Did you realize that LOUD does not equal INTENSE?
Once you realize this fact, you are well on your way to achieving the subtlety and nuance that makes the violin speak with greater inflection and expressive range.
When I first start to teach my students how to play violin expressively, I give them this general guideline: get louder when the melody goes higher and get softer when the melody goes lower in pitch. This is a starting point.
But as student progress in their expressive abilities, I start asking them for INTENSITY or CALM rather than volume.
So what is the difference?
Well, we don’t always want to rely on changes in dynamics for our phrasing and expression.
Have you ever heard someone whisper angrily?
It is emotional, intense, yet quiet. This is a WONDERFUL tool to learn to play with quiet intensity.

Let’s briefly review how we change dynamics on violin:
To play louder, we can

–Use more bow weight
–Use more bow speed
–Play closer to the bridge. (or all 3 for a HUGE change in volume)

To play softer, we do the opposite, i.e., use less bow weight, less bow speed, and go further from the bridge.

To achieve intensity, we can play louder, but to achieve that magical “quiet intensity”, we can:

–increase our vibrato speed
–punch the notes more with the bow (accents, colle’, etc.)
–elongate the notes more (tenuto, or loure)
–project our tone by focusing it like a laser…this is sort of louder….but it’s not just volume….it is just more focused, like a flashlight on a straight beam rather than diffused, fuzzy light. This can be accomplished by manipulating the sounding point combined with bow weight and speed, and it can also be enhanced by left hand technique, namely vibrato. Most professionals utilize both vibrato AND bow technique to achieve quiet intensity.

The only way to learn this is in experimentation and exploration. Choose an emotion that might come in handy for musical expression, maybe sorrow, anger, love. Try whispering a statement that represents that emotion to you. Notice how your diction changes, the pacing of your words, your breath.
Next try playing a minor scale with quiet intensity, reflecting the emotion you just whispered. Your diction is your bow articulation and left hand articulation.
Your breath is your bow speed.
Your choice of words are the notes.
The speed and width of your vibrato will emphasize the emotion you are trying to convey.

The more you can work on and develop these subtle techniques, the more you can make noticeable contrasts. That’s what etudes like Wohlfahrt Opus 45 are for…..to INCREASE your ability to create contrasts by developing these skills that are considered too subtle to make a difference.