Skype is taking its time with a VoIP app that exploits the recently unlocked 3G data channel on the iPhone. But they have a pretty good reason. They’re working on adding their own SILK wideband audio codec to a 3G version of their Apple App Store software. The SILK codec reproduces audio within a 8- 12 kHz bandwidth, far better than the stingy spectrum slice we experience on our landline and mobile phones.
Is wideband audio worth the trouble?
For various reasons, phone audio quality has remained the same since the 1950s– a 3.4 Khz sliver of sound. We’re living in an age of ubiquitous digital MP3 — a codec that captures and plays back music in the 20 kHz range— and our phones are limited by by industrial age technology based on inductors and copper loops.
The sound we hear from our phone ear piece is experienced as merely adequate because most, but not all, of the important information embedded in human speech is contained within a 3.4 kHz spectrum slice. Our phone network is engineered to effectively filter out critical higher frequency information that’s used by our brain’s audio circuits to decode human speech waveforms.
These missing frequency “bumps” (called formants ,which were discovered in the 1960s) make it especially difficult for listeners to distinguish between consonants, especially “s” and “f” and “m” and “n”.
And I won’t event discuss what the phone network does to music– it’s practically unlistenable.
So the answer is Y E S. Wideband audio is worth it.
For those who say that there’s no market and people won’t notice the difference: there were also some naysayers who claimed consumers would rather drink the diner swill than spend $1.50 for freshly brewed Ethiopian coffee.
The technology is available. The big stumbling blocks to greater wideband usage are that both sending and receiving devices must use the same or similar codecs, the digital signal processing software for sampling waveforms.
And that’s where Skype has an advantage. With over a half-billion subscribers and SILK (which, by the way, is now a royalty-free download for developers), they have an enormous opportunity to jump start wideband.
This may also give Skype a nice, albeit temporary, advantage as they move into the business phone market.