"The official word from Grado, and the unofficial word from the Grado surrogates on Headfi, is that each driver in the Grado lineup is different. What they mean by "different" is some kind of state secret. Having taken apart the iGrado, the SR60, the SR60i, the SR80, the SR80i, the SR225, SR225i, the SR325i and the SR325is, I can't give you any meaningful difference between them. The mylar is the same shape and thickness; the magnet is the same size and weight; the frame is the same plastic, with the same felt. If there's a difference, it's in the grill cloth, any doping used on the driver (none of which I ever noticed), the materials of the shell, the use or non-use of damping on the magnet back, the type of cushion used and the amount (and quality) of the wire used in the cable."
I talked to the guys over at grado many months ago about getting drivers for a project I was doing (I needed something like 30 drivers, and no I wasn't making speakers) And they closely guard there secrets or that is the place they have there drivers made(exact location) for obvious reasons.
However I have two opinions about this first: drivers on the SR line are exactly the same and they are all run through quality control and the best ones are selected for the higher level cans and are matched tighter and the ones that don't quite make the cut get the SR 60s and 80s 120s Etc.
Second Drivers used on more expensive lines (RS GS PS) are different from the manufacture because they are given a much tighter requirement for these. I would be interested to know how many ps 1000 drivers dont make the cut and are rejects.
There is a similar quality control system in use at the Rameriz Guitar Workshop: All the guitars are assembled and strung up without inlay or rosettes and finish and they are played by allot of local musicians in the assembly line and they are given a rating on something like a 1 - 10, Tens and 11s go on to be Ramerez 1As and better and 8s and 9s concert classicals 7s make good student models or good guitars to put electronics in and 5 and lower sell for less than 1500 dollars lower than a 3 gets reprocessed. With this system you pay more and get more VS a guy that lays out 14,0000.00USD for a guitar that is a total bummer and not as good as a 4000.00 dollar one of the same brand. Or spending all the time to make a great looking guitar that sounds like a 200, dollar one.
I am guessing this is a similar system used by grado for the SR line with the aforementioned exception of changing cables and other parts etc. this would also make it really easy for them to step up there sound like the did for the SR60i and the like, along with bigger cables and some better pads to make a SR120i or higher.
I MIGHT BE TOTALLY WRONG ABOUT THIS BUT I DOUBT IT.
