UltraEdge Explained — The Sound-Waveform Technology Behind DRS Edge Decisions
UltraEdge is the industry-standard acoustic system for detecting bat edges in DRS reviews. Learn how it differs from the original Snickometer, what the waveform display shows, and how the third umpire uses it to make caught-behind calls.
UltraEdge is a proprietary acoustic analysis system developed by Tomo Tech Pty Ltd (Australia) and now used across ICC-sanctioned international cricket as the primary tool for detecting whether a cricket ball has made contact with a bat in caught-behind and stumping DRS reviews. It replaced the original Snickometer, which was first used for television broadcast graphics in the late 1990s and gradually adapted for officiating purposes.
Key differences from Snickometer
| Feature | Snickometer (original) | UltraEdge |
|---|---|---|
| Audio input | Single stump microphone | Directional microphone with noise filtering |
| Display speed | Slight delay | Near real-time (< 0.5 s latency) |
| Noise filtering | Limited — picks up ambient sounds | Algorithm-filtered to isolate bat-ball contact frequencies |
| Use in DRS | Broadcast only (originally) | Official DRS tool at ICC events |
What the waveform display shows
UltraEdge presents the third umpire with a real-time waveform — a graph of sound amplitude over time — alongside synchronised high-speed video. When the bat makes contact with the ball, the acoustic energy spike from the impact appears as a sharp vertical rise in the waveform. The third umpire scrolls through the footage frame by frame, watching for whether the spike in the waveform coincides precisely with the moment the ball is adjacent to the bat in the video. A well-aligned spike confirms an edge; a waveform with no spike at that moment, or a spike that occurs at a different point in time, suggests no contact.
How the third umpire uses it in practice
The third umpire reviews the UltraEdge display in combination with multiple camera angles. They are looking for convergent evidence: a visual image that appears to show the ball passing close to the bat, confirmed by an acoustic spike at that exact frame. When both agree, the decision is straightforward. When they diverge — for example, a spike appearing slightly before or after the bat — the third umpire must consider whether the spike came from another source (bat on pad, foot on ground) and, if uncertain, give the benefit of the doubt to the batsman (if original decision was not out) or uphold the original decision (if given out).
UltraEdge limitations
Very thin edges — the ball grazing the outer face of a thick bat edge — can generate acoustic signatures too faint to exceed background noise after filtering, resulting in a flat waveform even when genuine contact occurred. Conversely, bat on pad contact can produce a spike that superficially resembles a bat edge. For this reason UltraEdge is considered strong but not infallible, and third umpires are trained to look for corroborating evidence from HotSpot (where available) and multiple video angles before overturning a not-out decision.
Frequently asked questions
Is UltraEdge available at every international match?
UltraEdge is a mandatory component of the ICC's full DRS package at ICC events. For bilateral series, availability depends on the host broadcaster's and board's DRS contract. Some bilateral series in lower-income cricket boards have operated with reduced or no DRS, meaning UltraEdge was absent. The ICC has progressively worked to standardise DRS availability across all international cricket.
What happens when the UltraEdge and the video disagree?
If the waveform spike does not align with the video frame showing the ball at the bat, the third umpire treats the spike as likely from another source (pad, ground, or clothing) and relies on video alone. If there is no spike but the video is ambiguous, the benefit of the doubt goes to the batsman if the original decision was not out — this is the standard 'if in doubt, do not intervene' principle of DRS.
Can UltraEdge detect a glove edge?
Yes. The bat and the glove holding it are treated as a combined implement under the Laws of Cricket. A ball that makes audible contact with the glove fingers (while the batsman is gripping the bat) produces an acoustic signature that UltraEdge can detect. If the batsman has let go of the bat and the ball hits the dangling glove, however, that is not considered contact with the bat for dismissal purposes.