Volume: This whistle is fairly loud. It can sound overpowering in the 2nd octave, even though it's not the loudest whistle I own. I don't know if that's because of harmonics or what, but it can be a bit painful in the high A, B and 2nd register C. I know there are some variations in Copelands produced (both by design and simply as variants in individual whistles), and I think I got a slightly quieter one. That said, it's still pretty loud compared to an Oak or Walton's. At the Texas Renaissance Festival, I needed a super loud whistle for Maypole--It was a large open area, no amplification, trafficked by hundreds of talking people. This whistle nearly fit the bill; it couldn't fill the space when it was at it's noisiest, but otherwise worked well. When the guy selling Susatos tried to sell me one of his, for more volume, we sat down and played mine VS. his side by side, and the Copeland turned out to be a slight bit louder. I reminded him that he could be heard further than me because he had a hidden microphone and amplifier in his booth. ;)

Responsiveness: Pretty fast. This whistle has very good above-average response time. There are slightly faster responding whistles out there, but not by much.

Tuning: Except for the slight bit of breath gymnastics on C natural, the whistle is in tune from D to high B, though you have to push it a bit on the top notes. At the Houston session, the players there favored the intonation of this whistle over my first Burke Al-Pro and my Silkstone..then again, I have mentioned that it was already pre-accepted that the Copeland was the "king of whistles", so I can't say how much of this had to do with actual intonation, and how much had to do with pre-conceived notions about what a whistle should sound like. Like most good pro whistles, you can push the tuning around with your breath, which means it'll be harder for beginners to master the instrument. I've heard troubling reports that now that Copeland Woodwinds has a more factory production going, there is some quality control issues with their tuning. Luckily, that wasn't the case in my older version. But I know that they have good customer service and stand by their instruments. If you have issues with your Copeland, they'll try to fix it, even if you got it secondhand.

C-natural: OXXOOO produces an c-natural about 10 cents sharp of true. You can bring it into true by breathing softer, or use OXXXOO which is right on. I just breathe softer.

Hole size and placement: This whistle has holes are fairly standard spaced and sized. I only keep this category around because some few whistles have extremely weird hole spacing. This isn't one of them.

Air volume and pressure requirements: This whistle takes a lot of breath. That was my biggest challenge with the Copeland low D I had, and the same design is evident in the high D. It took a lot of getting used to. I found myself breathing a lot sooner than I expected, and I never seemed to have enough breath to get the phrases out the way I wanted. That said, it is something you get used to after a while, if you put yourself to the task. As for breath pressure, I can say this: this whistle demands confidence from the player. The second octave requires you to be sure of yourself and really attack the notes, or the whistle will chastise you by falling into the first octave or blowing a raspy goose honk at you. In other words, a good amount of pressure is required for this whistle to really come into it's own. It's like a wild stallion that, when mastered with a firm hand, is a great racehorse, but if treated with too much gentleness will run away from you. This is especially true in the top half of the second octave.

Clogging: This whistle gets fairly wet, but never really clogged on me. When it gets too wet, though, the top half of the second octave becomes much harder to control, squeaking or honking more readily. For this reason, I couldn't really use it exclusively at 4-hour gigs, and instead relied on it and my Silkstone to get the job done as a pair.