Re: Image-source model with consideration of air absorption (William Hartmann )


Subject: Re: Image-source model with consideration of air absorption
From:    William Hartmann  <hartmann@xxxxxxxx>
Date:    Tue, 22 Nov 2011 08:03:11 -0500
List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>

Junfeng, Emmanuel, In a Green's function formulation, absorption can be included by adding a small imaginary part to the wave number or propagation vector k. Bill Emmanuel Vincent wrote: > The URL http://www.irisa.fr/metiss/members/evincent/Roomsimove.zip is > correct. > > I don't know about the Green function but you can read it from the code. > > Emmanuel > > > On 11/22/2011 11:57 AM, Junfeng Li wrote: >> Dear Emmanuel, >> >> Thanks a lot for your information. >> I found that Roomsim (http://media.uws.ac.uk/~campbell/Roomsim/) >> implemented this function. your Roomsimove cannot be found from the >> URL that you provided below. Could you check it again? >> >> My another concern is what the Green function ( exp(jwd/(4*pi*d) ) >> in the free field should be when it is extended when considering the >> air absorption effect? >> >> Do you have any idea? or references on this issue? >> (Though I believe it is a very easy question, I cannot find the >> answer, ....) >> >> Thanks a lot again. >> >> Cheers, >> >> Junfeng >> >> >> >> On 11/11/22, Emmanuel Vincent<emmanuel.vincent@xxxxxxxx> wrote: >> >>> Dear Junfeng, >>> >>> Roomsim (http://media.uws.ac.uk/~campbell/Roomsim/) as well as our >>> command-line software Roomsimove (for moving >>> sources)(http://www.irisa.fr/metiss/members/evincent/Roomsimove.zip) >>> account for this. >>> >>> Emmanuel >>> >>> -- >>> Emmanuel Vincent >>> METISS Project-Team >>> INRIA Rennes - Bretagne Atlantique >>> Campus de Beaulieu, 35042 Rennes cedex, France >>> Phone: +332 9984 2269 - Fax: +332 9984 7171 >>> Web: http://www.irisa.fr/metiss/members/evincent/ >>> >>> >>> On 11/22/2011 11:28 AM, Junfeng Li wrote: >>>> Dear list, >>>> >>>> I am now considering to generate room impulse response (RIR) using >>>> the well-known image-source method. However, I found that the >>>> traditional image-source method only considered the absorption of >>>> enclosure surfaces, without the consideration of air absorption. >>>> However, the air absorption should be also an important factor >>>> which affect the simulated RIR. >>>> >>>> To reformulate the image-source method, the Green function ( >>>> exp(jwd/(4*pi*d) ) in the free field should be extended to that >>>> with the consideration of air absorption effect. I searched this >>>> problem for some days. However, I did not find any reference. >>>> >>>> Could anyone point some references on this issue or the (source >>>> code of) improved image-source method that implemented this idea? >>>> >>>> Thank you so much in advance. >>>> >>>> Best regards, >>>> Junfeng >> > >


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