Re: objective measures of spatial impression of music recordings (Jonathan James Digby )

Subject: Re: objective measures of spatial impression of music recordings From: Jonathan James Digby <digbyphonic@xxxxxxxx> Date: Sat, 31 Jan 2026 09:39:49 -0000 This is a multipart message in MIME format. ------=_NextPart_000_00FF_01DC9295.8B4F1370 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Dear Frederico, =20 Heinrich Kuttruff in Room Acoustics (2009) states the following on IACC: =20 * Even within one seat width, the =EF=AC=82uctuations of the parameter are = quite high although it is inconceivable that a listener in a concert hall w= ill perceive any change in spatial impression when he moves his head by a f= ew centimetres. This shows us that still more research on signi=EF=AC=81can= t spaciousness parameters is needed. =20 There is a strong and curious connection between Griesinger=E2=80=99s =E2= =80=98InterAural Difference or IAD=E2=80=99 and Blumlein shuffling. Allow me to share a link to a recent conference paper (if nothing else, the= Blumlein and Gerzon references may help): https://urldefense.com/v3/__https://digbyphonic.com/research/rs2025/2025110= 5-DIGBY-HILL-WIGGINS-rs2025-paper.html__;!!BDUfV1Et5lrpZQ!WvSodN3XVlvjKU7M0= sJxcap1iNrkzQnWqzpRprHkQpFE8K_1RToim4W4PlKEC9BWV7fsXkmwvMe8pPtVhMIukz4$=20 =20 You could use the Reaper template made available for =E2=80=98alt_Blumlein = shuffling=E2=80=99 to derive your sum and difference with and without the l= ow-frequency first order shelf eq: https://urldefense.com/v3/__https://digbyphonic.com/research/rs2025/RS2025s= upplements.html__;!!BDUfV1Et5lrpZQ!WvSodN3XVlvjKU7M0sJxcap1iNrkzQnWqzpRprHk= QpFE8K_1RToim4W4PlKEC9BWV7fsXkmwvMe8pPtVQMHCP7k$=20 =20 As you may be aware, equalization of the difference channel affects the int= er-channel timing below the corner frequency of the low-frequency boost: th= is was Blumlein=E2=80=99s remarkable insight. =20 Side note:=20 After the Abstract in Griesinger=E2=80=99s paper the proposed =E2=80=98Diff= use field Transfer Function (DTF)=E2=80=99 is instead shown as =E2=80=98DFT= =E2=80=99 throughout =E2=80=93 common terminology for Discrete Fourier Tran= sform. Quite unfortunate. =20 I hope this helps. Best of luck. // Jonathan J Digby Audio Engineer Researcher +44 7833 151181 =20 From: Frederico Pereira <pereira.frederico@xxxxxxxx>=20 Sent: 29 January 2026 21:56 Subject: objective measures of spatial impression of music recordings =20 Dear list, Hoping this message finds you all well. =20 I have two audio signals of music pieces. One is mixed for standard stereo= presentation, while the other is a spatial audio mix for binaural presenta= tion. I am looking to find objective measures that could indicate differences in = spatial impression, like perceived "spaciousness" / "immersion" / "envelopm= ent". =20 I think a consensual metric would be the Left / Right channels IACC (1/3 oc= t bands).=20 Besides IACC, I am thinking of using the InterAural Difference (IAD), as su= ggested by Griesinger ("Griesinger, D. (1999, April). Objective measures of= spaciousness and envelopment. In Proceedings of the AES 16th International= Conference, Rovaniemi, Finland.). =20 I am here seeking advice on any other suggestions you might have that could= be used on the signal analysis of a continuous 2 channel audio signal. Also, are you aware of any available software toolbox that would have any k= ind of this "spatial impression" analysis conveniently implemented? =20 Thank you for your help, Kind regards, =20 - Frederico --=20 Frederico Pereira Mobile:+351 