Experienced User Creating Poor Readings

This is a transfer from a separate discussion.


Hi Koz! Long time no talk :slight_smile: That’s a good thing, I think! I’ve produced over a dozen books through ACX since we last spoke, all without a hitch… until now [grumpy face]. Just got an email from them that every single chapter of my most recent production has a “low RMS value.”

I looked through as many posts on the forum as I could find, and deduced that I need to do this:
Effect > RMS Normalize: Set the target to -20dB. > OK.

Is that accurate? Just download the RMS Normalize effect and apply it to each of the 40 files individually?
If so, can I apply it to the .mp3 files, or would you recommend that I apply it to the .aup files, then re-save each one as an .mp3?

Thank you!!

Effect > RMS Normalize: Set the target to -20dB. > OK.

I expect that to work, yes. The goal is to hit the show chapters between -18dB and -24dB.

can I apply it to the .mp3 files

You don’t do anything to the MP3 files short of maybe admire them. Those are throw-away. MP3 files get more and more damaged as you mess with them. Highly not recommended.

Keeping very high quality archives as AUP (more accurately, Audacity Projects) is not recommended, either. Yes, that works, but projects are brittle and prone to mysteriously not opening up when you need them most (somehow, they can tell when you’re in a panic). Export archives as WAV (Microsoft) 16-bit. Those don’t progressively degenerate and you can make a WAV into anything else.

Yes, you have to correct each chapter or whatever your production break points are, individually. Test each one individually, too. Did they say how much you missed them by? You may just be able to RMS-Normalize to a louder number, finish processing and go make coffee.

You can misadjust Limiter and create problems, too.

It’s actually reassuring all the chapters are like that. It’s not an evil one-off and chances are you did something silly, consistently. If you missed conformance by several KM/Miles, then there’s something else wrong.



Thanks for the speedy reply! They did not tell me how much I missed the mark by, which I find super annoying… and I agree it’s good that all the chapters got flagged, but I recorded this project right on the heels of another one, which passed their quality check without issue, so I’m a bit concerned that whatever I did wrong, I’m going to keep doing wrong from here on out, since I haven’t changed anything in my recording practices or mastering chain…

My current mastering chain is:
High Pass
Low Pass
Limiter (Hard Limit at -3.2)
Normalize (Apply Gain = 1, Level = -3.2, RemoveDCOffset = 1, StereoIndependent = 0)

Ok now that I think of it, I may have added the final step of the chain (Normalize) in between the last project I did and the one that they’re taking issue with… do you think that could be where the problem is? I kind of wondered if I was being redundant by Limiting to -3.2 and then Normalizing to -3.2… Should I remove the Limiter from the chain?

Thank you!


OK I ran ACX check, and it looks like they’re hovering in the -29 range (so not awful…)
I noticed that RMS Normalize only works on 2.1.3 and later – I have 2.1.1. Am I correct in assuming that in order to apply this filter, I need to upgrade to the latest version of Audacity? What if I do that and all of a sudden none of my files are available anymore? (Is that a thing that might happen?)

Is that a thing that might happen?

Yes. Audacity Project files are brittle and parts may not even open in the version that made them.

none of my files are available anymore?

What are “none of my files?”

We are now in a mode where we stop digging holes to climb into and find out what happened.

Ideally, you announce a chapter and immediately File > Export a WAV as a raw reading, errors and all. Then you make corrections as needed: cutting, filtering, and correcting and make your MP3 for posting to ACX and an Export a final WAV for archive. Where did you wander off the path?

I’m hoping you didn’t take the whole process up to final, Save a Project and go home. Projects are tiny time bombs because although they save lots of things handy for production, they do not save UNDO. In short, there’s no way to get back to the original reading. That’s over and above Projects occasionally not opening up at all.

Further, we can’t take effects and corrections out of a show, so once you create a final, it really is a final.

So what do you have and how did you do it? And don’t do anything else for a while.



