Testing Noise Floor for ACX

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Testing Noise Floor for ACX

Permanent link to this post Posted by emmacharlie12 » Wed Nov 22, 2017 10:12 pm

I'm trying to test if I have the right set up for ACX(after recording for the much less rigorous Librivox) and can't understand how to test the Noise floor on audacity 2.1.2, Mac. I saw some advice on a similar question that going to Amplify would give me the noise floor (I have 50) but I don't understand how this translates into ACX requirements(-60db).

Also, how do I check that the audio measures between -23dB and -18dB RMS and has -3dB peak values ? Is this also related to the noise floor?

Many thanks

Emma
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Re: Testing Noise Floor for ACX

Permanent link to this post Posted by Trebor » Thu Nov 23, 2017 12:06 am

emmacharlie12 wrote:I'm trying to test if I have the right set up for ACX ...

There is a plugin for Audacity which measures the ACX parameters, see ...
http://wiki.audacityteam.org/wiki/Nyquist_Analyze_Plug-ins#ACX_Check

How to install a plugin ... http://wiki.audacityteam.org/wiki/Downl ... ns#install
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Re: Testing Noise Floor for ACX

Permanent link to this post Posted by kozikowski » Thu Nov 23, 2017 5:06 am

That's one in a series of tools and processes we wrote for Audiobook Production.

viewtopic.php?f=64&t=96103

There is an error since the release of Audacity 2.2.0. You can't select the whole track by clicking above MUTE. That graphic doesn't exist any more. You click on the little blank spot in the lower right of the track INFO panel.

If you have reasonable recording hygiene, it should be possible to record a chapter, run it through those tools (in order) and out the door. The most likely thing to fail by far is noise. That's why it has its own document.

Just for grins, record a test track and submit it to the forum. We will run it through the tools and see what's what.

http://www.kozco.com/tech/audacity/Test ... _Clip.html

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Re: Testing Noise Floor for ACX

Permanent link to this post Posted by kozikowski » Thu Nov 23, 2017 5:18 am

To specifically answer you, the classic way to measure noise before all the fancy-pants tools was with Contrast.

Drag-select a portion of noise-only performance. Analyze > Contrast > Measure Selection (write it down) > Close.

I wrote up all the older things you needed to do to prove ACX compliance and it was pretty grim. Flynwill wrote ACX-Check as an integrated collection of several existing tools. Much better.

One note: ACX would just as soon you submitted in Mono. All the tools and processes work better in mono too. Some of microphone systems don't work in mono and you have to deal with that.

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