Snicko in Cricket: How the Snickometer Works

Snicko, short for Snickometer, is a cricket technology that detects whether the ball has touched the bat or glove by analysing sound from the stump microphone. A sharp spike on the audio waveform at the exact moment the ball passes the bat is treated as evidence of an edge. It is used by the third umpire in Decision Review System (DRS) reviews, mainly for caught-behind and bat-pad decisions.

Every cricket fan knows the scene. A batter is given out caught behind, reviews instantly, and the whole stadium watches a flat line on the screen. The third umpire waits for a spike. If it lines up with the ball passing the bat, the batter walks. If the line stays flat, the batter survives. That simple picture hides a surprisingly complex piece of technology, and understanding how it works makes every review easier to follow.

What Is the Snickometer?

The Snickometer is an audio-based edge-detection system used in cricket broadcasting and umpiring. It was invented by English computer scientist Allan Plaskett in the mid-1990s and was introduced on television coverage by Channel 4 in the United Kingdom in 1999. It began life as a broadcast tool: a way for television viewers to judge whether the umpire had made the right call on a close caught-behind appeal.

Over time, Snicko moved from the commentary box into the umpiring process. When the Decision Review System was introduced, the third umpire needed a reliable way to answer one specific question: did the ball touch the bat? Video alone often cannot answer that question, because a thin edge can be invisible even in slow motion. Sound can. The tiny click of leather on willow is distinct, and a sensitive microphone placed in the stumps can pick it up even when the cameras miss it.

How Snicko Works: Stump Microphone to Waveform

The system starts with the stump microphone, a highly sensitive microphone fitted into the stumps at the striker’s end. This microphone picks up every sound around the stumps: the ball hitting the bat, the ball hitting the pad, the bat hitting the ground, the ball thudding into the wicketkeeper’s gloves, and the general noise of the crowd.

That audio signal is sent to an oscilloscope, an instrument that displays sound as a waveform: a line that rises and falls as the volume and frequency of the sound change. When there is no contact, the line stays fairly flat. When the ball clips the edge of the bat, the line shows a sudden, sharp spike. The third umpire watches that waveform alongside slow-motion video of the ball passing the bat, and checks whether the spike lines up with the exact frame where the ball is beside the bat.

The key word is timing. A spike on its own proves only that a noise happened. The umpire must be able to prove that the noise happened at the precise moment the ball passed the bat, and not a fraction of a second earlier or later, when the bat may have hit the ground or the pad. That timing question is the hardest part of using Snicko, and it is the source of most of the controversies around it.

Snicko, Real-Time Snicko and UltraEdge

The original Snickometer required the operator to synchronise the sound and the video manually for every review. That manual step took time and left room for error. The newer version, called Real-Time Snickometer, removed the need for manual synchronisation for each piece of footage, which made the process much faster.

The current system used in most international cricket is UltraEdge, developed by Hawk-Eye. UltraEdge works on the same basic principle as Snicko — stump microphone plus waveform — but it uses the high-speed cameras already deployed for ball tracking, which capture images at up to 340 frames per second, and it synchronises the sound and the visuals automatically. That automatic sync is the main improvement: the third umpire can see the waveform aligned to each video frame without relying on an operator to line them up by hand.

Feature	Classic Snickometer	UltraEdge
Sound source	Stump microphone	Stump microphone
Display	Audio waveform beside video	Waveform synced to each video frame
Synchronisation	Manual, by the operator	Automatic
Camera speed	Standard broadcast cameras	High-speed cameras up to 340 frames per second
Main use	Caught-behind and bat-pad reviews	Caught-behind, bat-pad and LBW edge checks
Main weakness	Timing the spike to the right frame	Background noise in loud stadiums

How the Third Umpire Uses Snicko in a DRS Review

A typical caught-behind review follows a fixed sequence. First, the third umpire checks the front-foot no-ball, because if the bowler overstepped, the batter cannot be out. Then the umpire checks whether the ball touched the bat, using UltraEdge or Snicko. Only if there is evidence of an edge does the umpire move on to check whether the catch was taken cleanly.

For an LBW review, the order is different but the role of Snicko is the same. The third umpire first checks for an inside edge: if the ball hit the bat before it hit the pad, the batter cannot be out LBW, no matter how straight the delivery was. Snicko is the tool that answers that edge question, and ball tracking is only consulted if no edge is found.

