Today I have bought a new stereo system. The old one doesn't play CDs anymore and it only worked as a radio tuner, too big for that ;-)

We have gone to Media Markt because there you have a lot of options between to choose and finally, we select a nice Panasonic system, the SA-PM9. After reading and thinking a lot about human interfaces design, I have built a filter in my brain and I can't resist fo analyze the desing of every object that takes my attention, like this new stereo.

Here you can see the front size of the stereo. No more user interaction with the stereo is in other side execept the up size with 1 button for the cassette and a plug for the phones. There are 15 buttons and a nice wheel fro the volume control.

The 4 central and bigger buttons are the mode buttons to change between CD, Tuner, Tape and a strange Stop button here, that breaks the user mental mode. When you select any mode, the button also is the Play for that mode so designers decide to put a common Stop button for all the modes here. Not very nice but effective. Also the Stop button has a hidden feature that is activated when you push the button for several seconds: a Demo mode in which the display changes between all the features of the system. By default Demo is on and when you shutdown the system, the display start to show you different features. This is the first time I discover why it is doing that. Yes, I haven't read the manual because I am in discovering mode for user.

Up from this for central buttons you can find a row of four buttons labeled "album" and "track" with back and forward labels. To the left of this row is the "MP3" label, so it is easy to think that this four buttons are for playing mp3 music. When I bought the system, I want one with MP3 and in the shop, you have all the main marks with this kind of system. With track buttons you also change between normal CD tracks, but the album bottons only work for the MP3 music.

To the right of the for main buttons you have the great wheel to change the music volume. It is so nice to change the volume with the wheel. If you rotate and reach the lower level, 84 dB (people won't understand this dB thing), you can continue lowering the level with the wheel, but it will remain in "-- dB". If you change the rotate direction, it inmediately start to upper the volume level. There isn't a fix point for max and min music levels. It is very nice.

To the left of the for main buttons you have the power on/off button, very easy to find because its red light. It is always with the red light, no matter the system is on or off. Not sure if maybe, it could have a green light when it is on and a red light when it is off, but the user has other signals that the system is on.

Down the four main buttons you have another row of 4 buttons. They are all located uniformly but there is clearly 2 groups: the two buttons to the left are for starting the surrond filter and changing the sound bass and treble (you have to push the button to find the features :( ). In the Sound button there is also a hidden feature that it is shown when you push the button for several seconds: the equalizator. In the demo I have seen that the machine has an equalizator so I play a little and found the feature, something impossible for a user without reading the manual.
The two buttons to the left are for rewind and forward (tape and CDs), and to find the channels in tuner. I think these four buttons will be better grouped together in the two pair as you have the for buttons for album and tracks.

Finally we have two buttons in strange places: in the right border of the system. One is for opening/closing the CD tray and the other is for start recording. The open and close button maybe will be better place over the CD tray, as in computers, and the record button ... I think desingers haven't found a right place for it. The same location for this two buttons could be found in other Panasonic systems.

Now it is time to take a look to the remote control. It has 34 buttons and put all together like a table with 2 entries. The for buttons central in the front side of the machine are also found in the central zone in the remote control, a good desing point, but the remote control is more complex and hard to find things in it. I will talk about it a more in the future but guys, you can desing better remote controls, I am sure.

I think the remote control is like the toolbar in a GUI application, where you can find the more used features in the system without using menus, but it is horrible that in some system, there are features only accesible from the remote control.