A digital audio player (DAP), more commonly referred to as an MP3 player, is a consumer electronics device that stores, organizes and plays audio files. Some DAPs are also referred to as portable media players as they have image-viewing and/or video-playing support. MP3 players are now regularly built into mobile phones, making them the most common form of digital audio player. In short, an MP3 player is a portable device that plays digital music files–although many MP3 players can do much more than that. They evolved from the portable cassette and CD players that we carried around in the 1980s and ’90s. Instead of bulky cassettes or scratch-prone compact discs, most MP3 players play files stored directly on the device. Aside from a pair of headphones, there is nothing extra you need to carry to enjoy your music collection.

An MP3 is a digital audio file compressed with a standard defined by the Motion Pictures Experts Group (MPEG). MPEG was formed to develop techniques for dealing with digital video; since most video also contains audio, MP3 was developed as an audio extension of that work. Officially known as “MPEG-1, Layer 3″, MP3 is a lossy compression algorithm that uses psychoacoustic modeling to reduce the size of audio files by up to 90%.

Psychoacoustics takes advantage of deficiencies in the human hearing system to throw away digital bits corresponding to sounds that cannot be heard. The human ear cannot hear soft sounds in the presence of loud sounds having a similar frequency; for example, a voice conversation becomes inaudible when a jet flies low overhead. This effect is known as auditory masking, and done correctly the discarded sounds will not be missed.

MP3 is a lossy algorithm in the sense that the original bits cannot be recreated from the compressed bits. In terms of hearing, however, MP3 is lossless because the human ear cannot distinguish between a CD recording and a properly encoded MP3 version of it. MP3s achieve this transparency at a bit rate of approximately 256 kilobits per second, or roughly one sixth of the 1.4 megabits per second required by the compact disc format.

MP3s can be recorded at lower bit rates, saving even more space, but audible differences begin to appear at rates below 128 kilobits per second. At these lower bit rates, MP3 can use a trick known as joint stereo to improve quality. Audio generally consists of left and right audio tracks. Joint stereo combines, whenever possible, the sounds common to both left and right tracks into one track. Instead of left and right, it has “common” and “different” channels.

Being an open standard, and therefore available to anyone, has played a major role in the widespread adoption of the MP3 file format. While specific implementations such as those by the Fraunhofer Institute may be protected by patents, there exist numerous open source implementations. MP3s were originally only playable on computers, but inexpensive, portable MP3 players such as Apple’s iPod have since been developed.

History

The immediate predecessor in the market place of the digital audio player was the portable CD player, which was sometimes referred to as a “portable audio device.”

Briton Kane Kramer designed one of the earliest digital audio players, which he called the IXI. His 1979 prototype was capable of approximately 3.5 minutes of audio playback but it did not enter commercial production. The related patents expired in 1988. Apple Inc. hired Kramer as a consultant and presented his work as an example of prior art in the field of digital audio players during their litigation with Burst.com almost two decades later.

The first mass-produced DAP was created in 1997 by SaeHan Information Systems, which domestically sold its “MPMan” player in the middle of 1998. The South Korean company then licensed the players to Eiger Labs which distributed them—now branded as Eiger Labs MPMan F10—to the North American market during the summer of 1998. The flash-based players were available in 16 MB storage capacity.

The Rio PMP300 from Diamond Multimedia was introduced in September 1998, a few months after the MPMan. It was a success during the holiday season, with sales exceeding expectations. Interest and investment in digital music were subsequently spurred from it. Because of the player’s notoriety as the target of a major lawsuit, the Rio is erroneously assumed to be the first DAP.

In 1998, Compaq developed the first hard drive based DAP using a 2.5″ laptop drive. It was licensed to HanGo Electronics (now known as Remote Solution), which first sold the PJB-100 (Personal Jukebox) in 1999. The player had an initial capacity of 4.8 GB, which was advertised to be able to hold 1200 songs.

