TubeNet

In their online catalogue in English, it seems WHF has following six backbores with a throat of 8.6mm.

----
W6 mixed form; 2/3 convex – 1/3 concave; very
wide bore

E6 very bowl-shaped; very warm, full sound; light
compromises in slotting

D6 slightly bowl-shaped; round, warm sound; open blowing with good slotting

C6 straight ; very direct response with sufficient
tone quality

B6 concave; very direct response; somewhat
more resistance; slight compromise in tonal
quality

S6 mixed form; 1/3 convex – 2/3 concave; narrow bore, nice sound
----

But, they seemed to also have F6, H6, J6, and M6 backbores now.

Does anyone know anything about these four backbores?

I tried several mouthpieces for my kaiser type BB tuba (PT50, Rudolf Meinl 0., Giddings Fossi, Giddings Baer CC Original, etc), and I have (for now) settled with a WHF mouthpiece (with a combination of BP10, B/H10, and W6). It works really nice for me, but wondered if I can improve it by switching a backbore.

Have you read page 5 onwards?
https://www.bachbrass.com/application/f ... 89_web.pdf

Hi, thank you for your comment.

I have looked at their online catalogue below (tuba page is between 33 - 38), and p.38 seems to be the page about their backbore:

https://www.whf-mouthpieces.at/kataloge ... F_Engl.PDF

But, I came across backcores that are not listed on their online catalogue.

So, I have an impression that this online catalogue may not be the most recent one (since they seem to be working on updating their website).

According to the recommendations of Windhager himself (as mentioned on the website of FMB (dealer) in Guetersloh (Germany), you may combine the B/H10 with the shafts D6, E6 and W6. D6 for a more compact sound, E6 for big, voluminous sound and W 6 for voluminous and smooth/velvety sound. I hope my translations from German are correct or at least useful.
Hubert

Thank you for your information!

And, I also realized (upon reading your reply) that FMB website has more information in German (which is not always the case in English page).

I purchased mine from FMB website. In FMB website, it said a combination of BP10, B/H10, and W6, as "Daniel Ridder" model. I like this combination, but I thought maybe I could change backbore for better slotting (for me), so will look into direction of E6 and D6.

Yes, you are right. Unfortunately, you only will know for sure by trying. I myself use an E6, but in combination with much smaller cup and rim (nrs. 6) and with a compact CC-tuba.
Hope you will find your "holy grail". Succes!
Hubert