The third umpire does not rely on Snicko alone. The waveform is read together with the video, and sometimes with Hot Spot, which is a separate technology that uses infrared cameras to detect the heat generated by friction when the ball touches the bat. A mark on Hot Spot plus a spike on Snicko is very strong evidence. A spike with no visual contact, or a spike that appears clearly before or after the ball passes the bat, is treated with caution.

Reading the Waveform: Bat, Pad, Glove and Ground

Not every spike means an edge. Different contacts produce different sounds, and the third umpire has to tell them apart. A ball hitting the bat usually produces a sharp, tall spike. A ball hitting the pad produces a flatter, duller sound. The bat striking the ground, which happens often when a batter plays a shot, can also produce a spike, and it is one of the most common sources of confusion.

That is why the timing of the spike matters more than its size. If the spike appears in the frame where the ball is beside the bat, it supports an edge. If it appears when the bat is already hitting the ground, or when the ball is still some distance from the bat, it does not. Experienced third umpires also listen for the character of the sound: the click of leather on willow is noticeably sharper than the thud of ball on pad.

Snicko Compared With Hot Spot and Ball Tracking

Snicko, Hot Spot and ball tracking answer three different questions, and a full DRS review may use all three. Snicko answers whether the ball touched the bat, using sound. Hot Spot answers the same question using heat: infrared cameras look for a bright spot where friction warmed the bat. Ball tracking, or Hawk-Eye, predicts the path of the ball and answers whether it would have hit the stumps in an LBW review.

Limitations and Controversies

Snicko has been at the centre of several high-profile controversies, most recently during the Ashes series in Australia in 2025. In the Adelaide Test, Australia’s Alex Carey was given not out on a caught-behind review even though Snicko showed a spike, because the spike appeared before the ball reached the bat and the third umpire ruled there was a clear gap. Carey later admitted he had edged the ball, and the technology provider acknowledged an operator error. In the same match, England’s Jamie Smith was given out caught behind when a spike appeared after the ball had passed the bat, which raised the opposite concern.

Those incidents illustrate the central weakness of the older Snickometer: if the sound and the pictures are not perfectly aligned, the umpire can be misled. The move to UltraEdge, with its automatic synchronisation, is designed to reduce exactly that risk, but it cannot eliminate it entirely. There will always be marginal calls where the spike is small, the contact is faint, and reasonable people disagree about what the waveform shows.

Why Cricket Still Uses Snicko

Despite its limitations, Snicko remains in use because there is no better way to detect a faint edge. Video alone misses thin edges. Hot Spot misses some edges too. Sound is the only signal that reliably captures the moment of contact, and the stump microphone is already in place for broadcast. Used carefully, with attention to timing and in combination with other tools, Snicko gets far more decisions right than it gets wrong.

Frequently Asked Questions

What is Snicko in cricket?

Snicko, short for Snickometer, is a technology that uses sound from the stump microphone to detect whether the ball has touched the bat or glove. A spike on the audio waveform at the moment the ball passes the bat is treated as evidence of an edge.

What is the difference between Snicko and UltraEdge?

UltraEdge is the modern version of Snicko. It works on the same sound-based principle, but it synchronises the audio and video automatically and uses high-speed cameras capturing up to 340 frames per second, which makes the timing of the spike more precise.

Who invented the Snickometer?

The Snickometer was invented by English computer scientist Allan Plaskett in the mid-1990s and was introduced on television coverage by Channel 4 in the United Kingdom in 1999.

How does the third umpire use Snicko in a DRS review?

After checking the front-foot no-ball, the third umpire uses Snicko to check whether the ball touched the bat. In a caught-behind review, an edge plus a clean catch means out. In an LBW review, an edge means the batter cannot be out LBW.

Can Snicko give a wrong decision?

Yes. If the sound and video are not perfectly synchronised, a spike can appear before or after the ball passes the bat, which can mislead the umpire. Background noise, the bat hitting the ground, and ball-on-pad contact can also create spikes that must be distinguished from a genuine edge.

What is the difference between Snicko and Hot Spot?

Snicko detects an edge using sound from the stump microphone, while Hot Spot detects it using infrared cameras that look for heat generated by friction when the ball touches the bat. The two technologies are often used together in DRS reviews.