According to Sax, the principle of the independent valves - for which he obtained a patent in 1852 and which he developed further in 1859 and 1867 - was designed to achieve a flawless sound for the instrument, without the faults of conventional instruments with valves, which could sound off-key when valves were used in combination. In the new system that Sax conceived, each of the six valves was independent and produced its own series of natural tones. Taking additional account of the notes that could be played without the use of valves, seven series of harmonics producing all the notes of the scale could be obtained. This principle could be applied to all valved instruments, such as trumpets, cornets, horns, saxhorns and trombones, but endured longest - until the middle of the twentieth century - in the trombone.

The independent tubes of each valve and the open position (i.e. without operating the valves) are connected either to a single bell or to seven separate bells. Instruments of the latter type are hugely impressive, acoustically trustworthy, but heavy, cumbersome and troublesome to make. A further disadvantage is the difficulty for musicians in mastering the new fingering, which is why the system did not gain long-term acceptance.