Rowuk used the term "partial series" in my recent post (copper or cheated?). I've seen this term used over and over here but must confess that I don't know it's meaning. Please explain "partial series". thanks.......... crow

You would do well to do an internet search for "overtones" or for the "partial series" in order to get a more complete explanation than I'm about to give. When we hear a musical note we're not hearing just one single frequency, but instead are hearing a mixture of frequencies, all of which are based on the basic frequency (or fundamental) of the note we're trying to play. What makes one instrument sound unique (e.g. trumpet) from another (e.g. clarinet) when playing the same pitch is determined by which of these additional frequencies (or "overtones") are present in varying strengths in the sound of each instrument. Mathematically, the frequencies of the partials are simply integer multiplicands of the original frequency. For example, we tune to A=440, which means that the air is vibrating at 440 times each second. If you simply multiply that x1, x2, x3, x4, etc. up until 13 or 14 (I can't remember the exact upper limit beyond which the human ear can't detect them), you get the frequencies of all the overtones, or partials, which make up that series. Clarinets have their unique tone because they have strong partials on all the odd numbers and relatively weak (or non-existent) partials on the even numbers, which is why they don't overblow at the octave. Flutes have essentially only the first 2 partials strong (x1, x2) with a weak third partial and then nonexistent partials above that, which explains why their tone is relatively weak compared to other instruments and why when you overblow on a flute you get an octave higher than the original note and then when you overblow again you get a note a fifth higher but weaker and out of tune. Brass instruments have all the partials present but in varying degrees of strength, accounting for different tone colors. That's why, with one set of valves pressed (or no valves pressed) we can play a pedal note (which is actually the fundamental for that particular combination of valves) and we can overblow to get an octave (what we usually think of as the lowest "real" note with that valve combination). Overblowing again we get a fifth higher (think no valves, pedal C, low C, G) which is the x3 partial. Overblow again and we get the x4 partial (C) which is two octaves above the fundamental pitch, the pedal note for that valve combination. Overblow again and we get the E, which is the x5 partial, then G, then comes the 7th partial, which is out of tune but is recognizable as a flat high Bb. Then comes the 8th partial, which is 3 octaves higher than the fundamental, the high C. And so on and so on. The 11th partial is out of tune as well as the 7th, if I remember correctly. Interestingly, we find that each successive overblowing creates an increasingly smaller interval -- octave (low c, if thinking of no valves), Fifth (G), Fourth (C), major 3rd (E), minor third (high G), flat minor third (out of tune high Bb), sharp major second (high C), major second (high D), and then above that the partials outline a major scale so it's possible to play an entire scale using no valves (if one can play up to double high C and beyond). That's a brief introduction into what the partial series is but I urge you to search it out and get a much more detailed (and probably more accurate) description.

It's the sequence of note you can get with the same valve combonation. So, for the open horn: C (pedal), C, G, C, E, G, Bb, C, etc... Why they're called partials, I couldn't tell you, but that's what people mean when they refer to a partial.

Crow, the fundemental note of a trumpet is when one wavelength covers the complete length of the instrument. Trumpeters refer to the fundemental as Pedal C. If we get two wavelengths in the instrument by buzzing higher and blowing a bit more strongly, that is the first "partial" because the horn is now divided in two parts acoustically. This first partial is our low C. Playing a bit higher will put 3 wavelengths in the horn. This is the second partial and our G sounds. The next partial is 4 wavelengths - our third space C, 2 octaves above the fundemental. The next partial puts 5 wavelengths in the horn and that is our 4th space E. The next one is 6 wavelengths and our G on top of the staff (an octave above the second partial with 3 wavelengths). 7 wavelengths is Bb above the staff, 8 is high C, 9 is D, 10 is E, 11 is an out of tune note between F and F#, 12 is high G. If you compare the numbers, you see doubling the amount of wavelengths is always an octave higher. The series is called "PARTIAL" because it "divides" up the wind column into "parts".

Crow, the fundemental note of a trumpet is when one wavelength covers the complete length of the instrument. Trumpeters refer to the fundemental as Pedal C. If we get two wavelengths in the instrument by buzzing higher and blowing a bit more strongly, that is the first "partial" because the horn is now divided in two parts acoustically. This first partial is our low C. Playing a bit higher will put 3 wavelengths in the horn. This is the second partial and our G sounds. The next partial is 4 wavelengths - our third space C, 2 octaves above the fundemental. The next partial puts 5 wavelengths in the horn and that is our 4th space E. The next one is 6 wavelengths and our G on top of the staff (an octave above the second partial with 3 wavelengths). 7 wavelengths is Bb above the staff, 8 is high C, 9 is D, 10 is E, 11 is an out of tune note between F and F#, 12 is high G. If you compare the numbers, you see doubling the amount of wavelengths is always an octave higher. The series is called "PARTIAL" because it "divides" up the wind column into "parts".