When did volume get a number?

Recently I sat in the newly launched Range Rover in a showroom and had a play with the in-car entertainment system. These days there are lots and lots of cars out there that have large screen displays in the console to control all manner of in-car systems from radio and CD to navigation, iPod connectivity/etc.

One thing about the Range Rover system puzzled me and I thought it was bad User Interface (UI) design. As is normal, the volume control is a separate rotary control that you turn anti-clockwise to lower the volume and clockwise to increase the volume. When I changed the volume, a large box appeared over everything else on the touch screen with a number to represent the volume. The problem was that this box stayed on the screen for what felt like 3-4 seconds during which time I couldn't do anything else on the screen which I found annoying. It’s probably less of an issue in real use (i.e. when you’re driving and not sitting still playing with the new system) but it did get me thinking.

I tried to think about when volume got a number attached to it and I've got an idea of how it happened. Once upon a time, turning the volume up or down on something (like a radio) resulted in the sound getting louder or quieter and that was all you needed to judge the level of volume.

Then someone invented the TV remote control. These were originally very primitive devices that often only had 4 buttons - channel up and down and volume up and down. The problem that this presented was that people needed a way to see that the buttons they were pressing were having the desired effect. This was easy with channels because the picture would change but with volume, that might be a little more subtle and so the on-screen numbers to indicate the level of volume was born.

That seems to have persevered ever since and there are lots of things that now have a number to indicate the level of volume but is that always sensible or necessary? I currently have a BMW which doesn't give me any indication that the volume has changed. Instead it relies on my trusting the fact that I twisted a control or pressed a button and it adjusts the volume accordingly and honestly, I've never had any problem with it at all - I've never even given it a second thought until I wrote this article.

The fact that the new Range Rover’s in-car systems put the volume in my way enough to make me think about it proves that it’s bad UI design. There were a lot of places on the screen where a discreet volume level indicator would fit perfectly (even if it was a number) but because I’m actually touching the control to make the adjustment - is an indicator really necessary?

When designing UI elements it is vital to question everything and make sure whatever you are adding provides real value. As a poster my wife bought me for Christmas says “just because we've always done it that way doesn't mean it’s not incredibly stupid” and in a similar way, even if it’s “new and impressive” - if there’s no justification for it then it’s still stupid!