The Pro DJ 100's cups are 50% metal. The outside half is metal and in the morning they're freezing cold. Underneath the pads it's all plastic, but this is probably due to cut costs and reduce weight. The metal part that makes the cups rotate is all metal and so is the internal part of the headband. Overall the build quality is very good and they only weigh about 6.5oz I believe it was.
Overall they feel like a closed version of a Grado SR-80 in a way. I think these could easily be modded. Unfortunately I accidentally cut the internal wires and they could not be repaired, so that's why I have to recable them! Expensive mistake, but at now I can have a silver cable!
I poked too many holes around the driver and it sucked out all the mids and created a massive amount of bass. I think only a couple holes would be perfect. Since this is closed, too many holes hurt more then helped, but I can fix it. These headphones get my vote for best mids and vocals of any headphone I have. Bass isn't anything special, but it's not bass light.
For some reason, just like the SR-80 these seem to need an amp to sound best. That's my big negative with them.
Like the Maxell DHP-II and JVC RX700, these are another pair that more people need to check into!
To be honest I've never considered Grados portable on any level but from week one of this thread people had been suggesting that I add some so in they went. Same with the M50, Denon HP700, and all of the other large DJ cans I've been meaning to add. I did review the ES7 but wasn't a huge fan - certainly didn't think they could compete with the HD25 or MS1 or M50. Plus the (dis)comfort was off the charts. I'll have to try the DJ100. I've been curious - how much of it is actually metal? I hope it's not just a huge glob of silver-colored plastic...