Poor audio quality during Skype conference

[David]

So I've never been a heavy Skype user, but I have been using it since the early public beta. I had a meeting last week with two others, and even though everyone was on a low-latency broadband connection, the voice quality was poor. There was constant "missing sound" (as in, packet loss), and often a section of voice would repeat. Has anyone else had this problem? Everyone was using the latest version, on Windows.

I'm thinking about switching back to TeamSpeak, since you can select the sound codec.

[patndoris]

Hi there David! I'm not a big Skype user either, but I have done it several times for various reasons. It seems the quality of the conference depends upon the person who initates the original call.

I have a contact who was on dial-up for example, and we could NEVER get a clear call going if he started it. Not even if all the other people were on broadband. But if someone with broadband initiated - it was just fine - even for the dial-up user.

I know you were all on broadband, but any possibility the person who started the call was doing anything that might have interfered with their connection speed?

-Doris-

[Yahooligan]

I usually get really clear quality with Skype, but some issues with Skype that might effect performance. Maybe one of the participants was being used as a "super node?"

[Jeff]

When you run the Skype client, your PC can become "used" by Skype as a so-called supernode. This is sort of a switchboard or directory of skype users who are online -- remember Skype is essentially a peer-to-peer network similar to the developers earlier product, KaZaA.

Skype claims that being a supernode would have a neglible performance penalty, but you can set a switch in the registry to prevent your PC from ever being used as a supernode.

Here's the instructions from the Skype security resource center:

Skype uses peer-to-peer communications in order to allow users to find one another. Consequently, a small percentage of our users will hold a record reflecting the online presence of other users. When one user holds a record concerning the presence of other users, the former is called a "supernode", or directory node.

Even though the traffic sent to supernodes is negligible, some institutions are interested in preventing users on their network from becoming supernodes and, thereby, answering directory enquiries for other users.

There are several ways to prevent Skype from becoming a supernode:

• Beginning with Skype 3.0, an explicit switch is provided in the registry settings to allow the disabling of supernode functionality.
• Any computer hosted on a network that is behind a network address translation (NAT) device or restrictive firewall will disable supernode functionality.
• Skype clients behind an HTTP or SOCKS5 proxy will not serve as supernodes.

Enterprises typically opt for using the registry setting technique for turning off supernode functionality, simply because it is very straightforward to deploy a Windows GPO that contains the appropriate registry key setting. However, universities often find this more problematic because the computers may not be owned or operated by the host institution, making it difficult or impossible to ensure that registry keys are set properly.

In these cases, it may be more useful to set up a SOCKS5 proxy. Skype can be configured to use a SOCKS5 proxy, regardless of whether the client finds itself on a network with a public IP address or on one with a private IP address.

While the use of a SOCKS5 proxy still requires manual intervention by the user, the use of a proxy allows the economical "shaping" of Skype traffic. It has the additional positive side-effect of reducing supernodes on the network, reducing false-positive intrusion prevention system alarms and allowing for accurate measurement of Skype usage on the proxied network.

Apart from that, you can also use the Skype Sound Set Up Guide to check that you're getting the best audio quality possible.

Finally, do you have the same voice quality issues with just two people (as opposed to a conference)? I've usually had excellent quality going person-to-person, but as soon as you add a third or fourth person, the quality is less predictable. A lot of times this can be traced to a shoddy mic or inappropriate mic volume settings (usally the gain is set too high), or when someone is NOT using a headset (mic picks up noise from the speakers).

If you have three people (A, B & C), test one-on-one first (A-B; B-C; A-C) and see if the quality is ok in each case. You're trying to determine where the weak link is, and if it's a network issue or local hardware or software issue. If it all works well one-on-one, then it may be as patndoris suggested, a matter of who starts the conference. Why? Hell if I know, but whatever works, eh?