Audacity

Audio Editing in Audacity - Basic

Audacity is compatable with Windows 98, ME, 2000, & XP, Mac OS9 and X, Linux, and Unix. To download the program go to the Audacity website.

  1. Before you start, go to your computer's sound control panel and make sure your input device (or your microphone) is selected as the audio input source. Then boot Audacity and go to preferences. Set the device(s) you are recording from and playing to in the audio I/O tab. If you are editing a pre-recorded file from your webcast for example, open Audacity then use the Import tool to open the pre-recorded file.The Quality tab sets the sample rate and bit depth. Jeff Towne from the Transcom Tools Content site says "Audacity can handle different sample rates and bit depths within a project, but these will be converted in real-time to the default session settings when needed. Although normally 16-bit is a sufficient bit-depth for webcasts, and you will save a good deal of disc space and processing power if you use that depth, Audacity sometimes creates grungy-sounding sound files when recording at 16 bit. I'd start with 16 bit, but if you have that problem, setting up your session to record at 32-bit float might solve it. Set that in the file format tab as the default export format." You can change the sample rate from the lower left corner also.

  2. Hit the red record circle in the transport panel to record. You can adjust the record level with the slider next to the microphone icon in the top right corner. You should leave it all the way up and change levels from your sound card or control panel. Make sure your input level does not go into the "red" (or hit the ceiling) on your meter as that will cause clipping. You can import audio into your Audacity project if you wish to combine more than one recording or add music etc. They will show up as new tracks.

  3. Editing tools -
    • the control toolbar is like any audio player transport buttons. Pressing the spacebar will start and stop play, and shift-spacebar will loop-play a selected section (called a region).

      Editing Tools
    • To select a section, click on the selector tool and drag over the part of the audio you want to change. Move the cursor over the edges of the highlighted section to grap and extend the length. Press Z to move the selection edges to zero-crossings eliminating clicks from edits.
    • For gain changes (also known as trim..it refers to the intensity of an audio signal), highlight a region (section) and use the "amplify" or "normalize" commands from the effect menu, or move the volume slider at the left of the track display. That slider sets the level for the track.
    • Use the draw tool like a pencil to re-draw waveforms to eliminate eliminate clicks or other distortions.
    • Click and drag over part of a track to zoom in. The magnifying-glass icons on the right hand side of the top of the track window can be used to zoom in or out in steps, to zoom to the selection, or to zoom out to see the entire project at once. A scroll wheel works as well.
    • Cut, Copy and Paste work as expected. Highlight audio you don't want and press delete. Audacity will close the gap. Audacity Editing tools
    • Use the silence selection tool (mute) if you'd like to remove audio without making changes to the timeline.Select audio you want to keep and click trim to selection to delete everything except the selected region. The silence selection icon mutes selected audio, but without moving any other audio regions, leaving a silent space, like hitting "mute" for that time range. Any other edits will close up that gap.
    • You can grab the vertical edges of a track and drag up or down to make it wider and easier to see for editing. The track can be reduced in size to see more tracks after you are finished editing
    • You can always undo edits, but not after you save. Audacity saves small ".aud" files that has all the editing data, so you can do multiple save-as steps to store different versions of the project, to retain flexibility without duplicating all the large sound files. Selecting view>history will show you a list of your actions, and by clicking on the various entries, the edits will revert to that stage of the edit, you can then discard all moves after that point by clicking the discard button. The history list is cleared whenever you save and you cannot undo after a save. Audacity has been known to crash, so save often.
    • You can use the Audacity plug-ins like the compressor, EQ, filters and normalizing. The Audacity "Noise Removal" effect is not the best and I don't recommend it. Audacity's effects need to be applied one at a time. To remove an effect, you have to step backward with "undo."

  4. Export selected parts of a project by highlighting them and choosing export selected from the file menu.

  5. Final MP3 - (for uploading into your blog) When you are done with the mixing and editing, (make sure your audio levels are high but not clipping) export your project by clicking File>Export As>an MP3. You may also Export as a WAV file or an Ogg Vorbis, another kind of compressed file. Just saving it will not make it a final mix. Be sure to us this Export tool so your final product can be uploaded to Webcast Academy, burned to CD or FTP'd.

  6. Learn Keyboard shortcuts for Audacity to speed up your editing time.

References

  • Information for this article is from The Transom Tools Content article by Jeff Towne
  • Level Headed ~ Jeff Towne
  • Processing Basics ~ Jeff Towne
  • Digital Editing Basics ~ Barrett Golding
  • Audio recording

    I used a small piece of a skpe conversation that Lee and I had while she was helping me with WireTap Pro. The first attachment is the segment edited and the second attachment is the same audio unedited.

    There are 4-5 places where her speech is slurred. It really bothers me but I was unable to correct it. I hope someone else has some ideas about how to avoid the "slurring sound" or how to fix it.

    I opened the aiff file from wiretap pro in audacity and then in both cases exported as mp3 files to post here.

    Audio Editing in Audacity

    Hello Everyone,

    I have created a page in the Book of Webcasting on basic Audio Editing in Audacity. It is simply a "how-to" and an introduction to editing in Audacity. Hope to follow up with a screencast soon. 

    Lee 

    Excerpt from Skype interview Part 2

    Good! ... I had breakfast while the attachment was uploading....

    I've posted this MP3 file because I'd much appreciate comments, tips for improvment. I regard it as an exercise for the assignments here.

    Details

    I recorded the interview, conducted on Skype, using PowerGram. PowerGram records in ogg, so I transferred to Audacity (straightforward) did minimal editing and then saved (exported) as MP3.

    Questions:

    1. Are PoweGram recordings of good enough standard for webcasting?
    2. What might have caused the echo in Paul's recording? (There was no loudspeaker).
    3. How can one avoid getting echo?

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    Excerpt from Skype interview

    Will explain attached file as soon as it has been successfully loaded.

    Taxonomy upgrade extras:

    Work in progress (con)

    Cursor froze in the first half of this message, so I decided to post and continue here. This has happened before and I suspect - will not use it - the apostrophe! - that seems to sometimes freeze the cursor.

    Jeff sent a message to the evo 2002 list reporting that he had done a screencast on window management. I have not found this yet,
    BUT I must look again.

    Practising Skpye interviews - did a trial, using Audacity, BUT, my voice - very good recording - interviewee - pretty faint. This was using a headcast, but separate mike (non-USB).

    At same time, recorded trial conversation with PowerGrammo.

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