29 April 2010

What is Sound?

Sound is made up of travelling compression waves, or oscillations in pressure.

Acoustics is the scientific study of sound.

Audio is sound within the frequency range which can be heard by human beings, which is generally considered to be between 12 Hz (Hertz: cycles per second) and 20,000 Hz (or 20 kHz). It's this audible range of sound frequencies that I'll be concerned with here.

We experience the frequency of a sound as its pitch: the higher the sound frequency, the higher the pitch (or note if we're talking about music). Some sounds are of too high a frequency to be heard by human ears (ultrasound) and some too low (infrasound). Think of a dog whistle, and then of the serious health concerns of people living too close to industrial wind turbines – Vibro-Acoustic Disease is caused by infrasound noise being transmitted through the ground.





Here is a simplified graphic representation of sound. One whole sound wave is shown, the horizontal axis representing time, and the vertical axis representing the oscillation in pressure from compression (+) to decompression, or rarefaction (−). It is a sine wave, or single pure tone, which doesn't actually exist in nature, but is useful in helping us to understand sound.

21 April 2010

Which Browser?

I'm often asked which web browser I use for my work and usually answer, all of them. I want the web pages I make to look and behave the same in all current browsers, so I use them all to test my work.

Although I use Macs for production work, I do have a PC laptop running various versions of Internet Explorer (IE) which I also use for testing. This shouldn't be necessary but IE was never truly standards compliant, which means that I usually end up writing extra (redundant) code to make my pages look the way they should have done to start with. Having said that, IE8 does behave better then earlier incarnations, but still has a long way to go. I'm sure that the internet would have evolved into a far more beautiful place if only Microsoft had properly implemented web standards in their ubiquitous browser. There are many web designers out there who would love to use some of the new features offered by CSS3, for example, but won't do so until IE actually supports them.

So which browser do I prefer? I've been using Mozilla's Firefox for some years, Apple's Safari being a little too quirky for my liking, especially in the way it renders text. It's also good to know that Firefox is open source software with hundreds of dedicated programmers across the world involved in its development. Support the good guys, I say. Failing that, Google's Chrome is very fast and offers lots of support for fancy HTML5 stuff.

I would urge anyone still using IE to try Firefox, Chrome, and Opera, and see which they prefer. These are small downloads (my last Opera download was 13.9 MB) and quick to install. You can usually import bookmarks from another browser, and you don't have to set any of them as your default browser until you are sure which one you prefer, so what do you have to lose?

Try testing your browsers on Ernest Delgado's excellent HTML5 website demonstration!