I’ve had only a few minutes one day with a 598, so I can’t say exactly. But since the HP100 is closed and the 598 is open, I would get the 598, as long as open back is OK for you. I don’t think you can go wrong with the 598 in any case – it’s a very good headphone. Watch carefully for any cracks to develop though, since there were many reports of that.
While iPhone users can expect that their phones are missing essential parts to look good, AAC is one of those codecs that maybe cut a few too many bits out of its data transmission. By using an aggressive psychoacoustic model of compression, AAC seeks to cut data where you wouldn’t normally be able to hear it anyway—but it gets a little too aggressive at times.
Marketed claims such as 'frequency response 4 Hz to 20 kHz' are usually overstatements; the product's response at frequencies lower than 20 Hz is typically very small. Headphones are also useful for video games that use 3D positional audio processing algorithms, as they allow players to better judge the position of an off-screen sound source (such as the footsteps of an opponent or their gunfire).
Smaller earbud type earpieces, which plugged into the user's ear canal, were first developed for hearing aids. They became widely used with transistor radios, which commercially appeared in 1954 with the introduction of the Regency TR-1. The most popular audio device in history, the transistor radio changed listening habits, allowing people to listen to radio anywhere. The earbud uses either a moving iron driver or a piezoelectric crystal to produce sound. The 3.5 mm radio and phone connector, which is the most commonly used in portable application today, has been used at least since the Sony EFM-117J transistor radio, which was released in 1964. Its popularity was reinforced with its use on the Walkman portable tape player in 1979.
Although modern headphones have been particularly widely sold and used for listening to stereo recordings since the release of the Walkman, there is subjective debate regarding the nature of their reproduction of stereo sound. Stereo recordings represent the position of horizontal depth cues (stereo separation) via volume and phase differences of the sound in question between the two channels. When the sounds from two speakers mix, they create the phase difference the brain uses to locate direction. Through most headphones, because the right and left channels do not combine in this manner, the illusion of the phantom center can be perceived as lost. Hard panned sounds are also heard only in one ear rather than from one side.
Although some headphones available are wired, many more are available that are wireless, and use Bluetooth to enable your music to be heard, even if the stereo or other device is several feet or even a few rooms away. Wired headphones deliver superior sound quality to wireless and Bluetooth because there's no chance of picking up interference from other devices, which sometimes happens with wireless headphones. In addition, wired headphones have no batteries to power them, so there's no chance of interruption should the batteries wear out.