAudio work process.
The most obvious application for VariAudio is pitch correction of vocals and instrumental solos, and while it may seem tempting to get straight in there, in the context of a real project it's usually more efficient to do a little editing work on your parts first. For example, when recording vocals, most people record several takes and compile a 'best of' version as their final performance. Such 'comping' is best done prior to any work with VariAudio, so that you get the best performance you can in terms of both pitch and expression, before doing any pitch correction.
With the performance compiled, it's easy to bounce it down (using the File / Export / Audio Mixdown option with the vocal parts soloed, or Audio / Bounce Selection) to create a single consolidated audio event. As VariAudio is accessed by opening an audio event in the Sample Editor, this makes for a simpler workflow, because all the pitch correction can be done in a single instance of the Sample Editor window. Depending on the recording level and/or quality of the performance, it might also be worth applying a little compression, EQ or gating during the bounce process (don't overdo it, though, as you can't undo it): it's useful to get as clean and even a signal as possible before applying VariAudio's pitch-detection process.
On the left, the pitch curve suggests the green segment actually contains two different notes. On the right, the segment has been split into two using the scissors tool and the segment boundary aligned with the change in the pitch curve and waveform.On the left, the pitch curve suggests the green segment actually contains two different notes. On the right, the segment has been split into two using the scissors tool and the segment boundary aligned with the change in the pitch curve and waveform.Pitch Perfect With VariAudio
In the Sample Editor, selecting VariAudio's Pitch & Warp or Segments tools will prompt Cubase to analyse the audio and extract pitch information from it. There's no user control over how this process operates, and while it does a good job generally, it's not foolproof. Two common problems occur. First, there might be sections of your performance for which no segment or pitch curve is created. This generally happens when the pitch‑detection algorithm doesn't have enough information to go on (for example, with a weak audio signal or sections of the audio that have little clear pitch information, such as plosives, sibilant or strongly sounded consonants). Second, as mentioned in the Getting Started tutorials, VariAudio might not always generate the ideal number of segments for a particular word or phrase.
Although the Segment tool can be used to expand an existing segment so that it includes a section of the performance that has not been detected by the initial analysis process, there's little benefit in doing this for sections with no relevant pitch‑based content. If there ought to be pitch‑based content (that is, the section is part of a sung melody) but none is detected, it may be that the audio signal is not of sufficiently good quality. If this is the case then re‑recording the offending section is likely to be a much better approach.
Dealing with the second issue by manually fine‑tuning the segments that have been generated is more straightforward. Obvious things to look for are individual segments in which the pitch curve shows a pitch‑shift of a semitone or more, but another possibility is to split segments that span two or more words, where the melody stays on a single pitch. Splitting these into single-word segments can give you greater flexibility to experiment with variations on your melody. The scissors tool is probably the easiest means of splitting the segment at the appropriate point. It's worth comparing the positioning of segment boundaries relative to your audio waveform: providing there's not too much of a clash with obvious shifts in the pitch curve, the segment boundaries can be suitably tweaked to coincide with the waveform envelope for each word.
Quick Fix Pitch?
On the left, the first red segment actually contains three words. On the right, this has been split into three segments and these could now be shifted individually if you wanted to experiment with an alternative melody.On the left, the first red segment actually contains three words. On the right, this has been split into three segments and these could now be shifted individually if you wanted to experiment with an alternative melody.Pitch Perfect With VariAudio
Once you've sorted out any obvious segment issues, it might be tempting to select all the segments and apply a dollop of Pitch Quantize. Although this might be appropriate if you have a decent singer to start with, or if you're subtle in the degree of pitch‑correction applied, when you want to achieve natural results it's much better to use your ears than to rely on the visual display. Some of the perceived character of a performance is often to do with subtle pitch variations, which means that making things too perfect can result in an undesirably mechanical feel. I find that it's generally best to focus in on specific problem notes and apply quantising to those, rather than blanket‑processing everything.
Currently, VariAudio doesn't offer scale‑specific quantising options, so the other obvious thing to watch out for is segments getting quantised towards a note that's not in the key of the song. This can be a particular problem with short passing notes, where the singer is moving up or down through a series of notes, without holding any of them for very long. In most cases, this can be easily fixed by positioning the segment by hand, but there will inevitably be times when this approach leads to obvious and undesirable audio artifacts, and it can simply be best to leave the short note uncorrected for a more natural result.
