Guide to small bore vs. large bore trombone

A tenor trombone is always tuned in Bb, but unlike the trumpet, it is a non transposing instrument (probably because trombone players like to call a bone for a bone instead of a Bb for a C). There are two main types of tenor trombones, the small bore trombone and the large bore trombone. Both can be fitted with an F attachment. The bore refers to the actual size of the tubing, measured at the point where you insert the mouthpiece. This results in the need of two series of mouthpieces, built to fit either small or large bore horns.

The small bore trombone is typically used by jazz players, and has a bright sound. Due to the larger tubing, the large bore trombone is more mellow, and is the first choice among classical trombone players. I use to describe the difference in sound by comparing the sound of a jazz or pop singer with an opera singer ́s, although the difference is not that big on small and large bore trombones.

    Small bore trombone

    Small bore trombones, often called jazz trombones, usually have a bore spanning between .480′′ to around .510′′ (or 12,2- 13mm), and the bell size is usually between 6,5′′-8′′ (165-203mm). The typical mouthpieces used with small bore horns have the size of a Bach 11 (small) to Bach 6 1/2 (medium). Some trombones have dual bore, meaning that the two tubes on the slides have slightly different sizes.

    Small jazz trombones rarely have F-attachement, but it not uncommon on medium sized jazz trombones (8′′ bell). There are a lot of well known small bore trombones on the market, including a bunch of top notch hand built instruments by manufacturers like Shires, Rath, Greenhoe and Edwards. There are also a number of well known trombone manufacturers that has been around for many decades, such as King, Conn, Bach, Getzen and Yamaha. Some famous models:
    King 2B .481/.491 dual bore, 7.38′′ bell
    Bach 16 .495′′/.509′′ dual bore, 7.5′′ bell
    Conn 6H .500′′ bore, 8′′ bell
    King 3B .508′′ bore, 8′′ bell
    Bach 36 .525′′ bore, 8′′ bell (semi large trombone, still using small bore mouthpiece)

    The range on a small bore trombone starts on the low E, going up as high as the chops allows.

    The extreme low range consists of the pedal tones, available one octave below the root on each position.

    Large bore trombone

    Large bore trombones, or symphonic trombones, usually have a .547′′ bore and a bell size of 8.5′′ (215mm). Typical mouthpieces used with large bore horns are Bach 6 1/2 (medium) to Bach 4 (large). Most large bore instruments have F- attachment, making the lower range more accessible. Where the small bore horns have a light and agile feel and tone, the large bore trombones have a darker, full sound with better control of the low range, making them more suited for symphonic and sacred music. On trombones without F-attachment, there is a gap in the range between low E and the contra Bb. This is solved with the F-attachment (except for the contra B which is still missing).

    On trombones without F-attachment, there is a gap in the range between low E and the contra Bb. This is solved with the F-attachment (except for the contra B which is still missing).

    Since the F-attachment makes the horn longer, the slides are not exactly the same as without, and there are only 6 available positions with the F-attachment activated. Newer trombones often have a so called open wrap F-attachment, making the instrument more responsive and minimizing the difference between playing with out without activating the attachment (the latter pic above).Most trombone manufacturers make large bore trombones. Well known models include:
    Conn 88 .547′′ bore, 8.5′′ bell
    Bach 42 .547′′ bore, 8.5′′ bell
    Yamaha YSL682 .547′′ bore, 8.5′′ bell

    Bass trombone

    Bass trombones are actually tuned as tenor trombones, but have significantly bigger tubing and bells. They are also large bore trombones, but usually they have both F and D- attachments and are fitted with larger mouthpieces (typical Bach 4 or Bach 3). They usually have a .562′′ bore and bells ranging from 9,5′′ to 10,5′′ (241-266mm). The extra attachment makes it easier and more convenient to use the low range, and the contra B is now available.

    If you think about the good bass trombone players you know, chances are great that they actually have a deep and overtone rich speaking voice – is it the voice that fits the instrument or the instrument that brings out the voice?

    Alto trombone

    The alto trombone is the least known model, and is smaller than tenor trombones. Where the tenor have a Bb on first position, the alto trombone have an Eb a fourth above. It is mainly used in classical music, both as a solo instrument and playing in the trombone section. A common alto trombone size is 470′′ bore with a 7′′ bell. A standard small bore mouthpiece will fit. It ́s a cute little thing that has a distinctive sound, but make sure you don ́t pull the slide of when reaching for 7th position!

    A common alto trombone size is 470′′ bore with a 7′′ bell. A standard small bore mouthpiece will fit. It ́s a cute little thing that has a distinctive sound, but make sure you don ́t pull the slide of when reaching for 7th position!

    Contrabass trombone

    Contrabass tromboneThe contrabass trombone is a rare but intriguing species, usually tuned a fourth below the tenor trombone making the low F the fundamental of the first position. They usually have two valves, making up for the fact that only major league basketball players would be able to reach 7th position… The length of the spit valve is a good indicator of the size of the beast.

    Soprano trombone (or slide trumpet)

    Soprano tromboneThe soprano trombone is basically a slide trumpet. It is tuned one octave higher than the standard tenor trombone. Since it uses a trumpet mouthpiece, it is quite different to play than a regular trombone. The bore is usually around .450′′ and the bell is the size of a trumpet bell, and the slide often only have six positions. Due to the different embouchure, the soprano trombone is usually played by trumpeters.

    I hope that you found this guide useful. Please leave a comment with your thoughts about your preferred trombone models! And as always, correct me if I got something wrong, such as my opinions…

    All the best,
    Anders

      Links to an overview of current trombones and discontinued trombone models

          One thought on “Guide to small bore vs. large bore trombone

          1. Thanks a lot. The information on this article was really useful. It’s kind of sad though cause I bought a Yamaha ysl 448g large bore trombone. I really wanted to head in a jazz direction and i should have got a medium bore (I still play classical). Thanks though

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