Godzilla's roar, what is actually making that sound?

[chacoguy]

Well?

[TWDuke]

Ted Cassidy.

[Kamino Neko]

A glove was run over the strings of a contrabass, then the resulting sound was altered. Google is failing me for reliable cites, so Ask Metafilter will have to do.

[CalMeacham]

I have heard the same explanation Tengu gives. It was authoritative, but I can't remember where it was. The glove was a leather one, and it was rosined up and run along a bass string.

[TWDuke]

How's this for a cite: http://www.akiraifukube.org/biography_part_four.htm ?

In 1954, Ifukube was asked by Toho to score Gojira (Godzilla), a giant monster film to be directed by Ishiro Honda. Many of Ifukube's colleagues tried to convince him not to take the job, thinking the film would not be a success. Ifukube did not listen to his detractors and accepted the project. As a result, his score for Gojira has become one of the most famous film scores in history and propelled Ifukube to heights of fame that no other Japanese film composer has ever reached. Additionally, Ifukube regarded his Gojira music as the best score he had ever written for a motion picture.

Ifukube also created Godzilla's trademark roar. Technicians at Toho originally went to the Tokyo Zoo and recorded the grunts and growls of several animals hoping to find the perfect sound effect for Godzilla's roar. Dissatisfied with the animal sounds they had collected, the technicians turned to Ifukube, an expert in acoustics, and asked him to produce the needed sound effect. After some experimentation, Ifukube recorded himself taking a resin-covered leather glove and dragging it along the loosened strings of a double bass (the largest and lowest pitched bowed orchestral string instrument) and slowed down the playback speed of the tape. The result was the now familiar Godzilla roar. Additionally, Ifukube created the sound of Godzilla's footfalls by striking an amplifier box with a large, knotted piece of rope.