Straight & Narrow
On the left, the singer has generated a large pitch scoop into the note. On the right, the Straight Pitch control has been used to make this less pronounced.On the left, the singer has generated a large pitch scoop into the note. On the right, the Straight Pitch control has been used to make this less pronounced.Pitch Perfect With VariAudio
VariAudio also has the Straighten Pitch function, which can be used to reduce the pitch fluctuations in a segment. Sometimes, these are fully intentional on behalf of the singer (for example, a controlled vibrato), but pitch variation at the start of a note, where a singer 'scoops' up or down into the target note, or more random pitch variation within a note, can often be usefully targeted using Straighten Pitch.
As with Pitch Quantize, it pays to focus solely on those notes that your ears tell you are in need of tightening, and to be as subtle as possible with the Straighten Pitch setting: just like a guitar player who bends notes to add character to a solo, some pitch variation within a note is often an important part of a singer's method, and again, too much correction will create an unnatural result.
On the left, a large amount of pitch variation is present in a long sustained note. On the right, the sustained note has been edited into a single segment and Straighten Pitch applied to reduce the overall pitch drift.On the left, a large amount of pitch variation is present in a long sustained note. On the right, the sustained note has been edited into a single segment and Straighten Pitch applied to reduce the overall pitch drift.Pitch Perfect With VariAudio
VariAudio is intended as a corrective tool, but it can also be used in a more creative capacity, to generate harmonies, for example, or double-tracked parts — or even to rewrite your melody. There's currently no user control over how formants are handled (something else for the wish‑list), so any shifting of notes more than a few semitones up or down has to be done with care, but as shown on page 88 of the Getting Started manual, where a new 'upward flair' is created, the results can be impressive. Even if the audio quality of your melody rewrite isn't acceptable as the final vocal, it can still provide a means of creating a useful guide track for a singer if you decide to re‑record the new melody.
VariAudio is an excellent addition to Cubase 5. Still in its first incarnation, it doesn't offer the same level of control as Auto-Tune EVO or Melodyne, but having it so neatly embedded within your DAW is a big plus. Finally, I should leave you with a health warning: good though VariAudio is, it cannot turn someone with limited singing technique into a Maria Carey or Robert Plant — so it's not a replacement for your singing exercises, or capturing the best performance possible as a starting point!
Thursday, April 28, 2016
Wednesday, April 27, 2016
Steinberg Cubase Tips & TechniquesTechnique : Cubase Notes
With even a basic hardware MIDI controller, Quick Controls make writing automation in Cubase much more convenient.
The Inspector's Quick Control panel provides slots for eight parameters.The Inspector's Quick Control panel provides slots for eight parameters.
Whether it's for mixing audio tracks or tweaking synth parameters, the ability to record, edit and save automation data as part of your music projects is now a powerful feature of all but the most basic of DAWs. Even a simple hardware control surface, such as a bank of sliders or rotary knobs on a MIDI keyboard, makes the whole process more tactile. The ease with which you could do this took a big leap forward with the Device Panels that were introduced in SX3 (see SOS March 2005), but Cubase 4 took things further by adding Quick Controls. These are much easier to configure than Device Panels, and offer some of the same functionality, though they are not full replacements. So, if you have a suitable collection of knobs to twiddle, let's work through some examples of Quick Controls in use.
I Want It Now
The Quick Controls dialogue box allows you to link your MIDI hardware's controls to the eight Quick Control slots.The Quick Controls dialogue box allows you to link your MIDI hardware's controls to the eight Quick Control slots.
Quick Controls is one of the panels that appears in the Inspector for both audio and MIDI tracks, and has eight parameter slots available. Setting up your Quick Controls is a three‑stage process, and I'll start with an overview of these stages before looking more closely at each in turn, offering some practical examples along the way. I'll also discuss a couple of less positive aspects.
The first task is to link a series of knobs or faders on your external hardware controller to the Quick Control slots. You can do so via a dialogue box found at Devices / Device Setup / Quick Controls (see screenshot opposite). Once made, these links are global, and apply to all tracks in all projects. So, if you've assigned QC1 to be controlled by the first knob on your MIDI hardware controller, that assignment will be consistent for any track that uses Quick Controls. This consistency is a big advantage of this approach.
