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# iZotope RX Loudness Control: Set LUFS and True Peak
- URL: https://izotoperx.net/izotope-rx-loudness-control/
- Published: 2026-09-20T14:19:40.000Z
- Updated: 2026-09-30T21:30:15.000Z
- Description: A practical guide to setting integrated loudness and true peak, separating program compliance from dialogue leveling, and checking the delivered file.
- Author: Brandon Hayes
- Tags: Workflow, Post Production, RX 12, Voiceover

iZotope RX Loudness Control brings a finished program to a set integrated-loudness target and true-peak ceiling. It applies one fixed gain change across the selection, and when that gain would break the True Peak setting, a post-limiter keeps the result inside it.

Think of it as a delivery-compliance module, not a dialogue balancer. It will not lift one sentence and pull the next one down, rescue a weak mix or tell you which platform specification to follow. Save it for the point where the edit, restoration, level rides, music, ads and transitions are settled.

## Loudness Control, Leveler and clip gain solve different problems

| Tool               | What it changes                                                                          | Best use                                                                             |
| ------------------ | ---------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------ |
| Loudness Control   | Fixed gain across the selection, with post-limiting when the true-peak limit requires it | Meeting a defined program-level loudness and true-peak specification                 |
| Leveler            | Time-variable gain written as an editable Clip Gain envelope                             | Smoothing words, phrases or sections whose levels vary over time                     |
| Manual clip gain   | Gain changes placed by the editor                                                        | Correcting individual lines, breaths, edits or scene transitions with direct control |
| Peak normalization | One gain change based on a peak target                                                   | Setting peak headroom when no integrated-loudness target is required                 |

The current [RX 12 Loudness Control documentation](https://docs.izotope.com/rx12/en/loudness-control.html?ref=izotoperx.net) marks the module as available in Standard and Advanced. The [RX 12 Leveler documentation](https://docs.izotope.com/rx12/en/leveler.html?ref=izotoperx.net) marks Leveler as Advanced and states plainly that it is not a loudness-compliant leveling tool. The site's [RX edition comparison](https://izotoperx.net/izotope-rx-elements-vs-standard-vs-advanced/) covers the wider feature split; confirm current availability before you choose an edition.

The distinction matters because a file can land on its final integrated target and still jump distractingly between speakers. Loudness Control measures the program as one whole. [Leveler](https://izotoperx.net/izotope-rx-leveler/) or clip gain reshapes the level relationship inside it. Get the internal balance right first, then run the compliance pass.

## Read the controls as parts of one specification

![RX Audio Editor with a complete program selected and the Loudness Control module open beside its loudness history graph.](https://storage.ghost.io/c/2e/c1/2ec1682b-08cc-4997-b0d0-7361fc45beb8/content/images/2026/09/izotope-rx-loudness-control--01-full-workspace.webp)

Loudness Control belongs at the end of the workflow, after the complete finished program is selected.

### Integrated loudness

![Close view of Loudness Control showing separate Target and Measurement columns for Integrated loudness and True Peak.](https://storage.ghost.io/c/2e/c1/2ec1682b-08cc-4997-b0d0-7361fc45beb8/content/images/2026/09/izotope-rx-loudness-control--02-target-measurement.webp)

Set the destination target on the left, then judge the measured result in the separate Measurement column.

**Integrated** is the program-level target. RX takes it in LKFS, and the manual confirms LKFS is the same as LUFS. The value describes loudness across the measured selection under the chosen standard, gating rules included when they are enabled. It is not a peak value, and it is not the level of every moment.

### Tolerance

**Tolerance** is the plus-or-minus margin allowed around the integrated target, measured in LU. The RX manual notes that standards commonly use a tolerance between 0.5 and 2 LU. Take the number from the destination specification instead of choosing a wider margin because it is easier to pass.

### Short-term and Momentary

**Short-term** loudness uses a moving three-second window, and **Momentary** loudness uses a moving 400 ms window. These controls enforce limits on shorter sections when a delivery standard defines them. Leave them off unless the spec asks for them; an arbitrary number here only makes the waveform look tidier.

A program can meet its Integrated target and still contain a short passage that breaks a Short-term or Momentary ceiling. The opposite happens too: every short passage can look reasonable while the full program misses its integrated target. The two readings answer different timing questions.

### True Peak

**True Peak** sets the maximum allowed true-peak value. It is a ceiling, while Integrated is an average program-loudness target. If the gain needed for Integrated would push peaks past that ceiling, Loudness Control can bring in its post-limiter. That stops a plain gain increase from ignoring the peak requirement, but heavy limiting is never automatically transparent.

## Gating stops quiet sections from dominating the reading

![Loudness Control interface with Integrated, Short-term and Momentary history plus the Program loudness gate control.](https://storage.ghost.io/c/2e/c1/2ec1682b-08cc-4997-b0d0-7361fc45beb8/content/images/2026/09/izotope-rx-loudness-control--03-short-term-gate.webp)

The timing curves answer different questions, while the program loudness gate prevents silence from dominating the integrated result.

Integrated loudness does not always count every sample equally. According to the RX documentation, the gates used for BS.1770-2/3 and R128 first drop momentary loudness below −70 LKFS, then drop material more than 10 dB or LU below the average momentary loudness. Silence, pauses and very quiet material therefore can't drag the program reading away from the sections that shape what a listener actually hears.

RX lets you switch the [program-loudness gate](https://izotoperx.net/izotope-rx-loudness-optimize/) on or off for a custom requirement. That switch is not a matter of taste: set it to match the named standard. The manual lists BS.1770-1 as the exception that does not use gating, while most standards supplied with Loudness Control do.

