The technology around rock music is a vast sea of wires and inspiration, great successes and forgotten failures. The mothers of invention were often electronics geeks as much into diodes as they were into music. Sometimes science inspired the technology, sometimes music did, and in some of the best cases, it was both together. There is much we take for granted, big and small. The instruments are obvious, the supporting gear not so much, unless you are a gearhead.

My first rock band had no tuner, so we “earballed” it, meaning, on our best days, we were only slightly (but still intolerably) out of tune with each other. We would do our best to align our A strings so that they sounded the same, then we would go off to our corners and tune the remaining strings. By the time we got to our high E strings, we would be way off one another, having to independently earball from A to D, D to G, G to B, and B to E. While tuners weren’t a sexy purchase compared to flangers and wah wahs, it was clear we had to have one.

For years I used a Boss TU-12, one of the first affordable electronic tuners. It was popular because of its price point and because it detected incoming pitch, so you didn’t have to manually select which note and octave you were tuning to. The compact device had two bold, arrow-shaped LEDs to show if you were flat or sharp (both would light if you were in tune), and a needle that swept across a small arced graph for even more precision. The problem with this tuner and others of its ilk was that the margin of error was significant. I remember having debates on stage with the bass player on whether we should follow the needle or the LEDs, since they sometimes gave different readings. I went with the LEDs because you could see them easily on stage. He went with the needle because it was most accurate. Even with an electronic tuner, we remained close and yet so far. It was still better than earballing.

Around the same time, my mates and I noticed a funky-looking device sitting on an amp at a concert. It was roughly the size and shape of a shoebox resting on its short side. It had a round window with an illuminated NASA-esque display, two big dials, and a place to plug in your guitar. It wasn’t until high school marching band that I learned it was a strobe tuner, the most accurate means of tuning instruments ever invented.

The established industry leader for strobe tuners is Peterson Electro-Musical Products, a name that hearkens back to the company’s early days when it made electronic tuners designed for organs that the company was also involved in making. Peterson released their first strobe tuner in 1967, nearly 30 years after Conn released theirs. They have owned the market ever since, and were the tuner of choice for artists like Frank Zappa, Jimi Hendrix, and Pink Floyd.

The original strobe tuners by both Peterson and Conn, acquired by Peterson in the 1980s, were elegantly simple mechanical devices and extremely precise. The boxes were basically stroboscopes with a dedicated purpose—tuning an instrument. Dig: A translucent wheel inside the tuner and visible through the display spins at a set speed based on the note you selected on the front of the box. Behind the wheel are lights that flash at the frequency of the note you’re playing into it. These lights affected the appearance of the strobe pattern on the wheel similar to how a movie’s frame rate effects the way wagon wheel spokes appear to move in those Westerns your Pa made ya watch. If the two frequencies match (the light and the revolutions per second of the wheel), the pattern on the wheel appears to hold still. If you are flat or sharp, the pattern would appear to drift left or right respectively. This simple mechanical device provides precise tuning down to 1/1000th of a semitone—that’s up to 30 times more accurate than most needle or LED-based tuners that have to include a significant margin of error in order to give any in-tune reading.

Peterson now makes tuners in a variety of flavors, from high-end laboratory-grade ones suitable for precision instrument makers and repair techs to software versions that live inside your studio recording software. They also just released a tuner for the iPhone. My favorite is Peterson’s popular stomp box tuner, the StroboStomp.

The StroboStomp II, which I use in my rig, is a very rugged pedal and clearly designed to take abuse. The pedal also acts as a mute or kill switch, which is great for when your complicated mad-scientist guitar rig starts belching high decibel, heavily processed feedback and you have no idea why. Stomping on the footswitch kills all signals to your rig while switching on the strobe tuner. Two little recessed buttons below the strobe display allow you to set and save parameters on the tuner. There are tuning presets for drop tuned and capo’d guitars, and preset Sweeteners that set the tuning for the temperaments of a specific instrument (to learn about temperaments, intervals, and the like, start with Pythagoras and don’t stop until you get to Buzz Feiten). Preset Sweeteners include 12-string guitar, standard six-string guitar, pedal steel guitar, bass, and violin. The strobe itself is LCD-based, and yet preserves the accuracy of mechanical stroboscopic tuners down to 1/1000th of a semitone (a semitone is the difference between a D and a D#, or one-half step on a piano or guitar).

The display on the StroboStomp II retains that early NASA appeal, and lets me precisely tune my guitar as fast as humanly possible, even from several feet away. I usually have to hit the same string several times on non-strobe tuners before I can determine whether or not I am actually in tune. And even then, I am probably only close. The StroboStomp is sensitive enough that one pluck provides the pedal with enough data to get the job done.

There is a reason Peterson tuners have been used by the vast majority of touring guitarists since the 1970s—ease of use, deadly accuracy, and reliability. In researching this column, I realized how complicated the science and theory behind tuning an instrument really is. It is something we all take for granted, even those of us who know what it’s like to have to tune by ear alone. In fact, it is our ear’s precision coupled with the limitations in equal temperament tuning that make precise tuning by ear nearly impossible. So while a mod effect or distortion pedal is a purchase with a more obvious gratification than a tuner pedal, once you become accustomed to precise tuning, you cannot go without it.