The dialogue box also includes a 'learn' facility. Once you've chosen the correct MIDI input, attaching a specific hardware controller to each Quick Control simply involves selecting a Quick Control from the list, moving the required hardware control (be it knob or slider) and then pressing the Learn button. Once all the entries are complete, pressing Apply, followed by OK, should complete this first stage of the process.
Assign Of The Times
A context‑sensitive menu makes parameter selection very easy.A context‑sensitive menu makes parameter selection very easy.
The second stage involves selecting target parameters for the eight Quick Controls in the Inspector display for a particular track. When you open the Quick Controls panel in the Inspector, you'll see the eight Quick Control slots, all initially blank. Clicking on any one of them opens a context‑sensitive selection menu from which any of the available target parameters can be selected. For audio tracks, this includes obvious parameters such as volume and pan position, but also parameters for any insert effects and send levels to FX channels — although note that the last of these only becomes active if the send is switched on for that track in the Sends panel of the Inspector.
For MIDI tracks, the available options include any parameters of a VSTi that can be automated — but there's a bit of a catch. For any of Steinberg's bundled VST Instruments, the menu lists all the parameters by name, which makes it easy to find the key parameters you want to put under Quick Control. With most third-party ones, however (at least, most of those that I've used with QCs), you get a rather unhelpful list of controller numbers instead — so either some hit‑and‑miss experimentation or consultation of the VSTi technical documentation will be required.
MIDI tracks pointed at a particular VSTi offer that instrument's key parameters for Quick Control in a named subfolder, as shown here for Mystic.MIDI tracks pointed at a particular VSTi offer that instrument's key parameters for Quick Control in a named subfolder, as shown here for Mystic.
There are some obvious targets for Quick Controls. For audio tracks, the most useful parameters include volume, pan (using the Standard Panner Pan Left‑Right control) and send levels. For example, if you're dealing with a vocal track, you might have send levels to both a reverb and a delay configured as Quick Control targets. A further possibility is to assign three Quick Controls to the gain, frequency and Q of one band of the track EQ. This gives you a single, sweepable band under Quick Control, which can be very useful when making initial EQ adjustments during a mix. Doing all of the above still leaves a single slot available, and this might be used for a particular Insert effect parameter, such as the threshold on a compressor or the drive level for a distortion or tube-emulation plug‑in.
For MIDI tracks, the selection is likely to be more varied, depending on which VSTi is involved, but volume and pan are again obvious candidates. Some care is needed, though. As shown in the screenshot on the following page for a Mystic‑based track, there are two parameters for both volume and pan: one pair at the top of the list, and a second under the Amp/Fx section. Both volume options would work, but to control pan you need to select the second, which links directly to the Pan parameter on Mystic's main GUI. Indeed, it's generally best to use options from the named section of the Quick Control selection menu, as these all link to the specific controls found on the VSTi interface.
For synths such as Monologue, A1 (if you have it installed from an earlier release), Prologue or Spector, the other obvious targets are in the filter section, or the key parameters for any built‑in effects. For example, controlling the delay level for the identical effects sections found in Spector, Mystic and Prologue allows you real‑time control over the loudness of repeated notes — which is perfect for another dance cliché, where the delay is raised in level for the last note of any melody line.
Once you've created a useful set of Quick Controls, these can be saved to a Track Preset — in theory at least!Once you've created a useful set of Quick Controls, these can be saved to a Track Preset — in theory at least!
Once you've created a useful Quick Control setup for an audio or MIDI track, the third and final step ought to be to create a Track Preset that you can load into future projects. I say 'ought' because — for PC users at least (I'm not sure whether this problem exists on the Mac version) — saving Quick Control settings in projects or as Track Presets can be problematic. Although Quick Control settings used in audio tracks seem to be saved and restored correctly via the usual Track Preset system (right‑clicking on the track within the Track List allows the Create Track Preset option to be selected from the pop‑up menu), for users of Cubase 4 or the initial v.5.0.0 release of Cubase 5, things can be less predictable for MIDI‑based tracks. The Quick Control parameter labels appear when a new track is created from the MIDI Track Preset, but the controls are not responsive (no blue value bar appears under each control), and the only way to restore operation is to choose each parameter again via the selection menu — which makes Quick Controls rather less quick than they might otherwise be!
