Freeware : Spectrum Analyzers for Windows

All Mac Win DtBlkFx by Rekkerd            FFT analysis VST  FreqAnalyst by Blue Cat Audio            A free real time spectrum analyzer DX, VST  MutilnspectorFree by VertexDSP            31 band spectral analyzer VST  Signal Analyzer by Rs-met            Oscilloscope / spectrum-analyzer VST  Sonic visualiser by Centre for Digital Music            viewing and analysing the contents of music audio files.   Sonogram by Christoph Lauer            Sound Analysis   Sonogram SG-1 by Ag-Works            real-time sonogram VST  SPAN by Voxengo            FFT spectrum analyzer VST  SPEAR by Michael Klingbeil            spectral analysis and editing based on a sinusoidal sound model   WaveTools by MDA-VST            Real time audio analysis tools