Resonance

What it is

Resonance is the tendency of an object to vibrate in response to a frequency it is naturally inclined to produce. Use the free chromatic tuner to check yourself on this. It sits in the acoustics section of the dictionary.

On a violin, this appears in two ways. The body has its own resonant frequencies and responds more strongly to some pitches than others. And the open strings vibrate sympathetically when a related pitch is played.

The combined effect is that some notes make the instrument ring noticeably more than others.

Sympathetic string vibration

The most directly useful form for a player.

Play a D on the A string. The open D string, untouched, begins to vibrate. The instrument produces more sound than the single stopped note accounts for.

This happens because the two pitches share a frequency relationship. The vibrating string transmits energy through the bridge, and the open string, tuned to a frequency present in that energy, picks it up and vibrates in turn.

It works for octaves, fifths, fourths, thirds and other related intervals, more strongly for simpler relationships.

Resonance as an intonation check

This is the practical payoff, and it is one of the most useful tools a violinist has.

A note played exactly in tune sets the related open strings ringing. A note slightly off does not, or does so weakly.

The difference is audible and, crucially, it is audible while playing. A student can hear whether a note is in tune from the amount of ring, without needing an external reference.

Advanced players use this continuously and unconsciously. It is one of the reasons experienced violinists play more in tune than the theoretical difficulty of a fretless instrument would suggest.

Teaching it explicitly accelerates a student's intonation considerably. Listening for ring is a more reliable and more immediate feedback mechanism than listening for pitch alone.

Why some keys sound better

A consequence of the same principle.

The violin's open strings are G, D, A and E. Music in keys built around those pitches produces more sympathetic resonance, because more of the notes align with the open strings.

D major, G major, A major and their relatives ring. E flat major and A flat major ring considerably less.

This is why so much violin repertoire is written in sharp keys, why an orchestral piece in D major sounds brighter than the same music transposed to E flat, and why students often find sharp keys easier to play in tune.

It is a genuine acoustic property of the instrument, not a convention.

Body resonance

Separate from string resonance and less directly usable.

The body has resonant frequencies determined by its dimensions, plate thicknesses, arching and enclosed air volume. Notes near those frequencies sound fuller and project more.

Two main resonances matter: the air resonance, determined mainly by the body volume and f-hole size, and the main wood resonance, determined by the plates.

An instrument where these fall at useful pitches sounds even across its range. One where they fall awkwardly may have notes that stand out or drop back.

This is part of what makes one instrument better than another and it is not adjustable by the player.

When resonance is unwanted

Occasionally.

An open string left ringing under a subsequent note produces resonance that muddies the texture. Players damp it with a finger.

In quiet passages, an instrument that rings strongly can sustain past where the note should have stopped.

In very resonant halls, the instrument's own resonance adds to the room's and can produce more sustain than the music wants.

These are minor concerns compared to the benefits.

How it is taught

Usually as an intonation tool, and it is worth teaching early.

The exercise: play a note, listen for whether the instrument rings. Adjust the finger slightly and listen again. The ring appears and disappears with small changes in pitch.

Students who learn to hear this develop reliable intonation faster than those working from pitch memory alone, because the feedback is immediate and physical rather than requiring comparison with a remembered sound.

The exercise that teaches it

Simple, and worth doing until the sound is familiar.

Play a scale slowly on the D and A strings. On each note, listen for whether the instrument rings beyond the note itself.

Some notes will ring strongly, particularly those related to the open strings. Others will not.

Then deliberately play a note slightly sharp, then slightly flat, then in tune, listening to the ring appear and disappear.

Most students have never noticed this and can hear it immediately once told what to listen for. It converts intonation from a guess into something with audible feedback.

Why sharp keys are easier

Worth explaining rather than leaving students to notice it as an unexplained pattern.

Music in D, G, A and E major uses many notes that align with the open strings. Those notes ring, the instrument sounds fuller, and the ringing gives constant intonation feedback.

Music in E flat, A flat and D flat major uses few such notes. Less ring, less feedback, and the instrument sounds comparatively closed.

This is why so much violin repertoire is in sharp keys, and it is a real acoustic property rather than a habit of composers.

There is a limit to what reading can fix. To have someone check your tone and sound production directly, book a no-commitment evaluation lesson. Private and group violin lessons in Sugar Hill, Cumming and Berkeley Lake, or call 470-789-2422.