Analogue Bass Synthesizer
The Minitaur may look like a simple beast, but there’s much more to Moog’s most affordable synth than meets the eye...
I have gone on
record, not least within these pages, to describe bass synths as basic
synths that just happen to play low notes. Most of the time, I do not
mean this in a particularly complimentary fashion, although there was
one exception — the original Moog Taurus — where a basic synth that just
happened to play low notes was a fabulous product that justifiably
remains revered to this day.
Moog discontinued
the Taurus in 1981 and replaced it with the short-lived Taurus 2. Often
described as a Rogue on a stick, this was much more flexible than its
predecessor, but sounded different and was widely (and often unfairly)
disparaged by the synthesizer community. Consequently, it wasn’t until
Moog emulated the original Taurus that a true successor was born.
I reviewed the Taurus 3 in the July 2010 issue of SOS and was impressed,
so much so that I bought one for my own use.
Today
we have before us the fourth in the series. This is a small desktop
unit named, with horrible inevitability, the Minitaur, and in real terms
it may be the most affordable Moog synthesizer ever released. However,
it’s not the basic, knobby analogue synth that it appears to be, because
(with the exception of the fine-tune knob) every knob and button has an
equivalent MIDI CC that can be used to control it from afar. What’s
more, while you can use it successfully in isolation, there are no fewer
than 20 additional voicing parameters (that I refer to as ‘hidden’ and
Moog calls ‘under the hood’) that become accessible when you use it with
its dedicated editor software (see below) or another source of MIDI
CCs.
The Bassics
The Minitaur looks good in its traditional Moog livery and, at just 22 x 14cm, its front panel is certainly compact.
But let’s start at the beginning. The Minitaur boasts
two oscillators that can generate either sawtooth or square waves. You
can detune VCO2 against VCO1 by up to plus/minus 12 semitones, and
fine-tune the whole instrument within a range of plus/minus one
semitone. Pitch bend is also provided, with a range of selected values
up to plus/minus 24 semitones, and with the Up and Down amounts
separately defined if desired. However, the pitch range lies only
between MIDI Notes 0 and 72 (the ‘C’ an octave above middle ‘C’) and
this is such a strict limit that you can’t offset the pitch, detune VCO2
higher, or even pitch bend above this.
In
addition to all of this, there’s a second hidden parameter in the
oscillator section that deserves special mention. It’s called Note Sync,
and it forces the phases of both oscillators to reset to zero degrees
when a Note On message is received. This is particularly useful when
using detuned patches because, without it, the fundamental may be
reinforced when you first play a note, attenuated (resulting in
a thinner sound), or even cancelled (resulting in a sound that initially
seems to lie an octave higher than wanted). Forcing the phase to align
at the start of each note eliminates this. I can’t remember when I last
saw this (if ever), but it’s very welcome, and I recommend that you
switch it on.
Having determined the waveform and
pitch of the oscillators, you can mix them in what seems to be a simple
two-channel mixer... except that it’s a three-channel mixer. This is
because any external signal presented to the audio input is mixed here
before being presented to the filter. There’s no physical control for
the level of the external signal, but you can determine its gain using
another MIDI CC, from zero up to 200 percent. The manual claims that
setting the VCO levels close to maximum will overdrive the mixer to
generate clipped (ie. more aggressive) sounds, but the effect is at best
very subtle, so don’t expect monstrous, distorted bass from the
Minitaur.
Next in the signal path lies the
filter which, as you would expect, is what the company describe as
a “classic” Moog 24dB/octave low-pass design. This offers the standard
controls for cutoff frequency and resonance and will self-oscillate when
you increase the resonance beyond its two o’clock position. When
I received the Minitaur, the cutoff frequency didn’t track at 100
percent, but this can be adjusted using yet another hidden parameter,
and a quick tweak set it to 100 percent, whereupon it could be played as
an additional oscillator or used to pick out specific harmonics
consistently as I played up and down the keyboard. You can also control
the cutoff frequency using its dedicated contour generator, and you can
even make the cutoff frequency velocity-sensitive (another hidden
parameter), although I found the maximum depth to be rather subtle,
which is a shame.
Finally, as far as the signal path is concerned,
there’s a simple VCA followed by a volume control. Well, simple, except
that you can use yet another pair of hidden MIDI CCs to control the
VCA’s initial level and make its gain velocity-sensitive.
