spectrum analyzer that shows 'live' input from the microphone

Question

I have a friend which helps children with speaking disabilities, and she needs some software that shows the amplitude of the sound immediately as the children speak through the microphone.

I have tried Audacity, but it has a delay of about one second.

Any recommendations on such software?

Note that the OS is Microsoft, and the software should preferably be freeware.

Answer 1

sndpeek

No idea if this is any use for you - it's Open Source:

http://soundlab.cs.princeton.edu/software/sndpeek/

sndpeek is just what it sounds (and looks) like:

real-time 3D animated display/playback
can use mic-input or wav/aiff/snd/raw/mat file (with playback)
time-domain waveform
FFT magnitude spectrum
3D waterfall plot
lissajous! (interchannel correlation)
rotatable and scalable display
freeze frame! (for didactic purposes)
real-time spectral feature extraction (centroid, rms, flux, rolloff)
available on MacOS X, Linux, and Windows under GPL
part of the sndtools distribution. 

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SFS/RTSPECT

Just found this too:

http://www.phon.ucl.ac.uk/resource/sfs/rtspect/

Windows Tool for Real-time Waveforms & Spectra

RTSPECT is a free program for displaying a real time waveform and spectrum display of an audio signal. With RTSPECT you can monitor the waveform and spectral shape of sounds being played into the computer's microphone or line input ports. RTSPECT can display one or two-channel audio signals.

Answer 2

Just found this one:

http://friture.org/

Testing it now.

Answer 3

Audacity does allow you to monitor the input from the mic without recording. Don't know if this would reduce/eliminate the delay you experienced, though:
"either select "Monitor Input" from the input meter's pop-up menu, or else just click on the input meter." http://audacity.sourceforge.net/onlinehelp-1.2/toolbar_meter.htm

Answer 4

With " Alchemy - Open Drawing Project http://al.chemy.org/ " you can use your mouse to DRAW the input sound waveform onto a canvas, even curve its shape. It is in vector form and is saved as an image. Speed can be increased by the movement of the wrist.

http://al.chemy.org/

Answer 5

A few other options from this question, particularly useful if you need something with few dependencies and easy to modify:

• A Spectrum Analyzer in one Python script using PyAudio, Chaco, scipy
• A Spectrum Analyzer using Python and PyQt
• A Spectrum Analyzer demo using Qt

Answer 6

Here's another free one. Shows a good spectrum with unnoticeable latency. Also has peak level indicators.

http://www.techmind.org/audio/specanaly.html

Answer 7

I found this thread looking for a real-time way to display spectra-versus-time, after losing the ability to use Adobe Audition, WHILE recording. In Audition, you can do a spectral display that has very little delay; as someone else said, if you use high resolution, there will be more delay. But a "good" program will use overlapping blocks of data so it can update the display very quickly. There's enough processing power in modern processors to keep up with a thousand frequencies in a fraction of a second of processing time, if the program is well written, and there's no point in more resolution than that if you're displaying on a screen that's "only" about a thousand pixels high. I'd submit that for stereo, 1k blocks of audio samples is plenty, unless you're expanding a part of the frequency scale as you can do in Audition. Recording at 44k samples/second, you get a whole new 1k block 44 times a second, and for me, that's plenty fast enough, without even any need for block overlap. Even 8k blocks would be more than 5 a second without overlap. Whether the software is written well enough to actually DO that is another matter.

Answer 8

Using the Volume Mixer isn't enough (right-click the speaker icon in the taskbar and select "Volume Mixer")? It will show level meters for all sounds being played through the system, and should include microphones as well.

Answer 9

There are always delays in software when you do this sort of analysis on a computer. Unless you're using a high-speed driver such as those included with the Creative Audigy or X-Fi cards which are tuned for real-time performance capabilities.

Answer 10

Here's a commercial offering that I found in a quick Google search, which offers a 30-day trial download so you can try it for free first to determine if it meets your needs (you mentioned that there's a preference for freeware, but not that free is a requirement):

  SpectraPLUS - FFT Spectral Analysis System
  http://www.spectraplus.com/