I typically record a chapter, save it as an Audacity project (titled chapter#_title_raw), then edit and master, save the result as chapter#_title_final, then export that file as .mp3 and upload to ACX. From now on, I’ll immediately export both my raw and mastered files as .wav as well.

So, to answer your question, that’s what I have… Raw and mastered versions of each chapter as Audacity projects. Also, as of this afternoon, .wav files of the mastered versions.

What I’m wondering is whether, for this project, I can do something other than upgrade to 2.1.3 in order to fix the RMS problem (e.g., use ACX’s “classic compressor” and then a limiter)?

Also, what do you think of my mastering chain? Is having the limiter and the normalize effect redundant?

Also, I have definitely been using Noise Reduction, which I saw you mentioned not to do… so I will stop that immediately.

Since you’re using the “Legacy Mastering” tools, I’m going to have to go back and read through that again. As I posted, you can’t back up to the original reading, and continually piling effects and corrections on top of each other is dangerous.

I’m not just blathering about saving everything. I still have original, clean WAV readings/recordings I did professionally five years ago.

Yes, RMS Normalize only runs in Audacity 2.1.3—and we assume later. However, SetRMS I think runs anywhere. does the same thing, but it’s stunningly slow. You might try that on a chapter to see what happens. Keep protection copies of everything.


Scroll down to Custom Tools and follow the instructions for SetRMS.

Then follow the first three instructions in Process. It’s too late for the first sentence.

If we push you through this reading, carefully save everything and install Audacity 2.1.3.


I know an install trick that allows me to select from different Audacity versions, but it only works on a Mac.

This is where somebody else drops in to tell you how to do that.


Do an ACX-Check on one of the chapters that failed. Post a screen grab of the analysis, or just write down the top three values and post that.

You will be stunned when you see how easy mastering is now with the new tools under Audacity 2.1.3.


ACX Stats:

Peak Level: 0.691830 (-3.2 dB)
RMS level: 0.040540 (-27.8 dB)
Noise Floor: 0.000044 (-87.1 dB)

Thank you!!

We’re going to cheat.

Select the clip. Effect > Amplify: 7dB (top number), [X] Allow Clipping > OK. I expect the blue waves to get bigger when you do that.

Effect > Limiter: Soft Limit, 0, 0, -3.5, 10, No > OK

Run ACX Check.

I am doing manually what the newer tools do automatically.

I got the 7dB value for Amplify by subtracting 20 from the ACX-Check RMS value. Ignore the decimal. You should be able to do that through the rest of the low volume clips.


Make sure you still sound like you after you make these corrections.


I will try this. Thank you thank you thank you!!
Then I’ll upgrade to 2.1.3 – what should my mastering chain look like there?
Reminder, my current chain is:
Normalize -6dB
Hi and Lo Pass filters
Hard Limiter -3.2dB
Normalize -3.2dB
Noise Reduction

We should find out how to install two different Audacity versions in Windows. I don’t think that’s a published process.


I cross-posted a question about installing multiple versions of Audacity.

You should either write down or screen capture the setup screens on each current performance correction you do. Put them in a safe place. Pretend someone gave you a fresh, new computer with Audacity, a raw sound file and said to perform your current correction suite.

Open the notes or your screen pictures and get to work.

What are the high and low filters, for example?


IT WORKED!!! And the sound quality is still excellent. Thanks, koz!

This is my current chain, with all the specs:

Normalize: Apply Gain 1, Level -6.0, Remove DC Offset 1, Stereo Independent 0
High Pass: Rolloff 48dB Frequency 80Hz
Low Pass: Rolloff 48dB Frequency 16KHz
Limiter: 0 Gain Left and Right, hold: 10, makeup: no, threshold -3.2 dB, type = Hard Limit
Normalize: Apply Gain 1, Level -3.2, Remove DC Offset 1, Stereo Independent 0
Noise Reduction: 6,6,6

A lot of that nit-picky, setting-by-setting goes away with the newer tools.

The only part that’s not automated is noise. That’s still a little magic.


This is how to install two different Audacity versions. You may not ever run two at the same time.