A Real Time Analyzer is a professional audio device that measures and displays the frequency spectrum of an audio signal; a spectrum analyzer

Spectrum analyzer

A spectrum analyzer measures the magnitude of an input signal versus frequency within the full frequency range of the instrument. The primary use is to measure the power of the spectrum of known and unknown signals...

 that works in real time

Real-time computing

In computer science, real-time computing , or reactive computing, is the study of hardware and software systems that are subject to a "real-time constraint"— e.g. operational deadlines from event to system response. Real-time programs must guarantee response within strict time constraints...

. An RTA can range from a small PDA

PDA

A PDA is most commonly a Personal digital assistant, also known as a Personal data assistant, a mobile electronic device.PDA may also refer to:In science, medicine and technology:...

-sized device to a rackmounted hardware unit to software running on a laptop

Laptop

A laptop, also called a notebook, is a personal computer for mobile use. A laptop integrates most of the typical components of a desktop computer, including a display, a keyboard, a pointing device and speakers into a single unit...

. It works by measuring and displaying sound input, often from an integrated microphone

Microphone

A microphone is an acoustic-to-electric transducer or sensor that converts sound into an electrical signal. In 1877, Emile Berliner invented the first microphone used as a telephone voice transmitter...

 or with a signal from a PA system. Basic RTAs show three measurements per octave at 3 or 6 dB increments; sophisticated software solutions can show 24 or more measurements per octave as well as 0.1 dB resolution.

Types

There are generally two types of RTAs:

1. RTAs employing analog signal processing, and
2. RTAs employing digital signal processing (DSP).

The main difference between the two types is that the analog

Analog signal

An analog or analogue signal is any continuous signal for which the time varying feature of the signal is a representation of some other time varying quantity, i.e., analogous to another time varying signal. It differs from a digital signal in terms of small fluctuations in the signal which are...

 RTAs use a series of hardwired, analog bandpass filters to break the signal into frequency bands prior to measuring it. Digital

Digital

A digital system is a data technology that uses discrete values. By contrast, non-digital systems use a continuous range of values to represent information...

 RTAs use digital sampling technology and microprocessor based digital signal processing to perform necessary calculations, such as Fast Fourier Transform

Fast Fourier transform

A fast Fourier transform is an efficient algorithm to compute the discrete Fourier transform and its inverse. "The FFT has been called the most important numerical algorithm of our lifetime ." There are many distinct FFT algorithms involving a wide range of mathematics, from simple...

s, to perform the measurements and thus do not need analog hardware filters to isolate each frequency band. The digital approach to signal analysis generally yields much higher accuracy and resolution and thus most RTAs currently in production use digital signal processing technology. Digital signal processing is more cost effective.

Professional Use

RTAs are often used by sound engineers and by acousticians installing audio systems in all kinds of listening spaces: Venues, home theatres, cars etc. The parameters that can be measured are the spectral aspects of sound reproduction caused by effects like resonances and constructive and destructive interference, but not imaging and spatial aspects. In professional audio many systems incorporate an RTA along with a device that also performs equalization

Equalization

Equalization, is the process of adjusting the balance between frequency components within an electronic signal. The most well known use of equalization is in sound recording and reproduction but there are many other applications in electronics and telecommunications. The circuit or equipment used...

. While measuring pink noise

Pink noise

Pink noise or 1/ƒ noise is a signal or process with a frequency spectrum such that the power spectral density is inversely proportional to the frequency. In pink noise, each octave carries an equal amount of noise power...

 or other test tones, such a controller can level out the frequency response by employing a set of adjustments in the appropriate frequency areas according to the system's interaction with the venue's size, shape and construction materials, among other things.

See also

• Architectural acoustics
  Architectural acoustics
  Architectural acoustics is the science of noise control within buildings. The first application of architectural acoustics was in the design of opera houses and then concert halls. More widely, noise suppression is critical in the design of multi-unit dwellings and business premises that generate...
  
  
• Real-time computing
  Real-time computing
  In computer science, real-time computing , or reactive computing, is the study of hardware and software systems that are subject to a "real-time constraint"— e.g. operational deadlines from event to system response. Real-time programs must guarantee response within strict time constraints...
  
  
• Spectrum Analyzer
  Spectrum analyzer
  A spectrum analyzer measures the magnitude of an input signal versus frequency within the full frequency range of the instrument. The primary use is to measure the power of the spectrum of known and unknown signals...
  
  
• Pink Noise
  Pink noise
  Pink noise or 1/ƒ noise is a signal or process with a frequency spectrum such that the power spectral density is inversely proportional to the frequency. In pink noise, each octave carries an equal amount of noise power...
  
  
• Auditory Scene Analysis
  Auditory scene analysis
  In psychophysics, auditory scene analysis is the process by which the human auditory system organizes sound into perceptually meaningful elements. The term was coined by psychologist Albert Bregman...
  
   incl. 3D-sound perception, localisation
• Audio Processing
• Sound Localization
  Sound localization
  Sound localization refers to a listener's ability to identify the location or origin of a detected sound in direction and distance. It may also refer to the methods in acoustical engineering to simulate the placement of an auditory cue in a virtual 3D space .The sound localization mechanisms of the...
  
  
• Source Separation
  Source separation
  Source separation problems in digital signal processing are those in which several signals have been mixed together and the objective is to find out what the original signals were. The classical example is the "cocktail party problem", where a number of people are talking simultaneously in a room ,...
  
  
• Timbre
  Timbre
  In music, timbre is the quality of a musical note or sound or tone that distinguishes different types of sound production, such as voices and musical instruments, such as string instruments, wind instruments, and percussion instruments. The physical characteristics of sound that determine the...