937356301 Audio and Acoustics, Perception Interaction and Usability Email:pereira.frederico@xxxxxxxx <mailto:Email%3Apereira.frederico@xxxxxxxx= om>=20 ------=_NextPart_000_00FF_01DC9295.8B4F1370 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable <html xmlns:v=3D"urn:schemas-microsoft-com:vml" xmlns:o=3D"urn:schemas-micr= osoft-com:office:office" xmlns:w=3D"urn:schemas-microsoft-com:office:word" = xmlns:m=3D"http://schemas.microsoft.com/office/2004/12/omml" xmlns=3D"http:= //www.w3.org/TR/REC-html40"><head><meta http-equiv=3DContent-Type content= =3D"text/html; charset=3Dutf-8"><meta name=3DGenerator content=3D"Microsoft= Word 15 (filtered medium)"><style></style></head><body lang=3DEN-GB link=3Dblue vlink=3Dpurple style=3D'wo= rd-wrap:break-word'><div class=3DWordSection1><p class=3DMsoNormal><span st= yle=3D'font-size:11.0pt;font-family:"IBM Plex Sans Text",sans-serif;mso-far= east-language:EN-US'>Dear Frederico,<o:p></o:p></span></p><p class=3DMsoNor= mal><span style=3D'font-size:11.0pt;font-family:"IBM Plex Sans Text",sans-s= erif;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=3DMso= Normal><span style=3D'font-size:11.0pt;font-family:"IBM Plex Sans Text",san= s-serif;mso-fareast-language:EN-US'>Heinrich Kuttruff in <i>Room </i>Acoust= ics (2009) states the following on IACC:<o:p></o:p></span></p><p class=3DMs= oNormal><span style=3D'font-size:11.0pt;font-family:"IBM Plex Sans Text",sa= ns-serif;mso-fareast-language:EN-US'><o:p> </o:p></span></p><ul style= =3D'margin-top:0cm' type=3Ddisc><li class=3DMsoListParagraph style=3D'margi= n-left:0cm;mso-list:l0 level1 lfo2'><span style=3D'font-size:11.0pt;font-fa= mily:"IBM Plex Sans Text",sans-serif;mso-fareast-language:EN-US'>Even withi= n one seat width, the =EF=AC=82uctuations of the parameter are quite high a= lthough it is inconceivable that a listener in a concert hall will perceive= any change in spatial impression when he moves his head by a few centimetr= es. This shows us that still more research on signi=EF=AC=81cant spaciousne= ss parameters is needed.<o:p></o:p></span></li></ul><p class=3DMsoNormal><s= pan style=3D'font-size:11.0pt;font-family:"IBM Plex Sans Text",sans-serif;m= so-fareast-language:EN-US'><o:p> </o:p></span></p><p class=3DMsoNormal= ><span style=3D'font-size:11.0pt;font-family:"IBM Plex Sans Text",sans-seri= f;mso-fareast-language:EN-US'>There is a strong and curious connection betw= een Griesinger=E2=80=99s =E2=80=98InterAural Difference or IAD=E2=80=99 and= Blumlein shuffling.<o:p></o:p></span></p><p class=3DMsoNormal><span style= =3D'font-size:11.0pt;font-family:"IBM Plex Sans Text",sans-serif;mso-fareas= t-language:EN-US'>Allow me to share a link to a recent conference paper (if= nothing else, the Blumlein and Gerzon references may help):<o:p></o:p></sp= an></p><p class=3DMsoNormal><span style=3D'font-size:11.0pt;font-family:"IB= M Plex Sans Text",sans-serif;mso-fareast-language:EN-US'><a href=3D"https:/= /urldefense.com/v3/__https://digbyphonic.com/research/rs2025/20251105-DIGBY= -HILL-WIGGINS-rs2025-paper.html__;!!BDUfV1Et5lrpZQ!WvSodN3XVlvjKU7M0sJxcap1= iNrkzQnWqzpRprHkQpFE8K_1RToim4W4PlKEC9BWV7fsXkmwvMe8pPtVhMIukz4$">https://d= igbyphonic.com/research/rs2025/20251105-DIGBY-HILL-WIGGINS-rs2025-paper.htm= l</a><o:p></o:p></span></p><p class=3DMsoNormal><span style=3D'font-size:11= .0pt;font-family:"IBM Plex Sans Text",sans-serif;mso-fareast-language:EN-US= '><o:p> </o:p></span></p><p class=3DMsoNormal><span style=3D'font-size= :11.0pt;font-family:"IBM Plex Sans Text",sans-serif;mso-fareast-language:EN= -US'>You could use the Reaper template