... in which the writer demonstrates his ignorance

[david_h]

Would a pair of sound-detecting devices about six inches apart help in locating the source of the sound?

You might need an extra pair, not attached to the source of the air flow.

More seriously, you'd probably also need some acoustic baffles as Conical Bore suggests.

Yes. Ears.

They, and their processing system, are designed for localising sound sources. I don't know if mine have equal sensitivity; if not frequent recalibration using visual data must be compensating.

I am not sure about the baffles - what I read about binaural recording makes me think it would be best not to mess with the system. Though maybe an experiment with a baffle between the embouchure and tone holes would help

An environment with few reflectors would be good - a mosquito in the room can be hard to locate until it gets close but in a big outdoor space it is usually easier.

A simple setup would be the blindfold the listener and then ask them to home in on the sound, facing where it seems to come from. Could test the ability to localise with a recording of a flute played on a phone speaker.

With only the players pair available I think it is easy to partially answer the question in the OP. If the sound was all comming from the lowest open hole it ought to be obvious when playing the bottom note. I can get a reasonable tone playing left handed (closing the holes is the harder) and the sound still seems to come from somewhere near the embouchure.

I reckon an experienced sound engineer, who is attentive to the requirements of his/her trade, can probably work it out without test equipment.

[fatmac]

Well, another scenario, take the head alone, blow into the embouchure opening, you get a note, now take the tube with holes in it, & blow down it..........

[Steve Bliven]

Well, another scenario, take the head alone, blow into the embouchure opening, you get a note, now take the tube with holes in it, & blow down it..........

I think there's general agreement that the sound is produced at the splitting edge in the head. What's unclear to the poor OP is whether some/any/none of the sound travels down the tube to exit at the tone holes or the flute butt.

Still not clear to me,

Steve

[paddler]

Sound is a vibration that disperses in all directions. The energy source that initially causes the vibration is the player's airstream that hits the splitting edge of the embouchure. Prior to hitting the edge that air stream has energy, but is not really generating much sound. When the airstream hits the splitting edge it causes some energy to go into the flute. The air column inside the bore of the flute resonates at various frequencies depending on which tone holes are covered and the speed of the airstream. The sound primarily comes from that resonating column of air. Its vibrations are transferred to the air outside the flute in various ways. First there is contact between the vibrating air column in the flute and the outside air at the embouchure hole. There is also contact at the open tone holes and at the open end of the flute, and through the walls of the flute itself. The vibration of the walls is measurable, and may contribute to the resonance of the air inside the flute, but does not cause audible vibrations outside (the flute is not a sounding box). The transmission of vibrations at the embouchure is always strong, regardless of the note being played. The transmission of vibrations via the foot of the flute is strongest when all tone holes are closed. The degree to which an open tone hole terminates the vibrating column of air inside the flute depends on the size of the tone hole and the frequency of the note being played. For example, baroque flutes with small tone holes have many cross-fingered notes, showing that the first open tone hole does not terminate the vibrating air column and hence the vibrations continue further down the flute bore and impact the outside air at other open tone holes too.