This seemed to be a genuine bug for MIDI‑based tracks (a quick search of the Cubase Forum at www.cubase.net will bring up a number of threads on the topic), but fortunately, it is one of the issues that Steinberg have dealt with in the recent Cubase 5.0.1 release which became available just as I was finishing this column. Incidentally, for those using a pre‑ 5.0.1 version, the Duplicate Track option suffers from the same problem, and some users even report that Quick Controls 'disappear' in the same fashion when reloading a project. While I've only had a short time to experiment with 5.0.1, things now seem to work perfectly, both when applying Track Presets and re‑loading projects that use Quick Controls. However, Quick Controls are still not 'active' if you duplicate an existing track. Once the new track has been assigned to its own instance of a VSTi, a Track Preset has to be applied to the duplicate to bring the Quick Controls to life.
A Few I Made Earlier
Use the Show All Used Automation option if you need to manually edit any Quick Control automation data for a particular track.Use the Show All Used Automation option if you need to manually edit any Quick Control automation data for a particular track.
This issue notwithstanding, I've created some example Track Presets that can be downloaded from the SOS web site at /sos/jul09/articles/cubasetechmedia.htm. These include a few alternatives for audio tracks and (fingers crossed!) MIDI tracks, aimed at a number of the VSTis that come bundled with Cubase. Each of these presets is suitably named, so it ought to be obvious what their intention is.
The files need to be placed in the user Track Presets folder. The exact location of this folder can vary depending on the operating system and your configuration, and it's also separate from the folder containing the factory‑supplied Track Presets. If in any doubt, the best way to find the correct folder is to create a dummy Track Preset with a distinctive name and then search your file system for the folder containing that file.
Obviously, the main application of Quick Controls is for the automation of key parameters, and the inclusion of the Read and Write automation buttons in the Inspector's Quick Control panel makes this very easy. Having engaged the 'W' (write) button during playback, any controller movements are then recorded — and engaging the 'R' button will then reproduce those parameter changes on subsequent playback. If you want to see and manually edit any of the automation data created, right‑clicking on the track and selecting the Show All Used Automation option will open up each parameter in a separate lane, which is very neat. One final point is that Quick Controls work for a particular track whenever that track is selected in the Track List: they don't require the Quick Control panel to be open in the Inspector.
Despite the bug I described earlier, Quick Controls are an excellent, and genuinely useful feature in Cubase — and ideally I'd like to see the same convenient means of control extended to control other aspects of Cubase. Currently, although Quick Controls can be used to control parameters on Insert effects for audio, MIDI and instrument tracks, they can't be used to change parameters on send effects other than send levels and pan. It would be great to have the same sort of functionality available to control, for example, FX channels, Group channels and the audio output channels of VSTis — but I'm afraid that's something that for the time being will have to remain on the wish‑list.
Advanced Compression Control
In this column in SOS April 2009, Mike Senior described a parallel compression method using five different compressors, each placed on a Group channel and fed by sends from the original vocal track, in order to mix and match the tonal characteristics of the various compressors. While the overall level of the final vocal can be controlled at a number of points in such a signal chain, varying the send levels to each of the compressors will dictate how hard each compressor is driven and this might, for example, be used to provide contrast between different song sections. As Quick Controls can be used to control send levels from an audio track, they provide a simple and convenient way to tweak these settings while experimenting.
Published in SOS July 2009
Tuesday, April 26, 2016
Steinberg Cubase Tips & TechniquesTechnique : Cubase Notes
No guitar effects in Cubase? Actually, there are more options than you can count...
With Apple including their Guitar Amp Pro plug‑in in Logic, Sonar coming bundled with Native Instruments' Guitar Rig, and Ableton adding their new Overdrive plug‑in to Live, guitar‑slinging Cubase 5 users might initially feel a bit left out. But you don't have to, because you can assemble some pretty amazing 'guitar racks' in Cubase: it's just that Cubase takes a more à la carte approach, where you need to draw on the existing effects as if they were stomp-boxes. A VST audio channel in Cubase offers inserts for up to eight series effects, including an amp simulator, so you actually have more options than with many pedalboard setups. Furthermore, you can add some quality 'studio effects', like the new Reverence reverb, as send effects. So think of Cubase as 'virtualising' a pedalboard, then bringing it into the studio so that its output can go to studio rack processors.
