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Roland V-Bass

Modelling Bass System
By Paul White

Roland's new V‑Bass refines the technology developed for the pioneering V‑Guitar systems to meet the demands of bass players.

V‑Bass viewed from front/top.Applying physical modelling to the task of simulating existing guitar amplifiers is no longer a novelty, but, in their new V‑Bass, Roland have gone somewhat beyond this remit. Derived from the technology underpinning their V‑Guitar units, the V‑Bass uses COSM (Composite Object Sound Modelling) technology not only to try to replicate popular bass guitar sounds, but also to synthesize entirely new sounds. Rather than triggering samples, as is the case with MIDI guitars, COSM works directly on the waveform generated by the string, so changes in playing style generally translate to changes in timbre. There are no pitch-tracking issues relating directly to the production of notes in COSM as far as I am aware, though I suspect some form of pitch tracking is used to control the filters used to shape the harmonic content of the sound. Additionally, pitch tracking is employed in a more fundamental way by the oscillator-based V‑Bass synth patches as well as those that involve automatic harmony generation.

Using The GK2B Divided Pickup

Like the V88 V‑Guitar system (reviewed back in SOS December 2000), the V‑Bass uses a divided pickup system, which is necessary for two main reasons. Firstly, it enables the waveforms and envelopes for each individual string to be remodelled independently (something virtually impossible to do when the strings are mixed, as in a conventional pickup) and, secondly, it makes polyphonic pitch reading possible for harmony generation and those synth bass effects that include a tracking oscillator.

Another less obvious reason for having a special pickup is that, for modelling to be successful, you have to start off with a consistent signal source, which in the case of a guitar or bass means a known pickup at a known position relative to the bridge. The divided GK2B pickup, which is supplied separately, can accommodate four-, five- or six-string basses as selected via a GK Setting button on the V‑Bass front panel. For optimum results, you have to enter the distance between each bridge saddle and the pickups, to the nearest millimetre. Spacers and sticky pads are provided for fixing the pickup and its associated control box, but using the included screws to fix the pickup more permanently makes height adjustment much easier.

The business end of the GK2B divided pickup module can be mounted permanently on the bass guitar, or can be fixed in place temporarily with supplied sticky pads.The business end of the GK2B divided pickup module can be mounted permanently on the bass guitar, or can be fixed in place temporarily with supplied sticky pads.The control section of the GK2B is essentially the same as that for the GK2A, with a volume control, a three-way GK/Mix/Bass selector switch and two buttons used for patch or mode selection. A degree of GK control re-assignability is available via the main V‑Bass unit. To avoid having a separate cable for the normal bass pickup, there's a small link lead that joins the bass output jack to the GK control box, so that this signal can be sent to the V‑Bass unit via the GK's multicore cable. This allows the bass output from the V‑Bass to feed an amplifier with the unmodified sound if required. Alternatively, both the direct output from the bass's usual pickup and the output from the GK pickup can be combined inside the V‑Bass floor unit, where the bass input is sampled at 24-bit, 44.1kHz and the GK input at 20-bit.

V‑Bass Hardware

Designed mainly for live performance, the V‑Bass is mains powered and follows the V‑Guitar's stomp-box format with seven large footswitches and a pedal that may be used for volume control, tonal effects such as wah, or other assigned functions depending on the patch type. The footswitches permit bank and patch selection, with four patches per bank, and real-time control of a selected function such as calling up the onboard tuner. The display is a 160 x 64-pixel backlit LCD with an additional dual-character LED read-out that shows the bank number, or the note name in tuner mode. Six function switches beneath the display provide a fast means of directly selecting up to six on-screen controls while editing. Other than that, the controls comprise a relatively small number of dedicated buttons, cursor keys and a rotary data dial. A conventional potentiometer sets the level at the output jacks.

In all there are 200 patch locations, 100 preset and 100 which can be overwritten by the user. A further footswitch mode allows individual effect sections to be switched in or out. Though the V‑Bass has MIDI connectivity (In and Out), it doesn't output MIDI note data like a guitar synth (though I've often thought the V‑Guitar series would benefit from including this), but rather uses MIDI for patch dumping, patch and bank changing, synchronisation and sending pedal data.

