How Long Is a 7 Hz Wavelength?
A 7 Hz sound wave has a wavelength of 49.03 meters, 4903.07 cm, 160.86 feet (160 feet and 10.34 inches) or 1930.34 inches when traveling in air at 20°C (68°F).
The formula for the wavelenght is λ = c/f where:
cis the celerity (speed) of sound = 343.21 m/s or 1126.03 ft/s in air at 20°C (68°F).fis the frequency = 7 Hz
λ of 49.03 meters, or 160.86 feet.
7 Hz Wavelength Depending on Temperature
The speed of sound in air depends on temperature. Here is how the wavelenght of a 7 Hz sound wave will vary according to temperature:
| Temp (°C) | Temp (°F) | 7 Hz wavelength (m) | 7 Hz wavelength (ft) |
|---|---|---|---|
| -40 | -40 | 43.7261 | 143.4583 |
| -35 | -31 | 44.1925 | 144.9884 |
| -30 | -22 | 44.6540 | 146.5025 |
| -25 | -13 | 45.1107 | 148.0011 |
| -20 | -4 | 45.5629 | 149.4847 |
| -15 | 5 | 46.0107 | 150.9538 |
| -10 | 14 | 46.4541 | 152.4086 |
| -5 | 23 | 46.8934 | 153.8497 |
| 0 | 32 | 47.3286 | 155.2775 |
| 5 | 41 | 47.7598 | 156.6922 |
| 10 | 50 | 48.1871 | 158.0943 |
| 15 | 59 | 48.6107 | 159.4840 |
| 20 | 68 | 49.0307 | 160.8618 |
| 25 | 77 | 49.4470 | 162.2278 |
| 30 | 86 | 49.8599 | 163.5824 |
| 35 | 95 | 50.2694 | 164.9259 |
| 40 | 104 | 50.6756 | 166.2586 |
7 Hz Half Wavelength and Standing Waves
The half wavelength of a 7 Hz sound wave is 24.52 meters, 2451.53 cm, 80.43 feet (80 feet and 5.17 inches) or 965.17 inches when travelling in air at 20°C (68°F).
Modes (or standing waves) will occur at 7 Hz in rooms where two opposing walls (axial mode), edges (tangential mode) or corners (oblique mode) are spaced by a distance d = nλ/2 where:
nis a natural (positive integer greater than or equal to 1)λis the 7 Hz wavelength = 49.03 meters, or 160.86 feet in air at 20°C (68°F).
7 Hz Standing Waves Distances
| n | Distance (m) | Distance (ft) |
|---|---|---|
| 1 | 24.52 | 80.43 |
| 2 | 49.03 | 160.86 |
| 3 | 73.55 | 241.29 |
| 4 | 98.06 | 321.72 |
| 5 | 122.58 | 402.15 |
Given the relatively large 7 Hz half wavelength, standing waves will occur at that frequency in small listening rooms.
You can try to minimze the room modes at 7 Hz by trying different speaker positions, listening positions or by placing bass traps. These can absorb frequencies as low as 63 Hz.
How To Convert 7 Hz To ms
A Hz (Hertz) is a cycle (or period) per second.
Because a 7 Hz wave will ocillate 7 times per second, we can find the time of a single cycle (or period) with the formula p = 1/f where:
fis the frequency of the wave = 7 Hz
The result will be expressed in seconds, so let's multiply by 1000 to get miliseconds:
1 / 7 Hz * 1000 = 142.86 ms.