In October 2001, Apple Computer (now known as Apple Inc.) unveiled the first generation iPod, the 5 GB hard drive based DAP with a 1.8″ Toshiba drive. With the development of a minimalistic user interface and a smaller form factor, the iPod was initially notable within users of the Macintosh community. In July 2002, Apple introduced the second generation update to the iPod. It was compatible with Windows computers through Musicmatch Jukebox (now known as Y!Music Musicmatch Jukebox). The iPod series, which grew to include microdrive and flash-based players, has become the market leader in DAPs.

In 2002, Archos released the first “portable media player” (PMP), the Archos Jukebox Multimedia. Manufacturers have since implemented abilities to view images and play videos into their devices.

In 2003 the first MP3 players were installed into mobile phones in South Korea and the first artist to sell songs as MP3 file downloads directly to mobile phones was Ricky Martin. The innovation spread rapidly and by 2005, more than half of all music sold in South Korea was sold directly to mobile phones. The idea spread across the globe and by 2005 all five major handset makers, Nokia, Motorola, Samsung, LG and SonyEricsson had released musicphones. By 2006, more MP3 players were sold in musicphones than all stand-alone MP3 players put together. The rapid rise of the musicphone was quoted by Apple as a primary reason for developing the iPhone. In 2007, the installed base of musicphones passed the 1 billion level, and today more than half of all moblie phones in the world have an MP3 player.

Although online music services such as RealNetworks’ Rhapsody also offer legal downloads through a subscription plan, the launch of the iTunes Store in 2003 established the model of selling individual songs and albums for purchase.

Operation

Digital sampling is used to convert an audio wave to a sequence of binary numbers that can be stored in a digital format, such as MP3.

Common features of all MP3 players are a memory storage device, such as flash memory or a miniature hard disk drive, an embedded processor, and an audio codec microchip to convert compressed sound into analogue form that is then played through the speaker jack.

Most DAPs are powered by rechargeable batteries, some of which are not user replaceable. Listening to music stored on DAPs is typically through earphones and stereo systems connected with a 3.5 mm jack.

Types

Digital audio players are generally categorized by storage media:

Flash-based Players: These are non-mechanical solid state devices that hold digital audio files on internal flash memory or removable flash media called memory cards. Due to technological advancements in flash memory, these originally low-storage devices are now available commercially ranging up to 32 GB. Because they are solid state and do not have moving parts they require less battery power and may be more resilient to hazards such as dropping or fragmentation than hard disk-based players. Basic MP3 player functions are commonly integrated into USB flash drives.

Hard drive-based Players or Digital Jukeboxes: Devices that read digital audio files from a hard disk drive (HDD). These players have higher capacities currently ranging up to 250 GB. At typical encoding rates, this means that thousands of songs can be stored on one player.

MP3 CD Players: Portable CD players that can decode and play MP3 audio files stored on CDs.

Networked audio players: Players that connect via (WiFi) network to receive and play audio.

Common audio formats

MP3 is the dominant format, and is nearly universally supported. The main alternative formats are AAC and WMA. Unlike MP3, these formats support DRM restrictions that are often implemented into files from paid download services. Open source formats, which are completely patent-free, are available – though less widely supported. Examples include Ogg Vorbis, FLAC, and Speex.

Most players can also play uncompressed PCM in a container such as WAV or AIFF.

Controversy

Although these issues aren’t usually controversial within digital audio players, they are matters of continuing controversy and litigation, including but not limited to content distribution and protection, and digital rights management (DRM).

Lawsuit with RIAA

The Recording Industry Association of America (RIAA) filed a lawsuit with Diamond Multimedia for its Rio players, alleging that the device encouraged copying music illegally. But Diamond won a legal victory on the shoulders of the Sony Corp. v. Universal City Studios case and DAPs were legally ruled as electronic devices.

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A few years ago 5.1 surround sound DVD video players looked likely to become standard kit in every living room in the technology friendly world.

