NoiseTools allows you to change the amount of storage used for audio and time history.
To access this setting go to the instrument configuration screen and look for Partition Editor under the Advanced Settings category.
This will show how much storage space is allocated to Audio and how much to Time History. By default, this will be around 80% Audio.
The estimated duration of each partition is also shown. This is based on the currently selected time history rate and audio quality and will be recalculated if you change either of those.
To change the partition sizes simply move the slider left or right and the percentages and estimated times will be updated. Once you are happy with it click the save to instrument button to save your changes.
Warning: Changing the partition size will cause it to clear the memory, all measurements still in the instrument will be lost.
This option is available on the Optimus Red but the audio partition is only used for Voice Tags so will normally be much smaller.