reachable on a three-valve instrument or via the seven-position slide on a trombone. Trombone and tuba in particular are often called upon to play pedal tones and "false tones" or "privileged tones" which have a pitch between the normal range and the fundamental. Horn The modern standard orchestral horn is a double B/F horn. The player can switch between the two modes using a thumb-operated fourth valve. The fundamental pitch of the F horn is near that of the tuba. Horn notation is a complex subject beyond the scope of this article, but what is written as middle C for the horn is the fourth harmonic of the unlengthened instrument, not the second. Horn music makes greater use of the higher range of the harmonic series than do most other modern brass instruments. Bass trombone The modern bass trombone is the same length as a tenor trombone, but typically has two valves, pitched in F and G♭. When combined, these valves put the instrument into D. The modern contrabass trombone is usually constructed in F and fitted with two valves in either D and B♭ combining to give A♭, or in C and D♭ combining to give A. The less common double slide contrabass in low B♭ is often fitted with a valve in F. All these instruments are notated in bass clef at concert pitch. Tuba The bass tuba is commonly available in F and E, while contrabass tubas are available in C and B. References Pitch Brass