Firstly, I'm very glad to hear your family is on the mend!
Nextly...Holy crap! More donuts than Boston P.D. on Fastnatch day! (If anyone here is a member of Boston's finest, I do mean this in jest, anyone who can keep that city under control has my utmost respect)
Those grooved ones have my particular attention, although my next step will be partial liberation of the driver. Anyone have any experience making new Gimbals? I think a peice of cut ABS pipe could be nearly perfect, and would alow us to experiment with different donut sizes more easily. I have seen a few examples of custom gimbals, but not many. (I still like the idea of brass or copper, especially after the steampunk grado thread that's floating around here.
Speaking of various sizes, what effect does the thickness of the donut have on the sound?
1. I congratulate you on that statement: ". . . would allow us to experiment with different donut sizes more easily." To be candid, I like making bigger shells. I started making smaller ones to fit the gimbals, but the gimbals can be easily replaced with more elegant gimbals that don't force us to fit our work into such tight tolerances. ABS pipe would be fine. Cut it thin and sand off all the sharp edges. Brushes and polished, you will have a nice and effective gimbal. Just enlarging the gimbal a few eighths of an inch will give you the freedom to make more rugged, durable shells and avoid throwing most of that precious wood into a box full of cores.
2. The grooved shells are the ones with double walls, which is my response to the tight tolerances. When you have to clear a 2" doughnut hole but layer two shells so that you don't go beyond 2 3/4", you end up with very thin shell walls. I don't like thinner walls. I created the double walls initially as a way of shoring up the durability of the shell, then realized that double-walling it provided two other benefits: (1) doubled contact surface and (2) a better grip. In the future, I may end up moving on to a form of bayonet mounting, to allow for "shell rolling" (a term whose time has finally come).
3. Although I have had some very good experiences with longer shells (picking up artifacts that relate to a wider, grander soundstage), I'm convinced that the most critical space is that which is closest to the driver. That's why I push for driver liberation - or at least partial liberation - and the use of effective first-stage shells. But even sticking with slip-ons, most of the work being done is happening in the first eighths of an inch where the compression waves of the driver are the strongest. I'm not saying the back end doesn't matter, because it definitely does. I'm just saying that if you had one area in which to focus, I'd focus on the area closest to the driver. Longer shells have their uses and their charms, but most of the time, there's a practical limit on how far out, beyond your head, you really want your shells to go. It seems like we sometimes get hung up on the visuals - at least of headphones as they're laying on a table top - and either forget about the sound or don't think about what we look like when we strap on some bull horns.
4. My longest shells now are 1 1/2" - which are plenty long. I go there because I get beautiful wood that sometimes comes to me that thick and I enjoy the luxury of having such long shells. But what I'd really like to do is incorporate the front of those shells as the "inner" portion of the shell. Now that I have a lathe, I'm going to be experimenting with maintaining the integrity of the thicker pieces and making the very front into the inner or "hat" portion of the shell. I think a distance of 1 1/2 inches from stem to stern is ideal (for both shells together). That said, I am no longer interested in giant GS1000-style gobstoppers hanging from each ear. I don't think the Grado headband was ever designed to handle something like that. I think it's inelegant and unnecessary.
5. When you speak of going to larger sizes - as in larger diameters - you are speaking my language. If you look closely at the orthodynamics, particularly the LCD-2, it's interesting how these designs copy a fair amount of the grill design from Grado. I know the type of driver is different, but when I look at something like this:
I can't help but notice the similarities to this:
Obviously, the two designs are different, using different drivers, but they also share similarities, including: a minimalist headband with what looks to be rotating gimbal rods, a gimbal design (though Grado does all the way while the LCD2 simply fastens the lateral clips right onto the shell), wood shells and large, open grills. I'm not saying one group actively copied the other (since the mechanics speak for themselves) but there's no reason why Grados could not have the diameters of the LCD2. The LCD-2, with its orthodynamic drivers, has an obvious reason for presenting a wider face, but Grado's 40mm driver merits the same treatment. Instead of tubing up, the next generation of Grado cans - if not modded ones - may well be one that uses the baffle disc commonly found on the K701 to widen the earspace to a circumaural "concert hall" enveloping the ears while also employing some form of the rear chamber for bass capture.
