It was July. The outdoor noise survey was at a construction site. And someone — nobody claimed responsibility — had left the sound level meter on the dashboard of the van for two hours while the team had lunch.

The meter's internal temperature, when they returned, was approximately 62°C. The operating specification said 'accurate from -10°C to +50°C.' Sixty-two degrees was, by most definitions, above fifty. The meter turned on. The display worked. But the first measurement showed the ambient noise level of a quiet suburban street at 78 dBA, which would make it louder than a vacuum cleaner.

The MEMS microphone's sensitivity had shifted due to thermal expansion. The preamplifier's gain had drifted. The ADC reference voltage had moved. Everything in the analog signal chain was operating outside its designed temperature range, and each element's small error compounded into a significant one.

The team noticed the readings seemed high. 'Must be a busy street,' said the junior consultant, who had apparently never stood on a suburban street before. They recorded thirty minutes of data before the senior consultant arrived, looked at the numbers, touched the meter, and said four words: 'Why is this hot?'

Thirty minutes of unusable data. One overheated meter that took forty-five minutes to cool to operating temperature. And a new rule taped to the dashboard: 'METERS DO NOT LIVE IN THE VAN.'

The Moral: Temperature affects every analog component in your measurement chain. SonaVyx's SPL meter can't control your equipment storage, but its calibration check before each session would catch temperature-induced drift before you collect thirty minutes of expensive garbage data.