Listening to the sounds…..of…….
Keep your eyes on the road and your hands upon the wheel….
I’ve been drivin’ all night, my hand’s wet on the wheel. There’s a voice in my head, that drives my heel…..
Let there be light…Sound…Drums…Guitar…Let there be rock!
Driving songs. We’ve all got a few that we love to plug into the CD player or USB or MP3 connections; plenty of bass, for that gut kicking thump; the crystal clear highs and the crisp mid range for vocals. What’s that? Bass? Midrange? Treble? What are these words of magic I speak of?
All sounds we hear, be it from our tv or MP3 or car stereo, are made up of certain wavelengths, frequencies that vibrate the air around us at certain amounts of times per second. Much like looking at a rainbow and seeing the seven basic wavelengths of light a rainbow shows, what we hear can be broken down into three simple categories and from that, what a good speaker system allows you to hear.
To use a very brief science lesson, frequencies are measured in Hertz (http://en.wikipedia.org/wiki/Hertz) and the lower the number, the lower the frequency of sound our ears may pick up. Low end frequencies generate a bass (pronounced base) tone (http://en.wikipedia.org/wiki/Audio_frequency) but also require the most power to generate. Bass sounds come from big drums, the kick in the gut from an explosion and, in home theatre speak, come from a sub woofer. cars, also, can be fitted to carry a sub woofer and work by utilising the air found within a car’s boot to create the sound.
Bass notes, in a physical sense, are of a very long wavelength and are, as a result, considered, omnidirectional (or, more specifically, the point at which the ability our ears have to localise sound’s source, ends), in that the source shouldn’t be able to be located. There caveat here, quite simply, is the frequencies that are considered to be sub bass and bass.
Moving up through the frequency ladder is mid range; this is generally accepted to be, in easy speak, the range of frequencies the human voice occupies. From the low but powerful tones of Barry White (http://en.wikipedia.org/wiki/Mid-range_speaker) through to the tenor notes of Robbie Williams to the octave stretching notes from Mariah Carey; from the kick drum or rhythm guitar that complements a singer, it’s this range of frequencies that can be either well balanced or overbearing, depending on the listening environment and your own ears.
At the top end, literally, is treble (http://en.wikipedia.org/wiki/Treble_%28sound%29). It’s the finish of a tap on a cymbal, the clink of a wine glass in a toast, the flick of a finger on an acoustic guitar….it’s the sound that is also easiest to identify which direction it comes from, as the wavelengths are so tight they make the frequencies more susceptible to being directionally identified.
When it comes to car audio systems, especially in modern vehicles, there’s been some subtle yet important changes. In days gone by, you could (and still can, to a point) choose to buy and install a radio head unit that slots into the spot your old and tired AM/FM radio previously occupied. Nowadays these things will have CD playback, a USB port (exactly the same as your computer) and a tiny 3.5 millimetre wide hole with Aux (Auxiliary) marked. Some will come with Bluetooth, the short range radio system so you can wirelessly send music from a smartphone. Some more expensive units will have a small LCD screen built in and a DVD player; the size and heights of these are measured in DIN (double DIN for the taller units) so most will be the standard DIN. 
When correctly installed, or from a factory fitted unit, they will then send sound through to the speakers. An aftermarket speaker of decent quality will have a broader speaker diaphragm (the physical speaker material) that will reproduce a range of bass notes and should have two smaller units in the centre. They will generate the mid range and treble notes. In today’s cars, the treble speakers are, generally, to be found in the pillars framing the windscreen, whilst the bass and midrange will be in the doors. Some cars will have the subwoofer unit, as mentioned previously, in the boot or cargo section.
When all is married up, balanced for left and right, front and back, you should be able to enjoy your preferred driving songs in full range, crystal clear sound, allowing you to sing along with the best of ’em.
Level 2, 9 Help Street