Tuned In To Music

Reflections from a lifetime

Why MP3s (& MP4s) suck

In 2005 I bought Laura, my wife, an iPod for Christmas.  She loaded up a bunch of tunes, put it on shuffle play, and fell in love.  Shuffle play would be very nice to have on our main sound system and Apple said you can have “CD quality sound” if you connect your iPod up to your main sound system using their dock.  Sounded good to me.  I hooked Laura’s iPod up to our sound system according to the Apple instructions to give it a test run.  I was fully prepared for the sound quality from the iPod to be less than the CD no matter what Apple said about “CD quality sound” but I thought we’d be using the iPod for shuffle play when we were busy doing things around the house and sound quality wouldn’t be so important.  When we wanted to listen, we’d use the CD player.  We picked a song that she had ripped to the iPod at random, cued up the CD the song had been ripped from in the CD player, and got ready to compare the two.  First I played about 30 seconds of the CD to have a reference, stopped it, and then played the same song on the iPod.  It literally hadn’t played 10 seconds before we both knew we wouldn’t pay 20 cents for sound that bad let alone the $200 or whatever it was that iPod’s cost at the time.  “CD quality sound”?  Not even remotely close. I like music.  A lot.  I’d go out of my way to avoid having to listen to music that sounded this bad.

I hadn’t payed much attention to MP3 technology because I hadn’t had any interest in downloading music from the net.  I thought the awful sound might be due to something we were doing wrong based on not knowing about the tech so I started to learn about it.  Took about 5 minutes to see what the problem is.  With MP3 and MP4 compression you’re throwing away most of the information present on the CD; it’s not surprising that what you have left sounds terrible.

Music is sound and sound propagates as a wave that is continuous in time.  Digital recording technology is not continuous in time, it records information in discreet bits.  When music is digitally recorded the continuous sound wave is sampled many times each second.  In other words, very brief snapshots of the sound wave are taken very quickly and then these short sound samples are strung together at playback so that it sounds to the listener like you have one continuous sound.  Because the bits of sound that fall in between each of the samples is lost, the digital recording has less information in it than the original sound wave.  This is why a digital recording never sounds just like a live instrument or voice.  The more samples you take each second, the more of the original sound wave you capture and the better the music sounds (assuming each of the samples is the same size).  The number of samples taken per second is called the bitrate and it is usually measured in kilobits per second abbreviated as kb/s.

MP3 and MP4 are compression formats that are designed to shrink the size of digitized files so that they take up less space when stored and less bandwidth when moved.  They are called “lossy” compression formats because information that was present in the orignal file is thrown away or lost when the file is compressed.  The designers of lossy compression formats for music claim that some of the info that is thrown away is “inaudible, or less audible to human hearing”.  Maybe it is, maybe it isn’t.  And what, exactly, does “less audible” mean?  Lots of room for marketing bullshit like “CD quality sound” there.

The question you want to ask is, how much info are they throwing away?  The bitrate for standard recording on a CD is 1411.2 kb/s.  MP3 and MP4 allow for variable bitrates with the trade off being smaller files but lower quality with lower bitrates and higher sound quality but larger files with higher bitrates.  The minimum “it’s good enough” bitrate (in other words, the crappiest sound quality they think people will pay money to hear) that has become something like an online standard is 128 kb/s.  This is the bitrate iTunes uses, for example.  Now compare the amount of info on the CD and the amount of info on the MP3 or 4 file ripped from the CD; 1411.2 kb/s of info on the CD and 128 kb/s left in the MP file.  An MP3 or 4 file has only kept a wee bit over 9% of the info that is on the CD.  In other words, a wee bit less than 91% of the musical info on the CD is thrown away when it is compressed into MP3 or MP4 format. 

91% of the info is lost!?  Are you kidding?  Nope.  If you threw away 91% of a two hour movie, you’d be left with an 11 minute film.  How good would your favorite movie be if all of it except for 11 minutes was cut?  For a lot of films you’d still be watching the opening credits when the movie ended.  If you threw away 91% of an hour long TV show, all you’d have left would be commercials – and you wouldn’t even have half of those.    How happy would you be if 9 out of every 10 songs on your iPod were deleted?  How well would your head do if your body was cut off and thrown away?  The question shouldn’t be why does it sound so bad, it should be why does it sound like anything at all.

The problem here is related to bandwidth, in both senses of the term.  “Bandwith” traditionally refers to a range of frequencies such as the range of audio frequencies, or the bandwidth, that humans can hear.  When MP3s and 4s eliminate info from the original CD source they probably shrink this bandwidth by cutting off the top and bottom ends of the human auditory bandwidth – they cut off the high treble and the low bass.  In order to achive a 91% reduction they must also eliminate a lot of info from within the bandwidth they keep.  By cutting way back on the richness of the info present in the bandwidth they retain, all of which is info people make use of when listening to music, MP3s and 4s are severely compromising the quality of the music as originally recorded. 

