Metric Halo SpectraFoo - Manual (Page 12)

Introduction
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In order for the human brain to properly integrate multiple sensory inputs and derive greater value from them,
the inputs must be truly synchronized. SpectraFoo is the first audio visualization system to provide high reso-
lution spectral and phase information that is fluidly animated and absolutely synchronized to the live audio
signal. It is the first audio analyzer anywhere to allow the user to tap into the power of synesthesia.
Like many other audio analyzers, SpectraFoo’s analysis engine is based on the Fast Fourier Transform (FFT).
The FFT algorithm is an efficient means of computing a Fourier Transform on a computer. The Fourier transform
was developed between 1804–1807 by the mathematician Joseph Fourier as part of a study of heat transfer. The
Fourier transform converts a continuous record of amplitude vs. time into a record of amplitude vs. frequency.
A modification of the Fourier Transform called the Discrete Fourier Transform (DFT) was developed to deal
with sampled rather than continuous waveforms. The FFT algorithm was developed as an efficient way of
computing the DFT on digital computers.
FFT-based analysis facilitates highly precise measurements. As a result, it has become a natural choice for
audio analysis systems. Unfortunately, FFT-based methods have historically been more suited to Electrical
Engineering-type audio measurements than dynamic measurements of musical program material.
A traditional technique is to subject the system being measured to a known, controlled test signal. In order to
get high-resolution measurements from the analyzer, one must wait for a significant period of time while the
output of the system is captured by the analyzer and then transformed. If you want to measure the average
response of the system, you have to wait for the analyzer to make many captures, transform them and average
them before you see the results.
With traditional transformation algorithms, the rate at which the signal is transformed is constrained by the
spacing of the spectral lines. As a result, many professionals who work in the creative side of audio have
resorted to using low-resolution RTA-type analyzers to get real-time information. SpectraFoo utilizes patent
pending technology to decouple the transformation resolution from the transformation rate. As a result, Spec-
traFoo is fast, fast, fast! It can perform multichannel FFTs up to 60 times a second, allowing you to see spectral
features as small as 2/3 Hz wide while staying absolutely synchronized with the source material. This allows
you to experience and analyze sonic events simultaneously!
In addition to its unmatched realtime performance, SpectraFoo also provides a full suite of highly precise
quantitative analysis tools, including a capture and storage system which is seamlessly integrated into the
monitoring environment. All of the intuitive knowledge you have gained via synesthesia can be leveraged on
top of the quantitative measurements that SpectraFoo provides.
The following is a guide that provides an overview of SpectraFoo’s features and capabilities. This guide assumes
that you have a basic working knowledge of the Mac OS and its standard techniques. If you are new to Mac
OS X, you should consult your Apple documentation before continuing.
System Requirements
• A Macintosh computer running Mac OS X 10.4.11 or newer – We generally recommend that you use
the latest available version of the OS. If you are using one of the previous releases (10.4 or 10.5), we
recommend that you updated to Apple’s final System Update for that release; Metric Halo only tests
SpectraFoo with the final System Update of previous OS releases.
• RAM – while SpectraFoo is completely compatible with OS X virtual memory, like all media applica-
tions, it benefits from more available physical memory. As a practical rule of thumb, all OS X systems
ought to have at least 2 GB of physical memory installed (4 GB or more preferred). If you plan on using
the capture engine or the delay finder, you will benefit from having more physical RAM installed, but
it is not required for correct operation.
• OpenGL – SpectraFoo can optionally take advantage of OpenGL acceleration to increase performance,
reduce system loading and reduce the likelihood of the fan turning on when used on a laptop. In order
for SpectraFoo to use OpenGL, your system must be capable of supporting Apple’s Quartz Extreme
technology. All shipping Macs support this technology, and this has been the case for a number of years