Wireless Speakers and Mini Amps - Searching for the Holy Grail
The two most frequent requests we get are for wireless speakers and miniature amplifiers, in that order. Has technology failed us so far in not being able to provide these? Or, is the concept simply impossible?
First on the list is wireless speakers. Speakers, unfortunately, do not work on their own. They require some form of power which makes an electro-magnetic field in the back of the driver and pushes it to and fro against a stationary magnet. This constant pulse of power back and forth causes the driver to move in complicated starts and stops which move the air in your room just like a real musical instrument. Without power, the drivers don't move. This power is usually provided to the speakers from an amplifier which is connected with wires. It's a simple setup that has worked for 100 years.
The difficulty arrives when you try to find a way to provide power to the speakers without using connecting wires. Thus far, engineers have been able to send very low levels of power through thin air in the form of radio waves or infra-red. This is how your remote control or portable telephone works. The level of power transmitted is very, very low -- so low that you can't even tell it's passing through you at the time. An amplifier which drives speakers may put out thousands or even millions of times more power than what is possible wirelessly today. So, the simple answer is that we have yet to find a way to transmit power through the air, only wires.
Some progress has been made in building powered speakers and then sending just the very low power music signal to them wirelessly. Some home theatre surround speakers do this. The reason the whole speaker industry hasn't gone in this direction is for the simple reason that you still need to plug the powered speaker into the wall. All that's been accomplished is to move the wire from one side of the room to the other. To complicate matters, we must consider that with powered speakers, the entire amplifier has to be small enough to fit inside the speaker. The result is that so far the quality of the few wireless speakers is horrific, on par with the sound you would get from a 1960s portable radio playing music through a cordless phone connection.
This ties into our next major request - miniature amplifiers. If it would be possible to make an amplifier so small that it could hide inside of a small speaker box and essentially be invisible to the user, we might be able to at least shorten up those dreadful wires!
It's no coincidence that the same problem with speakers requiring power affects amplifiers trying to make it. The problem is that to make a decent sounding amplifier, it generally has to be big. Specifically it needs a big transformer so that it can create enough reliable power to drive a decent set of speakers. Leaving issues of quality aside, it has generally been impossible to make an amplifier smaller than a shoe box that puts out more than 10 or 20 watts. Most speakers like to have 50 watts or more. To get something the size of a stick of gum that puts out 50 watts is a huge technical hurdle.
Luckly, there is a new amplifier technology called Class D (for Digital) and it does away with large transformers. Class D will allow manufacturers to get the size down to about the size of a pack of cards. At present the sound quality is not spectacular but genuine advancements are being made. This year will see some quality miniature Class D amps such as the forthcoming Pro-Ject Amp Box. You will still have to plug the Amp Box into the wall, but it address at least half the problem.
Finally, there is the issue of sound quality which is near and dear to us at Planet of Sound. There's an old saying -- "Wireless, good sound, cheap cost. Choose 2." Even in 3-5 years time, the wireless speakers that are likely to be available will probably sound worse than traditional speakers from 10 years ago. That's not really moving forward if you care about sound.
You might find a new respect for just how beautifully simple a strand of wire is...