I can’t really tell you about the D, but I own a Bb in both narrow bore and wide bore from Mack. The narrow bore IS very, very quiet, but man, is it sweet. The wide bore is considerably louder and that’s what I use in my praise band at church.
My cats ignore high B on my narrow bore Hoover, frown at it on my regular bore, and leave the room on the Burke.
I think a narrow bore Hoover will be too quiet to hear over another instrument. The regular bore is still a quiet whistle, though – that’s the one I often play around the house or at night.
My Hoover White Caps in D and E Flat are as loud and clear as they need to be. I have a narrow bore D (all brass w/ delrin type plug) that is very quiet. Also, an ‘older’ D (All-White w/ brass tuning slide) that I have that Mack ‘opened up considerable’ can hold it’s own anywhere–also loud and clear.
I have found Mack to be quite accomodating, though I have always had trouble describing the sound quality I am looking for. I usually resort to something like ‘it should sound nice.’
I thought I wanted a narrow bore - you know - for those times you would sooner not wake your spouse.
Mack sent a beautiful little whistle. I really liked the tone, but the holes for the top two fingers of the right hand were so close together, that I could never get comfortable playing it.
I asked Mack about it, and he said that some people could not get used to the fingering, and offered to replace it with his standard bore brass whistle.
I accepted the offer - thank you very much Mack. I think the standard bore is a not nearly as quiet as the narrow bore, but it is still a sweet sound, and you can overpower it with a Clarke original, so it is not loud. If you are a session player, be prepared to play as background.
You can’t ask for a more accomodating maker than Mack. He’s A+
Mack’s narrow bore is a LOT quieter even than the O’Brien. A LOT. It’s so quiet that sometimes it’s hard not to hit the third octave. But if you do, the tone is perfect.