The Net is rocking with sound - lots of it. In this three-part series, technical sound wizard and all-round audio guru, Gavin Starks, shows you how to make noise on your own Web pages
OK, so you've toiled for hours, building your statement to the world, your voice: your web page. Perfecting those words, tweaking those graphics, shouting at the
syntax - getting it all just right. Now you can add sound. So what? Well, how often do you tune into the Net and say "that was entertaining". Your voice isn't very loud on-line, if you've got something to say, why not actually tell people. If you've got a band, why not let people listen to it instead of ranting on for pages. Even better, if you've got friends on-line who like music, why not start sharing your tunes as well as your favourite chat and pictures.
Although the Net gives you lots of anarchic plagiarism opportunities, this is not very fair on musicians who rely on music for their income. If you want to put any commercial recordings (even clips) on the Net you must get a license to do so. Even if you're in a band that is signed up, you must check with your label. The people who make sure artists get paid are PRS (the Performing Rights Society, http://www.prs.co.uk/) and MCPS (the Mechanical Copyright Protection Society, http://www.mcps.co.uk/). They've been putting a lot of effort into sorting out Internet rights, just e-mail Gavin Robertson (email@example.com) with your queries.
//simple place to start listening
[caption] Virgin Net World Radio Tuner : a simple starting point for listening around the planet.
Getting sound into your computer
It's not difficult, but it does take a bit of effort to get it right - and you have spent all that time on the rest of your site, haven't you? Firstly what are you recording: is it your voice, music, a demo tape, your cat? If you've got a Mac or PC with a soundcard it'll usually have 2 types of input: mic and line. If you're recording from a tape, mini-disc or video you should plug whatever audio output they have into the line input of your PC [Tip: you can probably use the cable that connects your PC to your speakers to go from a headphone output into your PC]. If you're going straight from a microphone, plug it straight into the mic input.
If you have a PC use a sound recording tool, such as Sound Recorder (Program/Accessories/Multimedia/Sound Recorder). If you're using MS Sound Recording Tool, select Edit/Audio Properties to set the quality of the sound you want to record (the better the quality, the more disc space you will use, and the longer it will take someone to download). Telephone quality (640K/min) is fine for voice, Radio quality (1.2MB/min) should be fine for most music applications.
Launch your volume control program (Program/Accessories/Multimedia/Volume Control). To set the Recording level you will have to select Options/Properties, select Recording and make sure the appropriate input is enabled. So, if you're recording from the MIC input, select Microphone. Speaking into your microphone (or playing your tape) should show the on level bar. Adjust the Volume control so that the signal 'peaks' in the yellow. This is how you set the recording level of a signal. Experiment for a while to set the best level: too high (red) and the sound will distort, too low (dark green) and you won't hear it very well!
[caption] Setting your recording level. Try not to 'clip' the sound.
Clicking the 'record' button on the Sound Recording Tool, and play on your tape player should display a "signal" in the sound recorder window. It should look something like this:
[caption] Recording your sound. You can 'see' your sound in the middle window.
Practice recording as many times as you like until you feel happy with what you've got. If you make a mess of the beginning or end of your sound you can 'trim' it using the Sound Recorder functions. Just select the point you want to delete to or from then select 'Edit/Delete Before/After'. When you have finished, save the recorded sound to your disc as a WAV file.
[caption] Trim your sound to get rid of mistakes and make the smallest file possible.
As you can see, this is straightforward, but doesn't give you much chance to change things afterwards. What you really want is to be able to edit your creation the same way you would with a text document. There are a number of great applications which let you do this, 'Cool Edit' (http://www.syntrillium.com) is one of the best shareware applications for PCs and we'll be going into more depth about how to not only edit your sounds but how to manipulate them in lots of useful ways next month.
Download or Stream?
So, how do you get your sounds from Basingstoke to Bermuda via the Net? Well, the usual way of getting anything over the Net is to download it. This can be really tiresome for sound - you wait for ages and all you get is someone's awful blip-noises.