## Choose the destination specification before opening the module

No single LUFS target covers every podcast, audiobook, broadcast file and streaming service. Start with the current delivery document from the platform, network, distributor or client, and write down every part of the requirement:

- the measurement standard and version;
- integrated loudness and tolerance;
- true-peak ceiling;
- any Short-term or Momentary limit;
- whether gating is required;
- the file format and whether measurement applies before or after encoding.

These fields belong together. Copy a popular LUFS number without its tolerance, true-peak limit or measurement method and you get a setting that looks like a standard without following one. A preset is helpful when it matches the current destination specification, but its name doesn't prove the receiving platform still uses the same rules.

## Use Loudness Control on the complete, finished program

1. **Finish the content edit.** Lock [dialogue edits](https://izotoperx.net/clean-dialogue-rx/), music, ads, credits, fades and scene transitions.
2. **Repair defects.** Remove clicks, noise, clipping and other problems before making final level decisions.
3. **Balance the program internally.** Use clip gain, automation or Leveler where words and sections need different changes.
4. **Leave sensible peak headroom.** A badly over-loud mix can force heavy limiting once it is moved to the target.
5. **Select the whole deliverable.** The documented RX workflow uses Ctrl/Cmd+A or Edit > Select All when the entire clip should be processed.
6. **Choose the correct preset or enter every required field.** Confirm Integrated, Tolerance, True Peak, shorter-window limits and gating against the destination document.
7. **Render.** RX applies Loudness Control to the selection.
8. **Export in the required format.** Keep the source master and the delivery file separate.
9. **Measure the actual delivered file.** Check the exported or encoded result with the same standard the receiver uses.

The site's [RX Module Chain guide](https://izotoperx.net/izotope-rx-module-chain/) explains why restoration and level-shaping decisions should stay reversible until the signal chain is settled. The [RX import and export guide](https://izotoperx.net/izotope-rx-import-export-save/) covers the separate choices of file format, sample rate, bit depth and saved master.

## Apple Podcasts is one concrete example, not a universal preset

Apple's current [audio requirements for Apple Podcasts](https://podcasters.apple.com/support/893-audio-requirements?ref=izotoperx.net) recommend that overall loudness remain around −16 dB LKFS with a ±1 dB tolerance and that true peak not exceed −1 dB FS. Apple says these values are calculated according to ITU-R BS.1770-5 and that preconditioning should happen before encoding.

If you are preparing a file for that recommendation, those are the fields to carry into the loudness workflow. Don't reuse them for a broadcast, audiobook or another podcast platform's deliverable until you have checked that destination's own current rules.

Apple also warns that compression can clip the signal when the true-peak recommendation is ignored. That is why I'd keep the final encoded file in the QA step: an uncompressed master can be compliant while the delivery encode produces a different peak result. The site's [podcast cleanup guide](https://izotoperx.net/izotope-rx-podcast-cleanup/) covers the earlier dialogue-repair and editing decisions that should be finished before this last pass.

## Do not type an RMS requirement into a LUFS field

Some audiobook and legacy delivery documents give an RMS range instead of an integrated LUFS/LKFS target. RMS and LUFS are different measurements, so typing the same number into Loudness Control's Integrated field does not convert an RMS requirement.

Use the measurement the destination names. If the receiver asks for RMS, measure and adjust RMS with a workflow that matches its published method, and check peak and noise-floor requirements separately. Loudness Control only helps when the target is expressed through a compatible loudness standard.

The [audiobook cleanup guide](https://izotoperx.net/izotope-rx-audiobook-cleanup/) puts noise, mouth sounds, pacing and delivery preparation in their own stages. Recheck the platform's current submission page before delivery instead of trusting an old checklist copied from a forum or a preset name.

## Keep Loudness Control near the end of the chain

Any edit made after Loudness Control can change the measurement. A new intro, a replaced ad, trimmed silence, a music change, EQ, dialogue compression or a different fade can all move Integrated loudness, short-window readings or peaks. When the program changes, repeat the final measurement and compliance pass.

A dependable order is repair, edit, internal level balance, tonal work, assembly, Loudness Control, export and final-file verification. The [RX workflows hub](https://izotoperx.net/rx-workflows/) maps that order onto editor, plug-in, DAW and delivery routes. Treat it as a decision order, not a claim that every production needs every stage, and skip anything that doesn't solve a named problem.

## Common Loudness Control mistakes

### The file hits the target, but one speaker is still too quiet

Go back to clip gain, automation or Leveler. Integrated loudness can be correct while the internal balance is still poor. Fix the relationship between speakers, then rerun Loudness Control, because the program measurement has changed.

### The result sounds squeezed after rendering

The required gain may be pushing peaks into the post-limiter. Bring peaks down and improve the mix before the compliance pass instead of asking the limiter to absorb the whole correction. Also confirm that the selected target and true-peak ceiling belong to the intended destination.

### A preset passes in RX but the uploaded file fails

Check the exact exported file, the encoder, the channel layout and the receiver's measurement version. Presets can go out of date, and an encode can change peaks. Compliance belongs to the deliverable, not to the module window.

### The audiobook target looks wrong in the Integrated field

Stop and check the units. If the requirement is RMS, the Integrated LUFS/LKFS field is the wrong control for it. Use the meter and method the destination specifies instead of matching digits across scales that don't correspond.

Once the specification is complete, Loudness Control is simple: finish the program, enter the correct loudness and peak limits, render the full selection and verify the file that will actually be delivered. Moving the gain is rarely the hard part. Keeping program balance, measurement units and platform requirements from merging into one vague “loudness” task is.