A flute student who is trying to figure out why their flute is consistently flat. even though the headjoint is pushed all the way in, wrote to me on my "comments" this week, and so I thought I'd just add a checklist here for those who find their flutes seem consistently flat.
What could be the cause of a flat flute?
Most common causes of "flat" flutes (will not play in tune at A-440):
1. Headjoint cork is out of position.
The crown of the flute if twisted to tighten it, actually pulls the flute's headjoint cork outward a millimeter at a time for every revolution of the crown (many students don't know this.)
Check your headjoint cork position with your cleaning rod to see if it's set at 17.3 mm. The mark on the end of the rod should show in the center of the blow hole. Some cleaning rods are mis-marked. So if you suspect your cleaning rod's mark is incorrect (as some are) measure the cleaning rod's marking with a fine ruler in millimeters. The marking on the rod should be at 17.3 to 17.5 millimeters from the flat end. (double click picture to make larger, then use back button to return here.)
2. Your lower lip is over-covering the blow hole.
For playing in the low register, be sure that your lower lip is not over-covering the blow-hole. For low and middle register the lower lip should only cover 1/4 to 1/3rd of the blow hole of the flute.
3. You are trying to check your tuning with a cold flute in a cold room.
It takes a few moments for a flute to come up to pitch if it is cold. If you are trying to tune a cold flute, it will always sound flat. So, before tuning, close all the keys and breathe slowly through the closed tube to warm it up. Do this prior to beginning to tune, and in rehearsals, do this after several bars rest, so that the flute is warm when you re-enter the piece of music.
4. You are blowing too softly, too slowly, or too timidly.
This is very very common.
To learn to play a flute with a large, resonant, round sound is one of the first things you'll learn in private flute lessons at the intermediate level. Almost all beginners tend toward playing too quietly, and wasting their air (too large a lip-aperture, or unknowingly allowing air to escape through their nose as they blow).
To correct this, see this article on how to learn to play forte with a full sound.
For more information about common reasons for flat pitch see these articles on my website:
Why would novice flute band students play consistently flat?
How do I tune in a cold room or rehearsal hall?
How can I fix a flat low register?
Dozens more general Flute Tuning articles for beginners, intermediates and advanced players are here.
In general I think that it is possible (but very very rare) that the student who originally wrote to me about playing flat in pitch is playing a flute that cannot be made to play in tune at A-440. Some antique flutes still exist that are pitched at A-435 to A-439, and there are miscellaneous old band flutes (more than 40 years old) of unknown origin that may have a slighly larger diameter, or oversized flute length or headjoint length.
However almost every modern flute I've ever seen that played "flat" had either the headjoint cork in the wrong place (too far out) or the student was playing with slow air and a small sound and often too rolled in on the chin as well.
In general, to bring a flute up to pitch, if flat, the student needs to practice on a daily basis on increasing the amount of air speed that they blow the flute with. They need to increase the FORTE end of their dynamic range, and work on a smaller and more precise aperture in their lips to create a more vibrant and full, colourful sound. This takes time, and is best done with the help of a private teacher.
Once you've learned to play with a full rich and resonant sound, you may find that you indeed are pulling the headjoint out because the flute is now too sharp.
You may also find that you need to raise or lower the flute's pressure on the chin so that the "air-reed" is lengthened. This is all part of the learning curve for novice and intermediate flutists.
Once a flute's headjoint draw position allows the flutist to be consistently in tune (when warmed up) over all three octaves, and their skills are starting to develop for playing in tune using dynamics, it's a good idea to mark the best headjoint draw with a shiny-surfaces permanent marking pen, to allow quick assembly each and every time you put the flute together. Having a single placement of the headjoint develops consistency that is necessary to further discoveries about tone quality, air-speed and tuning.
You can always remove the mark and re-mark using such a marking pen (remove with alcohol)if your embouchure and style of playing changes over the course of your own tone development.
However I find that once located, the marking method is a boon for daily consistency. Student flutists can pre-set to their normal marking and then just heat the flute gently in order to play in tune with any ensemble.
For the novice flutist who's still working on all the variables (air speed, blowing angle, tone quality, pitch, etc.) marking the headjoint's draw is still an excellent method to guage what changes are being made over time.
Just by knowing that you played in tune for a week or two at a certain headjoint draw, and always lining up the same way, you may find that if you do find your flute playing flat, you'll know that it's only because you are:
a) playing in a too cold room
b) playing with too slow an air-speed.
c) rolling the headjoint inward, or over-covering with your lower lip.
d) aiming the air downward too far in angle.
e) and, last but not least; playing with other instruments that are sharp (un-tuned pianos, sharp string players, clarinets that are squeezing their reeds and sharpening unexpectedly etc.)
At least you aren't moving the cork around anymore, without realizing it, because you know now to leave the crown alone. hahahahaha.
Remember to check your cleaning rod's cork placement mark for accuracy.
There were a slew of cheap flute cleaning rods with wrong markings around for a decade or more. Doh. :>)
Hope this helps,