jboger wrote:OK, you got me on the reverse doppler effect. How would it have been produced in 1918 for objects traveling through air? Air doesn't have the right physical properties to produce this effect. I know that it has been observed in more recent times but only for such exotic materials as known as metamaterials. These are not naturally occurring materials and were not available in 1918 and not for many years. If this record includes a recording of an object (missile) supposedly moving towards the listener but somehow the pitch is made artificially lower (longer wavelength), then that's not really the reverse doppler effect but an artifact of the recording process.
But I've been wrong before so if anyone would care to enlighten me, I'm all ears.
As a physicist, I long thought about what could produce that reverse-doppler effect sound. The only (very weak) thing I could come up with is that perhaps a steep variation in air density/humidity could produce unusual effects, and possibly a battlefield saturated with yprite and black powder exhausts fits the hypothesis. But, as said, I don't really believe it.
Period witnesses, in any case, said the shells had some type of wings that would produce a whistle. I would say, in turn, that I'm fine with the whistle
per se; it's the increasing pitch that it's nonsense. It seems to me the sound of an object which is
accelerating, while a projectile can do nothing else than
decelerate once it leaves the cannon's mouth. Perhaps Katjuša rockets would produce a similar sound, but not a ballistic projectile.
I have to say that I completely ignore what kind of weaponry was used when the recording was made. In either case, however, there's something "suspicious" in the record. I don't think that self-propelling shells like Katjušas were available by the end of the Great War, but if that was the case, then the boombs and bangs of the cannons are artifacts. If the shells were shot with cannons, then the accelerating sound of the projectile is almost surely nonsense; moreover, the dB gap of the sound pressure between the boom of the cannons and the whistle and the voice orders would be many orders of magnitude. I doubt that even contemporary electronic equipment could deliver a decent recording of sounds of such different magnitude, go figure a primitive cylinder recorder, which had problems even capturing a piano and a tenor at the same time in a quiet room.
Summing it up, my educated opinion is that Mr. Gaisberg really did recordings of a gas shell bombardment, which are the less-than-impressive bangs, dings and crackles that can be heard on the background of the record. Then later, in order to "improve" the impact of the recording, while dubbing to disc other artificial sound effects were added with a bass drum and a whistle by people who saw a battlefield only in pictures, as well as by a self-appointed "commander" of the artillery unit.