made available for =E2=80=98alt_Blum= lein shuffling=E2=80=99 to derive your sum and difference with and without = the low-frequency first order shelf eq:<o:p></o:p></span></p><p class=3DMso= Normal><span style=3D'font-size:11.0pt;font-family:"IBM Plex Sans Text",san= s-serif;mso-fareast-language:EN-US'><a href=3D"https://urldefense.com/v3/__= https://digbyphonic.com/research/rs2025/RS2025supplements.html__;!!BDUfV1Et= 5lrpZQ!WvSodN3XVlvjKU7M0sJxcap1iNrkzQnWqzpRprHkQpFE8K_1RToim4W4PlKEC9BWV7fs= XkmwvMe8pPtVQMHCP7k$">https://digbyphonic.com/research/rs2025/RS2025supplem= ents.html</a><o:p></o:p></span></p><p class=3DMsoNormal><span style=3D'font= -size:11.0pt;font-family:"IBM Plex Sans Text",sans-serif;mso-fareast-langua= ge:EN-US'><o:p> </o:p></span></p><p class=3DMsoNormal><span style=3D'f= ont-size:11.0pt;font-family:"IBM Plex Sans Text",sans-serif;mso-fareast-lan= guage:EN-US'>As you may be aware, equalization of the <i>difference</i> cha= nnel affects the inter-channel timing below the corner frequency of the low= -frequency boost: this was Blumlein=E2=80=99s remarkable insight.<o:p></o:p= ></span></p><p class=3DMsoNormal><span style=3D'font-size:11.0pt;font-famil= y:"IBM Plex Sans Text",sans-serif;mso-fareast-language:EN-US'><o:p> </= o:p></span></p><p class=3DMsoNormal><span style=3D'font-size:11.0pt;font-fa= mily:"IBM Plex Sans Text",sans-serif;mso-fareast-language:EN-US'>Side note:= <o:p></o:p></span></p><p class=3DMsoNormal><span style=3D'font-size:11.0pt= ;font-family:"IBM Plex Sans Text",sans-serif;mso-fareast-language:EN-US'>Af= ter the Abstract in Griesinger=E2=80=99s paper the proposed =E2=80=98Diffus= e field Transfer Function (DTF)=E2=80=99 is instead shown as =E2=80=98DFT= =E2=80=99 throughout =E2=80=93 common terminology for Discrete Fourier Tran= sform.<o:p></o:p></span></p><p class=3DMsoNormal><span style=3D'font-size:1= 1.0pt;font-family:"IBM Plex Sans Text",sans-serif;mso-fareast-language:EN-U= S'>Quite unfortunate.<o:p></o:p></span></p><p class=3DMsoNormal><span style= =3D'font-size:11.0pt;font-family:"IBM Plex Sans Text",sans-serif;mso-fareas= t-language:EN-US'><o:p> </o:p></span></p><p class=3DMsoNormal><span st= yle=3D'font-size:11.0pt;font-family:"IBM Plex Sans Text",sans-serif;mso-far= east-language:EN-US'>I hope this helps.<o:p></o:p></span></p><p class=3DMso= Normal><span style=3D'font-size:11.0pt;font-family:"IBM Plex Sans Text",san= s-serif;mso-fareast-language:EN-US'>Best of luck.<o:p></o:p></span></p><p c= lass=3DMsoNormal><span style=3D'font-size:9.0pt;font-family:"IBM Plex Mono"= '>//<o:p></o:p></span></p><p class=3DMsoNormal><span style=3D'font-size:9.0= pt;font-family:"IBM Plex Mono"'>Jonathan J Digby<o:p></o:p></span></p><p cl= ass=3DMsoNormal><span style=3D'font-size:9.0pt;font-family:"IBM Plex Mono"'= >Audio Engineer<o:p></o:p></span></p><p class=3DMsoNormal><span style=3D'fo= nt-size:9.0pt;font-family:"IBM Plex Mono"'>Researcher<o:p></o:p></span></p>= <p class=3DMsoNormal><span style=3D'font-size:9.0pt;font-family:"IBM Plex M= ono"'>+44 7833 151181<o:p></o:p></span></p><p class=3DMsoNormal><span style= =3D'font-size:11.0pt;font-family:"IBM Plex Sans Text",sans-serif;mso-fareas= t-language:EN-US'><o:p> </o:p></span></p><div style=3D'border:none;bor= der-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=3DMsoNormal= style=3D'margin-left:36.0pt'><b><span lang=3DEN-US style=3D'font-size:11.0= pt;font-family:"Calibri",sans-serif'>From:</span></b><span lang=3DEN-US sty= le=3D'font-size:11.0pt;font-family:"Calibri",sans-serif'> Frederico Pereira= <pereira.frederico@xxxxxxxx> <br><b>Sent:</b> 29 January 2026 21:56= <br><b>Subject:</b> objective measures of spatial impression of music recor= dings<o:p></o:p></span></p></div><p class=3DMsoNormal style=3D'margin-left:= 36.0pt'><o:p> </o:p></p><div><div><div><p class=3DMsoNormal style=3D'm= argin-left:36.0pt'>Dear list,<o:p></o:p></p></div><div><p class=3DMsoNormal= style=3D'margin-left:36.0pt'>Hoping this message finds you all well.