Why Do My Calls Sound Like The Caller is in a Tunnel?

If a caller sounds like they are in a tunnel, the network is likely unable to supply enough Internet speed, or there is faulty networking equipment or a loose connection. Common symptoms of muffled audio include:

  • Inbound audio sounds muffled or like the caller is underwater
  • Inbound or outbound audio cuts out
  • Delay on the line, causing parties to talk over each other

To begin troubleshooting muffled audio, verify the integrity of the local network. VoIP devices require an upload and download speed of 0.1 Mbps each. Computers and connected devices such as wirelessly connected cellular phones, printers, etc. need an upload and download speed of 0.3 Mbps each. Jitter must be less than 15 – 20 ms, and packet loss must be 0%. To run the Nextiva Network Quality Speed Test, click here. Compare the results with the chart below.

Recommended Network Quality Speed Test Results

Firewall Access Rules control the flow of inbound and outbound Internet traffic from the local network to the public Internet. Both routers and firewalls use access rules to control traffic and verify the source and destination addresses are permitted to send and receive traffic on the local network.

Nextiva recommends that a local Network Administrator whitelist the following rules in the firewall:

Nextiva’s Firewall Access Rules

Need additional help? Click here.
Updated on November 22, 2019

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