The rim of the mouthpiece has a large affect on comfort. In addition to comfort, the contour of the rim does has affect on your performance flexibility between partials and range. Before we answer this question, let me preface this that all statements about what a mouthpiece will or won't do for you are merely a place to start. If you want support in your range you might look towards finding a smaller diameter or shallower cup. However after trying a smaller shallower mouthpiece, you may find that you actually prefer a smaller diameter with a deeper cup, or wider diameter with a shallower cup... or none of the above! Based on the sound you want to create, your facial anatomy, and a host of other variables, you may not fit solidly into a mouthpiece "rule of thumb" but having a place to start your search is key.
So, what is the rule of thumb about mouthpiece rim? Think of a flat box in the middle of the room. You are standing on the box and cannot step off of it, but you must cross the room to get to the water fountain. You are not concerned at all about tipping over, but you you are probably a little concerned about moving across the room. Now imagine a round ball in the middle of the room that you are balancing on. You need to get across the room to reach the drinking fountain. Your options of mobility are numerous, but you will need a lot more energy and strength to remain standing on the ball and not fall on your face.
This is a bit of an extreme analogy, but it sets up our "mouthpiece rule of thumb" nicely. A rounder room tends to provide more flexability, but takes a little more support to keep your sound and focus steady. A wider or flatter rim will provide stability with not as much effort, but can limit your flexibility. The rest is up for you to determine in your trial. What have others experinece? Find out in the results of this week's polled answers from the Denis Wick Buzz community.
Community Response: "A flat rim allows for more flexability."
"I’ve played lots of mouthpieces and recently my new lead piece that has helped me out the most is a flat one."
"Personally round rim tuba mouth pieces aren't quite my thing, trombone or trumpet ones are pretty soild though."
"Having nerve damage from wisdom tooth surgery, I have found that the corner of my mouth no longer seals. The flat rimmed mouthpiece is the only thing that combats this.."
"After playing a variety of mouthpieces I found that a flat rim help a lot with flexibility and accuracy when attacking a sound"
"I generally prefer a more flatter rim, makes it easier to switch embouchure positions to play lower or higher notes."
"Playing on a thick flat rim I've found allows the most forgiveness with lip placement. Rounded rims require a more specific set to fully amplify the buzz, in my experience. Everybody's faces are different."
"I recently switched to a mouthpiece that’s slightly wider and I feel that the slotting and width of the registers feels more comfortable to change between. But I haven’t really explored rim roundness."
Community Response: "A rounded rim allows for more flexability."
"The round rim is more comfortable to move around this creating an ease in flexibility"
"Since I’ve been in band, I’ve always use a round rim and it made it more easier to octave jump with a round rim. I would like to use a flat rim for once."
"Round rims have helped with leaps from the high to low register. "
"Semiflat is a good option for comfort and semisharp bite to get better articulations"
"Too much of a sharp edge on a trumpet mouthpiece always leaves my lips feeling worse and very uncomfortable however curved rims always allow my lips to mould my embouchure better. "
"My experience with these two types have always been closer to rounded mouthpieces. The first mouthpiece I’ve ever purchased came from the Steven mead series for my euphonium. I fell In love with the rounded rim and bought my own mouthpiece to try and build my range and tone around a mouthpiece that already gave me a healthy sound for the euphonium I also purchased for college ."
"Round rim tends to give me personally, more flexibility in getting those higher and lower notes out while flat rim is better for building stability in playing."
"Yo pienso que la flexibilidad depende de que tan cómoda sientas tu boquilla! En mi caso yo trabajo con una Denis Wick 1.5c y la uso para tocar en un Jazz Cuartet y también para hacer lead trumpet con la orquesta o Big Band"
"I have a big face so I generally use flatter mouthpieces. It’s cool though. I am a firm believer that you should be able to make anything sound good."
"My experience has been the flatter, the more "cushion" it can give if a player wants to lay into the piece with some more pressure, at the cost of flexibility. And rounder rims can lead to more flexibility, but lose some of the comfort as far as pressure goes."
"Rounded rim seems to allow the lips to relax and let the air flow easier. "
"With a round mouthpiece I have been able to get more flexibility but playing in higher ranges I need a flat rimmed one."
"Rounded rims tend to give more flexibility but the diameter of the rim may be a bigger concern. A flat rim can be a great choice if the diameter is on the smaller size."
"General consensus is round rim=better flexibility, but more straining to play. However, many mouthpiece with flat rims might give excellent flexibility (like the classic DW design)."
"Rounded thin rim seem to give (me personally) more flexibility, but it comes at a cost of endurance as the thinner rims cut into my embouchure more."
"I play one two mouthpieces currently, a Pt-50 and a Helleberg, and I have to say, especially in the lower register, the rounded rim of the Pt-50 is more flexibly, but I feel like my range and endurance is better with the Helleberg. I’ve been wanting to try DW mouthpieces for a long time now."