So Now It Ends…

…maybe. The words of the great philosopher Louis L’amour come to mind:

There will come a time when you believe everything is finished; that will be the beginning.

This is our last assignment so this series will end; and I likely won’t be using this particular platform to blog, so that is the end of this blog. However, I did enjoy doing this so I’ll probably open a science-based blog on another platform to explain some things, marvel over others, and stir other stuff up (see how many wingnuts tell me I don’t understand science while getting the grade-school basics wrong in their first sentence–it’s the Dunning-Kruger Effect again).

Without further ado, here’s today’s post–a tutorial (sort of buried the lede again, didn’t I?)–it is the same one in the iBook file (if you’re not a classmate, you won’t have that file).

Cleaning Up A Sound File with Adobe Audition

Most people use Audition to work with music files. I will give a quick and dirty (and not even the best methods) of cleaning up bird recordings. I use quick and dirty because 1) it still works, and 2) when you have thousands of recordings to listen to, you don’t want to be taking 5 extra minutes per recording to get a perfect rendition, when a 1 minute fix works 99% of the time.

rcki

1. Open Audition. Click File->Open.

2. Navigate to the file you wish to open. Or drag the file into the left sidebar from Windows Explorer, or Finder (Mac).
diagram1
3. Convert the file to Spectral-frequency Display (Shift-D), or by clicking the button outlined in red above.

diagram2
This is a recording of several birds, but there is a background hiss from wind and moving tree leaves, and there is traffic noise in the lower frequencies. We will reduce the hiss, and remove traffic noise to hear the fainter birds more clearly.

4. Use your mouse to highlight a section of the spectrogram.
diagram3

5. In the menu bar, click Effects->Noise Reduction/Restoration->Hiss Reduction (process).

6. Your menu on the pop-up box will look like this (minus the red ovals):
diagram4

7. In Presets (upper left) click the pulldown menu and choose Light (top red oval). Note the position of the straight blue line in the previous diagram.

8. Click the Capture Noise Floor button (bottom red oval). If it is greyed out, then you need to highlight a portion of the spectrogram recording with the mouse.

9. Your straight blue line should now be inclined or sloped.
diagram5b

10. Go back to the spectrogram and highlight the area from which you wish to remove the hiss. On your menu box, click Apply. For demonstration purposes only the first half of the sound file was highlighted so you can see the difference with the hiss removed.
diagram5

Next diagram shows what it looks like if you use High Hiss filter from the pulldown menu (for birds, don’t use this setting as it can alter the sound of the birds to the extent it may sound like a different bird).
diagram6

11. To remove traffic noise, use a similar method to removing hiss. However, we will use the Marquee tool to highlight and then delete the noise. It is the dotted square that looks ‘depressed’.
diagram6

12. Highlight the noise you want to remove.

diagram7

13. Click the Delete key on your keyboard. Notice the Marquee box outline remains. You can use your mouse to move it, and resize it, and hit Delete again to remove a different portion of the sounds. See next diagram with three deleted sections.

diagram8

In general, remove the hiss first, then use the Marquee tool. Otherwise, you could end up removing hiss from just the area selected by the Marquee tool instead of the whole sound file. As well, hiss removal works faster when used before the Marquee tool.
By the way, the title comes from a line uttered by the Kurgan just before the final head-chopping fight in Highlander (the original movie with Christopher Lambert who can look intelligent, not the tv series with the actor who has difficulty looking intelligent).

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s