I’m an audacity new user on Windows 7.
Thank you for this excellent application.
First, excuse me for my approximativ english…
I’m using audacity for bats calls identification.
My question :
Is it possible to “fix” settings for each file analysed ?
All the files I analyse are wave sounds (duration 5 secs) at recording frequence 192000 Hz
I would like to open each of them with spectrograms and sampling frequence divided by 10 (19200 hz) but i have to do this “handly” each time.
So, is it possible to have automatic settings presets (like a script or something else) and how might I do ?
I precise that I use Audacity “french” version…
I’m using recordings at 192000 Hz with spectrogram and sampling rate divided by 10 (so 19200 Hz) so i should see 9,6 Khz on my computer screen, BUT it’s not the case i only see 8,0 KHz. Why this difference ? Any explanation ? May it come from my computer screen (15"4) or from settings of Audacity ? How should i proceed ?
The theoretical maximum frequency for digital audio is half the sample rate. Thus for a sample rate of 44100 Hz (CD standard), the maximum possible frequency is 22050 Hz. In practice the maximum frequency is a little less than the theoretical maximum.
So, for a sample rate of 192000 Hz, the theoretical maximum frequency is 96000 Hz, and for a sample rate of 19200 Hz the maximum frequency is 9600 Hz.
I’m wondering why you need to reduce the sample rate from 192000 Hz to19200 Hz?
The setting that you are referring to are the default settings for the track Spectrogram view Audacity Manual
Those default settings can be changed in the Audacity Preferences:
“Edit menu > Preferences > Spectrograms”
See here for more information: Audacity Manual
Whether you change the default Spectrogram settings or not, you can zoom in or out vertically to change the frequency range that is shown. The maximum for the frequency range is half the track sample rate. One way to zoom in and out is to click on the vertical scale on the left end of the track. Left click to zoom in, right click to zoom out.
See here for more details about zooming tracks vertically: Audacity Manual
Also, you can make a track taller so that it is easier to see. Click and drag the bottom edge of the track up or down,
There is no point writing in the French Forum in English - you will not receive any answer. So I moved your post to the Windows board and merged with your existing topic which seems to be the same question.
Has Steve already answered your question? If you change the maximum frequency in Spectrograms Preferences to 9600 Hz, all tracks will by default display that maximum frequency. You have not resampled the track, only changed the maximum frequency the track can display.
If you always want to see tracks in Spectrogram view, change the “Default View Mode” in Tracks Preferences.
I knew that. For your information, bats sounds are high in frequence (usualy up to 20 khz) that’s why we record it at 192 KHz or more sometimes
Then in order to identify species or groups of species, we have to divide frequence by 10 (and multiply duration by 10 in the same time). We call it “time expansion”…
So then, when doing that, we can hear normally “unhearable” sounds and analyse it on computer.
Thanks for all the informations you gave, i managed to change some of the problems i had (reading directly as a spectrogram, “seing” 9.6 khz) and it’s verry usefull to me by saving time and energy loss
The only thing I can’t do up to now is to have automaticaly the sample rate reduced when reading a new file.
In fact I can change sampling rate in the preferences but each time i open new file it appears at his own original sampling rate (192000 Hz)
The Preference sets the project rate, not the rate at which files are imported. That is by design. Most people want to import a file at the sample rate it has, and with the project rate changing if necessary to match that of the file.