DIY Audio Rosanne Hutton, MindCross Training

Transcription

1 DIY Audio Rosanne Hutton, MindCross Training 402

2 MindCross Training & Consulting DIY Audio Rosanne Hutton MindCross Training 1 Goals and Objectives The goals and objectives of this presentation are to show elearning professionals how to create great sounding audio recordings when you don t have the budget to hire an audio professional. This presentation is geared towards those new to creating and processing audio files. 2 Topics Audio in elearning Fundamentals of audio Hardware and software requirements for DIY audio Recording and post-processing Audio samples Closing arguments 3 Session 402 DIY Audio Rosanne Hutton, MindCross Training Page 1

3 Audio in elearning Ways in which audio can be used Background Text/narration Similar to having an instructor in the classroom Podcast Internet MP3 players Mobile devices Audio tours Added bonus material/content Interview with an expert Listen to view/comments from. 4 Audio in elearning Helps make the learning more effective Makes learning more realistic Adds personality and dimension to learning Sometimes a requirement May allow more detail to be included Easy to do with minimal requirements Provides more options in the course design Text and visual presentation Overall creativity of design aspect 5 Audio in elearning Things to keep in mind Make it sound professional; high quality Keep it simple and easy to use Sometimes less is more Make it user-centric Considerations File size Audio, narration, text, etc. Visual and hearing impairment Globalization and localization 6 Session 402 DIY Audio Rosanne Hutton, MindCross Training Page 2

4 Fundamentals of Audio Waveform An image the represents the audio signal or recording Channels Mono (monaural) Recording or audio reproduction over a single channel The same sound comes out of the left and right speakers or headphones Stereo Recording or audio reproduction over a two or more channels i.e. Left and Right Mono channel waveform Stereo channel waveform 7 Analog and Digital Audio Analog Recording a continuous audio signal, represented as pressure waves, magnetic traces, vibrations, etc., onto magnetic tape, vinyl, 8-track, etc. Contains more audio information Recordings cannot be copied or manipulated without degradation Often contain more noise than digital recordings Digital Audio that is broken down and converted into bits - - a a series of ones and zeros - - for use by a computer Audio files are easier to reproduce, manipulate, and maintain without loss in quality In digital storage the waveform is broken up into individual samples; the sampling rate defines how often a sample is taken 8 Sample Rate Frequency Resolution The rate at which snapshots are taken (samples per second) of an analog signal in order to be converted into digital form Determines the frequency range of an audio file - - how many frequencies can be encoded in the audio signal The higher the rate the closer the audio is to the original Example Sample Rates Hz (11025 samples/second) - Low-end radio/speech * Hz (22050 samples/second) - High-end radio/speech; near FM quality Hz (32000 samples/second) - Standard broadcast rate; better than FM quality Hz (44100 samples/second) - CD quality Hz (96000 samples/second) - DVD quality 9 Session 402 DIY Audio Rosanne Hutton, MindCross Training Page 3

5 Bit Depth The bit rate or bit depth determines the amplitude resolution A higher bit depth will provide greater the dynamic range and lower noise levels Bit Depth Examples 8-bit (48 db of dynamic range) - Low-end radio/speech 16-bit (65,536 possible amplitude values) - CD quality 32-bit (192 db of dynamic range) DVD quality 24-bit Note: Each bit can encode 6 db of dynamic range 10 Audio Encoding The process of compressing/decompressing a data/audio file Accomplished using computer software, audio codecs Encoding may reduce the file size depending on the codec used Non-compressed formats.wav Windows PCM Microsoft WAVE format.aiff Audio Interchange File Format Compressed formats.mp3 MPEG-1 lossy compression.wma Windows Media Audio Lossy compression.riff Resource Information File Format 11 Audio Fundamentals Summary A digital audio file contains data needed to reproduce the sound wave. It s based on a combination of sample rate and bit depth. The sample rate limits the frequency range and the bit rate limits dynamic range and signal-to-noise ratios. 12 When recording you must specify the: Sample rate, channels and bit depth Then save the digital file Session 402 DIY Audio Rosanne Hutton, MindCross Training Page 4

6 Hardware Requirements Recording room Digital recorder Microphone Preamp (maybe optional) Digital audio workstation Headphones/speakers (optional) 13 Recording Room Considerations and items to review Acoustics Noise Room size Windows Ceiling height Hard surfaces Creating a recording room Use a walk-in closet Eliminate hard surfaces and sound proof Add foam/padding to the walls/windows Block out sound/noise Egg cartons 14 Digital Recorder Portable digital recorder or PC with sound card Sound card functions Recording - analog to digital conversion Microphone and line-in connections Playback digital to analog conversion MIDI interface Synthesizer delivers/generates the sound Frequency Modulation (FM) synthesis cheapest sound cards Wave table synthesis best sound cards Physical modeling simulated sounds Integrated audio support Sound card can be integrated with the mother board 15 Session 402 DIY Audio Rosanne Hutton, MindCross Training Page 5

