Mammut is a program that does audio processing in the frequency domain. Mammut does an FFT of the whole sound (no windows).
Doing a giant FFT of the entire sound, as opposed to splitting the sound up into short windows, is unusual. Such a method implies that time-related parameters are included in the spectral coefficients in a non-intuitive manner, and changes in the frequency domain may radically change developments in the time domain.
Mammut is a fairly unpredictable program, and the user will need to get used to letting go of controlling the time axis. The sounding results are often surprising and exciting.
However, Mammut is also ideal for more normal operations such as filtering, spectrum shifting and convolution. With no windows, the sound quality is optimal.