Posted by Ryan S. on January 20, 2000 at 14:36:35:
In Reply to: Re: Vented Valves posted by AL.H. on January 16, 2000 at 20:27:11:
Be aware that drilling a hole into the valve does something to your horn, the way it plays will be slightly altered. I compared a friend's 2155 before and after he had it drilled and we both noticed it takes about 10-15% more air volume to get the same sound out of the bell as before the operation was performed.