Connections are available on the rear panel for the GK pickup's multicore cable, the normal bass input and output, stereo outs on both jack and XLR and a headphone outlet. Additionally, there's provision to connect an optional expression pedal or footswitch. A selector switch enables the output to be switched from stereo to mono. Cursor keys and a patch/value dial provide the main navigation tools, while the LCD display keeps things simple by making use of icons and on-screen knobs with fast access via the soft function keys beneath the display. Where multiple pages are needed for editing, the two Page buttons are used to step through them. Saving and naming patches is quite conventional.

The first stage of sound creation is to model the guitar (or bass synth) itself, where the user can choose from 16 bass types, of which around a quarter are regular bass sounds (acoustic, electric and fretless) and the rest are, to varying degrees, abstract or synthetic sounds ranging from bowed strings to organ. Further subdivisions of the conventional basses include Vintage JB, JB, PB, Rick, T-Bird, Active, Violin and M-Man simulations — few bass players will have to think too hard about what these stand for! A dedicated button gets you into the COSM editing section and, after choosing a bass type, there's a degree of editability that varies according to the type selected. For example, the Vari Bass patch lets you change the pickup and body types, as well as other related parameters, but editing never gets too heavy, as the number of parameters in each section is kept sensibly small. It is, however, possible to change the size, and hence the resonant frequency, of acoustic bass bodies as well as to modify the attack and sustain of the plucked note.

Following on from the instrument section is the amp modelling, (again accessed via a dedicated button), offering the choice of a dozen amp models, most based on popular bass amp rigs. One of nine distortion effects can be combined with the amplifier model and there are five alternative speaker models ranging from 1x15 to 8x10. Part of the speaker section models the sound of that speaker miked up with a variable mic position parameter and the ability to blend the virtual miked sound with the virtual DI sound.

Each amp has a set of editable controls, including drive, plus a very flexible and wide-ranging EQ section, after which the signal is passed to the main effects section. I have to admit that this includes more effects than I've ever considered using on a bass, but you have to bear in mind that some of the more synthetic sounds can benefit from more radical treatments. Some effects require key information — Harmonist, for example, generates a real-time harmony based on the scale entered by the user. All the major and minor keys are included as standard, with the ability to enter a user scale, and the added harmony may be shifted by one or two octaves up or down relative to the original pitch. Effects may be chained (nicely depicted by on-screen icons again) and the sections comprise compression, wah, overdrive, amp modelling, EQ, pedal volume, noise suppression, modulation, delay, chorus and reverb, where modulation includes pitch-shifting options. Having chorus as a separate effect rather than as one of the modulation choices also makes a lot of sense, as it's a popular effect for use with bass guitars.

Effects that need to be connected before the amplifier model (such as compression) may be moved accordingly, and it is also possible to combine the modelled sound with the direct output from the bass's normal pickup prior to the modelling/effects chain. In general, the number of editable parameters is kept manageable, while still providing plenty of variety, so the compressor, for example, has just sustain, attack, tone and level controls, unless it's set to limiter mode, in which case it sprouts controls more usually associated with a compressor/limiter (threshold, release, tone, level and ratio).

Bass Models

The acoustic bass models are particularly malleable, as, in addition to being able to redefine the body size, there is also a choice of piezo and magnetic pickups or miking. On the other hand, the Vari Bass model lets you choose from solid, semi-solid or acoustic bass bodies with adjustable low end and resonance, based on several pickup types and positions, so if you can't get what you want from one of the normal basses, this is a good place to start experimenting. Note that certain of the bass models are not available when polyphonic effects are being used.

The fretless emulations are particularly interesting, as the modelling attempts to reproduce the unique attack sound of this instrument as well as the characteristic 'humming' tonality that comes from pressing the string directly against the neck rather than against a fret. A number of basic fretless types are available, after which the tone, colour and sensitivity can be adjusted. On the whole, the fretless patches were convincing, especially in the context of a mix.

