Volume surges after compression (audiobook recording)

[Abdiel]

Hello again --

After applying the recommended steps of Filter, Normalize, Limiter...

I think I could use a gentle Noise gate. Is there a recommendation on this too?

Cheers,
Abdiel

[steve]

ACX strongly recommend to NOT use a noise gate.

[Abdiel]

OK. Thank you.

[kozikowski]

Chris's Compressor is only partially developed. It doesn't like the ends of a performance. For example, it is recommended you add some unimportant sound to the ends of a show so the surging damage doesn't happen on valuable work. After the compression is completed, cut off the extra sound.

Chris isn't recommended for audiobooks because it also doesn't like high background noise and can produce pumping sounds on a theatrical reading.

The compressor is not likely to get fixed because Chris reached end-of-life.


Audacity Audiobook Mastering isn't the only process for producing ACX compliant chapters. But several readers have used it successfully and there is a caution not to mix different processes. If you do use mastering, use it as published.

We can sometimes recommend settings if you post a 10 second sound test to the forum.

https://www.kozco.com/tech/audacity/Tes ... _Clip.html

Home readers never pass ACX noise. The -60dB specification means your room background sound has to be 1000 times quieter than your voice. So no refrigerators, air conditioners, computer fans, or traffic sounds. Some affordable home microphones have quiet voice volume and can make their own noise. It can be really difficult to reach all three ACX specifications (Peak, RMS-Loudness, and Noise) at the same time. But sometimes we have tricks to get there.

Koz

[Abdiel]

Hello Koz --

Thank you for these insights. Very helpful.

I have never failed ACX, I'm looking to create the most pleasurable experience for the listener, and the most effortless mastering process for me.

I'll go ahead and post a sound test to the forum as you suggest.

Thanks again,
Abdiel

[Abdiel]

Abdiel Audacity Test.wav

(958.04 KiB) Downloaded 17 times

[kozikowski]

The test passes with simple Audiobook Mastering.

Screen Shot 2020-08-16 at 7.43.02 AM.png (26.38 KiB) Viewed 218 times

...but.

As you probably found, the background hiss is pretty stiff and annoying.

I can suppress it with Noise Reduction of the Beast. Drag-select some Room tone at the beginning and Effect > Noise Reduction > Profile, and then select the whole thing and Effect > Noise Reduction: 6, 6, 6 > OK.

Abdiel Audacity Test.mp3

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But that still wasn't quite enough and I wondered why.

This is a spectrum analysis of the noise by itself. Higher volume is up and pitch is along the bottom, high pitch to the right. We in California call 3Hz an earthquake. Low pitch rumble.

Screen Shot 2020-08-16 at 7.48.28 AM.png (80.18 KiB) Viewed 218 times

The mountain on the left may be just about right, but the mountain at 3000 Hz is not. 3000 Hz is the tone associated with fingernails on blackboard and baby screaming on a jet. That's why your background noise seems so harsh and annoying. Because it is.

This is the first time I've ever seen a microphone system do that. Congratulations. You're a unicorn. The voice is terrific, by the way.

What's the microphone and how do you have it connected?

Koz

[Abdiel]

Very kind of you to do all that, Koz. The microphone is an Aston Origin. But there are a couple of settings on it which can be adjusted, as shown in the photos. The setup shown is housed on a stand in a 'Portabooth'.

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IMG_20200816_162628a.jpg (48.96 KiB) Viewed 215 times

[kozikowski]

So.

It's a side-address microphone. You should be speaking into the side grill just up from the company name. The switch on the left should not be -10dB. -10dB setting is for playing a trumpet loudly or recording an explosion. The switch on the right is a rumble filter and doesn't make a lot of difference since Mastering is going to do some of that job anyway. Leave it flat.

That's a full-on, Phantom-Powered XLR microphone. How do you have it connected to the computer? Or are you recording on a computer?

Koz

[Abdiel]

Thank you, Koz. That helps a lot.

I've zoomed out with this photo, so you can see the setup. The other end of the MicPort Pro connects via a cable to USB port on my computer.

IMG_20200816_170234a.jpg (88.6 KiB) Viewed 214 times