Exploring the evolution of tuning machines, breaking down the importance of weight, placement, and gear ratios.
Although tuning is such an essential necessity, and key to an instrument's usability, the history and evolution of tuners is relatively simple. While there is resistance to technology among some of our fellow bassists and guitarists, the fact that most instruments of the violin family are still using old-style tapered-friction pegs tops us all. It's worth noting that there is onemember of this family that was an early adopter of geared tuners: the double bass! Could it be the earliest sign of bassists' greater openness to new technology?
The higher an instrument's tuning and frequency range, the more important tuning to exact pitch gets. Anyone who has ever heard an out-of-tune violin should be pleased about their additional fine tuners, which actually bring violins somewhat closer to what's used on tremolo-equipped guitars. (I'm curious if there has ever been a violin with a locking nut. Seems there should be!) For upright basses, the precision of geared machine heads marked the end of the need for fine tuners.
The first electric basses had the same-style open-geared tuners as upright basses, just slightly scaled down in size. (Today, the most popular tuners continue to be geared rotary tuners.) The next evolutionary step was to move to a smaller, closed housing, including permanent lubrication and, more importantly, less weight.
One reason why weight is so crucial is the tuners' location on the headstock. The headstock weight discussion could have been over when linear tuners showed up in the '80s. Not because of linear tuning itself, but because of their placement, which results in better overall weight distribution. You can read more about their functionality and advantages online in my “Introducing the Headless Bass" column. Despite the fact that the headless bass and its linear tuning have relatively no disadvantages, the rotary tuner still rules the market.
While it's sometimes said that bassists are some of the earliest adopters of new technologies, there is one trend that never took off for bass: automatic tuners. Automatic tuning is a motor-driven tuning process where, most often, a piezo system is sensing the pitch. It sounds pretty cool, but it had only a short period of popularity on the guitar market, and I don't recall ever having seen a bass equipped with them. While they are still available for guitars, they rarely make headlines any more. I think one reason for their limited success could've been the need for electrical power on an otherwise passive instrument—something that already keeps many of our 6-string comrades from using active electronics. There's also the extra weight of the six motors at an unfortunate location (the headstock). Could it perhaps be time to give them a try on a headless instrument's linear tuners?
Most bass tuners have a gear ratio around 20:1, which means 20 turns of the peg pin results in a full turn of the capstan. Note: Varying the diameter of the capstan is a very effective way to influence tuning, as any change in diameter results in a squared change of its circumference. The higher the gear ratio, the more precise the tuning, but there is a practical limit. Even though 100:1 sounds like a logical and aspiring improvement in terms of precision, a simple restringing would call for the aforementioned electric motors. For argument's sake, let's just say 20:1 is enough, but it's curious that for years no one really questioned why the gear ratio has to be the same for all of the strings.
Canada's Graph Tech, however, did recently make the step in offering accommodated gears for each of the strings. While first only available for guitars, they are now available for bass. The system is marketed under the brand “Ratio," and Fig. 1 shows the different gears for a 4-string bass, where the varying gears range from 48:1 for the 4th string to 23:1 for the 1st string. One might wonder which of the different parameters Graph Tech wanted to keep constant across all strings, but it's as simple and logical as this: One turn for a full note!