Purpose of 4+1

[DouglasJB]

I've though about this for a while, and cannot find a logical reason for 4+1 rotary tubas (5th valve for left hand). With 5 valves on right hand, you can adjust with your left hand. With 4+2 you generally have enough alternate fingerings to find something that works, but with 4+1 you want adjust anything. What was the purpose of 4+1 horns?

[tubeast]

The only reasons I can come up with are those of personal preference:

Somebody growing up with 4+2 might find it more convenient.

My experience: A thumb ring WILL compromise effective use of a thumb operated Valve, because it will block the thumb´s base Joint from contributing to the movement.
Some People just don´t want to deal with the concept of a handrest rather than a thumb ring.
Those People will decide to order a 4+1 horn.
Instead, I Chose to dismount the thumb ring and installed a wooden, self-carved handrest on my Willson.

[iiipopes]

I've though about this for a while, and cannot find a logical reason for 4+1 rotary tubas (5th valve for left hand). With 5 valves on right hand, you can adjust with your left hand. With 4+2 you generally have enough alternate fingerings to find something that works, but with 4+1 you want adjust anything. What was the purpose of 4+1 horns?

"Riding throttle" on a valve slide is a 20th century technique. the 4+1 horns were developed for the 5th valve to help intonation without "riding throttle." Look at the state of the art historically going forward, not from present day looking back.

[tubeast]

Another one comes to mind, from a manufacturer´s perspective:
If you´re already producing 4+2 horns, enhancing your portfolio to a 4+1 is a no-brainer and won´t require an all new set of parts.
Rerouting the mechanical setup to the right thumb is a totally different and more taxing job.