Redesigning Volume Buttons, Old Style
I thought it couldn’t get any worse than volume buttons. You know the kind: You get in your car, start it up, and get blasted by a wall of sound. And you continue to be blasted as you frantically search and then mash that tiny button again and again until the radio is once again at a reasonable level.
Many years ago, there was an amazing invention. It was called a volume knob. True, it was dictated by analog design: it was easier and cheaper for manufactures to use a knob directly connected to a potentiometer, then two buttons coupled to a complex circuit. Volume knobs had another advantage: besides being electronically simpler, they were also better interfaces.
There are three pieces of information you use when changing the volume: (1) what the current volume is, (2) how far between off and full blast the current volume is, and (3) how fast you are getting to your desired volume.
With the digital solution, without a display, you have no way to know how loud the radio is going to be when you turn it on. And even if there is a display, it usually doesn’t display anything until you have turned the radio on. So by the time the display tells you that your little sister was recreating a Nirvana concert in your car, the radio has already reduced your ears to bilge water. How many button pushes are needed to turn the volume down? How far away from volume-off are you? You can’t know the answer to these necessary questions with digital volume buttons. The interface fails on all three accounts: it does not tell you the current volume, the rate of change of volume, and the maximum and minimum allowed volumes.
On the other hand, a knob will let you know with one glance what the current volume is (you can even turn the knob quickly to off and up again if you want to set the volume without looking); one knob-revolution goes from off to on; and the rate at which you turn the knob controls the speed of volume change. The knob yields the three pieces of information effortlessly. And as often happens with good interfaces, the knob is a solution for more than just its intended application. Why do radios need a power button? What’s the difference between the volume being turned all the way down and the radio being off? They don’t, and there isn’t, respectively. Because it is so painless to change the volume, a knob can replace the power button: you turn the volume all the way down, there is a small click, and you know the radio is off. The same method does not work with volume buttons because they are slow, painful, and do not allow for freedom in tactile feedback.
So volume knobs are angelic and volume buttons are demonic. You get it. But how could it get any worse than buttons?
I was recently given a JBL On Stage iPod Dock. It has two non-buttons for setting the volume: They are sleek metallic pads engraved with a plus on one and a minus on the other. They aren’t buttons, you just put your finger against them to change the volume. It’s an interface out of Star Trek. The whole thing sounds wonderful. Until you try changing the volume. The biggest mistake is that there is no tactile feedback at all: you don’t know when you are actually changing the volume. To make it worse, the rate at which the volume changes is proportional to how long you’ve held your finger to the pad. Not only do you not know when you are changing the volume, but you don’t know how fast you are changing it. You are reduced to constantly massaging the buttons with quick jabs to coerce the volume where you want it. And because the interface is time-based you can never get the volume back to exactly where it was before. This is the peril of letting marketers do product design: what used to be a fractional second turn to set the volume has become a seven-second guessing game.
I went on a camping trip with my girlfriend this last summer to the Olympic Peninsula, JBL and iPod in tow. We listened to a lot of Enka, a form of Japanese music which has a wide dynamic range — from delicately soft to passionately loud. We were constantly alternating the volume between overcoming the car’s rattling and not destroying our ears. We timed ourselves setting the volume: 6.7 seconds on average. Of course, by that time the volume needed to be changed again. Needless to say we were very unhappy campers.