March 10, 2008

Recording sounds for Impress slides with eVoice

Author: Bruce Byfield

Over the last few years, has started to develop a respectable number of extensions, mostly for Writer and Calc, the two most widely used applications. The Extensions site lists only a handful that are unique to Impress. The recently released eVoice, which records sounds for direct insertion into a slide, is one of them. Once configured, eVoice is straightforward to learn, and becomes even more useful when you're working with other Impress features.

Extension logo

Before you can use eVoice, you need Java installed. The free IcedTea version that comes with Fedora will do, but the GCJ version that comes with Debian will not. For basic use, you also need a microphone that works with your system. Once you have met these basic requirements, download eVoice from the extension site and install it using Tools -> Extension Manager. After that, you'll have an eVoice menu and a new floating tool bar with a single icon.

To use eVoice, plug in your microphone to your sound card and select eVoice -> Insert from the menu. eVoice opens in a simple dialog with Record, Play, Stop, and Pause across the top, a duration graph in the middle, and OK and Cancel buttons on the bottom to use when you are finished.

As with pre-existing sound clips that you add via Insert -> Movie and Sound in the menu, clips created with eVoice show as a gray icon in the lower right corner of the current slide. If you click it, object handles appear, allowing you to drag it to another place on the slide when it gets in the way during slide design. The icon is not visible when you run the slide show.

Using eVoice, you can add one recording per slide; recording a second one overwrites the first. You can use the Play button in the dialog to hear your result, or, alternatively, click Slide Show -> Slide Show.

The most basic use for eVoice is to create narration for the slide. If you time the length of the clip, you can set the slide to display for the same time by selecting Slide Show -> Slide Transition -> Advance Slide - > Automatically After, and setting a time in seconds. If you are designing a slide show as an unattended demo -- say, for a trade fair -- you can have the show loop by selecting Slide Show -> Slide Show Settings -> Auto, and choosing an interval between repetitions.

However, that is only the beginning. If you choose, eVoice can act as a recording device -- one much simpler than a tool such as Audacity, but one that is also much easier to use. More creatively, you can replace the microphone with a two-way jack and record sound effects or background music directly from an MP3 player or stereo. If you carefully choose your clips and keep track of their duration, you can also use eVoice to create the illusion of continuous music in the background of your presentation.

Such an audio background can be especially effective when you minimize the transitions by running the presentation on a fast computer, with Slide Show -> Slide Transition - > Modify Transition - > Speed set to Fast. You will also want to set Modify Transition -> Sound to No Sound. If you are using music, you should also try to set the transition to a quiet point in the music, so that it is less noticeable. Creating an audio background can be time-consuming and full of false starts, but if the presentation is important enough, you might consider it worth the effort.

Several versions ago, Impress gained the ability to insert prerecorded sound clips. However, in its default state, Impress continues to lag behind Microsoft PowerPoint because it is unable to record sounds or sync slides with CD tracks. Now, eVoice halves the distance between Impress and PowerPoint. By adding sound recording to Impress -- and doing so simply and seamlessly, as far as end users are concerned -- eVoice immediately establishes itself as one of the must-have extensions for presentation designers.

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