Question

Your cousin’s voice sound different over the telephone than it does in person. This is because telephones

     do not transmit frequencies over about 3000 Hz. Since 3000 Hz is well above the normal frequency of

     speech, why does eliminating these high frequencies change the sound of your cousin’s voice? Carefully

     provide the reasoning behind your answer.

Answer 1

This is because of compression and the digital algorithm used to digitize that voice. On cell phones and voip lines, your analog voice sound is “translated” (digitized) into proprietary audio formats. Then sent via a data packet to, via a whole bunch of transmitters and server stations, to the other person's phone which is then played for them and voila, you have a phone conversation. If you cut the latency, and figure out a way to make it truly two way dynamic audio, then you've even mimicked a land line copper wire phone conversation. Cell providers are pretty close to that already. Anyway, as you can presume, millions of calls are made a day, or even a minute depending on what provider you are, so you have to move billions of data “voice” packets around, constantly. All that bandwidth is costly and adds up real quick. To shave on that expense and to make latency issues better, the companies compress the audio files as much as possible thus lowering the overall file sizes and therefor making less of a data packet to send around town. But, you can't have it all.