Getting backing tracks to the same volume levels - ReplayGain vs Normalization vs Loudness Normalization etc

Audacity 3 Help Forum Windows
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I’m a musician and I have a set of backing tracks ready to go for my gigs, but I noticed some volume fluctuations between them. The backing tracks are from different sources - some I made myself, some are from different backing track companies. As a result the volume levels fluctuate a little but still noticeably enough. What’s the best way to sort this out?

I did some research and it seems like you can use ReplayGain, Noramlization or Loudness Normalization in Audacity to fix this.

I tried ReplayGain in Audacity and it does seem to make audio files the same volume. I’m not quite understanding what ReplayGain does - is it basically just some sort of automatic clip gain? Or is it doing something else like adjusting the RMS, loudness (LUFS) etc? I saw a video that said ReplayGain sets tracks to 89db, but what has this got to do with loudness?

However it seems like the loudness of the tracks I adjusted with ReplayGain are quieter. I know that for commercial levels you want to have your LUFS level at least somewhere between -14 and -11 LUFS. However when I adjust audio to this loudness range using the Loudness Normalization in Audacity, it is WAY higher than the level that ReplayGain sets it to. So doesn’t ReplayGain adjust the loudness at all and not to the correct range for commercial releases?

What is the difference between ReplayGain, Noramlization and Loudness Normalization in Audacity and which is best to volume level a set of backing tracks? They’re WAV files btw.

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ReplayGain, WaveGain, MP3Gain, Loudness Normalization, and Apple’s Sound Check all try to match the perceived loudness. That’s what you want.

ReplayGain was introduced before LUFS was standardized but the concept is similar. And newer versions may actually use LUFS.

If you don’t know this, ReplayGain is a player feature so your player software has to support it. (If you open a ReplayGain’d file in Audacity, you get the original unadjusted volume.) WaveGain and MP3Gain make “permanent” changes to the audio so they work anywhere.

If your player software doesn’t support ReplayGain, WaveGain (here) might be your best option.

ReplayGain, WaveGain, and MP3Gain all check the peaks and by default they won’t push the peaks into clipping (distortion), even if that means the track can’t hit the loudness target.

The target loudness is such that most songs end-up lowered in volume and most can hit the target without clipping. If you use Loudness Normalization, you’ll have to check for clipping yourself.

However when I adjust audio to this loudness range using the Loudness Normalization in Audacity, it is WAY higher than the level that ReplayGain sets it to.

Of course, that depends on what you start with and what YOU set it to. :wink: Audacity won’t tell you the LUFS level, although it obviously has to know “internally” before it can do Loudness Normalization. But you can use the Youlean online loudness checker.
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I saw a video that said ReplayGain sets tracks to 89db, but what has this got to do with loudness?

Yeah, that’s confusing but there is “method to their madness”. :wink: It’s a dB SPL reference (acoustic loudness in the air). They have chosen a somewhat arbitrary calibration between the digital and acoustic level.

The only standardized calibration between acoustic and digital levels is in movie theaters where the LUFS for dialog is lower than standard ReplayGain, leaving headroom for loud effects.

The reason for that is that our ears are more sensitive to mid-frequencies, so the frequency content has to taken-into account for perceived loudness (which is what makes it different from RMS). And, the Equal Loudness Curves mean that when you turn down the volume it sounds like you’ve turned-down the bass even more. So when you take frequency content into account, you have to consider how loud you are actually listening in order to match perceived loudness.

I’m sure the LUFS also assumes a “normal” listening volume but we see the digital level, making it easier to understand.

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Thanks for your reply.For playback, I’m loading my backing tracks (WAV files) into a Digitech JamMan looper which is then connected to my mixing desk - this allows me to start/stop and cyle through the tracks with footswitches for better convenience. I don’t know if ReplayGain only applies if you’re playing mp3s on an mp3 player, though? But when you apply ReplayGain normalization in Audacity it just seems to even out the track gain for each piece of audio you apply it to.

As for loudness normalization possibly producing clipping, I know that in a DAW like Cubase you can add a brickwall limiter after the maximizer and set the brickwall limiter so it won’t allow the signal to clip, however I don’t know if it’s possible to do something similar in Audacity?

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I’d say use WaveGain. It’s easy to use and it can batch-process.

It depends on the player. Wikipedia has a list player software that supports it. I wouldn’t expect your JamMan to support it. I use ReplayGain on Winamp on my computer and Sound Check on my antique iPod that docks in my vehicles.

Do you mean Loudness Normalization? Audacity doesn’t come with a ReplayGain effect…

YES, it makes the same linear adjustment to the selection without affecting the dynamics just like a regular volume control and justt like ReplayGain. You normally apply it a whole song (or whole album) so there are no sudden jumps in volume in the middle.

Audacity has Limiter if you don’t mind altering the sound or if you want to knock-down the loud parts of a track.

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What is the difference between ReplayGain and WaveGain? Is WaveGain a plug in you add to Audacity?

