Tone is a frequent topic among harp players, but it is not a simple concept that is well defined.  Tone is the Holy Grail of harmonica.  It is related to the musical timbre of the instrument, but most often encompasses other playing elements as well.

Tone is about
That sound: good.
That sound: Clean and full and Big and fat and
Round and warm and Sweet and clear.  or
Notes that sound:
Bitter and shrill or Light and airy or Bright and piercing or
Powerful and edgy...
That aren't weak and wimpy or tentative, but that
Speak out and Sing,
Confidently, with
Your voice.
Or softly whisper
Your secrets.
That rip through you and
Grab your insides and
Tear the emotions out of you.
That's good tone.

Tone production relates to the whole of playing a note: how it is attacked, how it is sustained, what (loudness variation) dynamics are applied, how it ends: abruptly or smoothly or tailing off, and what effects are used on it when, such as vibratos and/or tremolos, or slurs or other combinations with other notes.  A player with good tone uses many different techniques, timbres, effects, and varieties of note shaping to produce his/her notes.  Notes shouldn't just happen.  Notes should be willfully created.  All of them.

Phrasing relates to how notes are played in succession, whether smoothly with legato or abruptly with degrees of pizzicato or staccato, how dynamics and musical space are used to frame notes and passages and set them apart from other phrases in the music.  In grammar, a phrase is a related set of words formed to express an idea.  In music, a phrase is a related set of notes used to express a musical idea.  Phrasing, while distinct from tone, is not unrelated to it.  In much improvised play, it is the musical idea that is maintained from instance to instance of a song, not the precise notes and timing.  Just like when you have an opinion or idea to express in words, you don't always say it the same way, using the same words in the same order with the same emphasis--so it goes with musical ideas too.  Musical ideas can be replicated in phrases using different notes and timings, so long as the feel remains consistent.  What has this got to do with tone?  Well, if you take away specific note sequences and timings for the basis of a musical idea, you have reduced the number of musical elements left to worry about.  Tone (strictly timbre) is one of those remaining musical elements.  Rhythm is another that is partially left.. the groove--the underlying beat pattern and beat emphasis is normally kept consistent to maintain the feel of a phrase, even if the rhythmic patterns of the note durations is not kept the same.  The vibrato element of tone is one element that can be used in setting the feel to a phrase.  The tone of the notes should be appropriate for the phrase being played--the tone should augment the musical expression.  The tone can work together with the other phrasing elements--including dynamics, note durations, and rests--to enhance the musical statement that is a phrase.

Tone comes from the entire musical system that produces the note, from the instrument to the player to the setting to the amplification.  Of this sound production system, the player is by far the largest most dominant factor when it comes to tone.  Through out these pages I talk about techniques that enhance your ability to make different sounds with the harp, and provide a basis for overall good tone.  Here are some elements to pay particular attention to, to pick up on when you see them associated with other topics and techniques:

Common Elements of Good Tone

Effect Combinations

Though the elements of tone are described individually, they are often used in combination to produce the final sound.  Just because they are discussed separately doesn't mean they are used in isolation.  There are lots of examples of effects used in combination.. here are a few:

Practicing Tone

Practicing tone means practicing all the elements that go into tone production, some of which are mentioned above.  It does not mean playing lots of notes.  It means playing each note for a long time, manipulating it with your mouth and hands and tongue and breath to try to make it sound as good as you can, in as many different ways as you can.  Practicing and playing with good tone is not hurrying to the next note, it is lingering on each note to show the details.

Practicing tone means listening to the sound of each note, and being aware of the details.  The more you know, the more you will notice, the more details you will hear.  You can actually practice tone by learning what different playing techniques sound like, and listening to identify what techniques of note formation and shaping are being used.  The songs Misty and Stormy Seas are full of examples you can try to identify and analyze to see how the techniques contribute to the tone and the music.  The section on diatonic techniques includes sound samples to help you learn to identify and understand what the player is doing.  Once you can hear and know and think about what can be done, only then can you try to do it.

What the player is doing.  Is doing.  Try to do it.  Doing.  Do.  Something active, not passive.  Good tone is active.  It is willfully produced, it is not something that just happens because of the harp you use or the amplification equipment you play through.  Tone is something the player puts in the note. Something the player does, actively, willfully, by exercising control over him/herself, his breathing, her playing, their music.

But the timbre of different instruments, amps, and mics does vary.  The degree or possibility of certain kinds of tonal manipulations can be different on different equipment and under different conditions.  But remember, good tone is not passive, not just something that happens.  Good tone is control over notes that is done by the player.

Practice playing one note for a long time, listening to its sound, its voice, its nuances.  Change it subtly, change it dramatically, play it soft, play it loud, play it gradually softer and softer, play it gradually louder and louder.  Play it straight, play it with vibrato, change the depth of the vibrato, waver the pitch, oscillate the volume, let it fade out, make it end abruptly.  Hold it for a long time.

I think it is good to practice tone--especially a big fat full round horn-like tone--on lower key (pitch range) harps (say, key of A or lower is better).  The lower notes require a larger resonance chamber, and you have to open up and get big on the inside more for low key harps than on higher key harps (say key of C and higher).  I even suggest working on extended-range low key harps, like a low D or even a "tenor" C like a Hohner 365.  Bends and vibratos on low harps require a tighter grip on the air stream, and larger mouth and muscle movements--and maybe I just like their sound.  Since different key harps have their own character, it is good to practice tone on a full range of keys, including low, medium, and high harps (say, D and higher).  Work on higher key harps requires smaller movements and more subtle control of the muscles.  You can't really get a big fat horn-like sound out of a high key harp, and it's harder to get a bright, brittle, piercing, or flute-like sound on a low harp.

Whenever you play, whatever you play, give each note its due.