As to the acoustics of it all, I'm hoping somebody like Terry McGee will weigh in and offer their thoughts.--James
Urk! Better late than never, I suppose!
The foot, it seems to me, has a lot in common with the embouchure. It's at one end of the flute, is poorly understood, and seems to affect people differently.
Historically, we started with the baroque style flute, terminating in D. What I'd call the Short D foot.
In the late 18th century, English makers added C# and C, making what I assume we'd all call a C foot. They scored a lot of flak from people like Quantz and Tromlitz, as these authorities argued that the extension down to C weakened the D note substantially. To get down to C, the bore has to continue to taper narrower and narrower, far smaller than that of a Short D flute.
(There were some flutes that only had the C# - the nautical explorer Mathew Flinders played a beautiful boxwood flute by Richard Potter that only went down to C#. German and Austrian makers also made feet going down to B, Bb, A and even G!)
When it came time to invent the keyless Irish flute in or around the 1970's, several approaches appear to have been taken. Some makers went with the 8-key's C foot, just leaving off the C# and C keys, but preserving the C foot length and bore. I (and maybe others, I just don't know) created what I now call the integral foot - a foot terminating at D like the Short D foot, but integrated onto the RH section. No point in having a separate foot if there are no keys on it. And no point having the length and bore of the C foot if (as Quantz, etc had maintained) it screwed up the all-important low D note.
But some players wanted the full length of the old 8-key flute, so I (and maybe others, again, I really don't know) investigated what could be done to retain the C-foot length, but avoid Quantz's alleged weakening of the D. I call the result a Long D foot. Not just a C foot without keys, but a reworking of the bore to give a D note as full as that on a Short D flute.
So that gives us these feet options:
- Short D, as per the baroque and early keyed flutes
- C foot, with C and C# key
- the less common C#, B, Bb, A and G feet of history
- C foot, but with the C and C# keys not present
- Integral foot, as per Short D but integrated with the RH section, and
- Long D - a foot optimised for D, but with the length of a C foot.
(the two last being inventions of mine, but perhaps also of others)
There may be more options; I'd be keen to hear.
So having summed up the history and the resulting options, let's return to the topic - what are the pros and cons of the various approaches?
Acoustically, I'd say the Short D, Integral foot and Long D approaches are best (assuming you only want to go down to D. Obviously if you want to go down to C, then you have no choice but to adopt the C foot). I agree with Quantz et al, a C foot, with or without the C and C# keys, noticeably weakens the D. The science backs it up, and the difference to me is quite night and day.
But that's when I have to bring something quite bizarre to your attention. Not everyone agrees! I've met plenty of players who don't seem to notice the difference. (I don't think I've met anyone who actually thinks the D is enhanced by that extra baggage, but they may well be out there.) And I have no reason to think that they are having me on - to my ears they can produce as good a D on a C foot as on a foot optimised for D. But there are more who can't, and so that brings me to the conclusion that, like embouchures, feet are a matter of personal taste. And therefore quite an important matter to find out which team you are in.
As Fats Waller put it so sensitively:
Oh, your feet's too big
Don't want ya 'cause your feet's too big!
Mad at ya 'cause your feet's too big
I hate ya 'cause your feet's too big
You know your pedal extremities really are obnoxious.
But there are also matters other than acoustics. The Short D/Integral foot flute is considerably shorter than a flute with the C foot, C foot without keys or a Long D foot. This can be seen as a pro or a con, depending on a number of issues. The longer flute is probably more visually attractive, but many customers have said to me that the session in their pub is so cramped a short flute is essential. A short flute is lighter, but may not be so well balanced as a long flute. A "head heavy" flute is a liability, but short footed flutes don't have to be head heavy - it depends on issues like whether the head is lined, how much stuff is above the embouchure and whether weight has been redistributed into the lower parts of the flute. Argghhh! Am I answering questions or posing them?
Summarising all of this, I'd say that many players will do much better with a foot optimised for D (whether short or long), and so if you are having difficulty getting the kind of low D you want, you may want to check out a flute with a D-optimised foot. Just like if you are not happy with your flute playing overall (after putting in enough work!) you might want to check out the results you get from a more modern embouchure cut.
The question of visual aesthetic remains a personal taste issue. The question of fitting in a cramped session environment is a practical issue.
If you decide you need or would prefer a short flute, make sure it's well balanced. It shouldn't drop away from your lip when you take your fingers off. You shouldn't have to keep it there by pinching it with your left hand or holding it down with R4. A short flute should play like a storm!