Glenn and anyone else having trouble with this exercise, Iâ€™m not sure what Bb horn you play, but if itâ€™s a Bach Stad (Model 37) you may benefit from a simple modification. Here is a TPIN post I that wrote several years ago that might give you some additional â€œequipmentâ€ insights. After I wrote this post, I received a response from an instrument repair guy in the Valley and he told me to bring my horn in so that he could have a look at it. When I arrived at the shop, he took my horn, turned it over and took out a very small screwdriver from under the counter. There was a set screw on the post that was holding the threaded rod on my horn (I had not noticed this screw in the 20 plus years that Iâ€™ve owned the horn!) and once he had loosed the screw he simply slid out the rod. Since I had the measurements from my instructorâ€™s horn and had talked with the instrument repair guy prior to coming into the shop, he had a new third valve slide threaded rod waiting for me that was 2 and 5/8 inches long. He then made some low profile nuts (he turned them down on a lathe), and the fit is just perfect. I would suggest that anyone knowledgeable in horn repairs could help you with this "retrofit". I continue to be amazed every time I play this excerpt at how great that low F sounds! If the slides canâ€™t be thrown out quite far enough on your horn, Mannyâ€™s exercise will never quite make sense (too much lipping involved). Playing the horn in the resonant center (given the proper slide length â€“ after modification) without any lipping, the sound of the low F will be perfect!