Subject: Re: perceptual evaluation of cochlear models From: Mark Cartwright <mcartwright@xxxxxxxx> Date: Wed, 1 Oct 2014 18:36:30 -0500 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>--047d7b15ac6d60873c050464f9f1 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Hello auditory list, So, in regards to Francesco's third item (the role of space), what is the latest research in partial loudness and masking in regards to spatial position/separation? Does a model exist yet for which an angle of separation is input and its effect on partial loudness and masking is output (e.g. either a binary yes/no release from masking or the change to the masking threshold, etc.)? Or any similar function...? Thanks! Mark On Mon, Sep 8, 2014 at 11:44 AM, ftordini@xxxxxxxx <ftordini@xxxxxxxx> wrote: > Hello Joshua, > Thank you for the great expansion and for the further reading suggestions= . > I may add three more items to the list, hoping to be clear in my > formulation. > > (1) A perhaps provocative question could be: is there a loudness or more > loudnesses? (is loudness domain dependant?) Should we continue to tackle > loudness as an invariant percept across classes once we move onto the mor= e > complex domain of real sounds? Rephrasing: once we define an ecologically > valid taxonomy of real world sounds (e.g. starting from Gaver), can we > expect the loudness model we want to improve to be valid across > (sound)classes? Hard to say, I would attempt 'yes', but granting differen= t > paramenters tuning according to the dominant context (say, speech, music, > or environmental sounds). *[hidden question: are we actually, ever, > purely "naive" listeners?]* > > (2) A related question: can we jump form the controlled lab environment > into the wild in a single step? I'd say no - The approach followed by > EBU/ITU using real world, long, stimuli is highly relevant to the > broadcasting world, but it is hard to distinguish between energetic and > informational masking effects using real program material mostly made of > speech and music. Sets of less informative sources taken from > environmental, natural sounds may be a good compromise - a starting point > to address basic expansions of the current loudness model(s). Such > stragegies and datasets are missing (to my knowledge). > > (3) The role of space. Psysiologically driven models (Moore, Patterson) > are supported mostly by observations obtained using non-spatialized, or > dichotic, scenes to better reveal mechanisms sorting out the spatial > confound. However, while spatial cues are considered to play a secondary > role in scene alaysis, spatial release from masking is, on the other hand= , > quite important in partial loudness modeling, at least from the energetic > masking point of view and especially for complex sources. This is even mo= re > relevant for asymmetric sources distributions. I feel there is much to do > before we can address this aspect with confidence, even limiting the scop= e > to non-moving sources, but more curiosity with respect to spatial variabl= es > may be valuable when designing listening experiments with natural sounds. > > *[If one asks a sound engineer working on a movie soundtrack: "where do > you start form?", he will start talking about panning, to set the scene > using his sources (foley, dialogue, music, ...) and **then** adjust > levels/eq ...] * > > Best, > -- > Francesco Tordini > http://www.cim.mcgill.ca/sre/personnel/ > http://ca.linkedin.com/in/ftordini > > > > > >----Messaggio originale---- > >Da: joshua.reiss@xxxxxxxx > >Data: 06/09/2014 13.43 > >A: "ftordini@xxxxxxxx"<ftordini@xxxxxxxx>, "AUDITORY@xxxxxxxx"< > AUDITORY@xxxxxxxx> > >Ogg: RE: RE: perceptual evaluation of cochlear models > > > >Hi Francesco (and auditory list in case others are interested), > >I'm glad to hear that you've been following the intelligent mixing > research. > > > >I'll rephrase your email as a set of related questions... > > > >1. Should we extend the concepts of loudness and partial loudness to > complex material? - Yes, we should. Otherwise, what is it good for? That > is, what does it matter if we can accurately predict perceived loudness o= f > a pure tone, or the just noticeable differences between pedestal incremen= ts > for white or pink noise, or the partial loudness of a tone in the presenc= e > of noise, etc., if we can't predict loudness outside artificial laborator= y > conditions. I suppose it works as validation of an auditory model, but it= s > still very limited. > >On the other hand, if we can extend the model to complex sounds like > music, conversations, environmental sounds, etc., then we provide robust > validation a general model of human loudness perception. The model can th= en > be applied to metering systems, audio production, broadcast standards, > improved hearing aid design and so on. > > > >2. Can we extend the concepts of loudness and partial loudness to comple= x > material? - Yes, I think so. Despite all the issues and complexity, there= 's > a tremendous amount of consistency in perception of loudness, especially > when one considers relative rather than absolute perception. Take a TV sh= ow > and the associated adverts. The soundtracks of both may