When you have a setup that you like, you can easily save it as a track preset — or, better still, create multiple track presets for different types of sounds. Cubase can even make a fine host for live performance, should you decide to trade your rack of effects for a svelte laptop that patches directly into the PA system, as you can switch instantly between racks. (I'll cover how to do this at the end of the article.)
Before I get started, one quick note of caution. Because you need to play 'through' Cubase in order to hear the effects, you'll need a low-latency system — which means a fast computer, and a good audio interface, with quality ASIO or Core Audio drivers. Even if an interface has a 'zero‑latency' monitoring feature, that won't do you any good, as it will simply route the input signal to the output, without going through Cubase or any of its plug‑ins, which kind of defeats the purpose… Preferably, you should also have an interface with a high‑impedance input (suitable for guitar and bass). Many modern interfaces have an 'instrument input' which will do the job, but if not, you'll need to use a guitar‑friendly preamp, compressor, or similarly 'neutral' effect to feed a line input (or use a DI box).
Your Virtual Pedalboard
With this in mind, here's how to create a virtual 'pedalboard' in Cubase. Feel free to substitute your own choice of effects, but I've found this to be a good starting point.
• Go to Project/Add Track, and choose 'Audio' to create a single, stereo audio track.
• Next, click on the track's Edit button (e), which will open up the VST Audio Channel Settings window.
• Cubase includes a chromatic tuner, and the first slot is the best place for it, so that you can keep your axe in tune without bypassing other effects. Click in the first insert field, and in the plug‑in list choose Other/Tuner to load an instance of it here.
• I like to insert a compressor after this, to add some sustain and even out the guitar's dynamics, for a more consistent distortion sound. So for the second insert slot, choose Dynamics/Vintage Compressor, then click on the insert's Edit button to see the compressor's interface, and set up the parameter values as desired. A good starting point would be Input at 17 and Attack at 8.9, with Punch and Auto set to On. You'll probably need to adjust the Input (effectively the Threshold in this case) according to the level of signal coming into the plug‑in. Set the Output to a level that's as high as possible, but doesn't approach clipping.
• Similarly, insert the Soft Clipper into the third insert slot and click on its Edit button. For settings, try putting the Input at ‑0.0, Mix at 55, 0.0, Second at 100, and Third at 57. As with the Compressor, set the output to a high level, again stopping short of distortion. These settings are intended to get you started; you may want to tweak them depending on your guitar, pickup, playing style, and so on.
• For the fifth insert (leave the fourth empty), go to Distortion/AmpSimulator and click on the plug‑in's edit button. For the Amplifier Model, select Crunch, and try the following parameter values: Drive at 8.7, Bass, Middle, and Treble all at 5.0, Presence at 6.2, and Volume set to 5.0. For the Cabinet, select Cabinet 2, with Lo Damping at 38 and Hi Damping at 35.
• In the sixth insert, to get a bit of interesting stereo information from our mono guitar sound, select Spatial/MonoToStereo, and try Width at 170, Delay at 10.0, Color at 10, and Mono switched off.
• Now let's add some slap-back room delay. In the seventh insert (which, incidentally, comes post‑fader in Cubase, as does insert eight), go to Delay/StereoDelay. In the left channel, try setting Delay to 1/16T, Feedback to 6.5, Lo to 50, Hi to 15000, Pan to ‑100, and Mix to 20, and enable Sync, Lo Filter, and Hi Filter. Use the same values for the right channel, but with Delay at 1/16, Feedback at 7.3, and Pan at 100.
• Now that we have some stereo information, we can create a big, wide guitar sound. In the eighth insert, go to Spatial/StereoEnhancer, and start with Width at 168, and all buttons set to off.
• We'll add EQ to give some polish and let the guitar cut through a little better in a mix. Enable a stage in the standard channel EQ (which comes after the inserts in the signal chain), and choose the Parametric II response. Add a boost of around 4‑5dB at 3.5kHz, with a Q of 0.2.This screen shows the VST Audio Channel Settings and the roster of effects used to create our basic guitar rack.This screen shows the VST Audio Channel Settings and the roster of effects used to create our basic guitar rack.
