Every headphone has its virtues. While some headphones just flat-out suck, different designs produce their own kind of excellence. To me, the PortaPro has an ingenious design. It's all so minimalist, and yet so terrific within a minimalist framework. These are headphones with a nothing headband, a nothing shell and very tiny "nothing" cushions - yet they sound surprisingly good for something made from "nothing."
Can you get better headphones? Yeah, of course, but probably not at this price and with this amazing portability. These headphones are made to be literally folded up and put in your pocket. Now, how can you make them BETTER? Here's what you do:
1. Mod the cushions by pinching out a hole in the center of their minimalist padding. You'll get clearer, crisper, HF.
2. Cable up. The cable on these is minimal, which means there's impedance fighting you from the outset. Flimsy wire merits an upgrade. Even ordinary speaker wire, terminated with a $5 plug, will give you stronger bass.
3. Believe it or not, the PortaPro can be woodied. A little wood would bring out more warmth and slam in the delivery. Absent that, you should take some Dynamat and deaden the metal on the back. This will give you less mud and better detail.
The iGrado uses the same drivers as the SR60 but with one catch. The shells aren't really shells. In the first iteration, they weren't even "open." They were made to look like shells while actually enclosing the entire shell in plastic. Not surprisingly, they lacked something when compared to the SR60. Can these drivers be fixed? Yes, with similar mods as above:
1. Mod the cushions by pinching out a hole in the center to make the sound clearer and more open.
2. Get rid of that flimsy cable. Yes, Grado says it's using UHPLC wire, but if you'll look at the gauge of the wire, it's pitiful. The best copper in the world is of little use if there's no gauge to it. Cable up. Even standard 24 awg wire would be a step up, especially if you went with a four-wire braid so you could split the groundwire. A short four-foot cable using something as simple as CAT5 cable (unsheathed) would give you very low impedance and improved signal clarity.
3. Separate the driver housing from the plastic rear shell, then drill through it to create a real event. Then take a small piece of Dynamat or other commercial damping and really damp that back plate. You'll immediately notice better detail in the mids and treble.
I don't know beans about the PX1000 so I'll leave that issue to someone else.