Triangular (Bartlett) window for FFT spectrum analysis.
Window function: W[n] = 1 - abs(2n/N - 1), where n is the sample index and N is the window length.
Pass this value to the window parameter of AudioListener.GetSpectrumData or AudioSource.GetSpectrumData. The window is applied before the FFT to reduce spectral leakage between frequency bins.
The triangular window linearly tapers samples toward the edges of the block. It reduces leakage compared with FFTWindow.Rectangular with less taper than FFTWindow.Hanning or FFTWindow.Hamming. Use it as a middle ground when rectangular leakage is visible but a full raised-cosine window is not needed.
Additional resources: FFTWindow, FFTWindow.Rectangular, FFTWindow.Hanning.