compute required amplification power

#!/usr/bin/env python3

import math

def amp_power_required(lreq, spl, hr, d2, dref):
    dBW = lreq - spl + (20 * math.log10(d2 / dref)) + hr
    return math.pow(10, dBW / 10)

# Speaker sensitivity measured at 1 W at 1 meter distance
spls = [82, 84, 86, 88, 91, 92, 94, 96, 98]

head_room = 6 # dB
distance = 3 # meters
desired_loudness = 85 # dB

print(f"Loudness: {desired_loudness} dB @ {distance} meters")
print(f"Head room: {head_room} dB")
for spl in spls:
    W = amp_power_required(desired_loudness, spl, head_room, distance, 1)
    print(f"W: {W // 1}\tSPL: {spl} ")

"""
Example:

Loudness: 85 dB @ 3 meters
Head room: 6 dB
W: 71.0	SPL: 82 
W: 45.0	SPL: 84 
W: 28.0	SPL: 86 
W: 17.0	SPL: 88 
W: 9.0	SPL: 91 
W: 7.0	SPL: 92 
W: 4.0	SPL: 94 
W: 2.0	SPL: 96 
W: 1.0	SPL: 98 
"""