I have not played the Wessex but have played the Besson 956 and the York 3056 (same tooling but built later). I am NOT a fan and now play a 3 valve Sterling Virtuoso. The only 4 valve baritone I would play (if I had to) would be the Besson Prestige 2056. My favorites these days are the 3 valve NEO and my heavy bell Sterling Virtuoso.
That said, here are the issues with the 956/York 3056:
1. Intonation - The horn is pitchy. Speaking in treble clef, middle A (1-2) is sharp. Use 3rd valve. Middle Bb (1st valve) is flat-ish. 6th partial (F, F#, G) is a bit sharp. High B (2nd valve) is FLAT. Use 1-2 or 1-3 to bring it up. D below the staff (4th valve) is spot on but Db (2-4) is flat. The low F (2nd partial) in the 4th valve range is ok using (1-4), but as you go further into the 4th valve range you have to start using alternate fingerings. There is no low Db (just above pedal C), even with all 4 valves down you just get a D.
2. Design - The 4th valve compensating design on this horn was an afterthought. It was a bare minimum redesign of the 3 valve 955 Sovereign with an "F attachment" crammed in. The 3rd valve is borrowed directly from the 955s 1st valve to complete the compensating loops. It has just the little 3 valve compensating "nubbins" on the back of the horn. This is why pitch is so poor in the 4th valve ranges. The Prestige 2056 has a full set of proper length compensating loops and solves this particular problem.
3. Ergonomics. To squeeze in the extra tubing for the 4th valve, Besson had to make the horn MUCH deeper fron to back. Therefore the grip around the outer brance/3rd valve slide normally used for the left hand is larger than most 4 valve euphoniums. The angle of the 4th valve is such that it is easier to play with the middle finger than the index finger of the left hand. The horn is heavier (much) than the 955 Sovereign and you cannot rest it on your lap to carry the weight. Like all baritones, it requires spinning the horn to complete water removal. Further, there is an awkward loopback tubing section in the 4th valve loop that makes water removal difficult unless you pull it and the 4th valve slide. Putting the mess back together is hard to do if you are mid-song.
So, it has a 4th valve which makes fingering a bit easier for euphonium players. BUT, it is heavy, awkward to hold, has very marginal pitch, and is really a bollixed together design. The Prestige 2056 solves most of these issues except for grip depth and weight. OTOH, I know that Helen Harrelson plays one of these (at least she used to).
Doug
Adams E3 0.60 Sterling bell - Prototype top sprung valves
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