Does anyone know of a free software tool or package that allows one to do signal analysis. Im looking for something that I can handle at least a million samples gracefully and have tools like a spectrogram (with configurable params like fft size, window, padding, etc) and a waveform viewer. I have worked with companies in the past who have such tools but they are home grown (these tools are often written in matlab with a gui tacked on the front).
Any help would be appreciated. If such a tool does not exist. I am interested in possibly created an open source one which runs atop matlab.