computer science

Smaart

Smaart is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Smaart rather than just read about it. In short: Smaart (System Measurement Acoustical Analysis in Real Time) is a suite of audio and acoustical measurements and instrumentation software tools introduced in 1996 by JBL's professional audio division. It is designed to help the live sound engineer optimize sound reinforcement systems before public performance and actively monitor acoustical parameters in real time while an audio system is in use.

Key takeaways

Smaart belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Smaart to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Smaart from memory before moving on to harder problems.

Reference excerpt

Smaart (System Measurement Acoustical Analysis in Real Time) is a suite of audio and acoustical measurements and instrumentation software tools introduced in 1996 by JBL's professional audio division. It is designed to help the live sound engineer optimize sound reinforcement systems before public performance and actively monitor acoustical parameters in real time while an audio system is in use. Most earlier analysis systems required specific test signals sent through the sound system, ones that would be unpleasant for the audience to hear. Smaart is a source-independent analyzer and therefore will work effectively with a variety of test signals including speech or music. The product has been known as JBL-SMAART, SIA-SMAART Pro, EAW SMAART, and SmaartLive. As of 2008 the product has been branded as simply Smaart. An acoustician version has been offered as Smaart Acoustic Tools, however as of Smaart v7.4, Acoustic Tools have been included within the Impulse Response mode of Smaart. A standalone sound pressure level monitoring-only version called Smaart SPL was released in 2020. Smaart is a real-time single and dual-channel fast Fourier transform (FFT) analyzer. Smaart has two modes: Real-Time Mode and impulse response mode. Real-time mode views include single channel Spectrum and dual channel Transfer Function measurements to display RTA, Spectrograph, and Transfer Function (Live IR, Phase, Coherence, Magnitude) measurements. The impulse response mode will display time domain graphs such as Lin (Linear), Log (Logarithmic), ETC (Energy Time Curve), as well as Frequency, Spectrograph, and Histogram graphs. Impulse Response mode also includes a suite of acoustical intelligibly criteria such as STI, STIPA, Clarity, RT60, EDT, etc. Smaart has been licensed and owned by several companies since JBL and is currently owned and developed by Rational Acoustics. First written as a native Windows 3.1 application to work within Windows 95 on IBM PC–compatible computers, in 2006 a version was introduced that was compatible on both Windows and Apple Macintosh operating systems. As of March 2016 Smaart was in its 8th version.

Use Smaart is based on real-time fast Fourier transform (FFT) analysis, including dual-FFT audio signal comparison, called "transfer function", and single-FFT spectrum analyzer. It includes maximum length sequence (MLS) analysis as a choice for impulse response, for the measurement of room acoustics. The FFT implementation of Smaart includes a proprietary multi-time window (MTW) selection in which the FFT, rather than being a fixed length, is made increasingly shorter as the frequency increases. This feature allows the software to 'ignore' later signal reflections from walls and other surfaces, increasing in coherence as the audio frequency increases. The latest version of Smaart 8 runs under Windows 7 or newer, and Mac OSX 10.7 or newer, including 32- and 64-bit versions. A computer having a dual-core processor with a clock rate of at least 2 GHz is recommended. Smaart can be set to sample rates of 44.1 kHz, 48 kHz or 96 kHz, and to bit depths of 16 or 24. The software works with computer audio protocols ASIO, Core Audio, WAV or WDM audio drivers.

Transfer function

Smaart's transfer function requires a stereo input to the computer because it analyzes two channels of audio signal. Using its dual-FFT mode, Smaart compares one channel with the other to show the difference. This is used by live sound engineers to set up concert sound systems before a show and to monitor and adjust these systems during the performance. The first channel of audio undergoing analysis is connected directly from one of the main outputs of the mixing console and the second channel is connected to a microphone placed in the audience listening area, usually an omnidirectional test microphone with a flat, neutral pickup characteristic. The direct mixing console audio output is compared with the microphone input to determine how the sound is changed by the sound system elements such as loudspeakers and amplifiers, and by the room acoustics indoors or by the weather conditions and acoustic environment outdoors. Smaart displays the difference between the intended sound from the mixer and the received sound at the microphone, and this real-time display informs the audio engineer's decisions regarding delay times, equalization and other sound system adjustment parameters. Although pink noise is a traditional choice for test signal, Smaart is a source-independent analyzer, which means that it does not rely on a specific test signal to produce measurement data. Pink noise is still in common usage because its energy distribution allows for quick measurement acquisition, but music or another broadband test signal can be used instead. Transfer function measurements can also be used to examine the frequency response of audio equipment, including individual amplifiers, loudspeakers and digital signal processors such as audio crossovers and equalizers. It can be used to compare a known neutral-response test microphone with another microphone in order to better understand its frequency response and, by changing the angle of the microphone under test, its polar response. Transfer function measurements can be used to adjust audio crossover settings for multi-way loudspeakers; similarly, they can be used to adjust only the subwoofer-to-top box crossover characteristics in a sound system where the main, non-subwoofer loudspeakers are flown or rigged but the subwoofers are placed on the ground. One of the traces in the Smaart display shows phase response. To properly align adjacent frequency bands through a crossover, the two phase responses should be adjusted until they are seen in Smaart to be parallel through the crossover frequency. The transfer function measurement can be used to measure frequency-related electrical impedance, one of the electrical characteristics of dynamic loudspeakers. Grateful Dead sound system engineer "Dr. Don" Pearson worked out the method in 2000, using Smaart to compare the voltage drop through a simple resistor between a loudspeaker and a random noise generator.

Real-time analyzer

… excerpt ends here. Continue reading the full article.

Illustrations

Smaart: JBL-Smaart version 1.0 demo for Windows 3.1 (1995) — JBL-Smaart version 1.0 demo for Windows 3.1 (1995)

Worked examples

Example 1 — a first encounter with Smaart

Start with the simplest possible case. Write down what Smaart claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Smaart before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Smaart ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Smaart

In research: Smaart appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Smaart in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Smaart is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1996 software, Acoustics, Audiovisual introductions in 1996, so understanding it makes those chapters shorter.
In everyday life: Look for Smaart outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Smaart in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Smaart means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Smaart out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Smaart in simple terms?

Why does Smaart matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Smaart?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Smaart.