Sean,
The short answer to your question is that there is no need to buy an expensive tuner to tune a pedal steel guitar; any decent tuner that displays Hz and cents will do.
There are tuners like that for under $20, such as the Seiko mentioned above.
The other thing you will need is a tuning chart, and Jeff Newman’s will do fine; it is available as a free download at:
http://www.jeffran.com/tuning.php
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Here is the longer answer as to why tuning the pedal steel is so challenging…
About 2500 years ago, the Greek mathematician Pythagoras used mathematical ratios to discover the musical intervals that sounded the most in tune to the human ear. When a fixed-pitch instrument is tuned to “Pythagorean Tuning†based on the “pure†or “perfect†interval between the root and the fifth scale-notes of the key, most people find this tuning system very pleasing and harmonious.
For more info:
https://en.wikipedia.org/wiki/Pythagorean_tuning
However, there is a big problem with “Pythagorean Tuningâ€, and that is that it only works for a couple of closely related keys; certain notes in other keys will sound out of tune. This is due to the mathematics of calculating musical interval ratios between root and fifth notes that Pythagorean Tuning uses.
- For example, an A note will be 440 Hz in the key of A, but be 446.1 in the key of D. A difference of 6.1 Hz will sound very out of tune, even to non-musicians!
Why does this matter to steel guitarists?
Because much of the time when you engage a pedal or knee lever, you are effectively playing in a new key:
- When you step on the A and B pedals together, you are effectively modulating from the key of E to the key of A; now the root note is A and the fifth scale tone is E.
- When you engage the A pedal and the knee lever that raises your E’s to F, you are effectively playing in the key of C#; now the root note is C# and the fifth scale tone is G#.
This means that the note which was the root in one key is no longer the root and neither is the note that was the fifth scale-tone. And the third scale-tones are often out of tune in the new key, which means that many chords do not sound good.
The “Equal Temperament†Compromise
Pythagoras' “pure intonation†tuning system was widely used for over 2000 years, despite the limitation to just one or two keys.
In the 1600s, JS Bach joined the movement to alter the tuning system so that music could be played in all 12 keys, by writing a collection of preludes called the “Well-Tempered Clavierâ€. To perform these preludes, the clavier (an early form of a piano) was tuned “equally temperedâ€, a compromise tuning in which an A always equals 440 no matter what key is being played. This compromise is not noticeable to most non-musicians—and musicians just learn to accept it.
For more info:
https://en.wikipedia.org/wiki/Equal_temperament
https://en.wikipedia.org/wiki/The_Well-Tempered_Clavier
This compromise “Equal Temperament†(ET) tuning system became widely used in the Western world, and is the system used in most electronic tuners. However, many pedal steel guitarists are not comfortable with how their steel guitars sound when tuned to ET, and they adjust most of the notes with “Just Intonation†(JI) which is very close to Pythagoras’ “pure intonationâ€.
For a good summary of all of the above topics:
https://en.wikipedia.org/wiki/Just_intonation
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“Just Intonation†tuning charts for the pedal steel:
Many years ago, Jeff Newman used a very accurate stroboscopic tuner to measure the frequency of the “Just Intonation†tuning system that Lloyd Green used in the recording studio. From these measurements, Newman produced his first tuning chart based on A equals 440. (Later he produced a second version in which A equals 441--apparently to accommodate “cabinet dropâ€.)
I prefer Jeff Newman’s first tuning chart (A=440) with the pedals down, and then I adjust the pedals-up B strings from the pedals-up E strings to accommodate cabinet drop. I got this idea from Larry Bell at:
http://www.larrybell.org/id29.htm
I still use a Boss TU-12 tuner that I bought 20 years ago for about $45--with a copy of Newman’s tuning chart taped inside the cover.
What looks to me to be the same tuner is now called Boss TU-12H, and it still costs just $45!
However, any chromatic electronic tuner that displays both Hz and cents should work fine.
I hope this is helpful.
-Dave