I read today on Macworld UK’s website that Yamaha has released a new USB speaker system. That in itself is not terribly interesting (unless you happen to work for Yamaha, or you’re in the market for such a thing), however Macworld went on to say
The system pushes out 20-watts of sound through use of the company's amplification technology that boosts signals carried over USB by a factor of ten.
I’m sorry… run that by me again?! It “boosts signals carried over USB by a factor of ten”?!
Signals carried over USB are digital signals. How strong the signal is over your USB cable has no effect on the sound at the output, provided it’s strong enough to be distinguished from noise. The only things that determine the power of the sound at the output are the DAC, the analogue audio amplifier, and the speaker(s) to which it is attached. What’s more, unlike analogue audio signals, there is no inherent voltage level for digital audio signals. A sample value of +32,767 might correspond to 1µV, or it could correspond to 1MV. So it doesn’t even make sense to talk about boosting the signal by a factor of ten on the basis of sample values.
This is probably a sloppy error on somebody’s behalf, unlike the thoroughly deceitful practices of the makers of so-called “digital cables”, which are usually an excuse to charge the customer for a cable of quite unnecessarily high quality, which—unbeknownst to most consumers—will make generally no difference to the final audio quality, since it is only eliminating noise from the highly noise-immune (and often error corrected) digital signal, not from the final analogue output1.