Gallery: 23 sweep(s) rendered
15 changed files+15−15
docs/gallery/bow-amplitude-strike.jsonmodified+1−1View file
@@ -2,7 +2,7 @@
22 "sweep": {
33 "id": "bow-amplitude-strike",
44 "title": "Sheet: initial bow (drumstick strike)",
5- "text": "The same sweep excited by the default drumstick strike (30 g at 3 m/s) instead of the corner push.",
5+ "text": "The same sweep excited by the default drumstick strike (30 g at 3 m/s) instead of the corner push. The trend reverses: struck, the flat plate rings brightest, and the 6 mm bow gives the dullest sound, with about 10 dB less energy above 2 kHz than the default, presumably because the curvature couples the bending motion to the in-plane motion and its loss. The peak pressure is the same in all four clips, since the impact itself sets it.",
66 "param": "bowAmplitude",
77 "unit": "mm",
88 "scale": 0.001,
docs/gallery/bow-amplitude.jsonmodified+1−1View file
@@ -2,7 +2,7 @@
22 "sweep": {
33 "id": "bow-amplitude",
44 "title": "Sheet: initial bow (push and release)",
5- "text": "Real sheet metal has a bow of a few millimetres, which makes it a shallow shell with an asymmetric stiffness. A flat plate has a symmetric, purely hardening nonlinearity; the bowed sheet moves energy out of the inaudible sub-50 Hz range into the audible partials and produces the slow wobble of a real sheet.",
5+ "text": "Real sheet metal has a bow of a few millimetres, which makes it a shallow shell with an asymmetric stiffness. A flat plate has a symmetric, purely hardening nonlinearity; the bowed sheet moves energy out of the inaudible sub-50 Hz range into the audible partials and produces the slow wobble of a real sheet. In these clips the flat plate and the 1.5 mm bow are about 8 dB quieter than the 3 mm bow, and the centroid rises with the bow.",
66 "param": "bowAmplitude",
77 "unit": "mm",
88 "scale": 0.001,
docs/gallery/bow-shape-strike.jsonmodified+1−1View file
@@ -2,7 +2,7 @@
22 "sweep": {
33 "id": "bow-shape-strike",
44 "title": "Sheet: shape of the bow (drumstick strike)",
5- "text": "The same sweep excited by the default drumstick strike (30 g at 3 m/s) instead of the corner push.",
5+ "text": "The same sweep excited by the default drumstick strike (30 g at 3 m/s) instead of the corner push. The bow across the height again gives the lowest sound (a centroid near 460 Hz against 650 Hz for the bow across the width), while the peak pressure is the same for all three.",
66 "clips": [
77 {
88 "label": "across the width",
docs/gallery/bow-shape.jsonmodified+1−1View file
@@ -2,7 +2,7 @@
22 "sweep": {
33 "id": "bow-shape",
44 "title": "Sheet: shape of the bow (push and release)",
5- "text": "The same 3 mm sag as a bow across the width, across the height, or as a dish curved both ways.",
5+ "text": "The same 3 mm sag as a bow across the width, across the height, or as a dish curved both ways. With the push at a corner, the bow across the width gives the loudest and brightest sound and the bow across the height the lowest.",
66 "clips": [
77 {
88 "label": "across the width",
docs/gallery/push-amount.jsonmodified+1−1View file
@@ -2,7 +2,7 @@
22 "sweep": {
33 "id": "push-amount",
44 "title": "Push and release: push amount",
5- "text": "The corner is pushed by a given amount, held until the sheet settles, and released over 20 ms. A larger push stores more energy and, because the stiffness rises with deflection, produces a stronger pitch glide and a stronger transfer of energy to the higher partials.",
5+ "text": "The corner is pushed by a given amount, held until the sheet settles, and released over 20 ms. A larger push stores more energy and, because the stiffness rises with deflection, produces a stronger pitch glide and a stronger transfer of energy to the higher partials. The 2 and 5 mm pushes are nearly linear and very quiet, with most of their sound below 100 Hz; the 20 mm push is about 10 dB louder than the default and has far more energy above 500 Hz.",
66 "param": "pushAmount",
77 "unit": "mm",
88 "scale": 0.001,
docs/gallery/push-release.jsonmodified+1−1View file
@@ -2,7 +2,7 @@
22 "sweep": {
33 "id": "push-release",
