Good PC software for basic audio spectrum visualization.

[buck converter]

I am looking into doing a science fair to see what a fan does to audio at various speeds. (if you don't know what i'm talking about, go talk into a fan). I don't have a digital oscilloscope, but I found a nice app for my Android that looks nice, but i'm looking for a basic software that could work with my laptops audio input. I does not have to be free, but less than $10 or free trial.

[PChi]

A couple of options are Audacity https://sourceforge.net/projects/audacity/ and Arta http://www.artalabs.hr/. They can both show an FFT plot of level versus frequency. There are others as well.

[jimmc]

Another free one... Visual Analyser http://www.sillanumsoft.org/

[g0mgx]

This is a ham radio targeted app but its very good:

http://www.rfspace.com/RFSPACE/SpectraVue.html

[ruairi]

Room EQ Wizard (REW) is my favorite.  It's free, very very powerful and looks great.  It also have a very large user community so the support is good.

https://www.roomeqwizard.com

[macboy]

Look for something that does a spectrum "waterfall". You may be able to see the modulating effect over time.

[b_force]

ARTA is all you need for all your acoustic measurements.
Much better than REW (imo)

http://www.artalabs.hr/index.htm

[ruairi]

ARTA is all you need for all your acoustic measurements.
Much better than REW (imo)

http://www.artalabs.hr/index.htm

Not to derail the O.P.'s thread but I'm curious what you find better about Arda (genuinely).  I've used Arta for some acoustic work but it was an older version and while it worked I didn't find it to be great, I was a Fuzzmeasure user at the time.   REW is my go to and I haven't found anything I wanted to do that I couldn't. 

[b_force]

ARTA is all you need for all your acoustic measurements.
Much better than REW (imo)

http://www.artalabs.hr/index.htm

Not to derail the O.P.'s thread but I'm curious what you find better about Arda (genuinely).  I've used Arta for some acoustic work but it was an older version and while it worked I didn't find it to be great, I was a Fuzzmeasure user at the time.   REW is my go to and I haven't found anything I wanted to do that I couldn't.

I guess more freedom, but mostly it simple has more under the hood so to speak.
So you can use ARTA also for general electronics (amplifiers and so on) and acoustics.
REW is/was a bit more focused on speaker measurements only.


I never liked the REW interface and looks, very confusing and not professional looking.
But things have changed a lot the last few years to be very honest.

So my advice is try them both.