LUFS levels change when mixed down to one track

BACKGROUND: I am editing a podcast and would like to achieve -16LUFS for it to be at the right level for Spotify, apple etc.

I am setting ‘Loudness Normalization’ on each individual track containing dialogue to -16 LUFS

THE ISSUE: However, once all tracks are mixed down to one, the Youlean meter is showing different LUFS levels under the ‘INTEGRATED’ heading as much lower (-28 to -22 LUFS).


  1. Is it better to apply ‘loudness normalization’ only at the end when all tracks are mixed and rendered OR, is it better to apply ‘loudness normalization’ to each separate track AND then again once mixed together?

That meter ignores the track gain slider setting …

YouLean ignores track gain silder

If you combined 2 tracks each -16LUFS with the track gain sliders at 0, the result would be deafening, ( louder than -10LUFS).

Thanks Trebor!
I am not sure I fully understand what this means .
So do I need to adjust the gain (negative direction) so that the Playback level (on the little grey bar in Audacity) stays below -6dB?
Are you able to tell me how I can rectify this? :smiling_face:

Thank you!

The YouLean meter readings are only valid if the track gain slider is on 0dB.

You stated you mixed-down more than 1 track which had been nornalized to -16LUFS
and the result was “-28 to -22 LUFS”.
That can only happen if the gain sliders on those tracks have been turned down below zero.

If the final-mix you export for upload is -16LUFS (when its gain slider on 0dB) that’s all that matters.

You may need to apply compression with make-up gain to reach -16LUFS loudness.

You can use Audacity to record what popular Spotify podcast waveforms look like,
to give you an idea what to aim for, e.g. how much headroom, what the frequency content is.

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It’s probably more-straightforward to mix & export, then re-import and set the level as a separate “mastering” step. It’s best to export-as floating point WAV (“32-bit float”) as a temporary format because floating-point can go over 0dB without clipping (without distorting). Note that your final production shouldn’t go over 0dB (peak) even if you use a format that can support it.

When you normalize loudness you still might get clipping. That’s actually very-likely at -16dB LUFS. If that happens you should use the limiter or “compromise” and lower the level.

Note that mixing is done by summation so mixing usually increases the level. But with dialog, hopefully only one person is talking at a time so there may not be any actual mixing of the sounds.

All of the popular streaming services will apply their own loudness normalization. But they won’t boost the peaks into clipping so you can end-up with levels lower than their standard target.

Okay thank you for your help!

I never knew this, thanks!! So is it still worth aiming for -16 LUFS if this is all done their end anyway?

Hi DVD Doug, sorry for all the questions…
Is it still worth applying ‘loudness normalization’ (to -16LUFS) on each separate track Abwfore doing the mix and export and doing it again?

Yes, only one person speaks at a time, except for the occasional agreeance with the speaker e.g. ‘yes’ or ‘ahhhh’

However, I do have intro and outro music (I use auto-duck to reduce the music when someone is speaking) - could this be what is affecting my LUFS levels when mixed and rendered down to one track?

Thank you!

I think you’re working too hard. You should be producing the work that is “legal” (not overloaded) and pleasant sounding and then apply LUFS/mastering just before shipping it out the door.

While the show is on the timeline—in whatever form—the bouncing sound meter will tell you a summation of loudnesses. If it starts smashing the right-hand limit and lighting the red alarm, then you have overvolume problems.

Screen Shot 2023-08-12 at 8.55.08 AM

Someone posted an Audacity Audiobook Mastering centered around LUFS rather than the Audiobook RMS standard. I didn’t write it down which means I think there was something wrong with it.???

More research and/or coffee.


Thank you! And thanks also for letting me know I’m looking into this way much - that is also super helpful. I did wonder why I was feeling so bogged down with it all :laughing:

Must look this up… :wink:

It’s a much older standard based on electrical power. I suspect the ACX company got rolling before the LUFS Audio Quality thing got going, so RMS it is.

I almost always write it “RMS (loudness)” to avoid throwing a mystery label in there.

It’s Root Mean Square, by the way. The area under the curve if you got that far in math class. Raw Energy. The good news is everybody knows what it is. The bad news is it doesn’t “know” what sound is. It measures all sound the same whether or not you can hear it. I’m not joshing.

One of the steps in the Audacity Audiobook Mastering Macro is a tonal control which deletes thunder, earthquakes, large trucks rolling by, poor quality USB microphone rumble, and other very low pitch sounds. RMS will try to read all those as very high volume, and they have nothing to do with your show.


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