Unlike
the Taurus, but like the Minimoog, the dual contour generators —
hard-wired to the VCF and VCA — are ADS(D) designs, whereby the Decay
control also determines the length of the Release phase (or not, as
determined by the status of the Release On/Off button). Moog have been
a bit naughty here, describing these devices as ADSRs but, given that
you can’t set the length of the Decay and Release stages independently,
this is misleading. The fastest Attacks, Decays and Releases are each
claimed to be as fast as 1ms, and they are, indeed, so snappy that, with
the Attack and Decay knobs set to zero, clicking occurs. This can
sometimes be interesting at the starts of notes, but it’s always horrid
at the end of them, so I never set the Minitaur’s Decay knob to zero,
even when I wanted notes to stop abruptly. (This, by the way, is
a compliment, albeit a strange one.) Moog claim that the slowest contour
times are as long as 30s, but I found them to be considerably shorter
than this — not that this was ever a problem.
Modulation
is via a single LFO. This only generates a triangle wave, but has
a wide frequency range from 0.01 to 100Hz. You can route the modulation
signal to the oscillators (both VCOs affected equally up to plus/minus
one octave) and the filter cutoff frequency (up to plus/minus five
octaves), and control depth using a mod wheel or anything else that
generates the appropriate MIDI CC. You can also sync the LFO to MIDI
Clock, with divisions ranging from 64th-note triplets to four
semibreves, and reset its phase whenever you play a new note (‘LFO key
triggering’), which is important if you want every note to be
consistent.
The final controls belong to the
Glide section. There are three glide types, again accessed using
a hidden parameter. These are Linear Constant Rate (the time between
notes increases as the interval increases), Linear Constant Time (the
time between notes is consistent, no matter what the interval), and
Exponential (which is the type of glide found on the original Taurus
pedals). There’s also a hidden legato mode, which disables the glide
unless you are still holding the first note when you play the second. As
I said... it’s not as basic as it appears to be!
In Use
All
of the Minitaur’s front panel controls (except its Fine Tune knob)
respond to MIDI CC numbers and can be edited via the Minitaur Editor
software. But that’s not all: the software also allows you access to
a variety of other controls that are otherwise hidden, as seen here.
Be clear from the outset; the Minitaur is not
a Taurus 3 module. Although it shares some similarities with the Taurus
3, there are many differences, so while you can use the two for the same
purposes, it will perhaps be more interesting to compare it with the
original Taurus, which remains the iconic instrument of its type. But
before doing so, let’s get a small number of niggles out of the way.
Firstly,
Moog describe the Minitaur in numerous places as having a “one knob per
function design”. This is not true. It would be true to say that it has
a “one function per knob design”, but this is a different thing. The
Minitaur does not have one knob per function because many parameters are
only accessible via MIDI. For much of the review, I had the Minitaur
connected to an Arturia AE Factory keyboard and its associated MIDI
Control Centre software running on my Mac and, towards the end of the
review, Moog kindly supplied me with a pre-release version of the
dedicated Minitaur Editor (see below), which proved to be a boon.
Without these or something equivalent, much of the Minitaur would have
remained inaccessible.
Secondly, two of the
parameters accessed by MIDI CCs — the note priority (high/low/last) and
legato modes — are not described in the manual, and you will only
stumble across them if you read the MIDI CC table in the appendices.
Thirdly,
I found that when I connected the Minitaur to my MacBook Pro, using the
USB port next to its psu input, the synth generated a low-level, but
nonetheless unacceptable chattering noise. Because I had encountered
this once before, I recognised it as noise from the Mac’s power supply,
so I transferred the USB cable to the port on the other side of the
computer. This reduced the noise considerably, but when I pulled out the
PSU cable (leaving the Mac to run on its internal batteries) it
disappeared entirely. I am not sure where the blame lies for this, but
if you’re planning to use the Minitaur with a laptop, it may be worth
checking to see whether you encounter anything similar.
Now
let’s move on to the good stuff, and address the question we all want
answered: can the Minitaur play and sound like the original Taurus? To
answer this, I liberated my Korg MPK130 MIDI pedals from the store room,
hooked them up to the Minitaur and placed them next to my Taurus.
Unfortunately, having not used my Taurus for some time, I had to open it
up and go through its tuning and scaling routines. To be fair, this
took less than an hour, but it pointed out an immediate advantage of the
Minitaur over its ancestor!
Presets can be saved via the Minitaur Editor software.
Having set everything up correctly, could I now
imitate the decade-defining Taurus preset of the original pedals? The
answer was, as I had expected, not quite. The original Taurus had
unusual attributes such as a link between the Attack time and the
contour amount, as well as coupling between the filter and the audio
amplifier, and these had very pleasing sonic consequences, including
a growl in its Attack phase that is very hard to describe, but
recognisable when you hear it. So, given the much more complex synthesis
architecture of the Minitaur, it’s a compliment to Moog that the sound
is close enough for most players and listeners not to give a damn. Would
the subtle difference bother me? To be honest, no. I would be more than
happy to record with the Minitaur or take it out on stage, and I am
confident that neither you nor anyone in the audience would be able to
tell the difference. Hmm... I had better qualify that statement.