<o:p><= /o:p></p></div></div><div><p class=3DMsoNormal style=3D'margin-left:36.0pt'= ><o:p> </o:p></p></div><div><p class=3DMsoNormal style=3D'margin-left:= 36.0pt'>I have two audio signals  of music pieces. One is mixed for st= andard stereo presentation, while the other is a spatial audio mix for bina= ural presentation.<o:p></o:p></p></div><div><p class=3DMsoNormal style=3D'm= argin-left:36.0pt'>I am looking to find objective measures that could indic= ate differences in spatial impression, like perceived "spaciousness&qu= ot; / "immersion" / "envelopment".<o:p></o:p></p></div>= <div><p class=3DMsoNormal style=3D'margin-left:36.0pt'><o:p> </o:p></p= ></div><div><p class=3DMsoNormal style=3D'margin-left:36.0pt'>I think a con= sensual metric would be the Left / Right channels IACC (1/3 oct bands).&nbs= p;<o:p></o:p></p></div><div><p class=3DMsoNormal style=3D'margin-left:36.0p= t'>Besides IACC, I am thinking of using the InterAural Difference (IAD= ), as suggested by <span style=3D'font-size:10.0pt;font-family:"Arial"= ,sans-serif'>Griesinger </span>("<span style=3D'font-size:10.0pt;= font-family:"Arial",sans-serif'>Griesinger, D. (1999, April). Objective mea= sures of spaciousness and envelopment. In<span class=3Dgmail-apple-converte= d-space> </span><i>Proceedings of the AES 16th International Conferenc= e, Rovaniemi, Finland</i>.).</span><o:p></o:p></p></div><div><p class=3DMso= Normal style=3D'margin-left:36.0pt'><o:p> </o:p></p></div><div><p clas= s=3DMsoNormal style=3D'margin-left:36.0pt'><span style=3D'font-family:"Aria= l",sans-serif'>I am here seeking advice on any other suggestions you might = have that could be used on the signal analysis of a continuous 2 channel au= dio signal.</span><o:p></o:p></p></div><div><p class=3DMsoNormal style=3D'm= argin-left:36.0pt'><span style=3D'font-family:"Arial",sans-serif'>Also, are= you aware of any available software toolbox that would have any kind of th= is "spatial impression" analysis conveniently implemented?</= span><o:p></o:p></p></div><div><p class=3DMsoNormal style=3D'margin-left:36= .0pt'><o:p> </o:p></p></div><div><div><p class=3DMsoNormal style=3D'ma= rgin-left:36.0pt'>Thank you for your help,<o:p></o:p></p></div><div><p clas= s=3DMsoNormal style=3D'margin-left:36.0pt'>Kind regards,<o:p></o:p></p></di= v></div><div><p class=3DMsoNormal style=3D'margin-left:36.0pt'><o:p> <= /o:p></p></div><div><p class=3DMsoNormal style=3D'margin-left:36.0pt'>&nbsp= ;- Frederico<o:p></o:p></p></div><p class=3DMsoNormal style=3D'margin-left:= 36.0pt'><span class=3Dgmailsignatureprefix>-- </span><o:p></o:p></p><div><d= iv><p class=3DMsoNormal style=3D'margin-left:36.0pt'>Frederico Pereira<br>M= obile:+351 937356301<o:p></o:p></p><div><p class=3DMsoNormal style=3D'margi= n-left:36.0pt'><i>Audio and Acoustics, Perception Interaction and Usability= </i><o:p></o:p></p><div><div><p class=3DMsoNormal style=3D'margin-left:36.0= pt'><a href=3D"mailto:Email%3Apereira.frederico@xxxxxxxx" target=3D"_blank= ">Email:pereira.frederico@xxxxxxxx</a><o:p></o:p></p></div></div></div></d= iv></div></div></div></body></html>= ------=_NextPart_000_00FF_01DC9295.8B4F1370--

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