Why is zero VU not the same as zero dBFS?

They are different scales with different references. Zero VU corresponds to minus eighteen dBFS RMS in the EBU convention, which is why material peaking near full scale reads several units above zero on this display rather than at it.

Why does the meter miss my loudest moments?

Because it integrates over three hundred milliseconds by design, so a transient shorter than that is averaged with the material around it. That smoothing is the standard's intent and matches perception, but it means this meter cannot be used to catch overs.

What is average rectification?

Taking the absolute value of each sample and averaging them over the window, as opposed to squaring them as a root-mean-square meter does. The two measures track each other closely but not identically, and the rectified version is the one the VU convention specifies.

Why is only one figure shown instead of a separate left and right reading?

The display is a whole-file summary, so a single integrated value is what it reports, with the channel count noted in the caption. If a per-channel balance question matters, the phase meter reports the relationship between left and right directly.

What does a dash instead of a number mean?

The file is quiet enough that the reading would be meaningless, so it is suppressed rather than displayed as a very low number. Empty or near-silent files are the usual cause.

VU Meter

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VU Meter reads a dropped file the way a classic needle meter would, averaging the level over three hundred millisecond windows and referencing zero VU to minus eighteen dBFS. The result is a deliberately slow, averaged reading rather than a peak one.

What is VU Meter?

An integrated figure dominates the panel, with a bar beneath it spanning minus twenty to plus three VU, a marked point at zero, and a row of window bars showing how the reading moves through the file.

What the meter presents and how it is derived:

An integrated VU figure, with a dash in place of a number when the file is quiet enough to be effectively silent.
The underlying average-rectified level in dBFS, shown alongside the channel count and sample rate.
A bar scaled from minus twenty to plus three VU with a tick at zero, and a gradient from green through yellow to red as it rises.
One bar per three hundred millisecond window, so the movement of the average across the recording is visible.

The reading is built from average rectification rather than root mean square, which is the distinction that makes a VU meter a VU meter: the absolute value of the signal is taken and averaged over the integration window, so the ballistics are slow and steady in the way the standard intends. The three hundred millisecond integration is the classic figure, and zero VU is referenced to minus eighteen dBFS RMS in the EBU R68 convention, so a file peaking at zero dBFS generally reads a few units above zero on this scale. The consequence of that deliberate averaging is the meter's best-known behaviour: it under-reads fast transients, which is a feature rather than a fault, because the needle was designed to track how loudness is perceived rather than to catch every spike. When the reading looks lower than the peak level suggests, that gap is the transient content the ballistics have passed over. The 300 millisecond integration is the figure the standard specifies, and the zero VU reference is a convention rather than a property of the audio, so the same file would read differently against a different reference. What the scale is designed to show is whether a programme sits around its nominal point consistently, and a reading that drifts far from 0 VU says something about level control rather than about peaks.

Where this meter should not be relied on:

Fast transients are systematically under-reported, so it is a poor choice for catching clipping or overs.
The scale tops out at plus three VU, so very hot material reads as a full bar rather than as a number beyond the scale.
Only one integrated figure is given, with no separate left and right readings.
The reference is a convention, so a file calibrated for a different standard will not read against it directly.
Nothing is exported and no peak value is reported here.
It is a measurement only, with no gain applied as a result.

Use it for the job the convention was designed for: judging how a mix will feel to a listener, matching levels between takes in a session, and checking that a programme sits near zero VU over its length rather than drifting. When peaks and true peaks are the concern, the peak program meter and the true peak meter report those without the deliberate smoothing.

How to use VU Meter

Drop an audio file onto the panel; no settings are needed and the measurement runs immediately.
Read the large integrated figure against the bar, treating zero VU as the reference point.
Look at the average-rectified dBFS line beneath it to see the underlying level.
Scan the window bars to check whether the average holds steady or drifts across the file.

When to use VU Meter vs related tools

VU Meter is the right reading when the question is how loud a file feels rather than where its samples peak, so it suits session level matching and programme checks. PPM Meter answers the opposite question with fast peak integration and an over indicator, and RMS Meter gives a squared-average measurement with a peak figure alongside it. For readings tied to platform normalisation, Loudness Meter (LUFS) is the meter designed for that purpose.

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