Slayer 2

Slayer 2: Guitar Synthesis
Manufacturer: reFX
Preduct Site: http://www.refx.net/pro_Slayer2.htm

Reviewed by Joshua Fielstra

Let’s be real for a minute. Every guitar solo performed on anything other than an actual guitar will be looked at with industry disdain. Sampled or synthesized emulations won’t really sound like a guitar in the end, and it’s especially unforgivable if played on (gasp) a strap-on MIDI controller (the dreaded “keytar”). Every die-hard head-banging guitarist will find out where the offending poseur lives and pour beer on their head (and not that fancy microbrew stuff that synth geeks drink). I’ve seen it happen.

·Clean Demo ·Electric Bass ·AmpCab ·Pedal Wah ·Feedback ·AngelFlange

But what if there was an emulation that wasn’t really an emulation at all, but attempted to deliver something so brutally close to the Real Thing that it was no longer a mere guitar-like novelty? This is what Slayer2 (reFX, $89.99 US, $30 upgrade from v1) attempts to offer. Does it succeed? Let’s get dirty.

[The following review and corresponding audio files were created while auditioning Slayer2 on a 1.8GHz AMD Athlon PC with 1 Gb of RAM running Steinberg's Cubase SX 1.06 as the VSTi host application. The audio examples have no further processing beyond Slayer2 applied.]

The Concept

Slayer2 is an expansion on the original Slayer softsynth (also offered by reFX). Unlike other guitar VSTi’s (such as Steinberg’s Virtual Guitarist), it attempts to provide a solution for musicians who want a guitar sound in their studio tracks but don’t want to use loops or samples as the basis for the sound engine. For this reason, Slayer2 behaves more like a physical modeling plugin than anything else. It is capable of emulating electric guitar, electric bass, and even some acoustic renderings. Because of its somewhat open-ended physical modeling architecture, it can also create things which are none of the above but are their own fictitious pseudo-guitar instruments.

Figure 1—the Slayer2 interface

Once installed in the host application, Slayer2 loads and behaves just like a standard VSTi. Compatible with both PC and Mac platforms, installation is as simple as dumping the Slayer2 system files into the host application’s plugins folder. On the first pass, this installation technique seems to merely be opening the floodgates for all kinds of illegal proliferation around the internet, since there is no formalized process that registers the plugin with the operating system. On the other hand, nothing beats simplicity, maximum compatibility, and instant gratification. Anyone who has spent time installing plugins that feature dedicated installation routines knows that it can frequently be a hassle to get your plugins to show up in the pick list you want them to in your host application. This is particularly the case for those of us who like to categorize our plugins by creating subfolders. For this reason, dumping a few system files exactly where you want them is about as simple as it gets.

Once loaded, Slayer2 in its default state consumed only about 5% of my total VSTi host's resources. It’s not a CPU-hungry instrument, by any means.

ARCHITECTURE

The signal path in Slayer2 consists of a waveform generator (which the documentation calls a synth/physical model hybrid), followed by an insert effects matrix, further followed by an amp/cabinet modeling algorithm, exiting finally through another insert effects matrix. There are plenty of input parameters at each stage in the signal path, allowing for an exceptionally diverse final product. Furthermore, all of the insert effects and amp/cab models are available as standalone audio plugins that don’t require the Slayer2 VSTi to be loaded. This is darned handy if you want to try applying some of the outstanding speaker simulations to “real” electric guitar tracks or anything in need of serious dirtying.

When describing the Slayer2 sound engine, the most logical starting point is the series of parameters that will define the physical properties of our virtual guitar. There are 3 kinds of pickup emulations, 9 string models, and two knobs that adjust the size and material of the guitar body. The first stage in the signal path is the string simulator that generates the initial waveform. The string models range from variants with a “steel” feel, to models intended to be used as a basis for acoustic and electric bass sounds. There are also two open-ended string types with somewhat random harmonic spectra that are well-suited to synthesized guitar emulations. Coupled with the string type, there is a section that allows the type of electric pickup to be chosen (none, single, or double coil). The actual position of the coil on the guitar body can subsequently be moved to taste, as can the location along the bridge that the pick will actually strike the strings. As in the real world, both of these variables can dramatically affect the final product. The size of the guitar’s body can be adjusted as well (larger sizes tend to mimic the sound board of say, a contrabass) and the material construction of the guitar body can be varied from wooden to metal and everywhere in between. Whew! There are a lot of highly-detailed environmental variables at work here in this initial section of the sound engine, and since many of them are continuously variable, knobs can be moved for hours and never yield the same thing twice. This is both a blessing and a curse reminiscent of the days of analog dials, knobs, and humidity—save your work if you want to be able to recreate something you did only ten minutes ago. I managed to amass a saved bank of subtly but progressively deviating products in a very short time.