This drastic reduction of info within the bandwidth of human hearing that results in such a marked decrease in sound quality is carried out in order to save “bandwidth” in the “data transfer rate” sense of the term.  Internet connections, fast as some of them currently are, cannot move the enormous amount of data recorded at a 1411.2 kb/s bitrate at speeds that will make consumers happy and encourage them to download music from the net.  They also take up a lot more storage space on the hardrives of playback devices like iPods.  Would you have been willing to pay whatever you did for your iPod if it only held one tenth as many songs? 

The multinational companies marketing the hardware you buy to listen to music in MP3 and 4 formats tell you that the sound they produce is indistinguishable from the sound present on a CD of the same music. “CD quality sound!”  They tell you panels of experts say so.  If you believe this, I have a beautiful parcel of land in sunny Florida you’d surely been interested in buying.  Another approach they take is to tell you that, yes, CDs will sound better than MP3s and 4s but only if you have a really expensive “audiophile” sound system that is well beyond the means of most people.  The people who make cheap, crappy electronic equipment that can be mass-produced in low-wage factories outside the US and sold for enormous profits at Best Buy would love it if you believe this.  You’re going to have to have better sound reproduction equipment than an iPod or a $250 stereo-in-a-box to hear the difference between a CD and an MP3, but not that much better.  Another way to look at it is this:  The difference between an MP3 or 4 and the same music on a CD is huge.  If your sound reproduction gear doesn’t let you hear it, you’ve got shitty gear.  Most CDs sound infinitely better on a decent entry level sound system.  Just because you can’t hear that it’s there doesn’t mean you’re not missing it.

Discussion of other issues with limitations in sound quality of music heard in compressed formats can be found in the post The (Deteriorating) Sound of Music.

02/06/2007 - Posted by | music, music tech, Music technology, Opinion


  1. Did you even listen to any of the better encoded MP3 options available before you wrote this diatribe? So you’ve arrived at some basic understanding of how lossy compression works and you’ve decided to damn the entire format just because you realized that 128 kb/s encoded mp3s do not sound as good as a CD? Listen to an mp3 encoded with lame at 320 kb/s, or even one encoded with a variable bit rate and 160 kb/s minimum and make the same sweeping generalizations about the format. Or better yet, show me that FLAC is inferior because it’s “thrown out” 30-40 percent of the music.

    Comment by lossless | 07/30/2007 | Reply

  2. Kmurnane is correct: lossy compressed music files do sound worse than CDs – no matter the bitrate. If you don’t hear the difference you are probably hearing impaired. There actually are lossy formats that come close to CDs (e.g., ogg) but close is not the same. FLAC is not a lossy format like Mr lossless implies on July 30 2007 but it is LOSSLESS, meaning you don’t throw out any valuable data – you just arrange the bits in a more efficient way.
    Anyone telling different is not involved in music – rather some tech head who “knows” it must be so, but never even listened to recorded music on even a half decent rig (no, your Best Buy computer speakers don’t begin to cover that!).

    Comment by He is correct | 10/30/2008 | Reply

  3. I don’t have a computer at home and am a vinyl listener so I can’t really comment on mp3 as I am definitely biased.Of the few examples I have heard some of them sound appalling, like an old wireless radio from the 1930’s or a telephone receiver.
    However it appears to be the direction music is heading in. I have read that at 360kbps you can get dolby digital (what they have on dvd) which is pretty good(though some stuff comes out a bit squeaky.) Can anyone tell me more on this?

    Comment by Corporal Clegg | 12/16/2008 | Reply

  4. I am totally with ‘lossless’ on this one. Any MP3 at 256 kb/s (especially 320) is almost indistinguishable from a lossless format such a WAV (found on CDs). FLAC, AIFF or M4A (Apple Lossless) files are completely lossless, and are 60% of the size of a WAV file. “Throwing out 40% of the song”?! That’s not accurate in the least.
    The MP3 format has a lot against it because of people who don’t care about sound quality. 128 kb/s does sound very bad. That’s less than half of a good quality MP3 (320 kb/s). Some people don’t care about quality, but just because MP3s give you the option of lesser quality doesn’t mean you need to write off the whole format. Less than 1% of the world can tell the difference between an MP3 ripped at 320 and the CD, or a FLAC file, that apparently lost 2/5s of the song!
    Also, the 1411.2 kb/s bitrate of WAV is useless, and basically wasted space. It’s like adding 1000 spaces to the end of a text document – it may be bigger, and you can say it’s 1500 characters instead of 500, but you’ve still only got 500 characters of content. No human ear can tell 1500 kb/s from 500 kb/s. It’s impossible.
    Find a good quality OGG, MP3 or AAC track. All encoded to a compressed format, all near indistinguishable from the CD, in good quality.

    Comment by Evan | 05/12/2009 | Reply

  5. Hi there,

    I just found this thread while looking for something else, so I’m gona drop my 2 cents here, since I’ve been deeply involved with this question a while ago.

