Spectrogram 16.0.4 could be downloaded from the developer's website when we last checked. We cannot confirm if there is a free download of this software available. The most popular versions of the program are 16.0, 15.4 and 15.0.
This free PC program is developed for Windows XP/Vista/7/8/10/11 environment, 32-bit version. The program's installer files are generally known as Spectrogram 16.exe, gram 1.exe, gram.exe, gram12.exe or gram13.exe etc. We recommend checking the downloaded files with any free antivirus. This free software is a product of Visualization Software LLC. The software lies within Education Tools, more precisely Science Tools.
From the developer:
A freeware dual channel audio spectrum analyzer for Windows 95 which can provide either a scrolling time-frequency display or a spectrum analyzer scope display in real time for any sound source connected to your sound card. Version 4.2.0 replaces 4.1.2 and adds useful new features including spectrum averaging for noise reduction and more flexible scanning and recording capabilities.
You may want to check out more software, such as Sliding Spectrogram, DE1 Spectrogram Plotter or Spek, which might be similar to Spectrogram.