Normalize maximum amplitude [SOLVED]

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jim1001
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Joined: Sun Mar 18, 2018 5:56 pm
Operating System: Windows 7

Normalize maximum amplitude [SOLVED]

Post by jim1001 » Sun Mar 18, 2018 7:38 pm

The default setting for Normalize maximum amplitude in Audacity 2.2.1 is -1 dB. When I leave it at this I get a peak of -1 to +1 on the vertical scale.

However the manual page talks about bringing the peak up to 0 dB. This doesn't seem to tie up. Could it be made a bit clearer?

ps: is the Normalize maximum amplitude value referring to an absolute value? In which case should it be appended with a suffix?

Happy to get clarification - thanks.

steve
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Re: Normalize maximum amplitude

Post by steve » Sun Mar 18, 2018 8:33 pm

jim1001 wrote:The default setting for Normalize maximum amplitude in Audacity 2.2.1 is -1 dB. When I leave it at this I get a peak of -1 to +1 on the vertical scale.
If you look closely, the maximum peaks will be a little less than 1 (about +/- 0.9)
jim1001 wrote:However the manual page talks about bringing the peak up to 0 dB.
Please give a link and the exact quote.
jim1001 wrote: ps: is the Normalize maximum amplitude value referring to an absolute value? In which case should it be appended with a suffix?
As is common practice for signal processing, the full version would be "dBFS" (reference "full scale"). As is the convention in most audio applications, this is frequently abbreviated to "dB".
https://en.wikipedia.org/wiki/Decibel#Audio_electronics
https://en.wikipedia.org/wiki/DBFS
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jim1001
Posts: 6
Joined: Sun Mar 18, 2018 5:56 pm
Operating System: Windows 7

Re: Normalize maximum amplitude

Post by jim1001 » Sun Mar 18, 2018 10:24 pm

Thanks for reply.
Please give a link and the exact quote.
Here's the quote from this section:
there are three ways to bring the peak up to 0 dB (+1.0 to -1.0 on the vertical scale).

"Normalize the maximum amplitude" to -0.0 dB
Thanks.

steve
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Re: Normalize maximum amplitude

Post by steve » Sun Mar 18, 2018 11:52 pm

jim1001 wrote:there are three ways to bring the peak up to 0 dB (+1.0 to -1.0 on the vertical scale).

"Normalize the maximum amplitude" to -0.0 dB
Yes, that's correct.

"Full scale" is 0 dB, which is the range +1 to -1 on a linear scale.
Before you complain, yes I know that it is confusing to represent amplitude as dB in some places and a 0 to 1 scale in others, but that a quirk of Audacity's history. ;)

To Normalize to 0 dB / full scale / 1.0 linear absolute, you would set the Normalize effect to normalize to 0.0 dB.
Usually it is best to retain a little headroom, which is why the default setting for Normalize is -1 dBFS.
9/10 questions are answered in the FREQUENTLY ASKED QUESTIONS (FAQ)

kozikowski
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Re: Normalize maximum amplitude

Post by kozikowski » Mon Mar 19, 2018 12:21 am

I have a handy conversion chart.
Percent-dB_Conversion .png
Percent-dB_Conversion .png (11.48 KiB) Viewed 672 times
Click the graphic to see the whole thing.

Convert Percent to Audacity by moving the point to the left. 50% is 0.5. That's half-way which works out to 6dB. That's the only one I remember in my head.

Koz

jim1001
Posts: 6
Joined: Sun Mar 18, 2018 5:56 pm
Operating System: Windows 7

Re: Normalize maximum amplitude [SOLVED]

Post by jim1001 » Mon Mar 19, 2018 10:27 am

Thanks both for your time & the very informative replies. I understand it now.

All the best,
Jim

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