According to an article posted by Jay Friedman at his web site Jay Friedman.net January 8, 2004, he had his custom Schilke 51B made for him by Renold Schilke in 1958 when he was a student, and used it for 25 years, including in the Chicago Symphony. (25.63 mm, medium-shallow, 0.257" throat.)

The significance is that a professional trombonist chose to use a mouthpiece of those dimensions in a professional orchestra on the first part, most likely because it helped provide the upper register focus, and endurance, he needed in his position in the Chicago Symphony. What worked for him then can still work for many in similar situations today.

This is true. Friedman played his entire career on mouthpieces based on the “Geffert cup” which is essentially a V shaped cup. After the 51B he went to something like a 4G but with a deeper V shape cup, and eventually to something like a 3G with a very deep V shape cup. Parke, BrassArk, & Hammond all have his artist model(s) available which is what he’s played for around 30 years now. With all this being said, he and his entire section play bass trombone slides, and I believe Charlie plays an extra large dual bore bass slide, so his mouthpiece choices probably reflect partially on his and his section’s large equipment, and playing in the rather difficult Orchestra Hall in Chicago.

[quote="BrianJohnston"]This is true. Friedman played his entire career on mouthpieces based on the “Geffert cup” which is essentially a V shaped cup. After the 51B he went to something like a 4G but with a deeper V shape cup, and eventually to something like a 3G with a very deep V shape cup. Parke, BrassArk, & Hammond all have his artist model(s) available which is what he’s played for around 30 years now. With all this being said, he and his entire section play bass trombone slides, and I believe Charlie plays an extra large dual bore bass slide, so his mouthpiece choices probably reflect partially on his and his section’s large equipment, and playing in the rather difficult Orchestra Hall in Chicago.[/quote]
I have always enjoyed more V shaped cups with small bore throats.. The Bach G pieces were originally bass pieces, and for me they lack brilliance in the high and middle register. Still, I need a bigger piece than a 6 1/2 so the Friedman fits me very well..I have actually also gotten "KT mouthpieces" to plug and redrill it with a smaller throat ('250) so the sound is even more brilliant and easier to hit soft tones in the high register on a big horn..

Another thing; Friedman said in an interview that they(Schilke) could never copy the original backbore of the 51B so it's safe to say that his piece did not match the off the shelves ones

[quote="Tbarh"][/quote]
I have always enjoyed more V shaped cups with small bore throats.. The Bach G pieces were originally bass pieces, and for me they lack brilliance in the high and middle register. Still, I need a bigger piece than a 6 1/2 so the Friedman fits me very well..I have actually also gotten "KT mouthpieces" to plug and redrill it with a smaller throat ('250) so the sound is more brilliant and easier to hit soft tones in the high register on a big horn.._____________________________________________

V shape cups work better for me as well. Nicer sound in my opinion, and I can direct the air where I want it better than on a bowl shape cup.

Jay told me he doesn’t like bowl shape cups due to the blow back that can occur.