It doesn't have to be like this. With sound you can 'encode' it so that as soon as the person on the other end of the line has downloaded a tiny, tiny bit, it'll start playing (this should happen almost straight away). While it's playing, it'll download the next bit and so on, so you should never get a break in the sound. This is called 'streaming'. Unfortunately sometimes the Net gets really busy, there's just not enough space left for your stream and you get the dreaded 'Net Congestion' message.
Whether you're downloading or streaming it's best to use some of the new technologies to pack your sound into as small a parcel as possible. Some products allow you to choose whether you're going to let people download the sound file completely before they play it (like with a WAV), or stream it straight away. Others let you 'stream' sound using Java (e.g. Emblaze, http://www.emblaze.com) or the standard Internet protocol, HTTP (e.g. RealAudio, http://www.real.com). This means your Service Provider doesn't need to have any special tools - you can do it all yourself. We'll be looking at the many different ways to encode your sound later in this series.
Consider is how Net-friendly you want to be, and how much you really think people want to hear your stuff. Use this to decide whether to go for a lengthy download - to get higher quality, or streaming - to get that instant effect.
Make it small and people might stay long enough to be interested. Make it interesting and fast and they'll come back.
A real CD-quality recording uses 10Mb every minute. You could do this, but don't bank on a huge audience of 28.8Kbps users (who can only get 170K per minute).
The WAV format doesn't give you the best quality against file size since it was never meant to be used for the Internet, so all these net-friendly sound formats really make a difference.
Common sound file formats explained
AIFF/AIFC: Silicon Graphics and Macintosh use this format
AU: Original format for UNIX machines, it's now the standard audio format for Java
RAM: You'll often see .ram files on a web page. They're what's known as meta files, since they just point at the actual sounds. They're needed if you use a dedicated server to deliver your sounds
RA: RA files contain the actual RealAudio encoded sound itself. They are often accompanied by a .ram file which acts as a 'pointer' to the actual sound
MIDI: MIDI files do not contain sound, they give a musical score to your soundcard -don't be too disappointed if that Blur track sounds like cheesy-organ-specials of the '50s
RMF: Rich Music Format downloads the sound you want to a special player, then uses MIDI to play it. This way you can make sure everyone hears the right sound, even if they have a poor soundcard
MPEG: One of the most popular compression standards in use on the Internet, the "Layer 3" format is particularly good.
SND: Macintosh, SUN and NeXT all use this extension, although the actual encoding algorithms differ
WAV : The most widely used basic sound-file format. It can come in many 'flavours' from CD-quality to broken-walkman
PCM: Pulse Code Modulation is the underlying default 'algorithm' for storing WAV files
Encoder: The software that squashes your sound into the smallest space possible in a Net friendly format, without losing too much quality.
Channels: Mono is one, stereo is two (one for left, one for right).
Trim/Cut/Copy/Paste: yes, it really is the same as for your text document!
Clipping: 'Clipping' occurs when your sound level is too high and distorts. Digital sound is particularly unforgiving when this happens.
Sample Rate: Digital sound is just as a string of numbers which are 'snapshots' of the sound's level. The sample rate is how quickly the digital snapshots are taken (CD for example takes 44,100 snapshots a second)
Frequency Response: Tied directly to the Sample Rate, the higher the Sample Rate the higher the frequency (or 'pitch') you can record.
Dynamic Range: How much difference there is between the quietest quiet and the loudest loud. The greater it is, the more natural it sounds (e.g. 16 bit is better than 8 bit).
Normalisation: Fit the sound into the total dynamic range available
Gavin Starks is New Technology Manager at Virgin Net (http://www.virgin.net) and Chairman of Technical Committee of the International Webcasting Association - Europe (http://www.iwa-europe.org).
http://www.iuma.com/ - features the music of over 1000 independent musicians
http://www.audionet.com/ - 300 live stations and 400 events a day makes this quite an interesting place to drop by
http://www.hyperreal.org/ - volunteer run home to alternative culture, music and expression
http://the-duke.duq-duke.duq.edu/notes/LECTURES/sec2.htm - all about sound formats