The APU Spectrum Analyzer plug-in is a free spectrum analysis tool supporting a variety of FFT configuration options. Adjust the FFT window type (Rect, Hann, Hamming, Blackman, Kaiser) and size (from 64 up to 65536) to suit your needs.
Quickly switch between standard dB ranges or auto-range and view the frequency spectrum in log, linear, or note-based scale. Supports histogram hold for measuring long term frequency response. You can also adjust the bucket size independent of the FFT size.
System requirements: macOS 10.14 (x64, ARM), Windows 10 (x86, x64), OpenGL 3.2.
Supported software formats: Standalone application, VST, AU, AAX (Pro Tools 11+).