New Gear Review: Mono Synth & Bass Mono Synth by Electro-Harmonix
The Mono Synth and Bass Mono Synth pedals are the newest additions to Electro-Harmonix’s growing palette of synth emulations for guitar and bass.
Electro-Harmonix has a deep history of producing pedals that can take a regular guitar or bass signal and spit out an otherworldly synth sound, be it gritty, jagged, or smooth.
Pedals like the MicroSynth and Bass MicroSynth have long been favorites both in the studio and on stage for their characterful analog filter and slider-filled UI, making it easy to dial in just the right settings, even using a toe. However, both retail for more than $250, and both lack the ability to save presets.
A few years ago, Electro-Harmonix unveiled the Synth9 Synthesizer Machine, a polyphonic pedal that gave you the option of using one of nine classic synth-emulating voices, and allowed for the storage of nine preset sounds. The Synth9 was a huge hit, as were the other entries in the series: the Mel9 and B9, which emulated the Mellotron and Hammond B9 organ, respectively.
Now, there are two more pedals that take a bit from the previous designs but also add something new. Unveiled at NAMM 2019 along with the recently re-visited Attack Decay pedal, Electro-Harmonix’s Mono Synth and Bass Mono Synth are two new takes on processing your guitar or bass signal and turning it into a very convincing synth sound. With eleven different synthesizers on each to choose from, let’s see if these pedals continue in EHX’s long-standing tradition of producing cutting edge products.
Features
Five knobs adorn the front of both the Mono Synth and Bass Mono Synth: a knob for choosing the synth emulation, a dry volume knob, a volume knob for the synth sound, a sensitivity control (which also has some dual functionality—more on that later), and a single “Control” knob that modulates a key parameter or two.
The two pedals share the same layout and design, though the Bass Mono Synth has been optimized for bass signal. Both are purely monophonic, unsurprising given what’s on the tin. Playing polyphonically makes either pedal produce a digital splatter that isn’t very pleasant. Both pedals work best first in the chain and are especially sensitive to your note length. Overhanging notes will confuse the pitch detection, so playing with a slight palm mute helps keep things separated.
Each model features an input and a pair of dual outputs—one for the dry signal and one for the synth sound being generated (the dry volume knob only controls the dry level for the Synth output). This is handy and makes using the Mono Synth pedals in a larger rig easier, as it’s possible to maintain a dry signal for other processing. And as mentioned, each features the ability to store eleven preset sounds; essentially one knob position for each synth module sound.
Both pedals feature an expression pedal input, which allows control of a second parameter other than the one being controlled by the Control knob. Frustratingly, there’s no way to swap which parameters the knob or expression pedal controls. What you get is pretty much what you are stuck with, which is a shame because often the parameter that makes more sense to tweak is assigned to the pedal. Having an expression pedal is key to getting the most out of either the Mono Synth or Bass Mono Synth.
Saving presets is simple. Press and hold the left footswitch for two seconds to save a setting, which includes settings for all of the knobs and the expression pedal. The two pedals use different names for each of their synth models, and these are a bit abstract, especially compared to the more recognizable names on the Synth9 pedal that recalled the models they were emulating. On the Mono Synth, the acid emulation is called “XOX” whereas on the Bass Synth a similar sound is called “Acid.” Perhaps the legal team had to step in there.
In Use
Taking a look at the available sounds on the Mono Synth shows there are 80s synth pop and new wave tones aplenty. “Nu Wave” works well as a string emulation, whereas XOX works as a surprisingly suitable acid emulation. In a few of the models, the Sensitivity knob also controls the range of filter sweeps. This can lead to a bit more sonic variation but can also make setting an appropriate sensitivity level a bit more challenging. “Blister” featured a nice adjustable detune, producing a warm, warbly tone, while “Ghost” uses a soft vibrato with a slow filter envelope to great effect.
The Bass Mono Synth pedal has plenty to choose from as well, including funky Moog sounds, low sub octaves that will truly shake the ground, and a percussive sound called “Growl” that works wonders for replicating a punchy analog synth bass. The bass version of the pedal also paired particularly well with overdrives placed later in the signal.
To Be Critical
We had a few minor complaints with the Mono Synth and Bass Mono Synth. As mentioned, it would have been preferable if the expression pedal had the option to control either parameter for each synth sound. For example, in the “Wub” voice setting, the Control knob sets the speed of the modulation, while the expression pedal is set to control the filter’s center frequency. Reversing those roles would have been more useful.
And again, there can be high-pitched digital noises when the pedals don’t track well, so your playing definitely needs to be adjusted to take this into account.
Summing it Up
Electro-Harmonix took a simple idea and executed it well with the Mono Synth and Bass Mono Synth pedals. Both are easy to use within minutes of unboxing. The proposition of eleven useful synth sounds in a single pedal is indeed inviting for both guitarists and bassists, and the expression pedal and ability to save settings make these useful additions to your pedalboard.
So who will these pedals appeal to given the other options from Electro-Harmonix? The Synth9 is polyphonic and has two control knobs instead of one, and it uses a preset naming convention that is a bit easier to follow. However it’s also more than a $100 bump in price, as are the MicroSynth and Bass MicroSynth, which have even more user control given their full array of sliders.
But for those who are looking for a quick, surefire way to add a new palette of timbres to their four- or six-string instruments (and don’t need a whole lot of tweakability) Electro-Harmonix’s Mono Synth and Bass Mono Synth pedals will certainly fit the bill. At $125 each, they are a worthy and fairly risk-free investment.
Leo Maymind is a producer, DJ, and writer living in Los Angeles, CA. He is obsessed with sound, and you can reach him at lmaymind@gmail.com.
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