VoIP phone systems are reliable when the network behind them is healthy. When they’re not, the problems show up immediately in customer conversations:
- Voices cutting out or sounding robotic
- Delays that cause people to talk over each other
- Calls dropping mid conversation
- Echo or hollow audio
These issues are not just annoyances. They affect trust, sales, and customer service. The good news is that most VoIP call quality problems can be traced to a few root causes and corrected with the right network tuning.
This guide covers what jitter, latency, and packet loss actually mean, why they happen, and what your business can do next. IPM can also run structured tests and implement lasting fixes if you need outside support.
The Three Technical Problems Behind Most Bad VoIP Calls
VoIP breaks your voice into small packets of data that travel over your internet connection. Call quality depends on how those packets move.
Jitter
Jitter is variation in packet arrival time. If voice packets arrive unevenly, audio can sound choppy or robotic. Jitter is often caused by congestion or unstable connections.
Latency
Latency is delay. High latency causes the awkward half second pause where both people start talking at the same time. Some latency is normal, but too much makes conversation frustrating.
Packet loss
Packet loss is when voice packets never arrive. Even small percentages can cause missing syllables, garbled audio, or dropped calls. Packet loss is often the clearest indicator of a network or ISP problem.
If you fix these three issues, most VoIP systems will immediately improve.
Why Your VoIP Sounds Like You’re Talking Through a Tin Can (And How to Fix It)
That choppy, robotic, cutting-in-and-out call quality isn’t just annoying. It’s costing you deals, frustrating customers, and making your business sound unprofessional. The good news: it’s almost always fixable. The bad news: it’s rarely the VoIP provider’s fault.
Here are the five real culprits, in order of how often we see them:
Your Internet Connection Looks Fast but Isn’t Built for Voice
You ran a speed test. You see 200 Mbps download. You assume the internet is fine.
But VoIP doesn’t care about download speed. It cares about upload speed, and more importantly, upload consistency. A single phone call uses almost no bandwidth. But it demands that bandwidth be available without interruption, every millisecond, for the entire duration of the call.
The moment someone starts a large file upload, kicks off a cloud backup, or joins a video meeting, your available upload gets swallowed. The voice packets get delayed, arrive out of order, or get dropped entirely. Your caller hears choppy audio, weird echoes, or silence followed by a burst of garbled words.
Your internet might be fast. It might not be stable. Those are very different problems with very different solutions.
Your Office Network is Fighting Itself
The internet connection could be perfect, and you’d still have terrible calls if your internal network is congested.
Picture this: Accounting is uploading a massive QuickBooks backup. Marketing is running a Zoom call with screen sharing. Three people in the break room are streaming Spotify on their phones connected to the office Wi-Fi. And your receptionist is trying to answer a client call on the VoIP system that shares the same network as all of these devices.
Every one of those activities is competing for the same pipe. VoIP loses that competition every time because it’s the most sensitive to delays. A Spotify stream can buffer for two seconds and nobody notices. A phone call that buffers for two seconds sounds like the line went dead.
Your Wi-Fi is the Weakest Link
Wi-Fi phones are convenient. They’re also the #1 source of “my calls sound terrible in the conference room” complaints.
Wireless signals degrade through walls, floors, and distance. They compete with neighboring networks. They struggle when too many devices connect to one access point. And they create a particularly nasty problem called “roaming,” where a phone silently switches from one access point to another mid-call, causing a brief but noticeable audio dropout.
If calls sound great at one desk and terrible at another, your wireless network is the prime suspect.
Your Equipment Firmware is Running on Nostalgia
Phones, switches, routers, and firewalls all run software that needs regular updates. Old firmware causes bugs in audio processing, random disconnections, and compatibility issues with your VoIP provider’s platform that didn’t exist when the firmware was current.
Misconfigured SIP settings or NAT traversal settings are even worse. These create the maddening “one-way audio” problem where you can hear the caller, but they can’t hear you (or vice versa). You both say “hello?” four times and then hang up.
Your Network Hardware Was Never Designed for This Job
A surprising number of businesses are running their entire phone system, their cloud applications, and their file sharing through a consumer-grade router from Best Buy and a stack of unmanaged switches from 2017.
These devices can’t support VLANs. They can’t enforce QoS. They can’t handle the traffic load when security services are enabled on the firewall. When VoIP starts sounding bad and you’ve ruled out everything else, the hardware itself is usually the last domino standing.
VoIP problems are often the first visible symptom of network infrastructure that has quietly outgrown its equipment.
How to Actually Fix It (A Structured Approach That Doesn’t Waste Time)
Stop guessing. Stop rebooting the router and hoping. Follow this sequence:
Step 1: Find the pattern.
Before touching anything, ask five questions:
Does it happen on all phones or just specific ones?