So now a few years on, what has happened to the original promise of surround sound music? Well the answer to that is ‘lots, but not nearly enough.’

For those that don’t know already, 5.1 surround sound is basically five speakers and a sub-woofer placed around your room allowing you to listen to music or a movie soundtrack literally surrounded by speakers. The film industry pioneered it for theatres and it then became available as a DVD player add-on for home entertainment systems.

Now at least 100,000,000 people world-wide own systems, which can and should be used for all manner of surround sound music DVDs.

I hear you say, ‘but surround sound music on DVD hasn’t really caught on. All that wire in my living room’.

Even though the consumer can buy a DVD player and surround speaker system cheaply enough, surround sound music hasn’t really caught fire yet. Why?

There are reasons why we should all remain confident that surround sound music will become more popular, but at the moment it’s still an infant child.

The amount of different DVD and surround sound formats is confusing and can be offputting.

The consumer desperately wants an end to the confusing compatibility war between different surround sound formats.

Many music artists would start producing DVDs if it wasn’t so complex, just as there are many consumers that would purchase a surround sound DVD system for the same reason. They should be able to buy a DVD player and play any product claiming to play DVDs.

Consumer surround sound formats currently include sound on video DVDs encoded as Dolby 5.1 surround sound or DTS; the competing DVD-Audio (DVD-A) and Super Audio CD (SACD) formats and MP3 Surround.

There are 5.1, 6.1, 7.1 systems, four speaker systems, even one speaker systems and ’simulated surround sound systems.’ Phew! See what I mean?

They all have their uses, but the I feel the music business would be wise to embrace one format. Every time the consumer buys a surround sound music product they have to research whether it will be compatible to their particular system.

The good news here is that slowly, but surely things are improving. As long as there is no ‘new’ new format to rock the boat, the problem of incompatibility could become a thing of the past.

There are many great web sites to visit which do explain (in as much detail as you could possibly imagine) all the different formats and help you decide what to buy.

How about all that wire in my living room though?

There are wireless speaker systems available, but the cheaper ones are for mainly rear-channel wireless amplification. This doesn’t quite get rid of all the wires and limits people who have odd shaped rooms. But they are better than nothing.

It would be great for a ‘let’s make it fun revolution’ to occur with surround sound, like the iPod. Small wireless speakers one could place anywhere. The recommended configuration would still be in a circle, but you’d have a license to have fun by placing them in different locations.

Certain types of music would not really benefit from this unconventional approach, but other types mixed specially for surround sound might not suffer that much and it would release the consumer from the pressure to set their systems up in a way that would please an audio engineer or DVD manufacturer.

Not enough of an improvement on CDs and overall lack of interesting music DVD products.

The amount of compression used for music on DVD video is far greater than CDs. So stereo music on CD is generally of a higher quality than stereo music on DVD. However, add the extra speakers and a properly mixed 5.1 surround sound piece of music and all of a sudden the playback bit ratio seems much less important.

‘What is’ you ask, ‘a properly mixed 5.1 piece of music?’

Recreating real space is what seems to interest some surround sound pioneers. The chance to paint a more precise musical picture by placing you the listener deeper inside a musical ensemble or concert venue.

This approach has got its merits, but it’s reliant on people having their speakers in precise locations, and that they will sit dead centre amongst them. Pluses can turn to minuses at this point. If you don’t have a perfectly set up system it might just sound weird, especially if you are used to the stereo CD mix from the same artist.

Apart from all the technical considerations, I consider a great 5.1mix a strong alternative to the stereo mix. Let’s say the artist already has their stereo mix. Why not make the surround mix something that really explores that extra space and is different from the stereo mix.

Give the consumer a choice of two distinctly different sounding mixes. This might inspire more people to make the effort to set up those surround speakers which are still sitting unused in the attic.

Currently it is almost mandatory to include some type of visual content on a DVD.

In a way, it’s a shame that ‘audio only’ DVDs haven’t caught on…yet.

