Ensure Audacity recording has 89 dB?

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orschiro
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Post by orschiro » October 28th, 2017, 9:10 am

Dear community,

I was told [1] my recording needs to have 89 dB. I am using Audacity for the recording.

I went on Reddit to ask for help [2] how to check whether my recording has 89 dB. The responses are super technical and complicated.

I cannot believe that it is so difficult in Audacity to check whether my recording suffices the dB criterion.

Any other Audacity users here? How do you do it?

Thank you!

[1] viewtopic.php?p=1405726#p1405726
[2] https://www.reddit.com/r/audacity/comments/791pgw/i_need_to_make_sure_that_my_recording_has_89_db/
Last edited by orschiro on October 28th, 2017, 10:00 am, edited 1 time in total.

TriciaG
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Post by TriciaG » October 28th, 2017, 9:15 am

There are a couple ways to check the volume of a recording.

OK, I was going to type it all out, but this wiki page details it better than I could: http://wiki.librivox.org/index.php/Questions_and_Answers

Post if you have more questions. We're here to help. :)
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orschiro
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Post by orschiro » October 28th, 2017, 10:31 am

Thank you so much!

The wiki page is helpful but I would like to improve it.

Can you please respond to my open questions [1]?

[1] https://www.useloom.com/share/27e98f2873e84fe2aac5571b4e78ce25

philchenevert
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Post by philchenevert » October 28th, 2017, 10:40 am

orschiro wrote:Thank you so much!

The wiki page is helpful but I would like to improve it.

Can you please respond to my open questions [1]?

[1] https://www.useloom.com/share/27e98f2873e84fe2aac5571b4e78ce25
Great question:
1. Do not allow clipping, so do not check that box (this would allow the new track to exceed normal levels whichare clipped)
2. Ignore the other values shown, New Peak Value.

Note that LibriVox aims at a that mysterious thing 'around' 89 db, which means a range of about 3 db on either side is acceptable. Hopefully the wiki mentions this.

Thanks for being so interacive and helpful! Ask lots of questions. I have some videos i have made, look inmy sig and any suggestions for improvemnts would be great!
Phil Chenevert, The LibriVox Video Guy
'm afraid that fulfilling my potential would really cut into my sitting around time. .

Need Help? Lots of Helpful Videos Here

TriciaG
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Post by TriciaG » October 28th, 2017, 10:53 am

Your question more has to do with using the Amplify effect than about using the ReplayGain plugin. :)

Bottom line if you don't want to read all the stuff below: Don't allow clipping, and ignore that second box with a number on it. ;)

Details:

As a general rule, never allow clipping. Clipping is when your wave forms hit the limits - top or bottom of the recording window. You end up losing data from the wave form that cannot be recovered, and this can cause distortion.

In your case in the video, you were making the file quieter (hence the minus sign when you go to amplify), so you're making the wave forms smaller. In this case you'll never run into a problem with clipping.

However, if your file were too quiet, you might have a case where it won't let you amplify as much as ReplayGain tells you to. This is because you have a spike (or more than one) in your recording that will hit the limit (it would clip) if it were amplified that much. You could either zoom into the spike and select just the spike to amplify it by a negative number to squish it down, or you could run the Compression effect on your whole file.

Here is a video on compression: http://www.youtube.com/watch?v=wJ3lOTDsN6c

My default settings are as follows:
Threshold: -17 dB to -13 dB
Noise Floor: -40 dB
Ratio: 2.5:1 or 3:1
Attack: 0.2
Decay: 1.0
NO checks in the check boxes

After compression, run ReplayGain again and amplify by how much it tells you.

This is for files that are too quiet, which isn't your case in the video. :)

---

The other box with the number in it, "new peak amplitude", is not something to worry about. Highlight your recording, go to Effects/amplify, and change the first box to 0. If your highest spike is 2.5 dB below the maximum, it'll show in there as -2.5 dB.

When you go to Effects/Amplify, it will default the first box to the highest you can amplify before hitting maximum (clipping), and the second box will show 0. Whatever number you put in the first amplify box will be added or subtracted from this maximum.

EDIT: Phil beat me, but I gave a lot more detail. ;)
Fiction, partly about jail atrocities: It Is Never too Late
Watergate Report, volume 3: Here
E E Cummings' time in French prison: The Enormous Room

orschiro
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Post by orschiro » October 28th, 2017, 11:02 am

> Thanks for being so interacive and helpful! Ask lots of questions. I have some videos i have made, look inmy sig and any suggestions for improvemnts would be great!

Wow these are great. Thanks for making and mentioning them! :-) If I have suggestions, I leave you a comment on the video.

> Bottom line if you don't want to read all the stuff below: Don't allow clipping, and ignore that second box with a number on it. ;)

Haha, thanks for the summary.

Now, if I could get access to the Wiki page, I am happy to do some edits to make it easier to understand for beginners like me!

dlolso21
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Post by dlolso21 » October 28th, 2017, 9:56 pm

Robert,

You should be able to access the Wiki now, details sent via PM.

David O

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Post by lurcherlover » October 29th, 2017, 1:52 am

The problem is that Audacity meters are difficult to read and use.

There are proper peak meters which are available as free downloads which will run alongside Audacity and give clear indications of peaks being hit and also give an update of true maximum peaks as well as being able to be set for gain and reference levels. One such download is (a VST) called dpMeter2 (by TBProAudio). Search and it will come up with a short manual as well.

The meters in Reaper will give a max retained reading on peaks as well.

Zero DBFS (decibels at full scale) is at the point of going over into distortion. In proper terminology you should keep to about -10 DBFS which will give you a good recording.

There can be as problem with peaks (spikes) which depend on mic technique to avoid them. But they often do happen even with the best mic technique. If there are only a few (as it should be hopefully) then you can reduce just the peaks by a few Db by isolation and reduction. You can do this even in audacity.

orschiro
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Post by orschiro » October 30th, 2017, 9:44 am

Thank you all for your help!

With your feedback I improved the Wiki page [1]. :-)

[1] http://wiki.librivox.org/index.php/Questions_and_Answers

TriciaG
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Post by TriciaG » October 30th, 2017, 10:16 am

Looks good! I made a couple very minor edits:
From there, leave all defaults and just click on OK. You should get a response such as:
ReplayGain level: -1.8 dB or
ReplayGain level: 2.7 dB.


This means that you have to use Effect > Amplify and set your amplification to -1.8 or 2.7 dB, respectively.Keep the defaults, make sure to not check the box for "Allow clipping", and confirm by clicking OK.
(I rearranged the last sentence so the "click OK" is after keeping the defaults.) ;)

Thanks for doing that!
Fiction, partly about jail atrocities: It Is Never too Late
Watergate Report, volume 3: Here
E E Cummings' time in French prison: The Enormous Room

orschiro
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Post by orschiro » October 30th, 2017, 10:25 am

Glad I was able to help! :-)

MagicMan
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Post by MagicMan » December 5th, 2017, 2:05 pm

Stay away from the latest release of Audacity. They are still trying to work out the problems with their upgrade. I use version 2.1.3 and if you can record with your input level between a -12 and -18dbs, the rest is a piece of cake. I did a video on this. You can view it here. You can scrub to 6 min 22 sec to skip the intro.

orschiro
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Post by orschiro » December 5th, 2017, 10:44 pm

This is great. Thank you for your video! :-)

MagicMan
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Post by MagicMan » December 5th, 2017, 10:55 pm

orschiro wrote:This is great. Thank you for your video! :-)
It was my pleasure. ;-)

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