Help me with RMS levels and mastering for ACX

Special Interest Groups Audiobook Production
21

Do you have any words of wisdom about how to go about these sort of chapters

Traditionally, that’s done with microphone management. You can whisper or present sotto-voce, but do it really close to the microphone so you sound close and intimate at normal speaking volume. You can yell, too, but yell off-microphone, so the timbre of your voice is yelling, but the volume doesn’t go up.

Oh, and while you’re in close, take care not to pop your P’s. Since the whisper voice is intended to be slightly unnatural anyway, talk across the microphone rather than directly into it.

Until you get good at it, you’ll need to see the volume meters and script at the same time. After a while you just know. This is also where good, real-time headphones come in handy. You can hear your volume adjustments as they happen and rely less on the meters.

You can try the compressors, but they don’t fit well with the other tools in the suite. Much better to do it at the performance step.

http://manual.audacityteam.org/man/compressor.html

Koz

22

If you’re doing a podcast, you might try Chris’s Compressor.

Chris is a full-on, completely automatic production processor. I use it to “tame” a download podcast and make it sound very like the processed broadcast version of the same show.

https://theaudacitytopodcast.com/chriss-dynamic-compressor-plugin-for-audacity/

I change the first setting, Compress Ratio from the 0.5 default setting to a stiffer 0.77.

Koz

23

you might try Chris’s Compressor.

As with most automated processors, you can fake it out by accident. Make sure you have something other than dead silence for the first second of a show and try to avoid very large, unnatural volume swings. It doesn’t handle those well. That’s why it’s not a Universal, Fix-Everything solution.

Koz

24

Here’s a clip from one my favorite voice performers, Molly Wood from NPR Marketplace. I couldn’t easily find a self-contained clip without the music.

http://kozco.com/tech/audacity/clips/MollyWoodMarketplaceClip.mp3

We had a graphic artist who could do that. He would give talks and travelogs over lunch and play to pack houses (screening rooms). SRO long since vanished. Squatting on the floor room only. There was a joke he could announce he was going to read the Burbank Phone Book and play to a capacity crowd.

Koz

25

I just joined this forum and saw this string, I have the same questions. I just got back from ACX that I have 10 (out of 19) chapters too loud and 1 too soft.

I have not found the lead note in the string, but I seem to have the same questions. I think I get what normalization and compression is doing to the wave form (I was a physics major so I get the math) , but my questions are, how do I get the RMS value in audacity?, and if I do the 19 files separately, will they all come out at about the same level or do I need to put all of them in one file, one big set of 19 tracks and normalize them all at the same time, or would that be so large a file that the computer will puke?

At least in this audio world, I’m really a total novice!

Oh, and to the author… Congrats on you second contract… I got one, a one hour book, then kept getting lots of rejections. Blasted out 10 auditions and got 4 offers in one weekend! 1st for a 13 hour book… I’m just got back all of the processing notes on that one… Getting the offers is exciting… Congratulations and keep going!

Thanks!

26

RMS means Root Mean Square or the area under the curve, which in audio is interesting to derive because of complex waveforms between 20Hz and 20000Hz. It also happens to correspond to loudness.

So when people tell you to set your RMS, they’re really complaining about loudness. ACX has very specific restrictions on loudness variations, -18dB to -23dB. 6dB is not that great a loudness variation and as long as you’re inside of that range, chapter to chapter variation should not be a problem.

Until relatively recently, we had no good way to directly set RMS. Now we do and the mastering process, assuming you get close at the microphone can shrink to a sentence or two.

Every time I write a Mastering Tutorial, something happens and I have to start over. This was the last pass.

http://kozco.com/tech/audacity/ACXMastering/ACXMastering.html

You’re good all through Comments

Custom Tools changed. We are now using RMS Normalize with a setting of 20dB (it defaults to 18) in place of SetRMS. You need to be on Audacity 2.1.3 or later!!

https://forum.audacityteam.org/t/rms-normalize/45334/1

Use the first three sentences in Process subbing RMS Normalize (20) for SetRMS.

If you have noise, that’s when the process falls to pieces. There’s different pathways depending on what your noise is.

I will eventually fix that publication…

Oh, sorry. Process chapter at a time. The new tools should keep you inside ACX conformance.

But the really bad news is the need to start with a raw reading. We can’t take effects and corrections out, so going back and fixing a badly processed reading is rough/sometimes impossible. We strongly recommend exporting your raw readings as WAV (Microsoft) 16-bit before you go on.

Koz

27

I have 10 (out of 19) chapters too loud

Do you know about ACX-Check? That’s an Analyze tool that automatically reads out (among other things) the three important AudioBook settings.

If you only missed loudness but hit the other two, it could be really rough to recover from that. Did you keep the original readings—before you processed them?

First reading?

Koz