Why Do MP3's always sound quiet when compared to a normal CD?

When compressed, MP3's lose on a lot of (so called non-essential) information. Result?  Low Dynamic Range!

So how comes some people say that MP3 is almost as good as CD when infact it sounds nowhere as good then?

75% people (an optimistic number) can't tell a difference between
the sound of an average quality CD player and an 128 kbps MP3 (ripped
and encoded professionally). For the rest, there is always a
difference. Here is an experiment for you to do.

1) Take a good musical album audio CD (Yanni live in Acropolis comes to mind)
2) Rip Track04 to .wav (PCM)
3) Convert this to 128 kbps CBR MP3 (keep the wave file intact)
4) Now convert again to 256 - 320 kbps High quality VBR MP3
5) Now queue all the track to your player and listen to the same
sections of the track carefully, specially sections where the music
rises or falls or single instruments are playing

You will definitely hear the difference!

If, like I have for over 40 years, you have been really listening to music, as opposed to hearing it in the background, as most people seem to do these days, while running/ironing/cycling/driving and god knows what else, then you can hear that MP3 is utter rubbish and Apple's so-called 'lossless' is, in fact, lifeless, and even a well recorded WAV file sounds different to a CD on a decent CD deck. But how many MP3 listeners will ever even hear a decent hifi any more? I believe they will eventually lose what slight interest they have in music, and the whole MP3 thing is killing the future of recorded music. If you really enjoy music as something more than background, try making A-B comparisons for yourself. The difference is startling when you do. Already you can hear that
"MP3's always sound quiet when compared to a normal CD"
Why? - because there's only one tenth of the info which we call 'music' actually there! If you dilute a fruit juice by ten volumes of water, you will think it pretty thin and lifeless, won't you?
No rocket science. In fact, when i was 11 and listening to 78's on a windup gramophone with steel needles, I heard more real music than I hear on an MP3. So it's not just a question of bandwidth, then.

Have always found MP3 lifeless - it's a shame as it's such a convenient format for music. MP3 files work the same as a JPG image file and as suggested above, each time you perform an action upon it like editing/converting/truncating it loses information as it is saved/recompressed. There is no such thing as lossless - big file file in, small file out - do the math. Live recordings often highlight the mediocrity of the format.

This was exactly my point in starting this thread, I thought it was only me not getting the whole MP3 thing as I find it missing soo much compared to CD or Vinyl and fail to get why people want to put all there music onto a pc to beam around the house when it sounds so rubbish? Sure I get the personal MP3 player as this is a fantastic way to have a great choice of music when on the move, but why listen to a inferiour sound when at home?

I quite agree about why anyone would want to listen to MP3's over "proper" CD sound.

However, I have bought myself a Media Server, which I am going to couple to the Onkyo 905 (when it arrives) so that I can listen to all my CD's around the house. I have recorded all my CD's in WMA Lossless for this purpose.

The reason that I made this decision is that I have just spent a lot of money on getting a full cinema surround system as well as the new Toshiba EP35 (when it arrives) in the last couple of months. My project for next year will be to get a good standalone CD player and (probably) a pair of Monopulse speakers (most girlfriend friendly). Just cannot afford it at the moment.

Having a Media Server also means that you can set up playlists for parties etc that pick from your entire CD collection rather than having the usual stack of CD's next to the player that then get destroyed by booze and stilletos (!)

But how can they refer to these compression systems a LOSSLESS when there is quite clearly a loss in the sound quality?

That is a question for the experts and not for me....

Microsoft blurb...

Windows Media Audio 9 Lossless
The audio quality of content that is compressed using this codec is the best of all Windows Media Audio codecs. It creates a bit-for-bit duplicate of the original audio file so that no data is lost, which makes it ideal for archiving content masters.

Depending on the complexity of the original, content will be compressed at a 2:1 or 3:1 ratio. Although this is lower than the ratio achieved with other Windows Media Audio 9 Series codecs, it provides the same benefits of compression while leaving the data intact.

Like Windows Media Audio 9 Professional, the Windows Media Audio 9 Lossless codec also offers dynamic range control using the maximum and average audio amplitudes that are calculated during the encoding process. Using the Quiet Mode feature in Windows Media Player 9 and later, users can hear the full dynamic range, a medium difference range up to 12 dB above the average, or a little difference range up to 6 dB above the average.

Of course! *DING* lightbulbs over my head!

I've always wondered why when I listed to an MP3, the volume appears to fluctuate. I thought it was my sound card being weird... It never occured to me that MP3 compression (make smaller) would also employ audio compression (making everything the same volume) before the comrpession stage to acheive high accuracy. That explains a lot!

This effect is also something I had not noticed until I got my current system, up from Mercury M3's driven by an 8000A (1st rev), see sig.

I have a personal vendetta against audio compression (making same volume) because it is the reason that a lot of SACD's don't sound as good as they could. Some people seem to think HD audio is good because it can do surround when in fact that is the least important part of it! You can't take recording X used on a CD and bung it on an SACD and expect more quality.

As for MP3 compression, I use Adobe Audition to compress mine, gives you lots of options. I always go for the highest quality VBR and .. more importantly, disable joint stereo and mid/intensity stereo, forcing it to encode the two channels separately. Intesity stereo really destroys your stereo image but joint stereo isn't so bad. Info here

 I can hear a startling difference between mp3's and cd's, especially when played on a decent set. Ever since I bought some decent headphones, most mp3 files are unlistenable. Most of the listening I do is sadly mp3, but that's because of the convenience of the format, it's small I can fit my entire cd collection on my mp3 player. I'm on the move alot, and music makes my commuting alot more worth wile.

Whenever I'm at home though, I always listen to cd's, also when I'm behind my computer. Mp3's are great in use, but I refuse to buy music online, mainly because of the rubbish quality and the DRM. I still buy a lot of cd's, probably more than I should, and I always make rips of my own cd's, always in EAC with LAME code. The settings I usually use are V0 or V2. It sounds pretty good, but still doesn;t really come close to cd's.