A QUICK GUIDE TO AUDACITY
Editing birdsongs and calls in the free software Audacity is quite simple when you get to know the basics of the layout. Personally I prefer to work in Spectogram view so I can see the noise, pings, handling noise, stomach rumbling and other unwanted parts of the recording. Push the small triangle up left (see inset below) and change between waveform and spectogram.Through this simple guide I hope you will be more familiar with this powerful tool and in the end publish more (and less noisy) birdsounds from around the world at xeno-canto.org
I use a PC for this guide, but it works more or less the same way on a Mac!
For further insight in setup of Audacity; read the article by Volker Arnold.
Linux/Ubuntu users: because **High Pass Filter** (among other filters) is a
**plug-in** which should ship with the Audacity package but does not show in the list of filters. It is found under
**Effects** right at the bottom in **Plug-ins 1-15**.* If you cannot find it there, first check if you have the file on your system under usr/share/audacity/plug-ins. It is called highpass.ny.* If you do not have it, then make sure you have Audacity version 2.1.2 (PPA) or higher - see <http://www.audacityteam.org/download/linux/< for more info - and you may need to install the extra filters from
http://wiki.audacityteam.org/wiki/Download_Nyquist_Plug-ins* If you do have it, then in Audacity, click on **Effects
--> Add/Remove Plug-ins** and install from there.
First you need to open a recording via File> Open
My 8 minute long testfile is a Bluethroat Luscinia luscinia from Northern Norway singing, the frequency range of the song starts at about 2 Khz and all the shady area below is noise from wind and rivers nearby. The birds mimics loads of birds in this recording! http://www.xeno-canto.org/379489
Open your file and then you will get a screen looking something like this:
NB My Audacity is a Norwegian version!
On the Y-axis (left vertical) is the frequency range from 0 Hz to ab 11 000 Hz (11 Khz), To change/zoom the frequency-range push left button on the axis above 0 Hz, shift-push left for opposite zooming of the scale.
The horisontal X-axis is in seconds and minutes, this total recording is ab 8 minutes long, I will work with only a part of this. To select a part of the recording set your pointer (arrow) on a place along the X-axis and push left mouse-button. Then hold and drag the mouse to the right or left to define the area you like to edit. TIP: On either side of the greyed out area a Hand will appear, drag the sides of the marked area with holding left button and release! The screen will now look like this:
Next step is to define how much of the bottom noise to filter, following the the left axis we can see the song starting at ab. 2 Khz so some of the noise below can be edited without affecting the song itself. I first choose to use Effect>High Pass Filter, set it to 1500 Hz and level 6 db. This will give you a soft start close up to maximum level without destroying the song itself. Black painted line indicates the area filtered.
In this case it's already quite smooth all the way to the bottom line (0-100 Hz) but often traffic, boats, engines, fans etc in the neigbourhood creates a hum that is annoying, and we can choose to filter that even further. I choose High Pass Filter, set 36 db and 1200 Hz. Now you will see it turns white (blank) and there is NO sound at all in the bottom part! To strengthen the effect: Ctrl + R
NB! This could create a less natural result, so test out before publishing! Listen to the results in the bottom!
NB! Normally 150-400 Hz and 36-48 db is sufficient for a nice result!
Noise reduction filter: This is normally enough and you can save the file, but sometimes White noise (wind or running water etc.) makes the birdsong less attractive, in Audacity there is a filter "Noise reduction" that can reduce this noise. If used wrong and too harsh it can destroy the quality of the song itself so be careful. I seldom set level higher than 5! First step is to drag an area with ONLY noise appearing, you do not want to filter the song itself. Then choose Filter/Effect > Noise reduction and set the level to 5 in step 1 "Get Noise Profile" , push OK. Then mark the area again and push Ctrl + R and it will do the job!
Below you will see the the final result and the uppermost noise is a bit lighter and less prominent, this without distroying the original song made by the bird!
NB! The Xeno-canto team do not reccomend this filtering, but for the listening to a noise-free recording it really helps!
You now have to export the final result to your harddisc or other media. Again mark/select the edited area and choose:
File > Export Selected Audio The box will ask you where to put the file. Push Save and you will get a new box - The Metadata.
here you name the recording f.ex. Bluethroat male singing, Troms County, Label a Album; Birds of Norway, Year, Additional info; Weather, recorder used, Mics etc. Then push Save and the new file will appear in your chosen folder.
NB! To choose as Mp3 - file you need a plug-in/addition to Audacity (MP3 Lame) http://manual.audacityteam.org/help/manual/man/faq_installation_and_plug_ins.html#lame
Listen to different versions of filtering 6dB 1200 Hz, 24dB 150, 450 and 1500 Hz and in the end unedited
File finally uploaded to Xeno.canto.org
HANDLING NOISE -CHIRPS ETC.
When you are out in the field there are always a chance you bring home sounds you never planned for, these could be yourself touching the microphone, cables, twigs touching the parabola etc. In audacity there are ways to get rid of such spiky noise, as long as the noise is not a part of the song/call. I share here some of my experience how to do it.
First step when you have identified the unwanted noise is to find and mark a nearby area with similar noiselevel as your noisy bit.
Then mark a portion of the recording and copy it ; Ctrl + C
Next step is to mark the noisy bit the same width (= amount of time) not to destroy the intervalls in the song sequency.
Then Paste; Ctrl + V
The vertical line is now gone and you can go further in editing the recording.
I choose to reduce some of the bottom noise, and uses High Pass filter; 6dB 1500 hz to reduce the general noise, then to reduce the coarse lowest part I chooses High Pass filter and 12dB 300Hz. In this case it should produce a nice noisefree file.