What MHz would my antique German/Austrian flute be playing at? It’s stamped, LP.
Thanks and best wishes,
Keith.
[Edit: Mz → MHz. - Mod]
Most likely “diapason normal”, A=435Hz, but might be 432 or even lower. Bear in mind that, with a tuning slide, just like contemporary English or other nationality flutes, it will have c 3cm/over a tone’s worth of tunability and that the design reference pitch will not be with the slide fully closed - that’s just the sharpest it can reach.
Of course, a 1 MHz flute is definitely high pitch. 
A flute pitched in MHz would more commonly be called a radio transmitter, likely made in the 20th century. Herz (Hz) will get you in the audible range.
Terry McGee has some info on historical pitch (at least for English flutes): http://mcgee-flutes.com/eng_pitch.html
But yes, for a German/Austrian flute, A=435 is probable…unless ‘LP’ stands for ‘Low Pitch’ (which would be odd on an instrument of Germanic provenance).
Though, interestingly, there is some overlap. For example, 20 kHz is within the hearing range of some people, but it’s also VLF (very low frequency) in the radio spectrum - used for navigation services and underwater communication. I have a radio that goes that low, but the selection of Top 40 stations down there is really crummy.
Also, of course, what’s vibrating matters - physical pressure waves in air or an electromagnetic field. If your flute is producing 20 kHz harmonics, it’s still not a VLF radio (and I remember this confused me for a long time).
Having just finished a Biography of Nikola Tesla, I"m happy to report he was early on investigating ELF (Extremely Low Frequency electromagnetic waves) and prophesied that the Earth had resonances of 6, 18, and 30 Hz. It was in the 1960’s researchers were able to refine this to a measure of 8, 14, and 20 Hz.
Along with his electromagnetic researches, he studied what would be today called Statics and Materials by studying the sonic resonances of structures. He had a series of run-ins with the NYPD when he nearly collapsed the building his Lab was in and terrifying the neighborhood that earthquakes were occurring when he studied the resonant frequency of structures with mechanical oscillators. Always the showman, he told the press he could bring down the newly constructed Brooklyn Bridge with a portable device that could fit in his pocket within a matter of hours of being employed. This, as well as the generation of chain and ball lightning up and down the streets of his lab late at night helped precipitate his moving out to Colorado Springs.
Be careful when you ‘honk’ the D on that LP flute! 
Actually, if you play your flute in or near a plasma, you definitely can generate radio waves with your flute. For example, acoustically modulating a carbon arc or an oxyacetylene flame. Don’t ask me how I know this. 
I’m guessing that Homeland Security just opened a file on you…
Best wishes.
Steve
No. Despite being English language abbreviations, “LP” and “HP” stamps are by no means unusual on later German/Czech/Austrian instruments. However, the precise import of such stamps should not be assumed. High or low relative to what? Bear in mind that the Markneukirchen/Graslitz makers were exporting instruments all over, including GB and especially the US. The majority of “LP” stamps do mean diapason normal A=432-5Hz, but sometimes they can mean modern Concert Pitch - low in relation to English high pitch - you need to check sounding lengths to be sure which. Similarly “HP” most often refers to English high pitch, A=450+, but conceivably it might signify modern CP, high in relation to diapason normal…
An Seanduine said: “Be careful when you ‘honk’ the D on that LP flute!”
Thank you very much. But too little too late. I am now missing six finger prints and my nose hairs.
I have a terrible cough and talk in a high pitched whistle …
What is more, I think my gonads have retracted.
K.
At the very least, I suspect that the physics department at Stony Brook University may still be angry at me. It turns out that sensitive lab instrumentation and other experiments in progress don’t like being bombarded with electromagnetic garbage by a mad intern. Who knew? 
Plasma speaker? Or would that be a plasma microphone?
Yes, exactly right.
Thank you all!
Best wishes,
K.