Circular breathing – The composers guide
Composers should also read the oboist's guide to this technique - which can be found here
Circular breathing can be used on the oboe in any register, with multiphonics, on fast passages as well as on long notes. It cannot be used, with one exception, on passages that require articulation simply because the tongue, which is used for articulation, is also employed for circular breathing.
On the video I demonstrate the exception to the rule. I have been developing a single tongue articulation that can be used with circular breathing. However to my knowledge there are only a couple of other oboists able to do this in the world; at the moment!
There is no need to notate circular breathing as the oboist will use it as and when needed.
There are limits as to how long a performer can maintain a continuous flow of sound and this is will vary from performer to performer. The problem is not the technique itself, which can take pressure off the performer, but the length of time the performer’s embouchure can last. This is the area that will tire first. I regularly perform works of six or seven minutes without rest and with no problem for the embouchure.