Wave Synth produces its sound by processing the string waveform, and it has many of the controls associated with a traditional analogue synth, including envelope shaping, a resonant filter and a choice of square or sawtooth waveforms. Osc Synth is similar in structure, but uses a pitch-tracking oscillator, so you have to be a little cleaner with your playing to get the best results. You also have to have the GK pickups positioned and adjusted properly, otherwise tracking problems can occur, especially on the bottom strings. In addition to a full ADSR filter envelope, this voice includes a sub-oscillator, pitch detuning, pulse width modulation (with variable speed and depth), envelope following (which replaces the normal ADSR level envelope control) and Hold. Hold lets you use a pedal to prolong the currently playing note indefinitely.

Filtered Bass routes the sound via a touch-sensitive resonant filter reminiscent of the Electro-harmonix 'Bass Balls' pedal, while the P-Bend settings cause both tone and volume change in response to pitch-bend. The Filter model is good for funk sounds, although these might seem something of a cliché these days.

ROLAND V‑BASS rear panel.Rear panel connections.

The Bowed model simulates the sound of a bowed string instrument using COSM modelling to rearrange the harmonics generated by the vibrating string, while Pipe does a similar thing to recreate the sound of a mellow woodwind instrument. Crystal rearranges the harmonics in yet another way to create more metallic sounds, while Brass emulates an analogue synth brass patch. All these models have a somewhat abstract quality, but are no less usable for that. The Organ model creates its sounds by combining COSM modelling with pitch-shifting to generate a number of basic sounds where three different octaves can be mixed, much like having an organ with three drawbars.

The Pedal Shift model is the bass equivalent of the guitarist's 'dive bomb' effect, where the pedal operates the pitch-shifter over two-octave range up or down. This can be switched to operate only on specific strings if required, though I feel a two-octave drop on the pitch of the bottom note of a bass guitar could be bad news for whatever speaker system is being asked to deal with the result! Poly Octave again adds one octave below the original string pitch, so care must be taken not to shake your monitors or bass amp to death.

The Poly Distortion model was introduced in the Roland GR300 guitar synth back in the '70s and it sounds very different to conventional distortion insomuch as chords remain clear due to the lack of intermodulation between strings. It is accomplished by having a separate distortion circuit for each string and, in this case, a tone circuit allows the distorted sound to be smoothed out as required. For more conventional distortion effects, there's a parameter that progressively mixes in the sound from the different strings, and when this is turned down to zero the effect is similar to feeding a normal bass into a distortion pedal. Four overdrive types are available as a starting point, and the distortion may be balanced with the original clean sound. Poly Slow Gear is again derived from the V‑Guitar and generates a slow fade-in for each note played, where the attack time and sensitivity can be adjusted.

The first point to make is that the system will only work properly if the pickup is installed as close to the bridge as possible, and somewhere close to the recommended string/pickup spacing. After installation, it's also very important to go to the GK setup page to enter the pickup configuration, distance from bridge, and to set the individual string sensitivity. This might sound like a bit of a chore, but you only have to do it once for each instrument and it only takes a few minutes. Because some players will have more than one GK-equipped bass guitar, the V‑Bass can store the settings for five different basses, allowing you to switch quickly between them.

The operating system is, on the whole, extremely well thought out, and the manual explains the control operation fairly well, but it still falls into the common trap of starting to tell you how to adjust the various parameters without first telling you what you've bought and providing an overview of its capabilities. A page of introductory text would have made all the difference.

Operating and programming the V‑Bass takes very little getting used to, so it's probably fair to say that the most important thing is the sound. Certainly the traditional bass sounds are very convincing, especially the 'Ricki' and those based on popular Fender instruments. There are no obvious artifacts to these sounds providing the pickup is installed correctly, though some of the acoustic bass patches were slightly noisy due to the amount of high frequency processing taking place. Taken in isolation, the acoustic bass sounds seemed slightly artificial, but in a mix, they actually worked really well. Exactly the same comments apply to the fretless simulations, which captured the essence of the instrument, other than the ability to do smooth slides — using a bit of creative string bending helped imitate the effect of sliding up to a note.

