Pedal Review: Mr. Black Tunnelworm
Review by Ian Garrett
The Pedal: Mr. Black Tunnelworm
The Point: Zero-Through Flanger
The Cost: $179.95
I confess my experience with flangers was fairly limited. I’m more of an overdrive/fuzz/delay kinda guy. I’ve had a few flangers recently, including the MXR Micro-Flanger, which is a more traditional analog-based flanger, and a TC Electronics Vortex, which is digitally based. And while I do like some modulation mixed in with my delay, I find a little modulation goes a long way. Which is why I found myself surprised by how much I enjoyed the Mr. Black Tunnelworm.
Perhaps a helpful simple definition of flanging is in order. Flanging is the practice of mixing at least two identical signals, with a small delay applied to one or more of the signals. This process creates a complex and incredible, albeit a sometimes cheesy, sound: the swept comb filter.
The Tunnelworm is the creation of Jack DeVille Electronics, who was very helpful in explaining a little more about what is going on internally with this pedal. I won’t go in to all of the details he shared. Suffice it to say, the Mr. Black website has a mountain of information on all things flanging. I felt like I was back in math class!
Three simple controls, yet many variables
The Tunnelworm has three controls – width, rate and zero (more on that last control in a moment). It is true bypass easy to power. And for those that care, the Tunnelworm is a DSP effect driven by an analog signal path. Your guitar signal goes through an analog pre-amp before being converted to a 24-bit data stream which is processed at 32MHz. Then it’s converted back to an analog signal which hits an analog output amplifier then to the output jack and downstream signal chain.
While the Tunnelworm seems like a simple pedal with just three controls, the variables of tones you get is pretty amazing. The Width controls the size of the sweep. If you start in the counterclockwise position, the width is off and the unit is then in "manual" or "filter matrix" mode. Here the Zero control is in charge – it essentially becomes the manual control of a typical flanger, although due to Tunnelworm being a through-zero flanger, the zero control allows the high point of the swept delay line to be advanced beyond the static delay line. Lastly, the Rate control is pretty straight forward. In technical terms, it adjusts the frequency of the hyper-triangle (rectified sine wave) applied to the modulated delay line. In nontechnical terms, it feels like a speed control.
Typically, flanger pedals modulate a delay line about a central point set by the manual control. This means that the delay time becomes both shorter and longer than the delay set by the manual control, if provided. If no manual control is provided, it is simply hard-set by internal components, like the MXR Micro Flanger. The width control generally determines how far the modulated delay advances and slows down from the central point set by the manual control. If the width control is negated (turned to zero) the modulated delay line's delay time is fully controlled by the manual control. This is what allows the "filter matrix" (technically a comb filter) to exist, like the EHX Electric Mistress.
With the width control turned clockwise, it provides a really large sweep which seems most useful when using Zero settings close to full counter clockwise - this puts the zero point far away from static delay line. In simpler terms, this generates a chorus type flanger tone, and with the Zero control fully counter clockwise, the Tunnelworm moves into chorus territory.
Enough geek talk, how does it sound?
Once I understood how things worked, I started with the width off, and turned the zero knob on to see what I could get. In the CW position, you get almost an AM radio station sound, your bass disappears, and your highs are sort of subdued . It does sort of sound like you’re playing in a tunnel. And when you move the zero knob counter clockwise, you can feel the lower end combing back in to play as if you’re exiting out through a tunnel.
I tended to like the Zero control around 10 or 11 o’clock, and then turned the width up just a bit, maybe around 9 o’clock or a tad less than that. At this point, the width control makes the tone wider, fatter, fuller. The rate control also comes into play, and if you keep it below noon, you get a nice chorusy type effect. Keep the rate low, and turn up the width for a thicker effect.
I really liked the tones I was getting with the rate turned up around 3 o’clock or a little past that, with the width control set back at 9 o’clock. This gave a nice vibrato tone, bordering on the rotating speaker effect. Very, very cool. If you set the width and rate quite high, you’ll get a wild effect that is akin to being seasick. So it can easily go from mild to wild.
With both the width and rate control turned lower (but not off) the overall effect is mellow, but it gives you a wider, lusher soundstage. After a while you might not realize it’s even on, it just becomes part of your tone. Until you turn it off, and suddenly you feel almost naked, like something’s missing.
I’m glad I got a chance to test drive the Tunnelworm, and it will be hard to give back! The range of tones is broad and diverse. I really liked the milder, chorus type of effect that I could dial in, but I like the somewhat odd, almost tape- like delay you can get, simulating a tape that is almost beyond its lifespan. And I liked the shimmering vibrato tones as well. Actually there wasn’t much I didn’t like about the Tunnelworm, and if you’re looking to add some life and diversity to your tone, this might be just the thing. Highly recommended.
5 – Tremendous product; among the very best
4 – Great value overall; exceeds expectations
3 – Definite contender, but look closely at the competition too
2 – Average at best; probably better choices exist
1 – Not ready for prime time