Vincent Bach was a rare combination of artist and engineer. He was constantly changing his mouthpiece designs until the mid 1960’s when they became more standardized.
The formalization of the 27 throat and backbore to cup letter (A=24, B=7, C= 10, etc.) created a standard for the mouthpiece making that is still used today. These standards are known today as the Classic Series.
|Model No.||Depth of Cup||Approx. Cup Dia.||Rim Shape||Throat||Backbore||Description|
|1G||Deep||28.00 mm||Medium thin, well rounded||.319"||800S||Extra large and deep for extraordinary power and depth of well rounded. tone. Among the largest and most powerful bass trombone mouthpieces produced today|
|1.25GM||Deep||27.50 mm||Medium thin, well rounded||.319"||800S||Cup is slightly smaller than 1G, but still very large and deep. Large throat and backbore for large, powerful, well in tune sound.|
|1.5G||Deep||27.00 mm||Medium wide, well rounded||.276"||429||A large mouthpiece with a powerful tone in the low register and great carrying power. For many years, the standard mouthpiece for the serious bass trombone player.|
|4G||Deep||26.00 mm||Medium wide, slightly rounded||.276"||429||Same rim and shank as the No.4 small shank tenor trombone. A versatile, large diameter mouthpiece especially useful when only one trombone is used for both the upper and very low register.|
|5G||Deep||25.50 mm||Medium wide, semi-flat||.276"||429||Same rim shape and diameter as No. 5 small shank tenor trombone. Similar playing characteristics as the 4G with a slightly smaller cup diameter.|
|6.5AL||Medium deep||25.40 mm||Medium wide, well rounded||.261"||420||Same cup, throat, and backbore as the 6.5AL tenor trombone but with a bass trombone shank. It requires a well developed embouchure.|