Skype and latency

http://www.punbb-hosting.com/forums/themodernvocalist/viewtopic.php?id=1671

Where did the information Skype is half-duplex come from?  I did a quick search, and some people believe it’s half-duplex in sound card and full duplex in USB stereophones.   This information doesn’t make sense either.

Anyhow, Skype, like Voice over IP, suffers mostly from latency–an inherent problem with the Internet that is difficult to solve.   There is a lag time due to electronics relay and congestion delays (not the speed of electricity).   Echo is usually used in telephony to reassure the talker’s own talk– telephony without echo sounds funny for the talker.

Telephony is designed to carry principally the higher frequencies of normal speech, which is what is needed for speech understanding.  Bassy parts of speech are unnecssary for speech comprehension, so is truncated to reduce bandwidth requirements.   As such, if one listens carefully to a regular phone call, it sounds tinny.   Bell Labs probably spent hundreds of millions of dollars doing research on this one topic and designing telephony to fool our hearing effectively.

Our minds are very clever at reconstructing the intended sound, so even though the sound may be tinny, a hearer can actually reconstruct most of the true sound.   However, telephony does not capture the true sound.

Skype is worse than regular telephony for a number of reasons:

1. Latency.
2. Lesser bandwidth, which means greater truncation of sounds.
3. Inferior receiver sender equipment.
4. Lesser proven reconstruction technologies of initial captured sounds.

Cell phone usually have inferior microphones and can even be worse.

Land lines are what telephony technologies are designed for, and will sound best, if one buys the more expensive equipment.

It makes me mad to hear singing instructor who believes they are doing students a favor by saving a few dollars with Skype.   In addition to the problems mentioned above, the best way to use Skype is with a headset, and I haven’t seen too many expensive Skype headsets yet (which tells me that its receiving sound exterperlation and its sending mic is lower quality).   And if both sides are using headsets, the problem that comes about is occlusion effects in singing from wearing headsets.

In summary, telephony equipment is designed to create an illusion of the sender’s true send, and actual sound is vastly superior.  Then in the order of quality– 1. great land line telephony equipment both sides   2. great cellular equipment   3. great sound cards   4. great headset  5.  great Skype, 6. and mediocre and inferior equipment all under.    I’m aware that I’m bound to be attacked by Skype advocates who say, you can hear this or that well.   My response is– listen to it carefully and try to reduce the power of one’s own mind to reinterpret, and you’ll see that telephony including Skype is inherently inaccurate.

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