I have searched for some time a suitable software (preferably free) that allows me to measure Bode plot of electronics circuits. There are commercial software, special hardware and special instruments for that (network analyzer can usually do that on radio frequencies), but I wanted something that uses the hardware I already has. After some searching HOLMImpulse seemed to be a good candidate for this.
HOLMImpulse is a freeware program for frequency- and impulse-response measurement. It can measure for example: Phase-response, Frequency-response and Harmonic distortion (THD). HOLMImpulse is freeware (Non-Commercial) Windows program and works with any PC sound card with no limitations.
At my tests Holm Impulse works extremely well as a measurement tool. I did not try speaker measurements, but it seemed to work well as a tool to measure frequency and phase response of different electronics circuits at audio frequencies (for example audio transformers). It shows also impulse response, noise levels and amount of distortion (THD or specified harmonics).
I tested the software with USB sound card and it worked well with it. The measurement range is limited to audio frequencies (20Hz-20kHz). This is due the are the software is aimed for and due limitations of PC sound cards.
If you are interested in alternative software to do similar measurements, check Speaker measurement, Holm Impulse, Visual Analyser and Panasonic WM-61A article for list of several alternatives.