Depending on the level of production the artist is looking to reach, it can be both very expensive and time consuming producing enough visual material to accompany all the music for a competitive DVD release.

Most musicians have a hard enough time producing their music let alone having to produce hour’s worth of videos as well. So you could say that the need for visual content (as exciting as it can be) is holding back the growth surround sound music.

Live concerts are the most successful type of music DVDs, mainly because they are relatively cheap to produce.

For ‘audio only’ DVDs to catch on, consumer expectation will have to be ‘re-trained’ to expect what they might consider as less. I feel that the days of distributing film or music products on any type of disk is going to disappear fast.

What does the future looks like for surround sound?

The real turning point will come when the Internet becomes surround sound friendly. A new MP3 surround streaming module has just been announced that allows manufacturers to build web radios featuring true 5.1 surround sound.

Many people surf the Internet sitting at their desk, listening to music for hours at a time. Soon they will be able to surf and listen in surround sound. Small near-field computer monitors would work perfectly.(especially wireless ones).

It’s inevitable that 5.1 radio and TV broadcasts will soon become the norm. Even without the music business, embracing surround sound as anything more than a small niche, the amount of people with a 5.1 system is steadily increasing.

At this point, surround sound music becomes a viable ‘audio only’ product. If the surround sound community can simplify the production process even more allowing the average project studio to easily create surround sound content, we should all benefit.

I predict there will be a tipping point where all of a sudden the ‘need’ for surround sound music will exceed the amount of available products.

Live surround sound music can be amazing. I went to Berlin and mixed a gig by the experimental Electronic band ‘Warren Suicide’. Instruments and vocals flying around the room in surround sound mayhem. It was great, and opened my eyes to what I hope is ‘the future’ for certain styles of music.

Dance music is an area I really hope starts to explore surround sound. The drum/synth based repetition is perfect fodder to trigger a quantum leap in 5.1 music production. All the technology is now available to present surround sound mixes in smaller clubs or ’surround rooms’ in larger clubs.

I have to quickly point out that the 1 in 5.1 stands for sub-woofer (a dedicated speaker designed to carry just low frequencies). This on its own is a major step forward for dance music fans.

DJ producers in particular can take control of the ‘low end’ of their tracks and shake the furniture more than ever before. Because one doesn’t have to squeeze all that low end into the same speakers as everything else it allows for a more overall dynamic mix.

Music mixed in 5.1 surround sound gives us the opportunity to produce and listen to music in a completely new way.

Both as a composer and as a engineer, I personally feel liberated, set free from the confines of stereo. In this case more really is better. The extra speakers/channels give you more ‘room’ to put your music.

My hope is for ‘audio only’ surround sound music to take off. Music is, after all, the world of the invisible – it seems a shame to connect it at the hip to pictures. Your mind processes visual images first, then sound. So pictures can distract people who might listen more carefully without them.

There is room for both music videos and surround sound music without the videos.

‘What kind of gear do you need to start mixing in surround sound?’:

a) A reasonably fast computer

b) Music software package that supports 5.1 mixing (Logic Audio, Pro-Tools etc.)

c) Minimum 8 channel audio interface (Motu, Digidesign )

d) Five matched self powered speakers, and a sub-woofer

Mixing In Surround Sound:

When I first started mixing something in surround sound, I went out and purchased three sets of Sony Mega Bass self powered computer speakers. After connecting them directly to my audio interface outputs, I then assigned the surround sound out-puts in Logic Audio. I opened a song I was working on and spread the instruments out around the channels and hit play… Wow! The five mini speakers sounded great. Mixing in a tiny bit of subs from my Genelec sub-woofer, it sounded even better.

I know… I can hear engineers crying out.. ‘But what about…?’ Well, it’s unconventional but as a starting point this system does work. Now I own a full set of Genelecs, but I still use this approach.

