A real-time analyzer (RTA) is a professional audio device that measures and displays the frequency spectrum of an audio signal; a

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. The input signal that most co ...

that works in

real time Real-time or real time describes various operations in computing or other processes that must guarantee response times within a specified time (deadline), usually a relatively short time. A real-time process is generally one that happens in defined ...

. An RTA can range from a small

PDA PDA may refer to: Science and technology * Patron-driven acquisition, a mechanism for libraries to purchase books *Personal digital assistant, a mobile device * Photodiode array, a type of detector * Polydiacetylenes, a family of conducting poly ...

-sized device to a rack-mounted hardware unit to software running on a

laptop A laptop, laptop computer, or notebook computer is a small, portable personal computer (PC) with a screen and alphanumeric keyboard. Laptops typically have a clam shell form factor with the screen mounted on the inside of the upper li ...

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

microphone A microphone, colloquially called a mic or mike (), is a transducer that converts sound into an electrical signal. Microphones are used in many applications such as telephones, hearing aids, public address systems for concert halls and public ...

or with a signal from a

PA system A public address system (or PA system) is an electronic system comprising microphones, amplifiers, loudspeakers, and related equipment. It increases the apparent volume (loudness) of a human voice, musical instrument, or other acoustic sound sou ...

. 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: # RTAs employing analog signal processing, and # RTAs employing digital signal processing (DSP). The main difference between the two types is that the

analog Analog or analogue may refer to: Computing and electronics * Analog signal, in which information is encoded in a continuous variable ** Analog device, an apparatus that operates on analog signals *** Analog electronics, circuits which use analog ...

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

Digital Digital usually refers to something using discrete digits, often binary digits. Technology and computing Hardware *Digital electronics, electronic circuits which operate using digital signals **Digital camera, which captures and stores digital i ...

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

fast Fourier transform A fast Fourier transform (FFT) is an algorithm that computes the discrete Fourier transform (DFT) of a sequence, or its inverse (IDFT). Fourier analysis converts a signal from its original domain (often time or space) to a representation in th ...

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.True Audio FAQ
/ref> 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 Interference is the act of interfering, invading, or poaching. Interference may also refer to: Communications * Interference (communication), anything which alters, modifies, or disrupts a message * Adjacent-channel interference, caused by extr ...

, but not imaging and spatial aspects. In professional audio many systems incorporate an RTA along with a device that also performs equalization. While measuring

pink noise Pink noise or noise is a signal or process with a frequency spectrum such that the power spectral density (power per frequency interval) is inversely proportional to the frequency of the signal. In pink noise, each octave interval (halving ...

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.

References

{{Reflist Sound Electronic design

Types

Professional use

See also

References