I should have written, I am confident that neither you nor anyone in the
audience would be able to tell the difference unless I used the
Minitaur to create and play the myriad additional bass sounds that it
can generate with ease, but which the Taurus could only dream about.
MIDI & The Minitaur Editor
The
Minitaur can receive MIDI data on both its MIDI inputs simultaneously,
and also sends MIDI data from its USB port. Every physical control
(again, except the fine-tune knob) transmits a stream of MIDI CCs when
adjusted, which means that you can easily automate changes by recording
and playing back these streams. The caveat is that the CCs are generated
in 7-bit format, which means that you might encounter significant
zipper noise when you replay the data. To demonstrate this, play and
simultaneously record a self-oscillating filter sound while slowly
sweeping the cutoff-frequency knob. There’s a tiny bit of unevenness,
but nothing to worry about. Now replay the recording. You’ll find that
the cutoff frequency has been quantised to semitone steps. This is not
a criticism of Moog, just a consequence of the original MIDI
specification. Happily, Moog have endowed the Minitaur with the ability
to understand 14-bit MIDI CCs, which vastly increases the resolution. If
you can create data in this format in your computer, far smoother
effects are possible.
After you register your
Minitaur, you will also be able to download its dedicated editor, which
will come complete with any USB drivers necessary to hook the synth to
your PC or Mac. Although the final version was unavailable at the time
of review, the nice chaps at Moog Music supplied me with a pre-release
version and software to update the Minitaur to be able to use it.
Installation was painless, and within minutes I realised what a huge
difference the editor makes.
All
of the Minitaur’s front panel controls (except the Fine Tune knob)
respond to MIDI CC numbers and can be edited via the Minitaur Editor
software...
The main page echoes the physical control panel of
the synth, while a second provides a clear and simple means for
accessing all of the hidden parameters. You can display these pages
simultaneously (hurray!), making it extremely quick and easy to edit the
synth fully. Then, when you have developed a sound that you like, you
can save it in a third (also simultaneously visible) page for later
recall. A sensible range of housekeeping facilities is provided, so it’s
unlikely to be too long before you’ll have complete libraries of bass
sounds at your disposal. However, at the time of writing, the editor is
a stand-alone application that doesn’t integrate with host sequencers or
DAWs. I hope that this will be addressed in the future, because it
would be useful to be able to select new sounds while replaying songs.
In the meantime, it should be possible to create and recall patches
within a suitable sequencer using the appropriate MIDI CCs — laborious,
but possible.
One other observation: when
idling, the editor consistently consumed in excess of 20 percent of my
Mac’s processing power (as reported by iStat Pro), and I have no idea
why it should do so. This may be something that Moog will optimise
before release, but I thought it worth noting.
So
is there anything I would change about the Minitaur? Well... yes, three
things. Firstly, I would ask Moog to add aftertouch control of the LFO
depth, filter cutoff frequency and loudness. Given that these are
already under the control of various MIDI CCs, and that the Minitaur
already knows when it’s receiving aftertouch (the MIDI message LED
flashes), it might be straightforward to add this as another controller.
Secondly, I would ask them to consider creating a version with the
hidden parameters accessible using physical knobs and switches. Sure,
this would be much larger and significantly more expensive, but an
enhanced Minitaur (the Miditaur or Maxitaur?) would be much more usable
on stage or, for that matter, anywhere else where hooking it up to
a MIDI controller or computer might be a pain. Finally, I would ask the
company to provide a mounting kit so that the Minitaur could be used
like a Taurus 2, with the synth itself standing at waist height above
the MIDI pedal board.
Conclusions
I
have to admit that I find the Minitaur very attractive, and I would
like to commend Moog on its clear controls and robust physical design.
With a sonic architecture that sits somewhere between the Taurus 3 and
the Slim Phatty, it does what it sets out to do with a minimum of fuss,
and I can imagine that some players will be happy to use it straight out
of the box without ever worrying about the additional facilities
offered by the hidden parameters.
However, one
thing confuses me; I can’t work out why Moog limited the Minitaur to
bass duties. Sure, it does what it says on the tin, and it does it
extremely well, but I created some excellent brass and flute sounds
using it, as well as many other patches from the Moog pantheon, and it
seems obvious that the Minitaur would sing as a lead synth too.
Nonetheless,
it’s a descendent of the Taurus, and I should accept is as such.
Whether a combination of MIDI bass pedals and the Minitaur will ever
feel quite as ‘right’ as my Taurus is another question, but I have to
admit that I thoroughly enjoyed using it in that fashion. Given the low
cost of the Minitaur and all the additional sounds and facilities it
offers, and given the second-hand value of the vintage pedals — which is
still equivalent to the price of a brand-new Taurus 3 — I think that
Moog may have a hot product on their hands.
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