- Is it worse at certain times of day?
- Is it only Wi-Fi phones or wired ones too?
- Is it inbound calls, outbound calls, or both?
- Is it one specific number or all calls?
The answers eliminate half the possible causes in five minutes.
Step 2: Run a real VoIP test (not a generic speed test).
Speedtest.net tells you download and upload speed. That’s not enough. You need a test that measures jitter (variation in packet timing), packet loss (data that never arrives), and latency (delay between sending and receiving). If jitter is above 30ms or packet loss is above 1%, your VoIP will struggle regardless of how fast your connection is.
Step 3: Separate voice traffic from everything else.
Put VoIP phones on their own VLAN. Keep guest Wi-Fi, personal devices, and streaming services on a completely separate network segment. Schedule large backups and updates to run after business hours instead of competing with phone calls at 10 AM.
This single change fixes the problem for about 40% of the businesses we work with.
Step 4: Configure QoS correctly (not just “on”).
Your firewall or router should identify VoIP traffic by VLAN, port, or DSCP tag and guarantee it priority over everything else. It should also respect your actual upload bandwidth limit, so it’s reserving a realistic amount for voice, not promising bandwidth that doesn’t exist.
We validate QoS by running simultaneous load tests and live calls. If the call stays clean while the network is under stress, QoS is actually working. If it degrades, it’s misconfigured regardless of what the settings page says.
Step 5: Go wired wherever possible.
If desk phones are on Wi-Fi and calls sound bad, plug them into Ethernet. The problem usually vanishes instantly. For employees who must be wireless, invest in business-grade access points with proper placement, channel management, and roaming optimization. Consumer mesh systems from Amazon don’t cut it.
Step 6: Build internet resilience into the plan.
If VoIP is mission-critical (and for most businesses, it is), a single internet connection with no backup is a gamble you’re making every day.
Add a secondary connection, even cellular LTE/5G as a failover. Configure your firewall to automatically switch voice traffic to the backup circuit if the primary degrades. Set up monitoring that alerts you when packet loss starts climbing, not after calls have been terrible for three hours, and the receptionist finally sends a frustrated email to IT.
These six steps, done in order, resolve VoIP quality issues for the vast majority of businesses we work with. Usually, within a single afternoon.
When to Bring in Professional Help
If your VoIP problems persist after basic checks, the fastest path is a structured network assessment.
A provider like IPM Computers can:
- Test jitter, latency, and loss from multiple points
- Review ISP performance and routing
- Validate switch, firewall, and QoS configuration
- Segment networks and improve Wi-Fi design
- Coordinate with your VoIP vendor using technical evidence rather than vague complaints
This avoids trial and error spending and helps you reach a stable solution faster.
Frequently Asked Questions About VoIP
How much internet speed do we need for VoIP?
VoIP does not require huge bandwidth per call, but it does require stability. Many VoIP calls use roughly 0.1 Mbps in each direction per call depending on codec and overhead. The bigger factor is whether your connection maintains low jitter and low packet loss when other business traffic is happening. A busy office may need higher upload speed and better ISP service quality, not just a bigger download number.
Why does VoIP calls sound robotic?
Robotic audio is usually caused by jitter and packet loss. When voice packets arrive late or not at all, your VoIP system attempts to fill gaps, creating the robotic effect. Network congestion, weak Wi-Fi, or ISP instability are common sources.
Does QoS always fix VoIP issues?
QoS helps a lot when the problem is internal congestion, but it cannot fix an unstable ISP connection. If your internet has packet loss or high jitter before it reaches your office, QoS will not fully solve the problem. It is still important to implement QoS correctly, but you may also need to address ISP or circuit quality.
Why do calls drop but internet browsing still works?
Web browsing is forgiving. Pages can load slowly and users may not notice. VoIP is real time. Even small spikes in jitter or a brief packet loss event can cause a call to drop. This is why VoIP problems can exist even when everything else seems fine.
Should we use Wi-Fi phones or wired phones?
Wired phones are generally more consistent. Wi-Fi phones can work well if the wireless network is designed for it, but they are more vulnerable to interference, weak coverage, and roaming issues. If call quality is a priority, wired Ethernet is often the most reliable option for desk phones.
Clear Calls Are Usually a Network Issue, not a Phone Issue
When VoIP audio is bad, replacing phones is rarely the first fix. Most problems trace back to how voice traffic moves across your internet connection and internal network.
By focusing on:
- Jitter, latency, and packet loss measurements
- Bandwidth and congestion management
- Proper network segmentation and QoS
- Strong Wi-Fi design or wired connections
- ISP performance and resilience
You can usually restore professional call quality and reduce support tickets.
If you’re ready to stop guessing and want a clear diagnosis, IPM can assess your network and implement changes that keep calls stable even during busy hours.
