CD vs MP3 [Archive] - Audio & Video Forums

PDA

View Full Version : CD vs MP3



Mayonnaise
03-14-2006, 07:23 AM
I know this question has probably come up a hundred times, but I'm trying to get very specific here. (I beg your indulgence)

Let's say I want to listen to Dark Side Of The Moon, which I have on CD and my iPod, why exactly would I choose the CD version over the iPod?

What wouldn't I hear if I played the iPod?

If I'm painting the family room and listening to music, am I really going to hear the difference?

Stone
03-14-2006, 07:42 AM
If I'm painting the family room and listening to music, am I really going to hear the difference?

No.

I'll let someone who has more time answer your other question as to the difference in sound quality between an MP3 and a CD.

teledynepost
03-14-2006, 07:52 AM
If you're not paying attention or in the other room, you probably won't notice unless it's 128k or less.

-Jar-
03-14-2006, 07:53 AM
I know this question has probably come up a hundred times, but I'm trying to get very specific here. (I beg your indulgence)

Let's say I want to listen to Dark Side Of The Moon, which I have on CD and my iPod, why exactly would I choose the CD version over the iPod?

What wouldn't I hear if I played the iPod?

If I'm painting the family room and listening to music, am I really going to hear the difference?

Before anyone can begin to answer your question, they'll probably ask you a dozen other questions in response..

1. What are you listening on? Headphones? Speakers? Depending on how you listen you may or may not hear a difference.

2. How sensitive are your ears? Have you ever noticed a difference between CD and MP3 before? Only you can really answer that question. If it sounds ok to you on your iPod, then that's what matters.

3. What rate are you ripping your MP3s? Everyone has their own threshhold at which they can hear a difference. For me, I can tell I'm listening to an MP3 with anything under 192 Kbits/Sec. For somepeople, they swear that 128 kbits/sec is "Cd quality" (to which most of us around here laugh). If you're unsure, use a higher setting. I use 160 kbits/sec for most of my stuff, just because I know I'll normally be listening to it on cheaper headphones/computer speakers. I use a higher setting for more audiophile quality stuff. Though, generally, I don't rip many MP3/WMA's.

4. How does it sound to YOU. That's the important thing. Don't go by what other poeple think you should be hearing, if you enjoy it, then that's what matters. Some people derive the same pleasure from an $50 Discman and ear buds that someone else derives from their $5000 Conrad Johnson tube amps.

5. Sit down and do some comparison listening for yourself. It might not be perfect, but it's a start. There are lots of resources on the web for learning to be a better listener. The problem is, everyone hears differently, so it's really difficult to generalize what one "should" hear when listening to DSOTM. Again, a lot of it depends on your equipment as much as the source software.

Just some things to think about :)

-jar

BarryL
03-14-2006, 08:04 AM
If I'm painting the family room and listening to music, am I really going to hear the difference?

I can't give you the technical specifications, but I'm sure you'll get them from someone before the day is out.

If you really want to LISTEN to the music, as an active activity in itself, then you will likely notice the difference compared to listening to the CD on excellent sound reproduction equipment. And that's the key.

For me, listening to my iPod on the car on subway, with lots of ambient noise, it makes no difference.

But for some things, like listening to the recent Pat Metheny Group CD This Way Up on my iPod recorded at 192bps, I cringe. You just don't get the full spectrum of sound, and on top of it, the sound is distorted. But when I play that, I want to listen to it. I need to go back and re-rip it as a .wav file to my iPod.

There's other stuff that also is distorted on my iPod as MP3, but it doesn't matter to me.

So, if you don't really get a buzz out of active listening, but instead like to hear the music and the songs, then MP3s ripped at high bit rates are good enough. Most people don't hear the difference, and most don't care. They want to hear the music and enjoy it, not listen carefully to it in all its aural glory.

Jim Clark
03-14-2006, 08:18 AM
What wouldn't I hear if I played the iPod?

If I'm painting the family room and listening to music, am I really going to hear the difference?

http://www.msu.edu/~buckeled/spectrum.htm

this is a spectrum analysis of a wav form under several different compression schemes. As you can see, using Shorten or .shn the compression is lossless. Once MP3 conversion begins you can see the frequencies that you will no longer hear. Clearly the higher the compression, the greater the loss of frequencies over a wider area. There is music that is being lost and as is demonstrated, it can be pretty significant.

As to whether or not you'll be able to hear it under the circumstances you describe, only you can make that call. The better and easier question is probably whether or not you'll care.

Regards,
jc

Mayonnaise
03-14-2006, 09:35 AM
your answers give me a lot to think about and I thank you. I rip my cds at 128. With my new speakers I've been getting a jones for DVD audio versions of some of my favorites. Like Back In Black, which is playing now.

It's funny, even if I can't hear the difference, I get a charge out of knowing it sounds better.

3-LockBox
03-14-2006, 02:12 PM
Each different bit-rate represents a different compression ratio; 128kbps is about a 10-1 ratio. That means for every 1 bit of information retained to represent a musical note, 10 bits are discarded. The higher the bit-rate, the fewer the bits are discarded and the more bits retained, and thus the more accurate the music program. Now a lot of the bits that the MP3 compression scheme is throwing out are superfilous to the music, such as ambient noise, master tape hiss, and things outside of our hearing range. However, when you use lower bit-rates, you will affect the natural timbre of most acoustic instruments, and even some analog electronic instruments as well. There's no way not to affect them. What happens is in the process of removing bits to accomodate lower bit-rates, you begin to affect the attack and decay elements of instruments and keyboards. The MP3 scheme is only smart enough to give you a representation of the music program, but not its nuances (If you happen to have an old Casio keyboard laying around, check out the attack and decay functions. if you shorten both the attack and decay of a note, then you'll see what I mean - it sounds too abrupt).

If we're talking about a piece of music you're very familiar with, then you probably will hear a difference when you're scrutinizing, but from another room...maybe...periodically. But no different than if you went from your main rig to a little boombox. For casual listening, anything 192k and over should suffice.

FWIW, I have listened to a variety of different bit rates, and I'd have to say that it depends on the type of music you're listening to as to whether or not you can tell the difference twix a CD and whatever bit-rate. I have a hard telling the bit-rates apart when I'm listening to hiphop or dance tracks at anything twix 128k and 256k. Even some metalcore seems unaffected below 192k. But a lot of my prog and jazz is just anemic at anything lower than 256k. Myself, I prefer 320kbps for downloading or ripping. There are a few MP3 sites that offer 256k and above for downloading, but its usually more expensive and takes much more time to download, not to mention space available. But I can still hear a difference twix CD and 320kbps on certain musical passages, but its usually very subtle. On rare occasion, I've heard things that were obvious, but like I said, its rare.

A lot of people are more interested on maximizing space on their players and could care less about sound quality. I know a guy who came up to me (as if he were about to lay a revellation on me) and asked if I knew that "you could rip and download songs at 64k? You could have over 500 songs on a 1Gig player!" (yipee!). So it'll depend on your priority - sound quality or memory space.

Mayonnaise
03-14-2006, 10:13 PM
That was great, simply great. Right on.