Where this gets confusing, if you’re thinking from a “I took music theory in college!” standpoint is that the keys of the instrument aren’t named the way you think they are. In “classical” music, we name the key of the instrument after the pitch we hear when you play a C-natural on the instrument. For example, if you play a C-natural on a trumpet, you’ll hear a B-flat, so the trumpet is in the key of B-flat. Play a C-natural on flute and you’ll hear a C-natural, so the flute is in the key of C. So, if an Irish flute is in the key of D, that must mean that if you play a C natural, you’ll hear a D, right? Wrong! With folk flutes, things are different – and they’re also inconsistent, depending on the flute or country of origin.
Irish flutes and whistles
For Irish flutes and whistles, the instrument’s key is determined by the sounding pitch when you cover all the holes, essentially playing the instrument’s lowest note. That means that if you play a D on an Irish whistle, you’ll hear a D. So the “Whistle in D” is in the key of C!
This concept gets even more mind-bending when you’re on a “Whistle in E-flat”. When you play a D on the whistle, you’ll hear an E-flat.
Whistle in E? Play a D, hear an E.
Whistle in F? Play a D, hear an F.
…and so on…
For this reason, some people will insistently call the whistle a non-transposing instrument, but I have absolutely no use for this way of thinking. Given the commercial settings we’re often facing, it’s unreasonable to expect musicians to constantly juggle which key of whistle is in their hands at the moment and remember whether 6-fingers is going to produce a D or an E-flat. For example, in the musical Come From Away, the flute book calls for 15 different whistles, covering nearly the full range of the available keys (in addition to other instruments). When making quick instrument changes to account for key changes (which are fairly prevalent in Broadway music), it would put far too much stress on a musician to think of each of 15 different whistles with a different fingering system. For that reason, it’s imperative that we standardize the notation of the sheet music so that everything for Irish flutes and whistles is written in the key of D or G, with the composer, arranger, orchestrator, or music copyist having “done the math” in the background to account for the quirky transpositions and key namings of these instruments.
Some trad players who are set in their ways might argue against this. Some actually prefer to pick up a whistle in E-flat, put all six fingers down, and think “Ahh, I’m playing an E-flat.” I do not and will never understand those people or how their brains work. I’m not saying we should change the system they currently use. But when we’re trying to fit that style of music into a another system that uses more modern conventions, we have to find ways to compromise and make it work. Without doing so would severely limit the accessibility of this type of music for classically trained players.
It is crucial that we urge composers, arrangers, orchestrators, and music copyists to transpose music for Irish flute and whistle into the written key of D or G whenever possible.
Note: another thing you’ll want to keep in mind is that, often, you’ll want a whistle that is in a different key than the tune you’re playing. Because the bottom end of a whistle or flute’s range starts on the 1st scale degree (“Do”, or in this case, D), you lose the ability to start a phrase with a pickup note on the 5th or 7th scale degree (“Sol” or “Ti”), which can limit your creative expression. Therefore, we’ll sometimes want to play the tune in the key of G, but on a whistle in D. That gives us access to a pickup note of D-natural or F-sharp to lead to the tonic. Whether or not this is ideal depends on the tune, but it should be kept in mind as an option.
Bansuri and Dizi
Bamboo flutes (bansuri and dizi) mostly follow the same convention described above, but there are some differences.
Typically, these flutes are “keyed” by the pitch heard when you cover three finger holes, rather than 6. It is also common for the flutes to be referred to by both its “Tonic” (the pitch heard when you cover 3 finger holes) and by its “Key” (the pitch heard when you cover 6 finger holes). This can be quite confusing, especially if you’re just getting started and looking to buy a flute. Don’t be afraid to ask questions before making a purchase. It’s ok to be a beginner at something again and ask for the right type of guidance!
Jeff Whittier is one of the more prominent bamboo flute makers in the United States, and made the flutes for many Broadway musicals, including Aida, The Lion King, The King and I, and Miss Saigon (the original version and the 2017 Broadway revival). His flutes are available for sale on One World Flutes. When looking at the listings, you can clearly see the distinction between a flute’s Key and its Tonic.