WD Blue 1TB: 30 dB (seek) / 29 dB (idle average)
WD Blue 2TB: 27 dB (seek) / 23 dB (idle average)

WD Blue 3TB: 27 dB (seek) / 23 dB (idle average)  

WD Blue 4TB: 27 dB (seek) / 23 dB (idle average)

WD Blue 6TB: 28 dB (seek) / 25 dB (idle average)

WD Red Plus 1TB: 25 dB (seek) / 24 dB (idle average)      
WD Red Plus 2TB: 27 dB (seek) / 23 dB (idle average)    
WD Red Plus 3TB: 27 dB (seek) / 23 dB (idle average)    
WD Red Plus 4TB: 27 dB (seek) / 23 dB (idle average)   
WD Red Plus 6TB: 30 dB (seek) / 25 dB (idle average)   

WD Red Plus 8TB: 30 dB (seek) / 27 dB (idle average)     
WD Red Plus 10TB: 38 dB (seek) / 34 dB (idle average)    
WD Red Plus 12TB: 29 dB (seek) / 20 dB (idle average)  
WD Red Plus 14TB: 29 dB (seek) / 20 dB (idle average)

WD Red Pro 2TB: 31 dB (seek) / 29 dB (idle average)  
WD Red Pro 4TB: 36 dB (seek) / 29 dB (idle average)

WD Red Pro 8TB: 36 dB (seek) / 29 dB (idle average)

WD Red Pro 10TB: 36 dB (seek) / 20 dB (idle average)

WD Red Pro 12TB: 36 dB (seek) / 20 dB (idle average)

WD Red Pro 14TB: 36 dB (seek) / 20 dB (idle average)

WD Purple 1TB: 22 dB (seek) / 21 dB (idle average)  
WD Purple 2TB: 24 dB (seek) / 23 dB (idle average)       
WD Purple 3TB: 24 dB (seek) / 23 dB (idle average)         
WD Purple 4TB: 28 dB (seek) / 25 dB (idle average)         

WD Purple 6TB: 28 dB (seek) / 25 dB (idle average)       

WD Purple 8TB: 29 dB (seek) / 27 dB (idle average)      
WD Purple 10TB: 29 dB (seek) / 20 dB (idle average)      
WD Purple 12TB: 29 dB (seek) / 20 dB (idle average)

WD Purple Pro 8TB: 29 dB (seek) / 27 dB (idle average)  
WD Purple Pro 10TB: 38 dB (seek) / 34 dB (idle average) 
WD Purple Pro 12TB: 29 dB (seek) / 20 dB (idle average)
WD Purple Pro 14TB: 36 dB (seek) / 20 dB (idle average)    

WD Purple Pro 18TB: 27 dB (seek) / 20 dB (idle average)

WD Gold 1TB: 28 dB (seek) / 25 dB (idle average)
WD Gold 2TB: 28 dB (seek) / 25 dB (idle average)
WD Gold 4TB: 36 dB (seek) / 29 dB (idle average)
WD Gold 6TB: 36 dB (seek) / 29 dB (idle average)

WD Gold 8TB: 36 dB (seek) / 20 dB (idle average)
WD Gold 10TB: 36 dB (seek) / 20 dB (idle average)
WD Gold 12TB: 36 dB (seek) / 20 dB (idle average)

WD Ultrastar 16TB: 36 dB (seek) / 20 dB (idle average)

WD Ultrastar 18TB: 36 dB (seek) / 20 dB (idle average)

SEAGATE Ironwolf 1TB: 23 dB (seek) / 21 dB (idle average)  
SEAGATE Ironwolf 2TB: 19 dB (seek) / 21 dB (idle average)
SEAGATE Ironwolf 3TB: 25 dB (seek) / 23 dB (idle average)    
SEAGATE Ironwolf 4TB: 25 dB (seek) / 23 dB (idle average)    
SEAGATE Ironwolf 6TB: 28 dB (seek) / 27 dB (idle average)  
SEAGATE Ironwolf 8TB: 28 dB (seek) / 27 dB (idle average)

SEAGATE Ironwolf 10TB: 32 dB (seek) / 28 dB (idle average)

SEAGATE Ironwolf 12TB: 32 dB (seek) / 28 dB (idle average)

SEAGATE Ironwolf Pro 4TB: 30 dB (seek) / 28 dB (idle average)

SEAGATE Ironwolf Pro 6TB: 30 dB (seek) / 28 dB (idle average)  
SEAGATE Ironwolf Pro 8TB: 30 dB (seek) / 28 dB (idle average)

SEAGATE Ironwolf Pro 10TB: 30 dB (seek) / 28 dB (idle average)

SEAGATE Ironwolf Pro 12TB: 32 dB (seek) / 28 dB (idle average)  
SEAGATE Ironwolf Pro 14TB: 32 dB (seek) / 28 dB (idle average)

SEAGATE Ironwolf Pro 16TB: 32 dB (seek) / 28 dB (idle average)

SEAGATE IronWolf Pro 18To: 32 dB (seek) / 28 dB (idle average)  
SEAGATE IronWolf Pro 20To: 32 dB (seek) / 28 dB (idle average)

Note:
"Seek" = Active
Idle = Sleep or low use

The noise level can be indicated by some manufacturers in "bels" which is equivalent to 1/10 dB.
For exemple : 2.8 Bels = 28 dB