have dialogue, > foley, ambience, music,..., all with levels over time. Yet consistently > people can identify when the adverts are louder than the show. Same is tr= ue > when someone changes radio stations, and in music production, sound > engineers are always identifying and dealing with masking when there are > multiple simultaneous sources. > >I think the issues that many issues relating to complex material may hav= e > a big effect on perception of timbre or extraction of meaning or emotion, > but only a minor effect on loudness. > > > >3. Can we extend current auditory models of loudness and partial loudnes= s > to complex material? - Hard to say. The state of the art in those based o= n > deep understanding of the human hearing system (Glasberg, Moore et al... = ; > Fastl, Zwicker, et al...) were not developed with complex material in min= d, > though when used with complex material, researchers have reported good bu= t > far from great agreement with perception. Modification, though still in > agreement with auditory knowledge, shows improvement, but more research i= s > needed. > >On the other hand, we have models based mostly on listening test data, > but incorporating little auditory knowledge. I'm thinking here of the > EBU/ITU loudness standards. They are based largely on Gilbert Soulodre's > excellent listening test results > >(G. Soulodre, Evaluation of Objective Loudness Meters, 116th AES > Convention, 2004.), and represent a big improvement on say, just applying= a > loudness contour to signal RMS. But they are generally for a fixed > listening level, may overfit the data, difficult to generalise, and rarel= y > give deeper insight into the auditory system. Furthermore, like Moore's > model, these have also shown some inadequacies when dealing with a wider > range of content (Pestana, Reiss & Barbosa, "Loudness Measurement of > Multitrack Audio Content Using Modifications of ITU-R BS.1770," 134th AES > Convention, 2013). > >So I think rather than just extend, we may need to modify, improve, and > go back to the drawing board on some aspects. > > > >4. How could one develop an auditory model of loudness and partial > loudness for complex material? > >- Incorporate the validated aspects from prior models, but reassess any > compromises. > >- Use listening test results from a wide range of complex material. > Perhaps a metastudy could be performed, taking listening test results fro= m > many publications for both model creation and validation. > >- Build in known aspects of loudness perception that were left out of > existing models due to resources and the fact that they were built for la= b > scenarios (pure tones, pink noise, sine sweeps...). In particular, I'm > thinking forward and backward masking. > > > >5. What about JND? - I would stay clear of this. I'm not even aware of > anecdotal evidence suggesting consistency in just noticeable differences > for say, a small change in the level of one source in a mix. And I think > one can be trained to identify small partial loudness differences. I've h= ad > conversations with professional mixing engineers who detect a problem wit= h > a mix that I don't notice until they point it out. But the concept of > extending JND models to complex material is certainly very interesting. > > > >________________________________________ > >From: ftordini@xxxxxxxx <ftordini@xxxxxxxx> > >Sent: 04 September 2014 15:45 > >To: Joshua Reiss > >Subject: R: RE: perceptual evaluation of cochlear models > > > >Hello Joshua, > >Interesting, indeed. Thank you. > > > >So the question is - to what extent can we stretch the concepts of > loudness > >and partial loudness for complex material such as meaningful noise (aka > music), > >where attention and preference is likely to play a role as opposed to > beeps and > >sweeps ? That is - would you feel comfortable to give a rule of a thumb > for a > >JND for partial loudness, to safely rule out other factors when mixing? > > > >I was following your intelligent mixing thread - although I've missed th= e > >recent one you sent me - and my question above relates to the possibilit= y > to > >actually "design" the fore-background perception when you do automatic > mixing > >using real sounds... > >I would greatly appreciate any comment form your side. > > > >Best wishes, > >Francesco > > > > > >>----Messaggio originale---- > >>Da: joshua.reiss@xxxxxxxx > >>Data: 03/09/2014 16.00 > >>A: "AUDITORY@xxxxxxxx"<AUDITORY@xxxxxxxx>, "Joachim > Thiemann" > ><joachim.thiemann@xxxxxxxx>, "ftordini@xxxxxxxx"<ftordini@xxxxxxxx> > >>Ogg: RE: perceptual evaluation of cochlear models > >> > >>Hi Francesco and Joachim, > >>I collaborated on a paper that involved perceptual evaluation of partia= l > >loudness with real world audio content, where partial loudness is derive= d > from > >the auditory models of Moore, Glasberg et al. It showed that the predict= ed > >loudness of tracks in multitrack musical audio disagrees with perception= , > but > >that minor modifications to a couple of parameters in the model would > result in > >a much closer match to perceptual evaluation results. See > >>Z. Ma, J. D. Reiss and D. Black, "Partial loudness in multitrack > mixing," AES > >53rd International