44 "title": "Push and release: release time",
5- "text": "How fast the finger lets go. An instantaneous release is a step in force and excites every mode, giving a click; a release over tens of milliseconds excites only the lowest modes, as a fingertip does.",
5+ "text": "How fast the finger lets go. An instantaneous release is a step in force and excites every mode, giving a click that is about 24 dB louder at its peak than the default; a release over tens of milliseconds excites only the lowest modes, as a fingertip does, and the 50 ms release brings the centroid down to about 100 Hz.",
66 "param": "releaseTime",
77 "unit": "ms",
88 "scale": 0.001,
docs/gallery/push-sign.jsonmodified+1−1View file
@@ -2,7 +2,7 @@
22 "sweep": {
33 "id": "push-sign",
44 "title": "Push and release: with or against the bow",
5- "text": "The sheet has a 3 mm bow across its width. Pushing the corner in the direction of the bow and against it are not equivalent: the shell stiffness is asymmetric, so the two cases have different low-mode frequencies and a different wobble.",
5+ "text": "The sheet has a 3 mm bow across its width. Pushing the corner in the direction of the bow and against it are not equivalent: the shell stiffness is asymmetric, so the two cases have different low-mode frequencies and a different wobble. Here the push against the bow gives a quieter and lower sound, with about 20 dB less energy between 500 Hz and 2 kHz.",
66 "clips": [
77 {
88 "label": "+10 mm (with the bow)",
docs/gallery/size-strike.jsonmodified+1−1View file
@@ -2,7 +2,7 @@
22 "sweep": {
33 "id": "size-strike",
44 "title": "Sheet: size (drumstick strike)",
5- "text": "The same sweep excited by the default drumstick strike (30 g at 3 m/s) instead of the corner push.",
5+ "text": "The same sweep excited by the default drumstick strike (30 g at 3 m/s) instead of the corner push. Struck, the larger sheets are louder and lower, the 18 by 24 inch sheet reaching about 105 dB at its peak against 100 dB for the smallest; the 24 by 36 inch sheet again puts much of its energy below 100 Hz.",
66 "clips": [
77 {
88 "label": "8 x 12 in",
docs/gallery/size.jsonmodified+1−1View file
@@ -2,7 +2,7 @@
22 "sweep": {
33 "id": "size",
44 "title": "Sheet: size (push and release)",
5- "text": "Plate dimensions (width by height) at the same thickness. Mode frequencies scale with the inverse square of the size, so a larger sheet is lower and slower; it also radiates more efficiently.",
5+ "text": "Plate dimensions (width by height) at the same thickness. Mode frequencies scale with the inverse square of the size, so a larger sheet is lower and slower, and under the same 10 mm push it also stores less energy and sounds quieter. The 24 by 36 inch sheet is an extreme case: its lowest modes lie near 10 Hz, below hearing, and most of its peak pressure is this infrasound, so it sounds much fainter than its sound pressure level suggests.",
66 "clips": [
77 {
88 "label": "8 x 12 in",
docs/gallery/strike-mass.jsonmodified+1−1View file
@@ -2,7 +2,7 @@
22 "sweep": {
33 "id": "strike-mass",
44 "title": "Drumstick: stick mass",
5- "text": "The same speed with a lighter or heavier stick. A heavier stick carries more momentum, stays in contact longer, and pushes the sheet further, which favours the low modes; a light stick gives a short, bright tap.",
5+ "text": "The same speed with a lighter or heavier stick. A light stick gives a short contact and a bright tap. A heavier stick stays in contact longer, which by itself favours the low modes, but it also pushes the sheet further, and the extra energy reaches the high partials through the nonlinearity. In these clips the two effects roughly cancel between 10 and 60 g, and the 120 g stick is both the loudest and the brightest of the set. The peak contact force changes little with the mass (about 180 N at 10 g and 230 N at 120 g), because the local response of the sheet limits it.",
66 "base": {
77 "excitation": "strike"
88 },
docs/gallery/strike-position.jsonmodified+1−1View file
@@ -2,7 +2,7 @@
22 "sweep": {
33 "id": "strike-position",
44 "title": "Drumstick: strike position",
