This was an experimental set where it worked out quite well. The smaller diameter exit hole worked very well with Magnum Drivers and produced alittle extra bass from what I could tell. Nothing was muddy. Didn't have alot of time with them and sent them off to the owner and let him give them a whirl. I told him I could widen the air hole if he didn't like it. So far so good.
One of my headbands as well. I've really arrived at a very nice version of the headband with great materials and very comfy. I haven't had any issues with installations nor does the headband peel away in hot humid climates any longer. They're as tough as they get.