[kwokwai]

I have purchased an anime music CD from a CD store, and I want to play the disc all the time, so I use a third party software to rip the music.
I don't know which sample rate is better, so I just chose 44100HZ and 48000HZ and so it created two MP3 files for me.

It seems that human ears can't really distinguish which of these two MP3 files has 48000HZ.

I notice that most of the MP3s I brought from the Internet are all
of 44100HZ.
Is it a national standard that all MP3 must be created with sample rate of 44100HZ?

[TheMajor]

Audio CD's are 44.1k, so you won't notice an improvement when ripping at 48k.

[kwokwai]

Originally posted by TheMajor
Audio CD's are 44.1k, so you won't notice an improvement when ripping at 48k.

Gee!!!!!!!! :rolleyes:
I have forgotten about the fact that 44100HZ is the maximum sample rate of audio CD.

Thanks, TheMajor!!!!!!

but then I am curious why it provides 48000HZ for users to choose from?

[TheMajor]

Originally posted by kwokwai
Gee!!!!!!!! :rolleyes:
I have forgotten about the fact that 44100HZ is the maximum sample rate of audio CD.

Thanks, TheMajor!!!!!!

but then I am curious why it provides 48000HZ for users to choose from?

Some formats use higher frequencies. I think DVD audio and SACD are 192k; not sure.

[kwokwai]

Originally posted by TheMajor
Some formats use higher frequencies. I think DVD audio and SACD are 192k; not sure.

Thanks for your reply!!!!!

[Crysalis]

you are correct though that human ears can't determine the difference between the two rates.

[horndude]

there's a theorem that relates to this if your wondering, its taught when your learning digital sampling theory, I learned this in college about 20 years ago

anyway, in order to digitize or sample an analog signal you have to set the sample rate to at least twice the frequency of the signal your sampling.........audio for the human ear tops out at about 20khz give or take, and most audio equipment doesnt even get quite that high normally, not without some attenuation anyway

when the audio cd format was being developed and its standards set they had two issues to deal with, one is sampling the audio at high enough rate and the other was being able to squeeze all that data onto a standard CD, and in order to do that they were stuck using a pretty minimal sampling rate, one that falls right on the minimum needed, hence the 44.1khz or 48khz that you see all the time

[003]

Originally posted by Crysalis
you are correct though that human ears can't determine the difference between the two rates.

Correct. However it IS possible to determine when a 44.1KHz track has been ripped in 48KHz with a poor upsampler. If the originally track is 44.1, you want to keep it 44.1.

[kwokwai]

Hi, everyone!
Another problem I notice is that I can't find bitrates rather than 320KBps, 256KBps, 196KBps and 128KBps in my aduio converter, and so
I get a question here: how do people convert an audio file to a MP3 of 127KBps or other weird KBps bitrates such as 117KBps, 127KBps.

Isn't 320KBps the maximum bitrate supported for MP3 audio files?
Why are some of my MP3s having higher than 320KBps, say 530KBps?

I find MP3 of 128KBps even have better audio quality than a MP3 of 252KBps or 172KBps.
So, I make the conclusion that 128KBps, 196KBps, 256KBps and 320KBps are the standard bitrates of MP3s.

Please comment!

[horndude]

they use variable bitrate encoding instead of fixed rate

some players display the current bitrate as the song plays, you can watch the bitrate change as it goes along when you play a variable bitrate mp3

generally the higher the bitrate the better the quality, and you will notice it more with songs that have lots of bass, a 128kbps rate is low enough that low notes will get distorted sometimes cause the way the codec works it tends to let small frequency changes and slow changing frequencies get attenuated