Use the table below to find reasonable starting inner diameter,  cup volume, and backbore.

If you know your preferred throat size, start there. Otherwise, #26 is a reaonable starting point.

The P  rim contour is reasonable starting point for many. It is a good basis of comparison and contrast when you try the other 4 (which you definitely should!)

This table will allow you to find approximate starting points for your fitting:

Do try all 5 contours!

• Note that the ones with more inner rim support play a bit smaller than others with more rounded inner rim.
• Pay attention to how it feels.
• Too sharp an inner bite may cause discomfort
• Too flat a contour may limit flexibility or compromise articulation
• If something feels off, try to put into words how you would fix it: “I want more outer rim support” or “I want the high point farther in/farther out” or “there’s a hot spot over my wonky tooth.” Then, you will notice if another profile fixes this. If none does, Vennture can EASILY incorporate the fix you just articulated into a custom profile. You can even do it yourself – VennCAD is SO powerful.

The right rim diameter is all about the right support for your chops and the way you play. Always try a size bigger and a size smaller than what you think you need, just to be sure.

Pro tip: for a quick-and-dirty test, adjacent-sized (i.e. .01″ bigger or smaller) rims mate well enough with a given cup. This allows you to try a bigger or smaller rim diameter without having to swap out cups and backbores and all.

Note: If you believe you are in-between rim sizes in the kit, this is easily handled! When you order your components or one-piece, there is a custom rim diameter option. So if you feel like you are exactly in between a 0.630″ and 0.640″ size, for example, choose “custom” and type in 0.635. If you are closer to the 0.630″ you could do 0.633, or 0.637 if you are closer to the 0.640″. At this point we are literally splitting hairs (an average human hair is about 0.007″ in diameter). These “custom” sizes are made to order (i.e. not in inventory), which takes about 3 weeks. But there is no additional charge for this!

As with everything else, test deeper and shallower cups to gain learning!

You may find that you will need throat and backbore changes to balance cups of different depths.

Note that, if you find you desire something between cup volume sizes included in the kit, you can specify a custom made-to-order cup volume either in a one-piece or screw cup order. If .070 cu in is too shallow and .075 cu in is too deep, consider entering .072 or .073 cu in. There is no extra charge for this! VennCAD™ makes it super easy for us to offer this.

We treat these here together, because throat and backbore form a unit: both physically (in that you insert the Vennturi™ throat insert into the backbore before screwing the backbore into the screw cup) and acoustically.

The throat of course creates a pinch point in the whole acoustic system. A tighter throat offers more resistance: something to “push against.” Ditto with a tighter backbore, though to a lesser extent.

The bigger impact of both is in terms of tone color and pitch:

• a smaller throat and larger backbore will tend to make the sound brighter by emphasizing higher overtones. They will also tend to spread the octaves; thus, if middle C is in tune, high C may tend sharp.
• a larger throat and smaller backbore will tend to make the sound more diffuse and dark by emphasizing the fundamental. They will also tend to compress the octaves; thus, if middle C is in tune, high C may tend flat.

After some experimentation, you will arrive at the optimal combination of throat and backbore for your playing situation. Note that switching between instruments of different keys may be accomodated by a change of throat and/or backbore. You can purchase different throat inserts and/or backbores to accomodate your different horns. Remember: the only thing better than a shiny new Classiq™ mouthpiece is multiple shiny new Classiq™ mouthpieces!