Hey Mgear,
I tested out the HE-500's for a few hours used the EF-5 amp and was considering them as an upgrade to my HE-4's. They sounded pretty amazing with sweet sounding mids which were almost "holographic". I wouldn't consider the headphones neutral at all with this midrange characteristic I was hearing but it was nice sounding for sure. The HE-500's were a much better headphone and the more forward mids were much appreciated over the HE-4's and they also had more bass impact which was nice. I've heard some of the higher end headphones(HE-6's, HD800's, HD650/600's, T1's, LCD-2's, PS1000's, GS1000's, D7000, and D5000's) I've owned RS1's, modded D2000's, HD580's, HE-4's, and HD-555's. So I have a bit of perspective of the sound signature from these headphones when compared against one another.
After I heard the HE-500's I wanted to test them out against the Grado's, because ever since I sold my RS1's I've been searching for something that would give me that kind of emotion I got while listening to those. It's the combination of PRaT, upfront vocals, and resonance from wood chamber that made everything sound alive with the RS-1's. I found them very special headphones while driven out of an RA-1, so I started auditioning the top-tier Grado's(minus the PS-1000's-too expensive!). I auditioned the RS-1's, GS-1000's, and PS-500's. I started with the RS-1's and PS-500's. I soley used my 4th gen Ipod classic and my Hifiman HM-601 which were both using flac or Lossless files. From my ears I thought the RS-1's were better with vocals, but only slightly and only on well recorded albums. On a poorly mastered or, slightly bright album the RS-1's were a bit too bright for me. The PS-500's from album to album were more consistent and seemed a bit easier to drive as well and just the right amount of brightness if any. From the HM-601 on low gain I was getting some pretty loud volumes at 40%. The bass also hit deeper on the PS-500's. The RS-1's were slightly more open, but way too treble heavy for my tastes. I went back and forth between these two for about an hour before deciding the PS-500's were the winner.
Now for the PS-500 vs. GS1000's... I listened to the same albums I listened to when AB'ing the RS-1's and PS-500's(Adele, Arcade Fire, Tool, Ratatat, Sublime, The Cranberries, Eric Clapton Unplugged, Incubus, John Mellencamp, Metallica S&M, as well as others). I found the GS1000's very dry in the vocals. They were not nearly as liquid as the PS-500's or RS-1's. Maybe it was the source I was using as I heard they can be very amp and source dependant, but I knew which headphone was coming home with me. Though I wouldn't call the PS-500's neutral in anyway, they bring out the best in music with PRaT, vocals, and very convincing string instruments. The HE-500's(not neutral to my ears either) had amazing vocals and a thicker more full sound than the HE-4's but knew it was going to be more annoying with amp choice, and source etc. and didn't have the PRaT of the Grado's. A little too laid back for my tastes though a great headphone. I would have chosen the HE-500 over the RS-1's and GS1000's if their wasn't a PS-500!! The PS-500 has smoother highs then the rest of the Grado lineup and it's easier to drive so for me, it's that much easier to live with. For convenience alone, I would have chose the PS-500s. The fact that, to my ears they sounded better than all the headphones I auditioned and were the cheapest of the bunch was icing on the cake!
Having said all this though, it's really up to the listener to decided what he/she likes best. Some like a neutral headphone, some like a bigger soundstage etc. I just wanted to simplify everything and love music again, and that's why I chose the PS-500's. Hopefully you found this info useful. If you have any questions at all, feel free to pm me.
Dustin
