Friday, August 3, 2007

Buying Guide for MP3 Players

The portable digital entertain­ment market in world is growing by leaps and bounds. In this plethora of products, it's really difficult to decide what is to be bought. Let us see some common guidelines below, but ultimately the most important thing for you to consider is what makes you happy as you listen to your tunes. So, the best thing is - go and physically check at least a few pieces, then considering your budg­et decide finally.

Remember, if the player is too complicated, you will really not feel good to use that. That is where the following guide will help you.

This means the way your digital audio player talks to your computer so that it can transfer music files. Though a few players offer the ability to wirelessly trans­fer files, you try to go for either a USB or a FireWire port. USB is the more commonly found port today. However, it is somewhat slower in regards to how quickly it transfers music from your computer to the player than the FireWire.

The display screen on most digital audio players these days is tiny. Using the screen is a must though if you want to see what music is playing, as well as navigating through options like volume control, song shuffling and the equalizer.

The main things to consider here include making sure you can see the display under all conditions, includ­ing being outdoors when there is a glare, as well as being able to read the characters on the screen without going blind.

File Types Compatibility
When music is copied onto your computer from a CD or downloaded from a Web site, the type of file it is saved as may vary. While it will often default to the .mp3 format, which is the most widely handled by digital audio players today, it could also end up as a .wav, .aac, .wma or some­thing else. The important thing to know from all of this is to check what types of music files your player supports.

How you get your music onto your digital audio player is important to consider. Most players ship today with some type of soft­ware which will allow you to com­pile play lists and copy files.
See the following things: Does the software provide guided instruc­tions, or are you left to struggle with a cumbersome help file? Is the inter­face easy to navigate, or a cluttered mess of buttons and words?

Storage Type
Do you plan on taking your player jogging, or using it as a supplement to your home entertain­ment system? Flash-based models are small and sleek, usually slipping into your pocket with no problem.

Protection of MP3 Players

The very portability of MP3 play­ers enhances the chance of their damage too often. The pock­et-size gadgets are often dropped, scratched, drowned, or exposed to extreme temperatures.
Broken LCD screens - This is very common. This happens because of careless dropping of the gadget or tampering with the handy product.

If your trousers are very tight, and you sit down, it's going to bend your pocket MP3 Player.

It may slip out of your shirt-pocket too.

Protection tips
  1. The most important precaution is to cover your player.
  2. There are clear plastic film cov­ers available that protect against scratches. Crystal Film covers are also good for this purpose.
  3. Screen-protector films are avail­able, which can be cut to fit the screens of various devices to pro­tect scratch.
  4. Protection against drops requires a thicker sheath. Silicone jackets may be used for this.
  5. Ultimate protection comes from a hard case.
  6. A case also protects the device from dust accumulation, which is a very common hazard.
  7. Extreme temperature is another peril. Freezing temperatures, for example, can crack an LCD. Do not take the device near ovens, stoves, heaters or any other hot gadget.
  8. Wrapping the headphone wire tightly around the player can put tension on the headphone socket, causing it to break loose.
  9. Products with solid-state memo­ry can better withstand jolts than hard- drive-based devices. This makes solid-state MP3 players better suited for activities like jogging and exercising.
  10. Handle hard-drive-based players with caution and avoid subjecting them to jerks and shocks.

Hard Drive-based Players

Flash-based players can offer all the comforts of having a portable digital audio player that is rugged and can withstand the roughest of shocks, but it can never offer the capacity of a hard drive-based player. Hard drive (HDD) players can hold your entire music collection, and more. So what is the latest in the HDD-based portable players' scene? Well, a lot, we must say. Let's find out.

Hard Drive-based Players with OLED screen having 262K color depth is now available. However, most of the players still feature the regular LCD screens and some changing lights. Just two-line LCD screen is also found. This, although serves the purpose, view­ing tracks on the player becomes cumbersome since you can only check two track names at a time when scrolling.