Most of the synth sounds are usable, though none sound exactly like the real thing. If I had to describe it, I'd say take an FM synth's attempt at the sound and then mentally morph that with fuzz bass and you'll be somewhere near. What the sounds lack in authenticity, they make up for in playability and their response to playing style, so don't let this put you off. Many of the more abstract synth sounds still have a guitar 'flavour' to them, except of course the ones based on the tracking oscillator, which sound a little more like a conventional synth. As mentioned earlier though, the oscillator patches are prone to mistracking unless the pickup is adjusted properly and the playing style is very clean. Other synth sounds, such as Wave Synth and Crystal (both of which use COSM modelling of the existing sound), are also capable of producing results very unlike a guitar, though I'm not sure what I'd actually use Crystal for, as it seems to strip away all the low frequencies and add dissonant high frequencies.

Final Impressions

For a device that must be technically very complicated inside the box, the V‑Bass is actually quite easy to use and is capable of mimicking pretty much any conventional bass sound, as well as producing very usable caricatures of fretless and acoustic basses. I think the synth side has a lot of creative potential, providing you don't look at it as a way of emulating other instruments. Instead, it produces quite obviously synthetic textures that may hint at, say, cellos, brass or strings, but which nobody would perceive as anything other than electronic. What's more, because the harmonic structure responds to playing technique, these sounds can carry a lot more expression than keyboard synth parts. Other than the temperamental pitch tracking on those sounds that need it, the only other element of the technology that didn't impress was the pitch-shifter, which is still betrayed by all the familiar artifacts when attempting to create large shifts, such as fifths or octaves.

On balance, the V‑Bass is a very powerful tool, especially for the live performer who needs to change quickly between very different bass sounds or who wants to use the bass guitar in a more novel and virtuoso way. In the studio, it can provide the complete spectrum of standard bass guitar sounds very easily, and most of these would be completely undetectable as emulations in a typical mix, while the synthetic sounds provide a welcome alternative to keyboard synthesizers. The cheaper alternative of a modelling bass guitar preamp may satisfy those users who don't need to model the actual guitar type and who are not interested in synth-like bass sounds, but there's no denying that the V‑Bass is as yet unique and can create bass sounds not achievable by any other means.

V‑Bass Processing Options

COSM Modelled Instruments:

  • Acoustic.
  • Electric.
  • Fretless.
  • Vari Bass.
  • Wave Synth.
  • Osc Synth.
  • Filtered.
  • Bowed.
  • Pipe.
  • Crystal.
  • Organ.
  • Brass.
  • Pedal Pitch Shift.
  • Poly Octave.
  • Poly Distortion.
  • Poly Slow Gear.

COSM Modelled Amps:

  • Concert.
  • Flip Top.
  • B-Man.
  • VO Drive.
  • Session.
  • T.E.
  • Bass 360.
  • Super Flat.
  • AC Bass.
  • MS Stack.
  • Hi Gain Stack.
  • Metal Stack.

Effects Algorithms:

  • Comp/Lim.
  • Pedal Wah/Auto Wah.
  • Overdrive.
  • Equaliser (fully parametric).
  • Modulation (Harmonist, Pitch-shift, Flanger, Phaser, Sub EQ, Chorus, Tremolo, Pan, Pedal Shift & Vibrato).
  • Delay.
  • Chorus.
  • Reverb.
  • Noise Suppressor.

Pros

  • Easy to operate.
  • Good emulations of popular bass sounds as well as more abstract sounds.
  • Comprehensive effects section.

Cons

  • Prone to pitch tracking errors on the oscillator patches and the harmony generator unless set up carefully.
  • Some of the sounds that rely on heavy filtering are a little noisy.

Summary

Modelling is always a compromise, but the V-Bass does an excellent job of replicating all the classic bass sounds as well as offering some unusual synthesis treatments.

information

V-Bass £899; GK2B divided pickup £109. Prices include VAT.

Roland UK +44 (0)1792 515020.

www.roland.co.uk

www.roland.com

Published August 2002