Text: I was looking at some spectrum envelopes of instruments on my analyzer tonight when it suddenly dawned on me how we can tell instrument sounds apart. I was looking at an oboe WAV file and noticed that there wasn't much consistency of which harmonic (1st, 2nd, 3rd, etc.) was the strongest across pitches. But what was constant was the frequencies of the peaks and valleys in the spectrum as a whole. Of course that makes sense. Those are the natural resonances of the tube! Then I looked at the write-up of my experimental reed pipes on Dr. Liljencrants' page. Sure enough! There were those spectrum envelopes based on the natural resonance frequencies of the pipes. And they certainly didn't look like the oboe or saxophone envelopes. Does this explain why an orchestral trumpet is so much nicer than an organ reed trumpet? Perhaps the fact that an orchestral trumpet must be in tune with so many pitches gives it a more even envelope compared to am organ reed whose resonator only needs to be tuned to the pitch being produced? -------------------- John Page has the more accurate description here. High speed photography shows that a properly curved tongue never actually strikes the shallot. The tongue flattens out with a very thin slit visible between the shallot and tongue. While it seems intuitively that the tip should finally hit the shallot, some kind of whip action, the greater curve at the tip prevents this. Flat spots or kinks will cause rattle, and another cause is a twisted tongue, sometimes harder to diagnose because there are not flats or kinks, yet the rattle is apparent. John Nolte [ If a metal reed were electrically isolated from the metal shallot, [ a capacitance meter circuit would provide an electric signal which [ varies with the motion of the reed. Modern conductive plastic [ material could be placed on the face of the shallot to yield a [ transducer whose conductance is in proportion to the contact area. [ -- Robbie As a rider to the reed voicing thread: if while experimenting with the curvature of a tongue the brass is curved and straightened several times, a mild hardening occurs preventing the tongue from ever attaining the correct curve. The only solution is to scrap the tongue and start again with a fresh -- very flat -- piece of brass. Normally "half-hard" brass is used, and the curvature is achieved by clamping the tongue onto the burnisher (a flat piece of hardwood) at its root end, and is curved with a single stroke from the clamped end, to the tip. The ideal burnisher is a cigar-shaped round tool with handle. Its slightly convex surface helps to keep the burnishing pressure central on the tongue, preventing a twist of the curve. Successful reed voicing is a skill achieved after much practice, and after a lot of tongues have been thrown away!

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