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                                                Posted:
                            
                                5 years ago                            
                            
                                4 juil. 2020, 08:03 UTC−4                            
                        
                        
                                                    Dear Harsch
maybe I do not fully understand your question but the Sound Pressure Level (SPL) is simply :
SPL=10*log (p/p_ref)^2 dB, with p_ref being the the reference pressure, typically 10^-12 Pa in air (different p_ref in liquids).
SPL  is measored in dB (non-dimensional) whereas pressure is measured in Pascal for SI units. Imperial units can be applied of course.
Hope this helps.
/Ulf
                                                 
                                                
                            Dear Harsch
maybe I do not fully understand your question but the Sound Pressure Level (SPL) is simply :
SPL=10*log (p/p_ref)^2 dB, with p_ref being the the reference pressure, typically 10^-12 Pa in air (different p_ref in liquids).
SPL  is measored in dB (non-dimensional) whereas pressure is measured in Pascal for SI units. Imperial units can be applied of course.
Hope this helps.
/Ulf                        
                                                
                                                                                                            
                                             
                        
                        
                                                
    
        Please login with a confirmed email address before reporting spam
     
    
 
                                                Posted:
                            
                                5 years ago                            
                            
                                11 juil. 2020, 06:13 UTC−4                            
                        
                        
                                                    
  Dear Harsch
  maybe I do not fully understand your question but the Sound Pressure Level (SPL) is simply :
  SPL=10*log (p/p_ref)^2 dB, with p_ref being the the reference pressure, typically 10^-12 Pa in air (different p_ref in liquids).
  SPL  is measored in dB (non-dimensional) whereas pressure is measured in Pascal for SI units. Imperial units can be applied of course.
  Hope this helps.
  /Ulf
Thanks for the reply,
I'll explain you. I am trying to optimize a room low band frequency response. When I measure the acpr.p_t in octave bands then the variation is quite huge, around 20-25dB. But when I just change it to acpr.Lp(Sound Pressure Level) then it gets changed to a target error of around 1-2dB. 
I am new to Comsol and didn't find a good difference between Total Acoustic Pressure Field(acpr.p_t) and Sound Pressure Level(acpr.Lp) in the user manual as well. What I mean is the that the relative distribution should not change when we change the units. Am I right? I have attanched reference images for both. Please check if you guide me on this.
                                                 
                                                
                            >Dear Harsch
>maybe I do not fully understand your question but the Sound Pressure Level (SPL) is simply :
>SPL=10*log (p/p_ref)^2 dB, with p_ref being the the reference pressure, typically 10^-12 Pa in air (different p_ref in liquids).
>SPL  is measored in dB (non-dimensional) whereas pressure is measured in Pascal for SI units. Imperial units can be applied of course.
>Hope this helps.
>/Ulf
Thanks for the reply,
I'll explain you. I am trying to optimize a room low band frequency response. When I measure the acpr.p_t in octave bands then the variation is quite huge, around 20-25dB. But when I just change it to acpr.Lp(Sound Pressure Level) then it gets changed to a target error of around 1-2dB. 
I am new to Comsol and didn't find a good difference between Total Acoustic Pressure Field(acpr.p_t) and Sound Pressure Level(acpr.Lp) in the user manual as well. What I mean is the that the relative distribution should not change when we change the units. Am I right? I have attanched reference images for both. Please check if you guide me on this.