FFT Sound Analyzer - Audio Analysis Software for Windows & Mac. Wave. Pad features two very useful tools for performing sound analysis on the spectral content of audio, the Fast Fourier Transform (FFT) and the Time- Based Fast Fourier Transform (TFFT), in addition to extensive audio editing functionality. These tools have applications in a number of areas, including linguistics, mathematics and sound engineering.
Sound Analysis and Synthesis Software Avisoft-SASLab Pro. Real-time spectrogram display with circular buffer recording; Digital filtering for removing noise. Best sonogram/spectorgram software out there? Read reviews, compare customer ratings, see screenshots, and learn more about Spectrogram. Download Spectrogram and enjoy it on your iPhone, iPad, and iPod. Spek – Acoustic Spectrum Analyser. Spek is free software.
This display is very fast - download the program and try it yourself! The screenshot below is of the Spectrogram display.
Gram Schmalz » Encoding Images as Sound & Decoding via Spectrogram. Encoding Images as Sound & Decoding via Spectrogramby Gram Schmalz. Introduction to spectrograms and sonic bitmap encoding. Are you a circuit confident exploratory encoder, Aphex Twin fan, or a keen electro acoustic busybody? Have you ever wanted to turn images into sound, and then back into images? I think my answer to all of these questions was yes, and as such I have put many hours into figuring out the best, FREE, methods to do this. This article will give you a bit of a head start if you plan to do the same.
Unfortunately since this article was written a few years ago, some of the links to examples and software are now broken. These have been crossed off, but left for reference sake. A few years ago, I created an installation call Signal + Noise, which explored the splintered nature of contemporary experience through the visceral lived moment, and the digital document. A large part of this installation relied on spectrogram encoding and decoding. I enjoyed learning these technologies and thought I might share that learning experience through this tutorial.
- Monthly Mystery Spectrogram webzone. These pages are Rob Hagiwara's professional web-space. For personal musings, please see Rob's blog. This is the How To page of.
- Raven is a software application for the acquisition. Two spectrogram views of the same signal at different time scales.
- Download spectrogram - Praat 5.3.56: Linguistic tool for studying sounds, and much more programs.
- Spectrogram Free Shareware.
So, we want to make a sound image that is viewable on a spectrogram. Well, it’s quite simple. A spectrogram is “an intensity plot (usually on a log scale, such as d. B) of the Short- Time Fourier Transform (STFT) magnitude. The STFT is simply a sequence of FFTs of windowed data segments, where the windows are usually allowed to overlap in time, typically by 2.
It is an important representation of audio data because human hearing is based on a kind of real- time spectrogram encoded by the cochlea of the inner ear”. In English, a spectrogram (also known as a spectral waterfall, or sonogram) is a time- frequency graph representing complex signals (such as audio) in an easy to interpret and analyze XY Cartesian grid format. On the graph: X (horizontal axis) represents time (depending on the spectrogram speed, the graph will move sideways along its X axis, showing the passage of time), Y (vertical axis) represents a frequency range as defined by the spectrogram.
A third property (the one that makes it useful for image encoding) is also manifest on the spectrogram: frequency amplitude, or volume. Within the spectral waterfall we have all the necessary elements to represent a bitmap image. The horizontal dimension of the image is manifest as time on the spectrogram, the vertical dimension by frequency (or pitch) and value is shown by the volume (or amplitude) of each frequency.
If you think of the image as a series of frequency columns it is easy to understand how an image can be encoded in audio. Each column with its corresponding frequency amplitudes is encoded one after the other over time (representing X) to build up a representation of the photograph. Unfortunately using existing software it is impractical to encode colour images in this method, however black and white images are surprisingly easy to encode.(if you are working on a specific project which requires colour images to be stored or transmitted in sonic formats, I recommend doing some research on Slow- scan television, a technique popularized by ham radio operators to transmit images back and forth. Fortunately everything you need is open source or freeware, unfortunately you’re going to need windows or linux, and so if you’re a mac user hopefully you have a second operating system installed on your computer.
Once you get the software it is actually super easy, some of these programs can be slightly difficult to locate. I’ll include a list of links to all programs mentioned at the end of the article. There is a number of different open source applications out there for all different platforms, but some of them are slightly better suited to our use because they have more adjustable parameters. Here are my recommendations for this experiment: Mac OS XWindows. Real Time (input)Audio. Xplorer. Spectrogram (gram.
Static(file analysis)Sonic Visualizer. Sonogram Visible Speech. At the time of this article being written, they are all free, so download the appropriate program for your use, and install it! Obviously I can’t give a tutorial on all these programs, or this article would be way to long, but the programs are all pretty self- explanatory. You just need to get the application running, and then find out what frequency range it is observing, so you can encode within that range. If you need a little more info on how to use a spectrogram, Rob Hagiwara has written an extensive guide to understanding and reading spectrograms, which is available here: http: //home.
Now you need an encoder, to change your image into sound. I have found three programs to use for this, two for windows, and one for Linux. Audiopaint and Coagula Light are the two Windows programs I located for completing this task (links at end). Ohmpie (ohmpie. com) wrote a program for Linux to synthesize spectrogram images, and was also kind enough to share his code, and write a pretty good analysis of the mathematics involved in the process.
I recommend checking it out even if you don’t use image. Encode, his Linux program. A little summary of what these programs do: Each of these programs performs the exact same task we did when looking at the bitmap image earlier in this article. It breaks down the image into columns of pixels, and represents each column as a time interval. Then, looking at the Y- axis of each column, the program decides what frequencies (for pixel Y position) need to be played at what volume (representing brightness).
The programs then use a multitude of sin waves synthesized at the corresponding frequencies and create an audio file that contains a simplistic rendition of the image. Download the encoding program of your choice, and get it running. Once you have opened the program, you’ll need a bitmap image to encode with. Import one using the import setting, on all these programs, and have a look.
You’ll need to change the audio parameters of the encoder, so look around and find the preferences panel that contains the Min and Max frequency parameters. You need to set these parameters to match the frequency range of the spectrogram you decide to use. You also need to look at the scale setting, there are a couple different scales you can use for these programs: Logarithmic, Exponential, or Linear. If the spectrogram you are using has an option for which one to use, Logarithmic seems to get the best image quality in my experience.
There is one other setting you’ll need to play with, duration, which controls how quickly the audio file plays, and also needs to correspond with the spectrogram program. Once you have the other stuff worked out, you can play around with this through trial and error and get it set right.
The duration will also need to change for every different aspect ratio in the images you use. You should be able to tell which one is which. At this point you’re pretty much ready to encode and decode. Fire up your encoding program, import your picture, and generate your sound. Fire up your spectrogram, and either import the file, or hook up a microphone or line input if you want to use the real- time method. Hopefully this has been a useful point in the right direction. I know I didn’t reveal all the mysteries of spectrogram encoding, but where’s the fun in figuring it out if you already know all the answers?
Doing some of the work yourself is where the fun and discovery happens, so get to it! Coagula Light Tutorial: http: //www. Jws. Mr. Sa. YI& feature=fvw.
Autumn – Image to Sound, by Binary Quandry (audiopaint example): http: //www. ZChcv. ISpectrograms: Audio. Xplorer (os x): http: //www.
Sonic Visualizer (os x and windows): http: //www. Spectrogram (gram. Sonogram Visible Speech (windows): http: //www. Sonogram. Smith III, W3. K Publishing, 2. 00.
ISBN 9. 78- 0- 9.