Confused RMS-normalizer

Hi, I am on windows 8.1 and have downloaded rms-normalizer, but when i try to enable it, i keep getting the message failed to register. can you advise?

Which version of Audacity? (look in “Help menu > About Audacity”).
Where did you download “rms-normalizer” from?
When does that message occur?

Version 2.3.0 of audacity, I followed the link on here, I couldn’t find the plug in istaller, but after fiddling about, the file appeared in the plug in manager as a new file, I enabled it then when I pressed OK it came up with the message failed to register.

We should get the posting a little stiffer. There is no RMS Normalizer. Not from us at least. There is RMS Normalize posted here.

Is that what you have? I only know of that one. If you have something other than that, then you have “Mystery Software” and that may be why Audacity doesn’t want to mount it.

That’s the one posted as part of the Audiobook Mastering Suite of tools.


I downloaded from the forum link on the mastering 4 topic.
If that doesn’t work, how can I download the necessary files to get the right tools

The plug-in installer comes with Audacity 2.3.2: Audacity ® | Download for Windows

Ok, so I suppose I simply upgrade then?
I followed the instructions as best I could to post a sample as follows.

I have upgraded to 2.3.2, can I now simply download ny files and install them

If you have already installed the plug-in, and have just upgrade Audacity, then the plug-in should still be installed and you will just need to enable it in the “Plug-in Manager” (

If the plug-in cannot be enabled, then there’s something wrong with the plug-in. As I don’t know exactly what you have installed, I have no way of knowing whether what you installed will work or not.

I have upgraded and the plug in installed properly. I now have the RMS normalizer and the ACX test software enabled in the plug in manager. I now have only to work out. How to get the peaks to -3dB the RMS to within -18 to -23dB and the floor to -60dB. I suppose it’s all trial and error. Or is there a magic formula. I did upload a sound sample above to ask if there are any problems. Thanks for your help so far.

Not exactly a magic formula, but there is an approach which is usually painless :wink:

After you have done all processing and editing:

  1. Apply “RMS-Normalize” and normalize to the mid-point of the desired range (I don’t recall exactly what that is off the top of my head, but it’s probably around -20 dB)
  2. With the entire track selected, open the “Amplify” effect (don’t apply it). The Amplify effect will show you how many dB below zero the peak level is.
  • If the Amplify effect offers to amplify more than 3 dB, then you need do nothing else (because the peak level is below -3dB).
    Cancel the Amplify effect.
    • If the Amplify effect offers to amplify by less than 3 dB, then the peak level is higher than -3dB, so you need to limit the peak level.
      Cancel the Amplify effect.
  1. If necessary (see step 2), use the “Limiter” effect with “soft limit” and a target level of around -3.5 dB, and “Make up gain = No”.

Thanks, that helps, but it leaves the noise floor at -59.8dB is this unacceptable? i know the acx checker says fail but…

It really helps to start with a good low-noise recording. :wink:

There is a [u]Wiki procedure for audiobook mastering[/u].

Any normal-linear volume adjustment will bring the peaks, RMS, and noise floor up-or-down by the same dB amount. Compression and/or limiting (with make-up gain) can bring-up the overall loudness (i.e. RMS) without boosting/clipping the peaks. But, it also boosts the quiet parts, including the background noise.

Did you use a rumble filter of some sort prior to normalizing? If not, I’d suggest that you do that.
Unless you have a very deep voice, the “Low roll-off for speech” preset in the Equalization effect is a good choice.
If you have a very deep voice, then a similar Eq setting, but a bit lower frequency should be used. Removing sub-sonic rumble can reduce the measured noise floor by several dB.

Yes, that’s what I’ve been following. I’ll reset I think and start the process again. After all I am so close. i can’t give up now.

Not VERY deep but deep enough, as you will hear on the sample above. I will try doing as you suggest. thanks. Watch this space!

Don’t get too hung up on the numbers. If the recording “sounds” clean and professional, then I doubt anyone will be concerned by 0.2 dB. On the other hand, if (for example) there’s an annoying whistle, then it will be rejected by ACX even if it is within the specification. The peak level is important because that is a technical requirement for commercial distribution. Similarly, the MP3 specifications must be met. The other figures can be considered guideline. If you are really struggling to get close, then that’s an indication of problems in your original recording.

Screen Shot 2019-09-12 at 09.43.27.png
That is an excerpt from the instruction page here.

The tools are intended to be used in order, and all the time. In general, if the tools aren’t needed, they don’t do anything, so you can always use all three. No decisions needed. By my count, about 12 seconds tops.

No, -59.3dB is not going to do it. You have to pass noise at -60dB and in general, you have to do it by a good margin. -65dB or so. Again, as above, if you have an irritating noise such as a whiny laptop fan, extra measures need to be taken. ACX will not pass those no matter what you do.

Baby screaming on a jet? Fingernails on blackboard? That sound.

Home readers never pass noise (it seems). The specification, in English, means your reading has to be 1000 times louder and clearer than the room or background noise. If you can tell your computer is on just by listening, kiss of death. Nobody’s apartment can meet that and even though I have a very quiet bedroom, I have to wait for the metrobus to go by.

“There goes the 380 Northbound. We’ll be reading that sentence again. @#$%”


thank you Steve and Koz for your help. I seem to have got it sorted now, apart from the occasional crashes. But otherwise ok. Thank you

apart from the occasional crashes.

Doctors have a thing they call the doorknob moment. That’s when the patient, who has made it through all the medical tests perfectly well, turns with their hand on the doorknob and says, “I cough up blood every night before bed. That’s not important is it?”

If you’re going to be doing sound production, it can pay handsomely to do a housekeeping sweep and find out why your machine occasionally crashes. Audio (or Video) production is stressful on a machine. Nobody cares if a spreadsheet or a document is a little slow, but audio works in Real Time. There’s no chance for the system to slow down a little and cool off or take a break.

How old is the machine and when was the last time you replaced the little CMOS watch battery? Optimized the hard drive? Done that virus check that goes all night? Do you have pets? I stop at my sister’s house every so often and suck the cat hairs out of the power supply fan.