928 

14 CFR Ch. I (1–1–14 Edition) 

Pt. 36, App. A 

(e) Step 5: Recompute new slope s

′

(i, k), in-

cluding one for an imaginary 25th band, as 
follows: 

s

′

(3,

k)=s

′

(4,

k) 

s

′

(4,

k)=SPL

′

(4,

k)¥SPL

′

(3,

k) 

• 

• 

s

′

(

i,k)=SPL

′

(

i,k)¥SPL

′

(

i¥1,k) 

• 

• 

s

′

(24,

k)=SPL

′

(24,

k)¥SPL

′

(23,

k) 

s

′

(25,

k)=s

′

(24,

k) 

(f) Step 6: For i, from 3 through 23, com-

pute the arithmetic average of the three ad-
jacent slopes as follows: 

s¯(i,k)=

1

⁄

3

[

s

′

(

i,k)+s

′

(

i+1,k)+s

′

(

i+2,k)] 

(g) Step 7: Compute final one-third octave- 

band sound pressure levels, SPL

′ 

(i,k), by be-

ginning with band number 3 and proceeding 
to band number 24 as follows: 

SPL

′

(3,

k)=SPL(3,k) 

SPL

′

(4,

k)=SPL

′

(3,k)+

s¯(3,k) 

• 

• 

SPL

′

(

i,k)=SPL

′

(i¥1,k)+

s¯(i¥1,k) 

• 

• 

SPL

′

(24,

k)=SPL

′

(23,k)+

s¯(23,k) 

(h) Setp 8: Calculate the differences, F 

(i,k), between the original sound pressure 
level and the final background sound pres-
sure level as follows: 
F(i,k)=SPL(i,k)-SPL

′

(

i,k) 

and note only values equal to or greater than 
1.5. 

(i) Step 9: For each of the relevant one- 

third octave bands (3 through 24), determine 
tone correction factors from the sound pres-
sure level differences F (i, k) and Table A36– 
2. 

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