Allan Segal, a reader of my blog, is making a custom clarinet barrel for me. His website Clarinet Concepts, describes him as Surgeon, Musician, Woodworker.
I've been trying Backun barrels again recently, and was frustrated at not being able to find a really glorious Cocobolo wood 64 length barrel to match the gorgeous 65 MoBa I bought a year ago.
In my email discussions with him I learned a lot about the facts and myths of barrels, and about some of the issues which arise with Cocobolo wood in particular.
Porous woods...coco in this case....have more dimensional instability with changes in humidity and temperature....That is the reason we make those barrels heftier. (Backun calls them Fatboys, but actually a British firm first used the term. I just call them hefty)
Color does not equate with density. Right now my stock of Cocobolo. billets is light with purplish streaks, but average in density. I do not stain. I could make anything LOOK brown just by burnishing the outside
The resistance is more of a bore issue. Outer shape may sometimes color the sound differently, but the blowing characteristic is more internal.
Another myth: Smooth bore v. porous.... If it sounds good, it is good. Opperman noted this a long time ago. Some of his barrels were rough inside. In fact, Moennig felt that some of the best clarinets were not smooth internally.
Be aware... ALL barrels narrow over time, esp. coco, and ALL barrel bores assume an ovoid shape. This will not necessarily show up with standard cylindrical bore gauges. That is why I suggest turning the barrel on the axis to find the sweet spot.
Allan has already started the process of making the barrel, from scratch. I have sent him the 65 MoBa Cocobolo for him to try to imitate the bore in the new one. He sent me some fun photos of the process, starting with a big block of wood. You can see them in the photo gallery below. (Click photo for larger view.)