Audacity RMS and ACX RMS Wildly Different

I’ve been trying to send the first chapter of my first ACX project, but the upload is getting rejected due to failed RMS levels. In Audacity it is showing them at about -20, but in ACX is showing as -27. That’s a ridiculous difference. My 15 minute checkpoint passed without issue, and the new file I’m trying to upload was pulled directly from that file, so I’m at a loss of what’s going on. I’ve seen other posts with the same issue, but there wasn’t any solutions, or the solutions were years old talking about Forced Mono during export, which doesn’t appear to be a feature in the updated Audacity. Is there something I’m missing?

Ensure that the track “Gain” slider is at zero before you export.
Also, the ACX plug-in will give incorrect results if you use real-time effects, because the plug-in measures the audio “data” before real-time effects are applied.

Thanks, but the Gain Slider is set to 0, and I don’t have any real time effects running. The file was part of a larger one that I broke down, and the rest of them worked without issue, just this one for some strange reason.

Which Audacity and what Computer?

Is your work in Mono? One bue wave? It’s not manditory, but it is recomended.

Yes, the older stereo to mono conversion did used to “help you” by automaitcally adjusting the volume by 6dB.

On my machine, Analyze > Measure RMS and ACX-Check give the same numbers. Or close enough.

???

Did you use 36Audiobook-Mastering-Macro, or did you you try to set the volumes and master the works yourself?

Koz

What does that mean?

You should be checking the whole file and the same file in both cases.

Part of the file can be different from the whole file.

I record in mono.

Yes, the Analyze>Measure RMS and ACX- Check are very close.

Mastered myself. New to this, and don’t know what the 36Audiobook-Mastering-Macro is.

The file I uploaded for the 15 checkpoint was the first chapter of the book, with the first part of the second chapter, since the 1 chapter was less than 15 minutes long. It was a recording I pieced together, from 2 other recordings since I record by chapter. I had to break the chapter recordings into parts, as per the authors request, and all but the first part of the first chapter passed. When I checked them in Audacity, before and after breaking them, they all checked out and were all very similar, but when uploaded to ACX, just that one was super wonky.

A Macro (chain, batch) is a list of instructions to tell other programs what to do. This particular one is “36” because the Audacity developers changed the Audacity program and I had to re-write some of the macro to catch up.

It applies a rumble filter (thunder, earthquakes), sets RMS (Loudness), and then a very gentle, graceful peak limiter.

It guarantees ACX RMS and Peak. If you recorded in a quiet, echo-free room, you may be done. It is a cousin to ACX-Check. ACX-Check inspects RMS, Peak, and Noise. Yes, ACX has on-line tools to do that, but they don’t check noise.

Just to do it, I announced a short voice test into an iPhone on the desk in my quiet office.

I cut it to length and applied Mastering.

Just to be obsessive, I applied gentle 6, 6, 6 noise reduction.

It easily passes all three ACX submission standards — and sounds exactly like me.

Screen Shot 2024-10-27 at 20.44.40

Koz

I think both of these tools are available in the Audacity manual/instructions. I’ll look in the morning.

Koz

Apparently, the official documentation only has the older “non-36” Mastering Macro. Also, apparently, the tools it’s standing on got changed again.

The “36” version should work everywhere. That’s today’s inspection tour.

The magic with a Macro is that it’s a plain text file. That means most computers are going to immediately hide the . t x t filename extension to “help you.” I forbid my computers from hiding anything.

36Audiobook-Mastering-Macro.txt (585 Bytes)
… should open up in most text editors but will look a little odd because lines of text are way longer than you’re accustomed to. Computers don’t think in 8-inch wide pages.

The first line is a comment:

Comment:_=“36Audiobook-Mastering-Macro.txt runs the ACX Audiobook Mastering Suite in Audacity 3.6x 20240730 Kozikowski”

I didn’t write the whole thing. Steve T Fiddle wrote the rumble filter based on broadcast and movie technology.

Koz

Post back if you have trouble with it. If you master manually, this will be a stunning improvement.

Select the chapter > Tools > Apply Macro > 36Audiobook-Mastering-Macro

There is no “OK.” It just does it.

Note: Mastering doesn’t do word-by-word volume setting. If you (or your client) likes to weave and bob in front of the microphone, this is not going to help you. There are other ways to deal with that.

Koz

I got nothing.

I read that four times and I still can’t settle in my head what you did.

We can wait for another forum elf. The elves live all over earth so timing can be a little odd.

Post back if you solve it.

Koz

I don’t know how else to explain it, or if it’s even relevant at this point. I just took a larger recording, and broke it up into several smaller recordings.

Thanks, I will definitely check it out

Measured how? You’re not using Audacity ACX-Check, right?

That would be ACX-Audiolab?

Stereo and Mono tend to go in 6dB steps, Double and Half. 7dB is an odd error. I would guess you actually measured it wrong.

I would be installing and trying ACX-Check on the mystery sound file. Also install 36Audiobook-Mastering-Macro.

Koz

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