I want to have an Audacity session that has multiple synched recoding tracks and a label track, which i know how to do. What i can’t figure out is how to add a track for the data output from a dB meter. I have tried all the import .txt formats but can’t seem to get it to work. The sample rate of the dB meter is 1 reading per second. How can I import this into the session so it will match the corresponding time stamps of the other sound files? And, yes, I have read this page: Sample Data Export - Audacity Manual
You may need to format the data before importing. Audacity expects labels to come in like this:
0.924925 0.924925 this is a point label
3.591592 4.516517 this is a region label
So for you, a likely formating might be:
1.000000 1.000000 45 dB
2.000000 2.000000 47 dB
and so on.
Technically, this is a tab separated value file (TSV) which you can create in excel and similar programs, and would just need to rename to something.txt to be able to import it.
As your dB meter likely will show volume averaged over 1s, the data it had produced likely won’t be a useful audio format. Audio expects to oscillate, going from positive to negative values, so Audacity is unlikely to be able to help you with this data directly (or as anything other than a label track)
Thank you so much. We got it formatted and imported with
1 2 56.4
2 3 57.7
3 4
etc.
But now i see why we are having some inaccurate low readings. We will try the 1.0000 to 1.000 region format.
We are not planning to play the data as audio. We are using it, calibrated with multiple recordings to test for speech communications errors in the operating room. So, we will be able to have multiple microphone tracks, a comments track for field observation notes, and then a track for the dB readings which will help us locate situations in the recordings where speech communication my suffer because of loud noises, etc.
As you also want normal audio tracks in the project, the dB meter track should be muted so that it does not interfere with playback of the audio tracks.
The dB meter data will probably be easier to visualise if you set “Display samples:” to “Connect dots” in Preferences.
If it’s practical for you, and if this will fit your needs, you can make a calibration with a tone, pink noise, white noise, etc., just before recording. Then you can get the SPL level from the recorded file. Of course this assumes you aren’t adjusting the recording levels while recording.
For example, if -10dB in Audacity corresponds to 80dB SPL, that’s 90dB difference and it’s just a matter of subtraction (adding 90dB, since you’re subtracting a negative) to get the SPL level from the digital level.
It gets a bit tricky because SPL is usually A-weighted and averaged, but Analyze → Measure RMS should track reasonably well. The optional ACX check plug-in will give you peak and RMS. Or the Amplify effect will default to the difference between the peak and 0dB. i.e. If Amplify defaults to 5dB, your current peak is -5dB, etc., and you can cancel the effect after noting the peak.