Review: MXR MB301 Bass Synth

Folks, let’s start with an attitude of gratitude: We live in the golden age of synth-bass pedals. We have more choices than ever, and the choices are so damn good!

Although it’s totally possible to get pro-level key-bass sounds with an electric bass by mixing and matching your favorite octave, envelope filter, compression, and chorus pedals, dedicated synth-bass units make it easy to quickly access fat, complex synth tones. The last few years have seen an explosion of options for every sonic preference, pedalboard size, and budget. With that in mind, let’s look at the new kid on the block.

How It Sounds

MXR’s MB301 Bass Synth, designed by Ian Martin Allison and the folks at Dunlop, features eight presets inspired by icons and their gear: “Thrillenganes” (Greg Phillinganes’ ARP 2600 on Michael Jackson’s Thriller), “Wonderful” (Stevie Wonder’s left hand), “Lizard Synth” (Herbie Hancock’s ARP Odyssey on “Chameleon”), “Synthadelic” (Bernie Worrell’s Minimoog on P-Funk’s “Flash Light”), “Sledge” (Tony Levin’s fretless, picked, and chorused tone on Peter Gabriel’s “Sledgehammer”), “Army of Synth” (the Arp 2600 bass line on Björk’s “Army of Me”), and “Nine Inch Synth” (Trent Reznor’s Minimoog on “Head Like a Hole”), as well as “Synthmau5” (a shortcut to the “dark atmospheric zone” of producer deadmau5).

Do the presets sound exactly like their inspirations? I was determined to find out, so I made a Spotify playlist of the tracks listed above, plus Stevie’s “Isn’t She Lovely” and “8ths” by deadmau5. Before I pressed play, I plugged a Dingwall John Taylor 5 into the MB301 and decided to fool around for a few minutes in front of my bootylicious Jule Amps Simone 500/Bergantino IP112 1×12 rig. When I looked up, a couple hours had gone by.

For the record, the presets do indeed get in the ballpark of their targets, but whether you can accurately nail those inspiring tones depends on your ears, your gear, your hands, and your standards. I had far more fun with the presets (and in “live” mode, without the presets) when I played along with Drumgenius and let the Bass Synth take me in new directions. Changing my picking-hand position, doing staccato “arpeggiator” lines with a pick, listening to notes bloom with the ENVELOPE parameter, upping the cheesiness quotient with CUTOFF, nudging up RESONANCE to peek through deep SUB MIX lows, putting the pedal into FREEZE mode, reaching for 808 tone, using an expression pedal to sweep each effect — it was a blast. When I wasn’t gleefully butchering “I Can’t Wait” and “You Dropped a Bomb on Me,” I was writing new riffs and plotting to use the Bass Synth in my next sound design project.

Many of my favorite key bass lines feature the expressive possibilities of mod and pitch wheels, and the MB301 more than held its own as I experimented with string bends and slides to mimic those effects. (In other words, the tracking rocked.) I enjoyed trying new approaches, taking pictures of each moment for future reference (or saving over the eight presets, which is easy), and learning how each knob changed my tone. I felt like I was making sounds I hadn’t heard before — which, by my definition, is success.

What’s Hot

The Bass Synth is beginner-friendly but capable of so much more under the hood: Dig the rich buffet of secondary parameters available by pushing the VOICE and SHAPE buttons, including controls for compression, tracking, noise mix, and optimization for 4- and 5-string basses. Recording the MB301 in stereo is as easy as flicking the CTR side switch to AUDIO and using ordinary two-conductor cables at the OUT and CTR jacks. The user interface makes it easy to experiment; twisting knobs is a great way to learn about synthesis. Thank goodness, too, for a manual that’s clear and concise.

What’s Not

If you’re a sound designer who wants deep control, the MB301 might not be your jam. Look elsewhere if you want to choose a waveform for each oscillator or use two different waveform types simultaneously.

I scrolled through the presets with an MXR Split + Tap pedal plugged into the CTR jack; scrolling without it just isn’t as much fun.

Some players report problems with certain power adapters, but you can bypass that drama by using Dunlop’s ECB003 9-volt adapter or any other 9-volt, 330mA center-negative power supply.

How It Compares

The MB301 sits in the sweet spot among alternatives: It’s more expensive but more diverse than an EHX Bass Mono Synth, and it’s about the same price as a Source Audio C4, whose app-accessible tweakability attracts some and repels others. In my experience, the Bass Synth tracks better than the more full-figured (and pricier) Future Impact v4, and newbies will find it far more accessible than the powerful but costly Boss SY-300. The MB301 shines precisely because it does what it does very well — and it doesn’t try to be everything to everyone. 

Buy This If…

• You don’t play keyboard bass, but you need good synth sounds, like, right now

• You play key bass but don’t have room in your luggage for a Novation Bass Station II

• Getting instantly usable synth tone is more important than making minute tweaks to filters, oscillators, and envelopes 

The MXR MB301 is practical, compact, built to last, and deeper than it might first appear. It kicks butt at a great price, and the interface is easy to navigate. Listen to what the Bass Synth does — don’t get stuck on whether it sounds like an analog keyboard, and let it lead you to new horizons.

MXR MB301 Bass Synth 

Price: $285.99

jimdunlop.com