I’m not sure I mean Loudness Normalisation. I am referring to using ReplayGain, a plug in you download and add to Audacity. Then you can use it to quickly adjust the gain of all clips using the ‘Normalization’ feature in the ReplayGain plugin. This 5 min video explains it if you have time to watch:

And what I mean about ReplayGain making the volume quieter than the separate Normalization or Loudness Normailization in Aduacity…take a piece or audio and Noramlize it with replay gain, then try the other Normalization or Loudness Normailization (set loudness to somewhere between -11 and -14 LUFS) plug ins with that piece of audio and you’ll see with ReplayGain Noramlization the audio is much lower in volume.

EDIT: I Googled WaveGain and found some info that said that ‘WaveGain is a lightweight Windows application whose purpose is to analyze WAV files, calculate, and generate the recommended gain adjustments, as well as apply the ReplayGain standard, used for measuring the perceived loudness of audio files’.

So is this saying that WaveGain and ReplayGain are essentially the same thing? The only difference is that it seems like WaveGain is a standalone program, whereas ReplayGain is a plugin.

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I just tried applying ReplayGain Normalization to all my backing track WAV files in Aadacity then I exported them, loaded them into my JamMan and tried them. It works fine! ReplayGain doesn’t actually lower the levels by a massive amount, but it seems to even out the differences in levels between each backing track so that’s great.

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I gave a link where you can download WaveGain. It’s not a common-popular tool, but it’s perfect for you!

They are essentially the same thing. They may use different loudness algorithms and different target loudness. There is no “perfect” algorithm… Two different people might not agree when two songs have the volume matched, especially if one starts-out quiet and ends-loud, or if one is rock and the other is classical, etc.

You may want to make some final tweaks by-ear, or maybe do the whole thing by-ear. (1)

Just don’t confuse these with regular normalization which is simple peak normalization without regard to perceived loudness. GoldWave calls it “maximize” which is a better English word, but the proper audio terminology is “normalize” which comes from math or statistics.

The ReplayGain plug-in for Audacity is based on the ReplayGain loudness algorithm but it’s NOT REAL ReplayGain which “tags” the file with a volume adjustment the audio player can use. The REAL ReplayGain doesn’t touch the audio data. The Audacity plug-in changes the actual audio data like WaveGain or MP3Gain, except the Audacity plug-in doesn’t automatically avoid boosting into clipping.

That plug-in was created before Audacity had Loudness Normalization so now it’s not really needed.

(1) Here’s the manual procedure for a limited number of tracks.

  • Peak normalize all of the tracks for “maximized” 0dB peaks.
  • Listen to them all and if they aren’t equally loud, choose the quietest one as your reference.
  • Adjust the others down to match the reference, by ear.

Now, you have a batch of maximized loudness-matched tracks!

You can use the same technique with LUFS (by checking the LUFS level with Youlean after peak normalizing).

BUT if you add another track later and it ends-up quieter after peak normalization, that’s your new reference and you’ll have to re-adjust everything down to match.

… ReplayGain and related avoid clipping by choosing a low-enough target volume that works with the vast majority of songs. The few that can’t reach the target loudness without clipping are adjusted for maximized 0dB peaks, so a few may still may be quieter than everything else.

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Thanks for your helpful replies! I think doing some slight adjustments manually is a good idea too - ReplayGain is fairly acccurate, but I don’t think it gets all the tracks 100% the same. When you say ‘Adjust the others down to match the reference, by ear’, do you mean by using the Envelope Tool on that piece of audio?

I was wondering actually, if I load multiplate backing tracks into Audacity to level correct them side by side, how do you export just one section/piece of audio rather than the whole project? I know in Cubase you just put your locators (start and finish points etc) around the section you want to export - is there something similar in Audacity?

Final thing, when you import multiple audio files into an Audacity project it seems to put them on different tracks. That’s not really a problem, but maybe it’s better to put them all on one track if that’s possible?

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That’s not what I meant… I meant using the Amplify effect or the volume slider to the left of the waveform. But you can use the envelope tool if you want to fade-up or fade-down certain parts. (That kind of thing is probably easier in Cubase or other DAW.)

ReplayGain (and these other’s) aren’t “levelers”. The intention is adjust the volume of the whole song (or a whole album) buy adjusting the volume of each song before before the song starts. When used as intended, a song that starts-out quiet and ends loud retains those dynamics… Just one adjustment for the whole song before playback starts. (And in album mode one adjustment before the album starts.)

how do you export just one section/piece of audio rather than the whole project?

Maybe I don’t understand what you’re doing… Export Multiple is one way. You can also select/highlight a section of audio and then Export Range: Current Selection in the export window.

Final thing, when you import multiple audio files into an Audacity project it seems to put them on different tracks.

You should get multiple files. You may need to re-import them (Import, don’t Open). Then, they will be on different tracks in the same project and you can drag them to the right to sequence them. (Drag the track name above the waveform).

When you play or export they will be mixed (to stereo or mono). But if they are sequenced so they don’t overlap you’ll be mixing with silence and they will play in sequence.