Wednesday, January 10, 2007

Sounding better- some of the time...

I see from the news that Apple have launched something called the iPhone, a multi purpose mobile phone device that hopes to do for the Telecoms business what the iPod did for the Minidisc- i.e. gain massive market share and hammer the competition to the benefit of purchasers.

It isn't widely known outside of IT circles that Apple Computer and Apple Records had a bit of a tiff, with the outcome that Apple Computer agreed to stay out of the music business. It terns out that Cisco have the rights to the name iPhone, so expect a new turn-on sound when it goes on sale- "Sosumi2".

My new Freebiephone* (tm) comes with a feature called "Wideband". What this means is that it has much better sonic performance than a regular phone. How good is the sonic performance of a regular phone? Grotty.

We can hear sounds from about 20 Hertz to about 20 KiloHertz, from a very low rumble to a high pitched shriek. A Hertz (Hz) is what used to be called a Cycle and a good analogy is a Rolf Harris Wobble Board- it rattles the air backwards and Forwards at a a low frequency of maybe 2-3Hz. (We don't hear the actual wobble, we hear higher frequency resonances).

At the bottom end, we can feel notes below this range, infrasonics being used to impressive effect on movies like "Earthquake!" where you could feel your seat and your innards rattling when it was switched on.

(Mains power is at 50 Hz, which you can hear as a low hum if you put your ear next to many household power supply devices like Phone chargers)

The high end cutoff varies according to age and circumstance. The younger we are, the higher we can hear (hence the ringtones above 16kHz that teenagers can hear and the teacher can't). Women can hear higher than Men, which strikes me as a Male defence mechanism against Nagshriek!

(When I was in my late teens, I found out at college that my hearing cut off at 14.5kHz, no doubt a side effect of wearing headset intercoms at Rock & Roll gigs.)

CD range is 20Hz to 22kHz (ish) and that is not considered as true HiFi by real audiophine buffs. Whilst we can't hear frequencies higher than our own personal range, the unheard sounds will interact with the heard ones to impact on the sonic experience. (Remember "Is it real, or is it Memorex?" adverts, where they broke a glass by playing a cassette? Yea, right...)

For the phone network, the acceptable range for intelligible speech was decided on donkeys years ago as the band from 300 Hertz to 3,400 Hertz, referred to as "Commercial bandwidth". Transmission equipment generally goes up to 4kHz so the Telcos used to borrow the 600 Hertz of headroom for out-of-band signalling in the days before digital. They also used to borrow inband for setup/calldown, notably 2,600Hz (US) and 2,280Hz (Eu) which you still hear on the telly occasionally to simulate a phone call in drama (the double chirp you hear on the hangup). 300Hz was effectively the roll-off point for the transmitters & receivers in the handset.

Now, my wideband phone can go from 50 Hz to 700Hz so it should certainly sound a lot less tinny. The trouble is that it doesn't. Why not? Because it is the only one. It is like having an HD ready telly but not having Sky HD, it performs exactly the same as the non-HD ones.

BT's 21st century Network promises Wideband, or at least it has been mentioned in presentations, when they described it as "near-CD audio quality)". (This is a bit like saying that a Mondeo is a "Near-Lexus experience" on the basis that you used to drive a Trabant!

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