Oval in format and with rotary valves and quite a wide bore, the Wagner Tuba has a horn mouthpiece which means that the mouth-pipe has to taper narrowly in order to receive it. The instrument is generally made in two sizes: Bb (tenor) and F (bass).
The length of tubing is the same as the Bb and F horns but with a fourth valve which works the opposite way to the fourth valve of a double horn, taking the Bb tuba down to F and the F tuba down to C. Operation of the four valves, unlike all other tubas, is with the left hand and, unlike other horns, the bell faces upwards. In a quartet of Wagner Tubas, there is a pair of Bb tenor tubas in Bflat and the two bass tubas in F.
Tenor tuba – pitch of the euphonium. Bass tuba – pitch of an F horn
Broadly speaking, the range of the Wagner Tuba is similar to that of the standard horn. Only two differences might be detected – the tenor tuba has greater flexibility than the bass tuba and the highest range of notes they can achieve is rarely found in the repertoire of works written for them.
The lower register of the Wagner Tuba is quite lovely being very rich in tone and notes are reasonably comfortable right down to the concert A below the bass staff even on the Bb tenor tuba. The lowest notes are the Bb below the bass staff down to the E below that (pedal notes – fundamentals). Then there is a gap going up, and the range is chromatic from the E below the bass staff up as high as the player can manage. Although the tessitura range can go quite high, notes above the concert D become uncertain except in the hands of professional players.
The above refers to the basic three valve tuba. On a four valve tenor tuba, the gap is filled in, or at least sort of filled in. Unless the player can make some arrangement to adjust the tuning while playing, most of the notes in the gap between the low pedals and the rest of the range, i.e., the notes between the pedal Bb and the low E, are progressively more and more sharp. This is one of the reasons why there is also the bass Wagner Tuba in F, which is exactly the same as the tenor, but a 4th lower. On a three valve bass WT, the gap includes that A below the bass staff. However, on the vast majority of bass WTs, there is the 4th valve, which is equivalent to valves 1+3. As mentioned before, notes with the 4th valve can get quite sharp, and this has been a problem with these instruments.
The solution, of course, is the double Wagner Tuba, in F/Bb, just like a double horn, where the tuning problems are all resolved – more or less. The problem here is that the full double Wagner Tuba is quite heavy (which tends to also dull the sound a little), and the purists, including many professional orchestras, prefer the traditional combination of two Bb tenors and two F basses. These are very expensive when made by the traditional European makers, and players have long sought out cheaper options ie. instruments often from retired players.
Recently however, the appearance of the compensating double Wagner Tuba, such as the Chinese instruments which are frequently imported nowadays has solved a lot of these problems. This solves most of the problems of the single instrument. Intonation is generally better, and the low range is perfectly acceptable although it might lack the slightly fuller sound of the single F tuba. The biggest advantage of the Chinese Wagner Tuba is that it costs a fraction of the cost of the European instruments, and definately represents excellent value for money. The Chinese have really targeted the ‘enthusiastic amateur’ market, with reasonably priced instruments of better than reasonable quality and accordingly, these instruments are now starting to gain the respect of professional performers and teachers.