Before and After

Presented along with this narrative is the before and after audio track of the disaster processed with Diamond Cut Productions DCForensics11 software to remove some of the noise and other anomalies.

The Hindenburg’s final excursion was intended to be the 62^nd round trip from Frankfurt, Germany to the United States. This photo was taken a few hours before the disaster that occurred at its mooring mast in Lyndhurst, NJ. The captain took a diversion over New York City and then along the NJ shore before its’ final destination at its mooring dock and hanger.

The Disaster

Ever since mankind walked the earth and observed the capabilities of our fine feathered friends, the birds, humans have desired to be able to fly like a bird and have pursued that end. Earlier than the days of Leonardo da Vinci, machines had been envisioned to permit us to take to the skies like the birds. The first practical flying machine was a blimp like structure (or Dirigible) driven by a 3 HP steam engine on. September 24^th 1852 when Henri Giffard flew 17 miles in France at the rip-roaring speed of 13 miles per hour. From that point forward, the race to produce a practical lighter than air flying machine was on.

It came to be understood that a rigid structure for an air ship would provide a more provide a more practical approach and one was first constructed by Count Ferdinand von Zeppelin in the 1890s in Germany. This prototype was powered by 2 internal combustion engines made by Daimler producing a total power of 28 HP total. This experimental lighter than air flying machine was dubbed the Zeppelin LZ 1 which began the era of the practical airship industry.

LZ 1 the first ridged airship using aluminum as the sub-structure.

Many Zeppelins were constructed and used for pleasure cruises, military surveillance and for dropping bombs on enemies. Most of these lighter than air Zeppelins met their demise due to mechanical failure and fire (they used Hydrogen rather than Helium as the air displacement mechanism in order to provide greater buoyancy). Hydrogen has lower density (greater lift) than Helium and its availability (the U.S. would not sell them Helium) was better than for Helium. The downside of Hydrogen was its flammability.

The Hindenburg flew 62 round trip flights between Frankfurt, Germany and the American continent. The destination was mostly the greater NYC area with Lyndhurst NJ as the mooring location.

The airship was 804 feet long which was almost the length of the Titanic and was propelled by 4 x 1,100 HP Mercedes diesel engines. May 6^th, 1937 becamethe Hindenburg’s last excursion across the Atlantic when itsattempted mooring at Lakehurst NJ resulted in a fire broking out near the tail section of the airframe. The disaster was recorded on cine (film) and audio disc as well. Audio was recorded on a lacquer disc via a Presto instant recorder for airplay later on WLS radio out of Chicago, Illinois by a newsman by the name of Herbert Morrison with the aid of radio recording engineer, Charlie Nehlson. At the time of the explosion, the heat was so high that it melted Morrison’s jacket and caused the cutting stylus of the Presto lathe to jump (which was quickly fixed by the engineer, Charlie Nehlson) so Morrison could continue on with the audio documentary. The human toll due to the disaster was a total of 35 dead out of 97 passengers and crew plus one of the ground crew. The Hindenburg disaster ended the era of lighter than air commercial flight and was replaced with fixed wing (heavier than displaced air) flight that we so commonly use today.

There are several theories concerning the ignition of the ship including sabotage, lightening, electrostatic discharge and electrical malfunction. None have been proven one way or the other. But one thing for certain is the fact that it held 7,000,000 cubic feet of hydrogen gas which fed the fire. Later in time, someone synced up the motion picture with the audio recording, which most of us have heard and seen before. (Hydrogen burns bluish, but eyewitnesses observed much red in the conflagration).

This shows one of four 1,100 Horsepower Mercedes Diesel Engines used to drive and steer the ship. These engines had the unusual capability of being reversible and also being serviced while in flight. A ramp ran between the air-ship and the engine pods so that the engineers could access them in flight.

Here is another photo of the Hindenburg flying over New York City, but taken from a different angle.

This photo shows the dining room on the Hindenburg. Note the glass windows above the walls on the right hand side of of picture which allowed the passengers to view the passage as it progressed between continents.

Another dining room photo showing the windows overlooking the surface over which the ship was flying.

Passengers enjoying the view from the lounge area of the airship.

Another view of a Hindenburg Dining Room.

Exploded view (no pun intended) of one of the Graff Zeppelin power cars (pods) which was of similar construction as the Hindenburg’s setup. It looks like a pretty dangerous jobs to have aboard these air-ships.

The remains of one of the power pods as seen after the disaster.

One of the Mercedes 1,100 HP Diesel Engines from the Hindenburg.

Another view of one of the engine pods as seen after the disaster.

One of the 4 x 1,100 HP engine pods with workmen ‘walking the plank’ to gain access to the engine proper.

The Hindenburg main control room (bridge).

The explosion that occurred as the Hindenburg approached the mooring dock in Lakehurst, NJ.

A different viewing angle of the explosion that occurred as the Hindenburg approached the mooring dock in Lakehurst, NJ.

Ground Crew running away from the flaming Hindenburg deluge.

The Remains of the Hindenburg after the disaster as seen from above

Herbert Morrison, the announced heard in the restored audio (his jacket melted due to his proximity to the burning remains of the airship.

Brief summary of the Hindenburg Recording Restoration process

The instantaneous Presto disc used by Morrison to record the disaster had numerous flaws which needed to be repaired. The software used in the restoration was DCForensics11.03. The first problem encountered was a “skip” by the recording lathe as it jumped out of its tangent when the explosion occurred. This was fixed using various Diamond Cut Edit commands found under the edit menu (sometimes used selectively).

While the recording was being made, much friction must have existed between the cutter and the disc was encountered making the recording slower in speed. This was observed using the high resolution spectrum analyzer and confirmed using the spectrograph. The speed change filter was adjusted until the 60 Hz line frequency noise moved up to a true 60 Hz (about a 5 Hz offset). This produced a more natural sounding human voice.

Next, was the issue of the very big clicks hear in various spots which were repaired using the big click impulse filter by itself? Smaller clicks and pops were reduced using the EZ Impulse filter using all three modes (scratch, crackle and narrow crackle). This was done by ear. The residual hiss was reduced via the Continuous Noise filter (note that the recording has a very limited bandwidth.

Finally, I applied the 30 band graphic EQ carefully to bring up the key speech elements of the human voice which improved the intelligibility of the signal.

Equipment used to capture the Hindenburg Disaster in real-time