In fact the best product supports AAC, MP3, MP3 VBR, Apple Lossless, WAV, AIFF, Audible formats. Most of the players sup­port only MP3, WMA, and in some cases, WAV playback.

Battery Type
Only a few players feature a removable Li-ion battery, which comes bundled with the player. Removable Li-ion battery packs are also available with a few products. Generally all the players come with regular internal Li-Ion batteries.

Most of the players have custom equalizer. A few have a game feature. Some of the sets allow playing video, viewing pho­tos and reading text files. Some players can act as USB hosts, which let you connect specific models of digital cameras directly to the players and transfer images to those. Generally, a pair of earphones with the player comes as a part of the package.

HDD-based portable audio players generally have to be used more carefully than flash-based players. This is because the HDD based players not only cost more, but are also more fragile due to moving parts. However, the newer generations of players are hell bent on proving this wrong.

Flash-based Players

Flash-based audio players are what most people will buy to hop aboard the portable digital audio bandwagon. This is mainly because they cost less than their hard drive (HDD) based compatriots, are lighter and more portable.

There may be an LCD color screen display or an OLED display. OLED displays consume less bat­tery power compared to regular LCD screens.

Today most players sup­port playback of MP3, WMA, WAV and ASF files. While MP3 and WMA support are bare minimum require­ments for players today, it is better to buy a player that supports more file formats. Though MP3 and WMA are more mainstream, other formats, such as OGG and AAC, are rapidly gaining acceptance. Though AAC is a proprietary codec, OGG is not, hence you should look for players that sup­port the OGG format at least.

Battery Type
Most of the players have internal Li-ion batteries. However, some of them may have room for AA batteries. Some other players do not contain any internal battery, and generally opt for an AAA battery solution.

While having an AA battery in the player does increase its weight, it generally provides more battery life when compared to the other types. On the other hand, players with AAA batteries generally look much sleeker and less bulkier.

Battery type is an important deciding factor, since internal bat­teries become weaker as time pass­es. In the long run, external battery solutions seem to be the better option.

Granted that not having a display does increase battery life, but managing or listening to songs on a player that lacks a display can be quite cumbersome. Nowadays, features such as text and image viewing are available on quite a few products. Also, features such as video is also entering Indian market.


Audio Codecs (MP3, WMA, AAC, etc.)
An Audio Codec is a computer pro­gram that compresses or decompress­es digital audio data, so that the file size of the audio data reduces to a fraction of that of the original raw data. There are a variety of Audio Codecs available such as MP3, WMA, AAC, FLAC, etc.

Audio encoding
Audio encoding is the process of analyzing the informa­tion in an audio file and rearranging it in a format that has been predefined by a Codec.

Bit Rate
A bit rate is the amount of information that is transferred per second (bit per second or bps). MP3s are measured in thousands of bits per second (kbps) and the higher the kbps, the higher the sound quality.

Compression ratio
This is the ratio of the file size of the encoded audio file to the file size of the same audio data in raw form.

LAME ain't an mp3 Encoder (LAME) is an open source MP3 encoder engine used in a large number of MP3 soft­ware titles.

Streaming audio allows for on-the-fly listening to an audio file. The audio file is streamed from a serv­er where it is received and stored in your buffer on your computer. If you use WinAmp or RealAudio, you will see a message displayed telling you that the audio file is being buffered. The file is not saved.

Ripping (CD Ripping)
The process of digitally extracting audio from CDs to your hard drive in other format

WOW is a state-of-the-art technology from SRS (Sound Retrieval System) Labs that uses special algo­rithms to improve the quality, dynam­ics, spatial experience and bass tone of digitally compressed audio files. In effect, WOW helps even small speaker systems including PC speakers and television deliver audio with richer bass and an enhanced 3D spatial experience.

Uses of mp3 players

Although MP3 Players are target­ed mainly at digital music enter­tainers, today they have been raised much beyond that. Let us find out what else they can do.

