Real-time FFT of the audio signal from a microphone? - Page 1
Forum section: electronics / testgear

author: cvanc
author_rank: Frequent Contributor
timestamp: January 24, 2019, 06:39:00 pm
content: Hi all-Let's say I want to see a FFT of the signal being picked up by a microphone. And let's say I want to do this in real-time or nearly real-time. I want to see changes as I move the microphone around.How would you do this? Especially, how would you best do this given constraints on cost and size?I know you could always use some vintage piece like a spectrum analyzer, fed with the amplified signal from the microphone. But is there a more modern, smaller, less expensive way to do this?Thanks.

author: hendorog
author_rank: Super Contributor
timestamp: January 24, 2019, 06:44:28 pm
content: There are plenty of apps on the Google App store which real time FFT on the mic (I guess they would also work on an external mic). No idea about IOS.

author: wn1fju
author_rank: Frequent Contributor
timestamp: January 24, 2019, 06:45:48 pm
content: Do you have a laptop? Plug the microphone into the microphone jack. Then...There must be a few dozen FFT Audio Analyzer programs, many of which are free, for download. Google it.I've used Spectran (www.weaksignals.com) in the past and it is great. Don't know how current the author has kept it although.

author: DavidDLC
author_rank: Frequent Contributor
timestamp: January 24, 2019, 06:56:31 pm
content: cvancIf you want to do this with electronics, I have PCB for a SMD LED matrix that is designed for this purposes.I made the PCB to replace a damaged LED matrix on a old equalizer.Let me knowDavid DLC

author: awallin
author_rank: Frequent Contributor
timestamp: January 24, 2019, 07:04:58 pm
content: gnu-radio probably has the bits and pieces to build scope/FFT/waterfall etc. displays quite easily from an audio source:something along those lines:https://wiki.gnuradio.org/index.php/Guided_Tutorial_GRC

author: alsetalokin4017
author_rank: Super Contributor
timestamp: January 24, 2019, 07:32:04 pm
content: You could do it in software or in single-chip solutions.Google or search YouTube for "arduino color organ" for many examples of software implementations of FFT with mic input and color LED outputs. Looking at the associated sketch and schematic files will show you how FFT is implemented in c++ on a microprocessor, and how to turn condenser mic output into something that makes sense to the processor.Or look for graphic equalizer display chips like MSGEQ7 for single-chip solutions.With software you can select frequency bands and make up your own display modes like with addressable RGB LEDs, get really fancy if you like.The single-chip solutions are more limited -- you get seven fixed frequency bands with the MSGEQ7 I think but it's cheap.

author: ebclr
author_rank: Super Contributor
timestamp: January 25, 2019, 03:31:40 am
content: If you don't want to reinvent the wellhttps://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313.TR0.TRC0.A0.H0.Xaudio+spectrum.TRS5&_nkw=audio+spectrum&_sacat=0

author: MikeP
author_rank: Regular Contributor
timestamp: January 25, 2019, 07:02:33 am
content: I have been using REW for many years. Microphone with ADC from MiniDSP - Umic.

author: The Soulman
author_rank: Super Contributor
timestamp: January 25, 2019, 08:33:15 am
content: There a many programs to choose from, I often use visual analyzer, not the most stable but about every setting can be tweaked.http://www.sillanumsoft.org/It will work with any audio input device that works with windows.

author: trobbins
author_rank: Frequent Contributor
timestamp: January 25, 2019, 08:44:32 am
content: I use the Spectrum Analyser app on my phone - can help you tell the difference between mains frequency hum, and twice that frequency