This tool provides the **horizontal and vertical spread** in (inches/feet/meters).

Enter

- H – the Horizontal dispersion angle
- V – the Vertical dispersion angle
- Distance away from the speaker

(the dispersion angle is sometimes referred to as the directivity angle in a specification sheet).

The unit of the spread is the same as that of the distance

**Background**

Most speakers have dispersion specifications in terms of Horizontal (H) and Vertical (V) angles. Numbers in the data sheet are specified in degrees.This dictates the **Spread** at a distance **d** away from the speaker using the formula:

**Spread = 2*d*tan(∠/2)**

where ∠ is the angle in radians

The wider the dispersion, the more uniform the sound propagation and therefore listening experience.

**Example Calculation**

Consider a speaker with Horizontal and Vertical dispersion angles 90^{o} and 60^{o}, respectively. At a distance of 5 meters away, the horizontal spread is 10 meters while the vertical spread is 5.77 meters.

As the distance increases, so also does the spread. For instance at twice the distance of 10 meters away from the speaker, the horizontal and vertical spread is 20 m and 11.55 m, respectively.

While the spread increases with distance, the Sound Pressure Level goes down. This tool provides the SPL at a distance away from the speaker.

**Related Audio System Design Calculators**

- Speaker Amplifier Matching – compute the amplification required to achieve a desired sound level
- Speaker Max SPL – find the maximum sound pressure level of a speaker from its peak rating
- Speaker Sensitivity – use the efficiency of a speaker to compute its sensitivity
- SPL for Multiple Speakers – find the noise level for multiple speakers connected in series at a known distance away from the source
- SPL Distance – can be used to compute the sound pressure level at a fixed distance away from the audio source.
- SPL Addition – use this tool to find the combined sound or noise level due to a number of different sources at any given location