Is 224kbps(VBR) MP3 good enough for iPhone/iPod?
224 kbit/s is not VBR, it's CBR. VBR varies the frame size to provide the most appropriate "bit rate" for the music it is encoding, taking into account the complexity of the music. A single VBR setting can give you one file that averages 120 kbit/s, while the next file might average 250 kbit/s.
Even when you resolve that (i.e. do you want CBR or VBR), your question still makes no sense. What is important is whether or not you can tell the difference between the original file and the compressed version when listening, and that doesn't just depend on your ears, but on the environment you intend to listen to the music in. The iPod/iPhone is just a storage location for the data, and hardly relevant at all to the question - you could be using it while jogging, or on public transport, or connected to your car stereo, or in a docking station, or connected to your home system, each of which has different characteristics and different background noise.
A quick read of the board will reveal that this sort of question is asked and answered regularly.......
I would suggest you look at last years 96kbps AAC listening test. Tis involved codec killer samples and even with that, that samples were hard to pick out.
Space is often at a premium on phones an the quality of these highly compressed files ere remarkable.
I agree with Ouroboros, in that a lot depends on how you will be using it. for example, I recently purchased a car with an mp3 player and an ipod imput through the line-out/earphone jack of the ipod.
After listing to the music on the ipos, i switched to some mp3 cd i had burnt, for use when I didn't have the ipod. You would need to be deaf not to be able to tell the difference between the two. I need to find out if I can hookup the ipod through the main flat jack to see if it is the ipod that is bad, or just the one output channel.
In this case, it would not matter much what you recorded at on the ipod