TextAloud is a Windows soft­ware that saves your text to audio files for playback on portable MP3 players. Imagine how much more productive, or just entertained you can be when you power up your downtime with TextAloud!

What can you really do?

  • Listen to eBooks or Online News in the car
  • Review work documents during business travel
  • Study for classes at lunch or dur­ing your commute
  • Get outside...your information can go anywhere
  • Send your favorite music to some­one

Save text as spoken audio
You can save your text as spoken audio MP3 or WMA files to listen while driving, taking a walk, or working around the house.

Be relieved of stress
In this fast moving world where throughout the day people get stressed due to several reasons, who does not seek relief? Well, Mind Tools' downloadable Relaxation MP3s can help you find the calmness and peace you seek.

Send your favorite music to your friend
The mp3 format being a compressed form of audio information uses file space more efficiently than that found on regu­lar digital compact disks. Thus, mp3 technology allows you to reduce the size of the music CDs and then you can send them through Internet.

MP3 Techniques

It may occur to you how does an MP3 file contain so much of data in so less space. To get such reduction of the amount of data, the MP3 format uses a few techniques and tricks. Let us just have an overview of those.

The minimal audition threshold
The minimal audition threshold of the ear is not linear. It is represented, according to the law of Fletcher and Munson, by a curve dug between 2 KHz and 5 KHz. It is not therefore necessary to code sounds situated under this threshold, because they will not be perceived.

The masking effect
This system is based on masking properties of the human ear. When you look at the sun, and if a crow passes by, you do not see it because of the too huge intensity of the light of the sun. In audio also, it is similar. In presence of strong sounds, you do not hear the weakest sounds.

Just to explain with an example, when an organist does not play, you hear the breath (sound) in the piping, and when he plays, you no longer hear it, because it is masked. It is therefore not necessary to code all the sounds. This is the first property used by the MP3 format to get some space. For this the MP3 encoder uses a psycho-acoustic model presenting the behav­ior of the human ear.

The bytes reservoir
Often, some passages of a musical piece cannot be coded to a given rate without altering the musical quality. The MP3 then uses a short reservoir of bytes that acts as a buffer by using capacity from pas­sages that can be coded to an inferi­or rate in the given flow.

The Joint Stereo coding
In the case of a stereophonic signal, the MP3 format can then use a few more tools, referred as Joint Stereo (JS) coding, to further shrink the compressed file size. In many mid-range Hi-fi sets, there is a unique subwoofer. However, you usually do not have the feeling that the sound comes from this boomer, but rather from satellite speakers. Indeed for very low and very high frequencies, the human ear is no longer able to locate the spacial origin of sounds with full accuracy.

The MP3 format can therefore (optionally) revert to such a trick by using what is called Intensity Stereo (IS). Some frequencies are then recorded as a monophonic signal fol­lowed by a few additional informa­tion in order to restore a minimum of spatialisation.

The second joint stereo tool is called Mid/Side (M/S) stereo. When the left and the right chan­nels are quite similar, then a middle (L+R) and a side (L-R) channels are encoded instead of left and right. This allows to reduce the final file size by using less bits for the side channel. During playback, the MP3 decoder will reconstruct the left and right channels.

The Huffman coding
The MP3 also uses the classic tech­nique of the Huffman algorithm. It acts at the end of the compression to code information. Thus, this is not a compression algorithm but a cod­ing method. This coding creates variable length codes on a whole number of bits. Higher probability symbols have shorter codes. Huffman codes have the property to have a unique prefix; they can there­fore be decoded correctly in spite of their variable length. The decoding step is very fast. This kind of coding allows saving (on an average) a bit less than 20% of space.

It is an ideal complement of the perceptual coding. During big poly­phonies, the perceptual coding is very efficient because many sounds are masked or lessened, but little information is identical, so the Huffmann algorithm is very seldom efficient. During "pure" sounds there are few masking effects, but Huffman is then very efficient because digitalized sound contains many repetitive bytes, that will then be replaced by shorter codes.