    As a musician and studio engineer, I’ve many times seen this issue came up from costumers (other musicians), specially while we was setting up the standards for digital recording medias at the old studio. We’ve ran several tests by the time using high quality speakers/headphones and acoustic rooms, and using several people to evaluate the results. Basically, we’ve noticed the human ear cannot distinguish between even a 128kbps and cda/wav. And we’re not simply talking about people that “likes” music here, we’re talking about musicians and people that breath and live music. Just to play safe, we’ve decided to save all data as 256kbps, and never looked back since then. Also, ironically, depending of the age, the same record the poster used to compare was very probably recorded itself at 256/512 kbps, and just converted to 1400 in the mastering process. So it’s basically a comparision of a 256kbps with a 256kbps, simply stored at different medias.

    The 1400kbps in cda/wav is actually not a matter of quality, but technical aspects of the media and data storage apporach. It’s not like you are missing anything by lowering the bitrate by less than half of it, its just a matter of what the human ear can catch. Also, music is not science or math, so regardless these numbers are a fact, it doesn’t necessarely means that a higher bitrate over a certain level will also imply more quality. It’s really a waste of space.

    So I’d say the last reply by Evan is the ONLY right answer here. Anything else is, sadly, just a reflex of the huge effort many record labels and iPod manufacturers do to protect their personal interests, which are pushing costumers to buy the original CD (inhibit piracy), or simply to buy iPods with more storage space.

    The poster said that he/she could tell the difference in 10 seconds? It’s almost funny 🙂
    More likely he/she had a bad cable connection, or a bad input connector, etc. If a person with really good ears is comparing (impartially) a wav/cda to a 128kbps mp3, theres no way the difference can be told.

    I’m sure most probably remember that this very same issue and arguments came up when CD itself came out. Many people resisted and kept saying for ages that vinyl quality was better, but thats probably just they way things are. Most people are simply resistent to changes in the medias they are used and attached to, and sometimes it takes a bit of effort to realize that a change is not always a bad thing. Keeping the mind open and receptive to all the good stuff technology allows us to do these days is a very wise thing to do.

    Comment by aka | 08/05/2009 | Reply

  6. For me, there is quite a big difference between the sound of a CDR burnt with songs in 192kbps-320 kbps and a store bought CD. After burning cds for years and recently going back to store bought CDs, for me, there is a quite a noticeable difference. I usually listen on a Denon or Teac micro hi fi system with decent speakers. Of course if you’re listening to crappy PC speakers all this is irrelevant anyway.

    Comment by Hmm | 12/13/2009 | Reply

  7. I just wanted to comment on what “aka” has said, claiming to be speaking for music engineers:

    “we’ve noticed the human ear cannot distinguish between even a 128kbps and cda/wav”

    This is ridiculous. I do believe most people may not be able to tell and wouldn’t care about the difference if they could, but there are some great blind tests on the web and me, personally, I’ve always passed them. If you’re dealing with genres like classical and jazz, where more attention is paid to the tone and texture of a variety of sounds, it is fairly easy to distinguish between a heavily compressed lossy file and a lossless recording.

    Later, you seem to be saying that in your capacity as a music engineer, you save the music at 256 kbps lossy and master from there – there are many ugly trends in music mastering these days, but if you’re doing this, your operation is an anomaly. That’s lousy for folks who would want to rip the music (thereby putting it through lossy encoding a second time, which almost always results in artifacts) and people who assume that they’re getting a good quality mastering job and putting it into a decent sound system.

    Comment by Smack | 12/09/2010 | Reply

  8. Reply to AKA- Are you a professional music engineer. If so I can’t imagine your clients would be happy with your work, if you can’t tell the difference between an mp3 and a full audio wav file. I too am a professional engineer and I can certainly tell the difference. For one with low quality mp3’s there is a very distinct flanging effect caused by over-compression, which can be heard when listening in a quiet room. It’s easy to understand how the average consumer is content with listening to mp3’s as they are convenient and I would imagine most people listen to music while on the go and use it as “background” noise. However, if you are an engineer and you spend your money making sure you have quality equipment such as high end studio monitoring headphones, rather than a pair of apple earbuds the difference should stand out clearly. I’m really not trying to put you down aka, but If you literally can’t tell the difference between an mp3 and a 1411 kbps recording, you may have some hearing damage in the higher frequency range. On a side note, earbuds cause major hearing damage be careful with those things.

    Comment by michaeljvandyck@gmail.com | 02/08/2011 | Reply

  9. For years, I couldn’t hear the difference in MP3 and CD-quality sound. But, once you begin to notice the shrill artifacts produced by a lossy format, you can’t un-hear them. Now, I can always tell an MP3 from lossless audio. Don’t get me wrong, MP3s are great for portability, but for listening on a decent home system, they are utter garbage. I’ll stick with my CDs.

    Comment by MusicLover | 04/20/2011 | Reply

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