The normal way to mix in surround sound is to have a matched system where the sub-woofer is driven from the speakers. A roll-off decides that everything below a certain frequency is sent on to the sub-woofer. I favour rooting the signal directly to the sub-woofer from a send on either my main out-put fadder’s or occasionally individual instrument fadder’s. This way I can choose which instruments to place in the sub-woofer and which not to.

I say to music mixers; ‘Approach the surround mix with a fresh concept, understanding that it can reflect a different side of the song/composition.’

I don’t recommend the approach of mixing both the stereo and surround mixes at the same time. It seems that one or the other will be compromised. You’re still ‘thinking in stereo’.

The effects needed and levels will be different in a surround mix. I find I use less processing overall especially compression, again it comes down to having more space to place the instruments.

So start fresh without any of your stereo effects haunting you. It’s one of those things that will save you time in the end, plus you will probably mix more creatively.

After a little guess work and experimentation I managed to figure out the right level to print my mixes. Again the sub-woofer channel was tricky, but after burning a few trial DVDs trying different levels I got the hang of it.

I played some mixes I had done in my studio at Real World and Metropolis Studios and they sounded right. It shows you can produce your own surround sound music at a reasonable cost, even in a project studio.

There are hours worth of surround sound production tutorials available from all the major music software companies. Just visit your software makers web site to get started.

Of course the absolutely best way to mix music in surround sound is to go to a top recording studio. If you’re just starting out with surround sound, mix a track with the guidance of a highly trained professional engineer, who has experience with surround sound mixing.

There are great audio engineers who would (for a smallish fee) come to your project studio and ‘consult’ with you on the technical elements of your mix.

If you are producing a DVD for commercial release, it’s still best to get your project professionally mastered. Any decent music mastering facility can (to a point) rebalance your surround mix, so if you are a little heavy or light on the subs they can deal with it then.

Tips on ways to create your own visual content:

The quality you want to achieve is normally connected to the expectations of your audience.

With enough time and energy you can make videos using a consumer DV camera and Final Cut Pro (or PC equivalent). DV cameras are generally just not quite good enough for any ’serious filming’, but if used creatively for certain situations it’s possible to pull it off. HD camera’s are much higher quality but still do cost a lot more to buy.

Live concerts and gigs can work well though. If you are doing a gig, ask around all the people you know and see how many DV cameras you could borrow. If you have four cameras set up around the club, one camera to roam around and some decent lighting on stage, you’re in business. Make sure the people operating the fixed cameras don’t mess around during the filming. No zooming and out or trying to track the movements on stage. Perfectly still videos are much better to edit. Then in your film editing software, you can cut between different angles and add zooms, even simulate camera movement.

There’s no guarantee, but if the actual performance is strong enough, some of the production values will be overlooked.

Done well enough, you can produce a DVD using still images, like a slide show – again a good film editing program allows you to animate still photos way beyond what one might think is possible.

There are some fantastic animation programs like Bryce 3D, and Cinema 4D that are worth looking into. Start producing convincing 3D text an logos.

Warren Suicide are a great ad-sample of a band who are embracing the audio – visual age. Their DVD was produced by them, and although they worked really hard on it, the finished DVD was not expensive to make, but is just as imaginative and entertaining as any big budget music DVD I’ve seen.

How do I get my mix on to a DVD?:

There are, as you can imagine, quite a few ways available.

The huge majority of DVD players in circulation use the DVD video format. So I recommend choosing Dolby 5.1 or DTS encoding, don’t worry too much about all the others. DTS sounds just as good to me, but I found more options were available with Dolby 5.1.

All you really need is Final Cut Pro and DVD studio Pro or the PC equivalents. DVD Studio Pro comes with a audio compression program called Apac. Apac allows you to compress your six channel mix into a single 5.1 file, ready to place on a DVD.

These programs are not cheap, but they are worth every penny if you’re considering commercially releasing your DVD. Between them you can edit and effect your video footage/audio content, add text, export the outcome in a format which is ready to be authored and finally burned on to a DVD. WOW! All in you back room – not bad.

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