Yes, combining multiple sources of sound can indeed increase the overall volume of the sound. When multiple sound waves combine, they can add up or interfere with each other, resulting in a higher or lower sound level, respectively. This phenomenon is known as constructive and destructive interference.
In the case of alarms, if you have multiple alarms and let them ring simultaneously, the sound waves they produce will combine, resulting in a louder alarm. By increasing the number of alarms or sound sources, you can further increase the overall volume.
However, it's important to note that there are practical limitations to this approach. Increasing the number of sound sources will eventually reach a point of diminishing returns, where adding more sources does not significantly increase the volume. Additionally, there may be physical constraints, such as the maximum volume capacity of the alarms or the acoustic properties of the environment, that limit the effectiveness of this method.
Furthermore, keep in mind that excessively loud sounds can be harmful to your hearing, so it's important to exercise caution and not expose yourself or others to excessive volumes for extended periods of time.