These are the settings I use as my basic rack for adding rock guitar sounds in Cubase, and you might also find it handy as a point of departure, so it's worth saving as a track preset. To do this, right‑click in the audio track containing the 'rack', and choose 'Create Track Preset' from the context menu. When the Save Track Preset dialogue box appears, simply name it and save it: now you can call up your rack for any audio track in any Cubase project!
The Fourth Insert
Remember the fourth slot, just before the amp modeller, that we kept free? This is ideal for adding other effects to shape your sound. No doubt, you'll have some favourite third‑party plug‑ins, but dig into the list of Cubase standard plug‑ins and you'll find some excellent choices for guitar. Here are some of my favourites.
Octave ('Other' category): This effect really surprised me because it tracks well, but inserting the compressor before the Octave plug-in improves the tracking even further. Distorting the post‑octave sound with the AmpSimulator gives a big distortion sound, even with only the Octave 1 level turned up. If you want more of a brontosaurus guitar, turn up Octave 2 as well. In general, I like to leave a fair amount of direct sound in the output mix. You can just as easily go in a cleaner direction by using only the Octave 1 output, and bypassing the AmpSimulator. Select the neck pickup on your guitar, pull back a bit on the tone, and you'll hear a sound that recalls jazz great Wes Montgomery.
StepFilter ('Filter' category): I'm a huge fan of Roger Linn's AdrenaLinn processor. When I play with groups like Air Liquide, it's the only gear I take other than the guitar, and of course a MIDI cable to sync it from the band's MIDI master clock. You can get many of the same effects from Cubase's StepFilter.The StepFilter offers synchronised filter effects that recall Roger Linn's AdrenaLinn signal processor.The StepFilter offers synchronised filter effects that recall Roger Linn's AdrenaLinn signal processor. StepFilter is basically a tempo‑sync'ed dual step‑sequencer, each with 16 steps, and there's a total of eight patterns. One sequencer controls filter cutoff and the other resonance. The filter response morphs from low‑pass to high‑pass, with a stop along the way for band‑pass. You can also copy a pattern, paste it into a different pattern, and create variations. All of these parameters, including pattern selection, can be used with VST host automation control. If you're into electronic guitar effects, you really should check this out — but also try the Tranceformer ('Modulation' category) and Chopper ('Other' category), which are similar, although Chopper works on amplitude, and Tranceformer syncs a ring modulator's carrier frequency to the project tempo'
WahWah ('Filter' category): What's a guitar rack without a Wah? Cubase's is really quite good: not only can you vary the band‑pass filter frequency, you can set high‑ and low‑frequency limits, and the Q at those limits. The frequency responds to host automation, but if you want to do real‑time pedalling, the WahWah shows up as a destination in any inserted MIDI track, so you just need a MIDI foot controller. Because insert four comes before the amp simulator, adding a wah there more faithfully duplicates the traditional rock wah sound, where guitarists patched it between the guitar and (usually overdriven) amp. The filter changes thus occur before distortion, which gives a very different sound compared to placing it after distortion. For more emphasis on the wah sound, you could remove the StereoDelay or StereoEnhancer effect, and place the WahWah in one of those slots instead.
Modulation: There are plenty of interesting options in Cubase that go beyond simple choruses. Try anything from the modulation category in the fourth slot (pre‑amp sim) and seventh or eighth slot (post‑amp sim).
Live Performance Switching
By choosing 'Enable Solo on Selected Track' in the Cubase Preferences you can switch between different 'racks' instantly, simply by selecting a track. By choosing 'Enable Solo on Selected Track' in the Cubase Preferences you can switch between different 'racks' instantly, simply by selecting a track.
This final trick is pretty cool for live use because these effects are very efficient, which means that you can have several tracks of 'racks' without straining your CPU. Go to the Mixer tab at File/Preferences/Project, and check 'Enable Solo on Selected Track'. Solo a track, and now all you need to do to call up a new sound is select a track, and the Solo will 'move' to that track. The change from one sound to another is instantaneous. Now it's time to amaze your audience!