The Magnum drivers are quite favorable performers. When finished, their sound can rival many of the higher end Grado and Alessandro headphones. Though, I will always encourage one to take time and listen to the upper end Grados, too. They hold their value quite well, so finding a bargain is harder to come by. But, the point I'm getting to is that there are variations in sound signature towards the top, too. The RS1i is a nicely refined headphone - yet, unless you're looking to hear how that refinement can connect your music to you, then it can be hard to appreciate the RS1i. If a person heard a pair of SR-60 Grados that was modified by installing wooden cups, then tried the RS1i, there wouldn't be a lot of "wow" factor initially. In that situation, a listener is expecting a sound that is 10x what the modified SR-60 was. Yet, it's a smaller gap and feels minimal initially ... but, when you pull up your music and have the time to go through some of your music where there are unique passages, the details will really shine through.
Again, the signatures can be quite different, so I wanted to recap on that. The PS-500 has quite a different signature than the RS1i, RS2i, etc. I has a somewhat laid-back upper frequency response, but does have quite a surprising amount of bass. But, I don't necessarily equate all bass to quality bass. With the PS-500, it seems like the bass, while there, present, thick and dark sounding could be appreciated by all, I've found it it isn't. It probably has as many objectors as those who might appreciate the sound. The Magnum drivers are a great alternative for someone who wants to be creative and build a pair of headphones that is unique and custom to that particular user.