5- "text": "Where the sheet is struck decides which modes are excited: a strike at the center excites only modes that are symmetric about both axes, while a strike near an edge or a corner excites the twisting and edge modes as well.",
5+ "text": "Where the sheet is struck decides which modes are excited: a strike at the center excites only modes that are symmetric about both axes, while a strike near an edge or a corner excites the twisting and edge modes as well. The central strike is the loudest and the lowest of the four, since it drives the low symmetric modes that radiate best; the off-center default is the brightest.",
66 "base": {
77 "excitation": "strike"
88 },
docs/gallery/strike-speed.jsonmodified+1−1View file
@@ -2,7 +2,7 @@
22 "sweep": {
33 "id": "strike-speed",
44 "title": "Drumstick: stick speed",
5- "text": "A wooden stick tip (30 g effective mass) strikes the sheet at 70 percent of its width and 35 percent of its height. Speed sets both the loudness and the character: the contact force grows with speed, the contact shortens, and more energy reaches the high modes. The sound grows brighter as well as louder.",
5+ "text": "A wooden stick tip (30 g effective mass) strikes the sheet at 70 percent of its width and 35 percent of its height. Speed sets both the loudness and the character: the contact force grows with speed, the contact shortens, and more energy reaches the high modes. In these clips the peak level rises from about 87 dB at 0.5 m/s to 109 dB at 6 m/s, and the spectral centroid from about 190 Hz to 1.6 kHz, so the sound grows brighter as well as louder.",
66 "base": {
77 "excitation": "strike"
88 },
docs/gallery/strike-stiffness.jsonmodified+1−1View file
@@ -2,7 +2,7 @@
22 "sweep": {
33 "id": "strike-stiffness",
44 "title": "Drumstick: tip hardness",
5- "text": "The Hertz contact stiffness K stands for the hardness of the tip: a soft (rubber or felt) tip has a low K and a long, gentle contact that excites mainly the low modes; a hard tip (dense wood, or a metal beater) has a high K and a sharp click.",
5+ "text": "The Hertz contact stiffness K stands for the hardness of the tip. A soft (rubber or felt) tip has a low K and a long, gentle contact that excites mainly the low modes: the softest tip here is about 17 dB quieter than the default and has almost no energy above 2 kHz. A hard tip (dense wood, or a metal beater) has a high K and a larger contact force, which makes the strike louder; in these clips the brightness does not increase further beyond the default value.",
66 "base": {
77 "excitation": "strike"
88 },
docs/gallery/thickness-strike.jsonmodified+1−1View file
@@ -2,7 +2,7 @@
22 "sweep": {
33 "id": "thickness-strike",
44 "title": "Sheet: thickness (drumstick strike)",
5- "text": "The same sweep excited by the default drumstick strike (30 g at 3 m/s) instead of the corner push.",
5+ "text": "The same sweep excited by the default drumstick strike (30 g at 3 m/s) instead of the corner push. Struck, the trend is the opposite: the stick meets a stiffer sheet with a shorter, harder contact (the peak contact force rises from about 170 N at 0.6 mm to 700 N at 2 mm), so the thick sheets are louder and much brighter.",
66 "param": "h",
77 "unit": "mm",
88 "scale": 0.001,
docs/gallery/thickness.jsonmodified+1−1View file
@@ -2,7 +2,7 @@
22 "sweep": {
33 "id": "thickness",
44 "title": "Sheet: thickness (push and release)",
5- "text": "Bending stiffness grows with the cube of the thickness while mass grows linearly, so a thicker sheet has higher mode frequencies, and the same push is a smaller multiple of the thickness, which weakens the nonlinear effects. Gauges 24, 22, 18 and 14.",
5+ "text": "Bending stiffness grows with the cube of the thickness while mass grows linearly, so a thicker sheet has higher mode frequencies. The same 10 mm push, however, is a smaller multiple of the thickness, which weakens the nonlinear transfer of energy to the higher partials, and in these clips this effect wins: the sound becomes lower and purer with thickness even though the individual modes rise. Gauges 24, 22, 18 and 14.",
66 "param": "h",
77 "unit": "mm",
88 "scale": 0.001,