Decibel/ volume reader

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Decibel/ volume reader

Permanent link to this post Posted by Toolless » Fri Feb 16, 2018 3:07 pm

Hello there
Can my audacity program detect the volume of sound in say decibels?
Thanks
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Re: Decibel/ volume reader

Permanent link to this post Posted by DVDdoug » Fri Feb 16, 2018 3:53 pm

If you mean the acoustic loudness of the sound in the air (dB SPL), no.

Your microphone and soundcard are not calibrated and your "recording" volume affects the digital level too. So, different microphones/computers/setups will read differently.

You can find the digital dB level of the file (dBFS) but again it's not calibrated, and "loudness" or "volume" are a little tricky. The acoustic & digital levels are directly correlated, so if you decrease the loudness by 3dB the digital level will also decrease by 3dB.

Audacity's meters show dB (dBFS) and if you click the little drop-down arrow to the left of the waveform you can change the scale to dB.

NOTE - The 0dB SPL reference is (approximately) the quietest sound humans can hear and dB SPL values are positive. The 0dBFS reference is the maximum integer value for the number of bit and the dBFS values are (usually) negative. Audacity uses floating-point internally so it can "temporarily" go over the 0dB maximum.
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Re: Decibel/ volume reader

Permanent link to this post Posted by Toolless » Fri Feb 16, 2018 5:49 pm

DVDdoug wrote:If you mean the acoustic loudness of the sound in the air (dB SPL), no.

I was more trying to monitor the volume of my voice


DVDdoug wrote:Audacity's meters show dB (dBFS) and if you click the little drop-down arrow to the left of the waveform you can change the scale to dB.
.

I only use audacity for basic recording tasks; so could you kindly tell me where/ what the drop down menu is for the wave form?

Thanks
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Re: Decibel/ volume reader

Permanent link to this post Posted by kozikowski » Sat Feb 17, 2018 3:16 am

Raw recording of your voice can be measured with the Audacity bouncing sound meter and the blue soundwaves on the timeline.

The sound meter should bounce up roughly between -6dB and -10dB.

The blue sound waves tips should reach up to about half-way—0.5 (50%).

That's a good comfortable volume between too high overload damage and too-quiet noise problems.

Image

Your sound meter will look different, but concentrate on the right-hand side.

Screen Shot 2018-02-06 at 16.01.17.png
Screen Shot 2018-02-06 at 16.01.17.png (19.43 KiB) Viewed 277 times


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Re: Decibel/ volume reader

Permanent link to this post Posted by DVDdoug » Sat Feb 17, 2018 5:01 am

could you kindly tell me where/ what the drop down menu is for the wave form?
Track Dropdown Menu

By default the waveform scale goes from 0 (silence) to +/- 1.0 (maximum). If you select Waveform dB, that scale will switch to a dB.
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Re: Decibel/ volume reader

Permanent link to this post Posted by Toolless » Sat Feb 17, 2018 7:51 pm

I understand a bit more about the blue sound wave on the time line now, and I found the drop down menu to change it into db. It kind of works like a mirror as the louder the sound the more it increases bough sides from the middle. But what I don't understand about it is the measurement. It start out at 60 in the middle and as the sound increases the number goes down and this should be the other way round!

And I see the sound meter now. But as above the more sound you put through the higher the gauge goes but the number decreases. So again it makes no sense what the db of sound actually is.

Also what is the highest db it can record?

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Re: Decibel/ volume reader

Permanent link to this post Posted by kozikowski » Sat Feb 17, 2018 11:12 pm

It's not 60dB. It's -60dB.

Sound starts out at 0dB maximum loudness and goes quieter to the digital limit, -96dB. It's important to keep that "-" in there. The numbers actually get smaller.

That bothers everybody. I saw one page where they decided to start measuring at the quiet point and go up. So maximum volume is 96. The problem with that, past the obvious need to do advanced math (Quick, what's 7dB lower than that?) is that it changes with the sound standard. 0dB overload is always the same no matter what standard you're using.

Except one. Audacity uses an internal standard of 32-bit floating. This is to keep the effects and filters from causing problems. It does not overload at 0db. You can accidentally make sound damage while you're editing, but recover very easily later.


Changing the blue sound waves into dB may seem like a terrific idea, but it pushes the most used sound range way up into the top of the display. AudioBook voice corrections, for, example are in the top 2 and 3dB range. That's impossible to measure in dB Waveforms.

That's not to say the percent range of blue waves is useful, either. There's is a request posted to keep them the same but label them both in dB.

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Re: Decibel/ volume reader

Permanent link to this post Posted by kozikowski » Sat Feb 17, 2018 11:27 pm

If you're doing spoken word, it is recommended that the sound meter peaks at between -10dB and -6dB and the blue waves tips are around 50%.

Image

Note that's with the waves in percent.

If you reach 0dB outside of Audacity, the sound will be permanently damaged and sound terrible—crackling and popping.

Recording low volume isn't safe, either. Audio electronics all make quiet noise. Usually ffffffffffff—spring rain in the trees. If you record too low, you and the ffffff sound will start competing with each other.

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Re: Decibel/ volume reader

Permanent link to this post Posted by kozikowski » Sun Feb 18, 2018 4:51 am

I've determine the missing value (through advanced maths).

Comfortable reading volume should fall somewhere between -6dB and -10dB on the bouncing sound meter (roughly the yellow segment), and the blue wave peaks somewhere between 50% and 30%.

And just to give you the feel of why we use dB at all instead of percent for everything, -60dB is a real sound value. It's a value of background noise measurement required for audiobooks, so most audiobook readers are very clear what that is. It works out to .001%. or 1/1000.

You can't see that on the normal Audacity timeline. The blue waves have turned into flat, straight lines a long time ago, and remember, audio CD quality sound keeps going to -96dB. Percent values don't map to audio very well.

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Re: Decibel/ volume reader

Permanent link to this post Posted by Toolless » Sun Feb 18, 2018 1:24 pm

kozikowski wrote:It's not 60dB. It's -60dB.

So if the meter starts off at -60db, then when the meter gets to 0, dose that actully mean it is 60db?


kozikowski wrote:If you're doing spoken word, it is recommended that the sound meter peaks at between -10dB and -6dB and the blue waves tips are around 50%.
http://www.kozco.com/tech/audacity/pix/ ... g-650w.jpg *BB image code blocked*

for the purpose of my task it will be one note sang at 400hrz (G#4-A4) between 100 and 130db

Now on the sound meter in your image, it stars off at -93 and goes upto 0. But on my program of Audacity it stars at -57 and goes up to 0; so what is happening hear?
is -57 and -93 absolute zero?

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