The temperature shown in the GLM software is the temperature of the main microcontroller of the speaker, as reported by the microcontroller itself. This information is useful for comparison between speakers, for example in a fault situation. The microcontroller temperature is very local, and should be fine up to around 80°C, though in practice it should never reach such a high temperature.
There are other temperature sensors, thermal modelling and protection functions in our SAM models. These make sure that temperatures never exceed what have been determined as safe limits for product longevity during our extensive Research and Development phases.
The variation between different speaker temperatures can be up to ±20% as the microcontroller temperature sensor is not very accurate.