1 min short, including the classic ding ding – hold tight
The charismatic London bus is gone from the streets of the city. I recorded one in 2005, as they were being phased out. There are many sites dedicated to keeping the memory of these alive, but not so many dedicated to one of the aspects many Londoners will remember them by – their quite unusual sound.
Part of their sound was a result of the dynamic between the conductor, passengers, and the driver. Unlike modern buses the driver was in his own compartment and never had anything to do with the public. That was left to the conductor, who collected fares and managed the starting and stopping of the bus by signals on the bell, which was the only means of communication with the driver other than the buzzer which performed the same function from the top deck and the open platform.
The bell was mechanical – a cord ran the length of the ceiling of the bus halfway over the left-hand row of seats. This cord went through the front wall of the passenger compartment to a clapper. When the cord was tugged, the bell sounded and both the driver and the passengers could hear it.
In London Transport usage, the bell signals were as follows-
One ring. This was for passengers, to indicate they wanted to get off at the next request stop. This was the only signal passenegrs were meant to sound, though obviously the temptation could get too much for London’s schoolkids at times.
Two rings. The conductor signals to the driver that everybody has boarded and disembarked from the bus and he can move off
Three rings. This depended on context – the most common was cancel the two ring move off instruction just given (either in error, or by one of the schoolkids) However, it could also mean ‘don’t stop at the next stop to take on more passengers as the bus is full and nobody is getting off’
and every frequent user knew the familiar sound of the conductor calling out ‘hold tight’ followed by a ‘ding ding’ of the bell.
The Routemaster had a really unusual engine and transmission sound. I believe that in the early 1970s they had a manual transmission, but this was replaced over that decade by an odd kind of automatic transmission. The engine was in the front, unlike most modern buses, and there was a bell-housing which protruded into the passenger compartment slightly just behind the driver – the passengers in the aisle side of the first row of seats could rest their foot on this. This was the seat I took to record the friendly sound of this bus, with its distinct speed-dependent tone, odd idling characteristics and typical squeal of the brakes.
These buses were about 50 years old when they were retired later on in the year. It took several goes to get a photo of a bus that was in reasonable visual condition.
Harmony is not the first thing that springs to mind when you think of chainsaws. I had the advantage of a large beech hedge to soften the sound a bit. Two guys must have been chainsawing away here, and the counterpoint one saw gives to another works quite well for me.
Resonant Bridge, contact mic with mass coupling to back of element
To a man with a contact mic mounted on a magnet, every sound source looks like a large lump of steel, same way as the guy with a hammer sees nothing but nails…
My luck was in when I came across this concrete footbridge across a dual carriageway. So I set up, carefully placing myself over the central reservation so drivers don’t get paranoid I’m about to zap ’em with a speed camera or throw stones or drop magnets on them. You get some funny looks attaching magnets and a piece of wire to a bridge by the other people, and the regional Police HQ is only 1/2 mile away. This unpreposessing bridge has a decent tone to it, presumably ringing to the vibration of the traffic passing by. Which was awesomely noisy – you don’t realise just how loud the tyre noise is on a road until you try and cycle a stretch like this and find your ears ringing afterwards. The contact mic worked its usual magic in getting rid of all this racket.
Resonant Bridge, traffic noise, OKMII binaurals w battery box
The two recordings with the contact mic were made, one with the mic held to the bridge with a strong magnet, the other with the same mic held to the bridge in the same way, but with an approx 0.5kg weight acting as a reaction mass on the other side of the piezo, to see if this picked up low frequencies better. You can hear the difference – or not, for yourself!
Piezo contact mics seem to cause a lot of pain for people losing low frequencies, but I do not feel I am short of low frequencies here, using a basic FET buffer. The peaks of the bridge resonance are 120Hz, 240Hz, 380Hz, 760Hz. There is, however, energy at 22 and 43 Hz at -36dB on the resonant peak, at a similar level to the broad peak around 3kHz which is probably the percussive sounds amplified by the piezo self resonance. The piezo was a Maplin YU87U 27mm 1.8kHz item terminated in 3.9Mohms, but the circuit could be improved to work better with a HiMD recorder mic input of 5k.