miércoles, 15 de diciembre de 2010

Formula 1 Bass Guitar??? The sound of the future F1 engines

The sound of Formula 1 engines is a beautiful example of how physics can explain nature and especially human inventions. Music itself is an even more beautiful example of the same thing, and trying to make a connection between Formula 1 and music is being a total pleasure for me during this year.

When I started thinking about how to make my guitar videos, I first calculated the theoretical pitch of current Formula 1 V8 engines. This way, we have the revolutions limit in 18000 rpm, which is 300 revolutions per second, that is 300 Hz. Given that a four-stroke engine cylinder has one explosion for every two revolutions, we have 150 explosions per second per cylinder. Therefore, the eight cylinders of a V8 engine make for a total of 1200 explosions per second, that is a sound of 1200 Hz, which is a musical note slightly above D6. However, the actual sound we hear on TV onboard laps has a predominant frequency of 600 Hz when the engine is on top revolutions, which is a subdivision of the 1200 Hz theoretical sound. That is the main frequency I play on my guitar videos, using appropriately tuned third and fourth strings past 22nd fret to have a 600 Hz sound (D5).

With the new engines, to be used from 2013 on, the revolutions limit is set to 12000 rpm, which means a reduction of the engine sound pitch by 12000/18000 = 2/3. Moreover, the engines will have 4 cylinders instead of 8, which will reduce by 1/2 the pitch of the engine sound. Altogether, we will have 2/3 x 1/2 = 1/3, so the 600 Hz sound on top revolutions will be divided by 3 to turn into a 200 Hz sound. That corresponds to a musical note slightly above G3, around the 3rd fret of a guitar for third or fourth strings, so I will have to buy a bass guitar if I want to play slow corners of a Formula 1 lap in the future, or even a contrabass for the Monaco famous turn 6.

You would say: why won´t you use the sixth string, which makes a lower sound? My answer is that I need that string to reproduce a lower frequency, which depends only on the revolutions and not on the number of cylinders. This frequency coincide with the engine revolutions expressed in Hz, so for current V8 engines on top revolutions it is 300 Hz.

The impact of the new regulations on the engine sound can be better understood if we watch the next video, which compares Raikkonen´s 2008 V8 engine with Schumacher´s 2004 V10. The revolutions were limited to around 18000 rpm for both of them:

First of all, note how the low frequency I talked about is the same for both sounds, as the revolutions regime for both engines is essentially the same. Now the readily noticeable differences between the sound of both engines are in the high frequency, and result from the difference between a sound of 600 Hz and one of 760 Hz, that is, only 160 Hz. Imagine the low a Formula 1 engine will sound to our ears when going from 600 to 200 Hz in 2013. It won´t be so different from the sound of a Rally car.

Formula 1 will still be visually attractive but its sound won´t be the same, it won´t be special anymore. There are some ecological reasons for the change but I believe it´s just for the image of Formula 1 and not to mitigate a real ecological problem. Let´s make another calculation to illustrate how the fuel use in Formula 1 is just a leaf in the forest of world fuel consumption:

A Formula 1 car consumes around 200 litres of fuel during a race. Let´s say free practises and qualifying takes 400 additional litres. 600 litres multiplied by 24 cars equals 14400, and 14400 multiplied by 20 races equals a total fuel consumption of 288000 litres in a whole Formula 1 season. 288000 litres is more or less the consumption of the cars stopped in traffic lights in a country like Spain in one day.

So please let´s stop blaming Formula 1 for wasting Earth resources and let´s be thankful to it as one of the most amazing visual (and acoustic) spectacles in the world, capable of bringing unique emotions to millions of people.