7 Microphones Types of microphones Dynamic Commonly used in live settings Condenser Commonly used in recording studios Requires power source to operate Phantom power Battery Input connections XLR XLR input USB connectors PC mic input (1/8" stereo minijack) 16 PreAmps (External) Microphone preamps are used to boost the signal Mic inputs on a sound card includes a preamplifier Quality not up to par Noise level is high Most commonly used with microphones having XLR connections Options Dedicated device Mixer allowing multiple inputs and controls Connects to your pc via USB 17 Headphones and Speakers Headphones or external speakers are especially important when using a laptop Important to test your recording using a variety of outputs PC speakers Various headphones External speakers 18 Session 402 DIY Audio Rosanne Hutton, MindCross Training Page 6

8 Software Requirements Software features to look for Recording Editing Multiple tracks Special effects A variety of codecs and supported file formats Free mid-level.. $ $100 Audacity Sony Sound Forge Audio Studio N-Track Studio WaveLab Professional..$200-$600 Adobe Soundbooth Adobe Audition Pro Tools M-Powered Cubase 19 Preparing the Talent Know the script Review it and be familiar with it Practice (out loud) What to eat/drink Lots of water - - hot water/tea Lemon, honey Eat at least an hour before recording Eat lean foods, fruits, and vegetables Stay away from fatty foods and dairy products Snack on licorice Avoid clearing the throat 20 Recording Setup #1 Connect via USB Preamp / mixer Connect via XLR input PC with sound card and recording software Recording room The talent / voice(s) with script in hand 21 Session 402 DIY Audio Rosanne Hutton, MindCross Training Page 7

9 Recording Setup #2 Connect via USB PC with sound card and recording software Recording room The talent / voice(s) with script in hand 22 The Recording Process Software settings (for speech) Record based on usage Frequency/sample rate Hz Channel.Mono Bit depth/resolution.16-bit Note: the file size produced is directly proportional to the sampling rate Saving files Plan a naming convention for your audio files Match audio file with page name (i.e. P1.wav, P2.wav) Descriptive name (i.e. RecordingProcess.wav) Save files as.wav 23 Audio Samples Low end recordings Low end microphone - $25 Sound card mic input Mid-range recordings USB microphone - $60-$100 USB input No mixer / preamp High-end recordings Microphone with XLR inputs $120-$500 USB PreAmp / mixer $50-$800 $500 Shure mic - WH30XLR Tascam Preamp Recording and editing software $400 Blue Snowball mic Recording and editing software 24 Session 402 DIY Audio Rosanne Hutton, MindCross Training Page 8

10 Post Processing / Post Production Editing audio files Noise reduction Amplification Mixing, adding music, etc. Editing can be very time consuming Convert to MP3 Dependent on authoring tool being used Batch conversion of all files 25 elearning Development with Audio Adobe Flash example of embedded audio file Import.MP3 files to library Add to stage / timeline Flash CS3 timeline Set sound properties Streaming Flash CS3 sound properties 26 elearning Development with Audio Adobe Flash example of embedded audio file (cont.) Publish Settings Compression: Sample rate: Speech 22kHz Flash publish settings 27 Session 402 DIY Audio Rosanne Hutton, MindCross Training Page 9

11 Podcasting What s a podcast? An audio broadcast for playback on a computer or digital music player Typically MP3 format A technology that distributes audio files via the Internet using an RSS feed and XML technology Similar to newsfeeds Users can subscribe to a Podcast and the client program captures the audio feeds and delivers them to the subscriber 28 Setting Up a Podcast Hosting server supports podcasts Create/record your audio files Based on a topic area Edit, mix, and convert to MP3 format Create a podcast channel (category/topic area) Add podcast episodes (specific title) and description Upload your MP3 file(s) Link the episode(s) to the MP3 file(s) Set up an podcast or RSS feed link on your website Setup a Feed Player on your site (optional) 29 Closing Arguments Maintaining audio files Tedious and time consuming A voice is more inconsistent that you may realize Talent turn-over is inevitable Text-to-speech is always an option Audio file naming conventions Matching file names to page names 30 Session 402 DIY Audio Rosanne Hutton, MindCross Training Page 10

12 Closing Arguments (cont.) Text-to-speech software For podcasts think about how you want to do it Interview style Music in background Test for the audience Different speakers, headphones, locations Different quality speakers, headphones PC/laptop speakers Built-in vs. external 31 Closing Arguments (cont.) Selecting the voice - - the talent Many public announcements use the female voice Who s your audience? As her sweet voice came mingling on the ear. Ah, who but knows what woman s voice can do! To every soul such melody is dear; Angelic harmony, and beauty too! ~ 19 th century English poet: John Clare 32 Session 402 DIY Audio Rosanne Hutton, MindCross Training Page 11