engineering

Loudness monitoring

Loudness monitoring is a engineering 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 Loudness monitoring rather than just read about it. In short: Loudness monitoring of programme levels is needed in radio and television broadcasting, as well as in audio post production. Traditional methods of measuring signal levels, such as the peak programme meter and VU meter, do not give the subjectively valid measure of loudness that many would argue is needed to optimise the listening experience when changing channels or swapping disks.

Key takeaways

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

Reference excerpt

Loudness monitoring of programme levels is needed in radio and television broadcasting, as well as in audio post production. Traditional methods of measuring signal levels, such as the peak programme meter and VU meter, do not give the subjectively valid measure of loudness that many would argue is needed to optimise the listening experience when changing channels or swapping disks. The need for proper loudness monitoring is apparent in the loudness war that is now found everywhere in the audio field, and the extreme compression that is now applied to programme levels.

Loudness meters Meters have been introduced that aim to measure the human perceived loudness by taking account of the equal-loudness contours and other factors, such as audio spectrum, duration, compression and intensity. One such device was developed by CBS Laboratories in the 1980s. Complaints to broadcasters about the intrusive level of interstitials programs (advertisements, commercials) has resulted in projects to develop such meters. Based on loudness metering, many manufacturers have developed real-time audio processors that adjust the audio signal to match a specified target loudness level that preserves volume consistency at home listeners.

EBU Mode meters In August 2010, the European Broadcasting Union published a new metering specification EBU Tech 3341, which builds on ITU-R BS.1770. To make sure meters from different manufacturers provide the same reading in LUFS units, EBU Tech 3341 specifies the EBU Mode, which includes a Momentary (400 ms), Short term (3 s) and Integrated (from start to stop) meter and a set of audio signals to test the meters.

Worked examples

Example 1 — a first encounter with Loudness monitoring

Start with the simplest possible case. Write down what Loudness monitoring claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, 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 Loudness monitoring 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 Loudness monitoring 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 Loudness monitoring

In research: Loudness monitoring appears in engineering 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 Loudness monitoring 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: Loudness monitoring is common in secondary-school and first-year university syllabi. It links to neighbouring topics Audio engineering, Broadcast engineering, Sound production technology, so understanding it makes those chapters shorter.
In everyday life: Look for Loudness monitoring 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 Loudness monitoring in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Loudness monitoring 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 Loudness monitoring out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Loudness monitoring in simple terms?

Why does Loudness monitoring matter?

Because it connects several engineering 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 Loudness monitoring?

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 Loudness monitoring.