2008-12-28: Recordings from our first Golden Gate Bridge walk are at last converted to MP3 and shared on our Sounds pages.

“Does the Golden Gate Bridge make sound?” That was the question as we set out to cross the bridge on the brisk morning of December 28, 2008. This was well before we had a web site. It was early morning and a little cold. Not too much traffic yet.

This first walk across the bridge yielded these 24 approximately 1-minute samples in 96 kHz 24-bit .wav format (these have been converted to .mp3 to reduce file sizes). A hand-held Sony PCM-D50 linear PCM recorder was used along with a Fishman V100 piezo ceramic violin pickup and a modified viola bridge. The bridge had a rubber bumper added where the strings normally go, allowing the feet to be pressed manually against the target; the idea was, if the bridge made sound, we’d buy a better mic. We didn’t know how close we could get to the cables or how large they were. The audio is sometimes scratchy as the feet of the viola bridge slip and click against the cables and other metal. Occasional bits of passing conversation appear, along with the constant strumming of the whole structure by vehicular traffic.

Audio files are available on freesound.org for re-use and mixing: each file link below points to the corresponding download page. If you do re-use the work, please contact us to post a trackback to your new composition and announce what you’ve done.

Sights and sounds

December 28, 2008

The walk starts on the east walkway leading up towards the cement pylons at the south end. The traffic noise is especially loud if the pavement is wet.

File GGB southeast approach SAE T01 at freesound.org

The first interesting metal appeared to be the various safety handrails. There are multiple short strands of steel on the traffic side. The outer handrail, though, is a thicker cable that follows the main “catenary” curve to allow safety lines to be fastened during maintenance activities.

File GGB inner safety rail SAE T01 at freesound.org

File GGB inner safety rail SAE T02 at freesound.org

File GGB outer handrail SEE T01 at freesound.org

The various suspender cables appear as clusters of four—actually, the ends of two “loops” over the main cable. Suspenders are longest near the towers.

File GGB suspender SE01SW at freesound.org

File GGB suspender SE02SW at freesound.org

File GGB suspender SE03SW at freesound.org

File GGB suspender SE04SW at freesound.org

File GGB suspender SE08SW at freesound.org

File GGB suspender SE12SW at freesound.org

File GGB suspender SE16SW at freesound.org

File GGB suspender SE20SW at freesound.org

File GGB suspender SE21SW at freesound.org

The towers have a thick sheet steel skin riveted to an internal bracing structure.

File GGB tower SEE at freesound.org

Once past the tower, the suspenders become shorter towards the center of the span.

File GGB suspender SE24SW at freesound.org

File GGB suspender SE28SW at freesound.org

File GGB suspender SE36SW at freesound.org

File GGB suspender SE44SW at freesound.org

File GGB suspender SE52SW at freesound.org

File GGB suspender SE56SW at freesound.org

File GGB suspender SE60SW at freesound.org

Suspenders are quite short at the center, and the structure—the way the cables arc over the saddles on the main cable, various bolts and stiffeners—can be appreciated. The sound here is quite different from that at the ends of the bridge or near the towers.

File GGB suspender SE63SW at freesound.org

File GBB center span east at freesound.org

By mid-day, the south approach has more traffic but less moisture. Compare this to the first sample.

File GGB southeast approach SAE T02 at freesound.org