After the basic properties of the guitar have been defined, you’re left with what is essentially a clean electric guitar (i.e. no distortion). [Audio demo #1 – Clean Guitar] For further tweaking, there are a series of knobs and switches on the guitar’s scratch plate similar to those found on a real guitar, plus a few extras. The standard electric guitar tone knob is present, and behaves almost identically to the real thing. There is also a knob labeled “Slap” that controls the amount of slap articulation applied when addressing the string (this is of course most effective with electric bass patches). [Audio demo #2 – Electric Bass] In addition, a somewhat primitive series of controls for shaping the sound’s envelope exists (e.g. whether a string is allowed to “ring out” or if it is to behave like a muted articulation), as does a Dynamics knob that controls the patch’s sensitivity to MIDI Velocity messages. This last control is more important than it looks, since higher velocities can actually shape the computations performed by the engine in order to recreate the “opening up” that occurs when strings are picked more aggressively.

When looking at the plugin’s deceptively simple interface, it’s hard to believe that there are actually 12 wildly influential parameters at work, and that they are capable of producing such diverse tonal possibilities. But unlike other forms of additive synthesis which usually require a bit of planning and a reasonably healthy command of the parameters involved, the Slayer2 engine is best discovered by simply pushing buttons and listening to how they affect the sound. This makes it “feel” more like a guitar and less like a synthesizer.

The only complaint with the interface would be that the variable controls lack a numerical display of any kind. When adjusting some of the parameters like Material, it is impossible to tell when you have passed from one material into another since there is no readout—only a knob with a notch in it that delineates clock face position. It also becomes nearly impossible to re-select a setting you had a few minutes ago unless you have a photographic memory when it comes to pot positions. Many softsynth developers have solved this problem by displaying the numerical or categorical value of the currently selected knob or slider in a dedicated LCD-like window shared by all controls.

It is also ambiguous as to whether certain parameters (like Material) exist as discretely defined steps, or are infinitely variable. Displaying the currently selected value would eliminate such ambiguities without making any dramatic changes to the individual controls necessary.

Having said that, let’s get to the really fun part.

SHRED, DUDE

The realism and playability of Slayer2 hinges entirely on whether or not it can deliver a distorted amplifier and speaker cabinet emulation that interacts with the string model in a realistic manner. After all, we’re here to rock out. Happily, this portion of Slayer2 is the single most intriguing module in the entire VSTi in my opinion. It quite literally can turn an uninspiring guitar sound into an organic wall of warmth and chaotic life. [Audio example #3 – Tube Amp/Combo Stack] More compelling, however, is the manner in which it handles inharmonic feedback. The amp section actually computes a distortion model based on which strings were plucked and which strings were not, thereby simulating the effect whereby cabinet output can move air molecules in the playing environment, further moving the strings themselves and creating a feedback loop. For this reason, you will occasionally generate a plucked harmonic based on the particular note, velocity, phrase articulation, and chord (if any) you just played. This is disturbingly convincing, and it’s fun to try and figure out what you did to create that harmonic and try to do it again. The nuances employed in the cabinet section are truly phenomenal.

The general architecture of the speaker section consists of 5 amplifier types and 5 cabinet types. One of each is in effect at any given time. The array of possibilities offered varies from traditional 60's tube setups to Marshall stack emulations. There are also specialized variants such as Pocket (a small and boxy practice cabinet) and Surf (an old-fashioned 1-stage tube amp). Like most real-life guitar amp setups, the overall sound of the amp/cab section can be adjusted using Drive, Presence, and Feedback knobs. Combining different amplifiers with different cabinets can have a rather dramatic effect on the final product. The Bandpass amp, for instance, combines a bandpass filter chain with a soft saturation algorithm. The Presence knob can then be used to control the bandpass frequency, and by assigning a continuous controller pedal to the Presence knob, a real-time wah-wah effect can be achieved. [Audio example #4 -- Pedal Wah] The amp/cab section is completed by a 3 band EQ.

Cranking the Drive and Feedback parameters really high can lead to a sustained feedback tone in the tail of the string’s envelope. As the fundamental decays, it is slowly overtaken by a pitch appropriate for the note/chord and amplitude of the string played. A weak amplitude will be overtaken faster, while a stronger pluck will resonate for a longer period of time before drifting off into the familiar sine wave-like feedback tone. This is no token digital distortion by any stretch of the imagination. [Audio example #5 – Feedback Tones]

IN FULL EFFECT

Slayer2 comes with a broad array of effect possibilities. There is a dedicated bank of 8 effect slots both before and after the amp/cab section, yielding a total of 16 discrete effect points. The effects themselves are primarily emulations of stomp boxes, and individual effects are thus dropped into an available slot much like a guitarist would drop a stomp box into a pedal board. In keeping with the stomp box feel, the interface for each effect has three familiar-looking knobs at the top of the pedal and a customary bypass peg just about where your foot would land

Figure 2—the Slayer2 effects matrix

The signal passes through each individual effect in series, so the order of the effects determines the processing hierarchy. Effects can be moved to a new location to change the order of the signal path.

