Good bass is one of the most common requests when specifying an audio system and yet is one of the most difficult parts to get right. The equipment being used rarely causes problems. Most decently designed amps and speakers are more than capable of producing plenty of good bass energy and yet many systems that, on paper, should sound wonderful in the “bottom end”, fail to impress.
In this short series of posts we’ll uncover some of the hidden truths of good bass and explain the science along the way. Don’t worry; we’ll make sure the science bit is as simple as can be!
This week some facts about waves…
Sound energy travels in waves. No matter what the sound is, from the highest soprano voice to the lowest action movie explosion all sound is just a periodic change in air pressure. Your ears are really good at picking these changes up. Even small variations in the air pressure, as long as they keep changing up and down, mean something to us. The faster the change in pressure the higher the note we hear. The bigger the change in pressure the louder the note we hear.
If you’re confused by sound waves (there’s nothing tangible to see them after all) just think of them as waves on the sea. Imagine for a minute that you’re standing on the seashore, feet in the sea watching the waves come in. The waves hit your feet at regular intervals, the biggest part of the wave is the peak and the bit in between is the trough. You’ll have noticed that the time between each wave is constant; this is the period of the wave and if we count how many arrive per second that would be its frequency.
Now think about the size of the wave. If your imagination has taken you to somewhere nice and hot (like Hawaii or the Caribbean somewhere…) the waves might be quite high. If you’re in the Mediterranean they probably be quite small. The height of the wave is it’s amplitude, in sound terms big waves are loud and small ones are quiet.
Finally, look out to sea and you’ll notice that you can see a series of waves coming toward you. They will all be about the same distance apart. If we measured the distance between them it would be constant. This is called the wavelength.
Sound waves travel just like waves on the sea with just one exception; sound waves can travel in more than one direction at once. Just think about dropping a stone in a pond, the waves go outwards rather than forward in a straight line. This is how bass travels…until it hits a wall that is!
We hope you enjoyed this post. If you did, why not let our webmaster know? Next week we’ll find out just what happens when bass waves hit a wall…
Happy listening!