In the ear of the CX 300 shields from very. Outside noise: Barely perceptible. Yes, he's there in the ear and presses - some might deter the one to have a foreign body in the ear - see above! After a few minutes but that is a matter of habit.
The sound: bass-strong, good mids, clear highs - here 5 Stars. This compared to the Koss Sparkplugs (bass-heavy, poor comfort, dull heights even with equalizer in the player) and the Genuine iPod plugs.
A note to the sound: poorly sampled MP3 or AAC, 128er 192er take rate and old songs from the 60s compared to newer productions: no wonder that varies the sound tremendously. In other words, depending on production date, sample rate and player sounds of a song by the same player super - the next plane only mediocre to: bad.
The CX 300 provides in total a good to very good listening experience, is well located and is ideal for jogging.
For cable Quality: thin earphone cord are to stay and it will probably always be, susceptible to breakage. This is nunmal so - gentler handling during storage may help. But who likes his players and good sound will be served quite well with the CX 300. My search has to Kabebruch one end: to be continued.