The effects section is a dramatic expansion and corresponding improvement on Slayer v1. Both the type and quality of the effects have been substantially augmented. There are selections from the standard guitar tool kit like fuzz boxes, octave pedals and tremolos, as well as multitap delays, choruses, and phasers (to name a few). There is even an auto-wah and talk box effect for the Peter Frampton in all of us (yikes). The effects themselves tend to have a “vintage” character to them—they are less like lush processor-intensive algorithms and more like what one might find in an actual pedalboard array. They don’t sound bad by any means, but they definitely don’t sound like laboratory-grade DSP powerhouses either. The Angel Flanger, for instance, has a wobbly over-the-top character reminiscent of 70’s analog electronics. [Audio example #6 – Vintage Flange] But, when it all comes together it sounds pretty convincing. As such, one wonders if some of the algorithms might have been deliberately “dumbed down” to lend some authenticity to the overall illusion. Whether or not this is true is irrelevant, because it works.

The fact that the effects can be applied both before and after the cabinets lends a sizable degree of flexibility to the signal chain. And the intense number of effects available at any given time is nothing less than welcomed overkill. Whereas I would frequently pile on effects from my own DAW arsenal when using Slayer v1, with Slayer2 there is simply no need whatsoever. In fact, for lead sounds, I found myself rarely using more than three effects at a time. The options are there though, especially since the included effects can be used as standalone plugins in the VST host application. Best of all, the effects have an astonishingly low footprint. During my load test, I filled all 8 slots of the post-amp effect bank and only incurred an additional 1% hit on the Cubase SX performance meter.

The only downer about the effects is that they behave like traditional insert effects—there is no wet/dry balance. 100% of the signal passes through each effect in series. Implementing a balance knob would be my primary suggestion for later versions. While this is of course not necessary for effects such as fuzz (which are traditionally treated as true insert effects), it would be very helpful to have a dry/wet balance on things like the multitap delay. I bear in mind that the current behavior is probably due to the fact that this is how a standard stomp box would behave; it’s tough to determine when to stick with the pedalboard novelty and when to bend the rules. Nonetheless, I often found myself fighting against the multitap’s Feedback parameter when in actuality all I needed was a little less of the effected signal.

THE ROADMAP

The documentation is above average. This, too, is an improvement on Slayer1. Whereas Slayer1 was sometimes an exercise in Germanglish, the current version is written by Marc Cooper, author of Cubase SX Complete (www.auxbuss.com).

I usually like to see as much reference material as possible, and while the treatment of Slayer2 isn’t exceptionally thorough, it is adequate for a plugin. There is also a helpful hands-on tutorial for those new to the Slayer concept.

THE GREAT GIG IN THE SKY

To assist in rendering an authentic guitar performance, Slayer2 contains a few playing aids. These are designed to help "bridge the gap" for performers not accustomed to playing guitar parts with a keyboard. Five Strum modes are offered, each of them helping to break up block chords so that they are not played all at once (since when using nothing but a pick, a guitarist is only capable of striking any one string at a given time). The strum speed itself can be controlled via a dedicated Speed knob. There is also a somewhat rudimentary arpeggiator, and an Autochord function that is capable of strumming major, minor, seventh, and minor seventh chords. Finally, a Powerchord function exists that automatically adds a fifth or fourth to the played note to give it the standard "power" feel.

I won't spend much time on these playing aids, because while I think they are good ideas, they don't compare to the quality of performance possible by just playing the desired articulation live. For instance, performers playing power chords rarely want to play them on every single note. Actual performances are more likely to be a mixture of power chords, single notes, block chords and strums, so in my opinion it's just easier to tailor the performance to taste by playing the desired articulation “manually.” It also sounds a little less clinical this way.

Slayer2 has a fairly extensive MIDI implementation. All of the continuous parameters available on the front panel have a dedicated MIDI CC#. This number cannot be changed, but most VSTi hosts offer a way to transform CC#'s on the fly. For instance, using Cubase SX's Input Transformer, I used my continuous control pedal (ordinarily CC #4) to transmit MIDI CC #86 and modulate the frequency of the bandpass filter in the above wah-wah audio demo.

The Slayer2 VSTi ships with 64 presets. These cover the gamut from dirty to clean and back again. In my opinion, the quality of the Slayer1 presets was a little bit better. There aren't as many good-old-fashioned distorted solo guitar presets in this version. However, I was able to create a collection of my own fairly rapidly due to the efficient and instant-gratification nature of the interface.

TO THOSE ABOUT TO ROCK

At $89 retail (US), Slayer2 really packs a punch. It’s also a tremendous deal for version 1 owners willing to shell out $30. There are a lot of other plugins out there that charge more for less overall utility. Considering the variety of sounds attainable, their respective quality, and the small overall CPU footprint of the instrument, it just seems to exclaim “good programming.” But we won’t use words like “programming”—there might be a jealous guitarist listening.

Joshua Fielstra is a Milwaukee-area musician and complete gear wacko. You can check out his electro-industrial project Netherfabrik at www.netherfabrik.com. You might also find him playing his keytar when he’s damned sure there are no guitarists within earshot.