Conference on Semantic Audio in London, UK, January > 27-29, > >2014. > >> > >>And in the following paper, there was some informal evaluation of the > use of > >Glasberg, Moore et al's auditory model for loudness and/or partial > loudness > >could be used to mix multitrack musical audio. Though the emphasis was o= n > >application rather than evaluation, it also noticed issues with the mode= l > when > >applied to real world content. See, > >>D. Ward, J. D. Reiss and C. Athwal, "Multitrack mixing using a model of > >loudness and partial loudness," 133rd AES Convention, San Francisco, Oct= . > 26- > >29, 2012. > >> > >>These may not be exactly what you're looking for, but hopefully you fin= d > it > >interesting. > >>________________________________________ > >>From: AUDITORY - Research in Auditory Perception < > AUDITORY@xxxxxxxx> > >on behalf of Joachim Thiemann <joachim.thiemann@xxxxxxxx> > >>Sent: 03 September 2014 07:12 > >>To: AUDITORY@xxxxxxxx > >>Subject: Re: perceptual evaluation of cochlear models > > >> > >>Hello Francesco, > >> > >>McGill alumni here - I did a bit of study in this direction, you can > >>read about it in my thesis: > >>http://www-mmsp.ece.mcgill.ca/MMSP/Theses/T2011-2013.html#Thiemann > >> > >>My argument was that if you have a good auditory model, you should be > >>able to start from only the model parameters and be able to > >>reconstruct the original signal with perceptual transparency. I was > >>looking at this in the context of perceptual coding - a perceptual > >>coder minus the entropy stage effectively verifies the model. If > >>artefacts do appear, they can (indirectly) tell you what you are > >>missing. > >> > >>I was specifically looking at gammatone filterbank methods, so there > >>is no comparison to other schemas - but I hope it is a bit in the > >>direction you're looking at. > >> > >>Cheers, > >>Joachim. > >> > >>On 2 September 2014 20:39, ftordini@xxxxxxxx <ftordini@xxxxxxxx> > wrote: > >>> > >>> Dear List members, > >>> I am looking for references on perceptual evaluation of cochlear > models - > >>> taken form an analysis-synthesis point of view, alike the work > introduced > >in > >>> Homann_2002 (Frequency analysis and synthesis using a Gammatone > filterbank, > >>> =C2=A74.3). > >>> > >>> Are you aware of any study that tried to assess the performance of > >>> gammatone-like filterbanks used as a synthesis model? (AKA, what ar= e > the > >>> advantages over MPEG-like schemas?) > >>> > >>> All the best, > >>> Francesco > >>> > >>> http://www.cim.mcgill.ca/sre/personnel/ > >>> http://ca.linkedin.com/in/ftordini > --047d7b15ac6d60873c050464f9f1 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable <div dir=3D"ltr">Hello auditory list,<div><br></div><div>So, in regards to = Francesco's third item (the role of space), what is the latest research= in partial loudness and masking in regards to spatial position/separation?= Does a model exist yet for which an angle of separation is input and its e= ffect on partial loudness and masking is output (e.g. either a binary yes/n= o release from masking or the change to the masking threshold, etc.)? Or an= y similar function...?</div><div><br></div><div>Thanks!</div><div><br></div= ><div>Mark</div></div><div class=3D"gmail_extra"><br><div class=3D"gmail_qu= ote">On Mon, Sep 8, 2014 at 11:44 AM, <a href=3D"mailto:ftordini@xxxxxxxx"= >ftordini@xxxxxxxx</a> <span dir=3D"ltr"><<a href=3D"mailto:ftordini@xxxxxxxx= bero.it" target=3D"_blank">ftordini@xxxxxxxx</a>></span> wrote:<br><blo= ckquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #c= cc solid;padding-left:1ex"><div></div><div>Hello Joshua, <br>Thank you for = the great expansion and for the further reading suggestions. <br>I may add = three more items to the list, hoping to be clear in my formulation.=C2=A0 <= br><br>(1) A perhaps provocative question could be: is there a loudness or = more loudnesses? (is loudness domain dependant?) Should we continue to tack= le loudness as an invariant percept across classes once we move onto the mo= re complex domain of real sounds? Rephrasing: once we define an ecologicall= y valid taxonomy of real world sounds (e.g. starting from Gaver), can we ex= pect=C2=A0the loudness model we want to improve to be valid across (sound)c= lasses? Hard to say, I would attempt 'yes', but granting different = paramenters tuning according to the dominant context (say, speech, music, o= r environmental sounds). <i>[hidden question: are we actually, ever, purely= "naive" listeners?]</i><br><br>(2) A related question: can we ju= mp form the controlled lab environment into the wild in a single step?=C2= =A0 I'd say no - The approach followed by EBU/ITU using real world, lon= g, stimuli is highly relevant to the broadcasting world, but it is hard to = distinguish between energetic and informational masking effects using real = program material mostly made of speech and music. Sets of less informative = sources taken from environmental, natural sounds may be a good compromise -= a starting point to address basic expansions of the current loudness model= (s).=C2=A0 Such stragegies and datasets are missing (to my knowledge).<br><= br>(3) The role of space. Psysiologically driven models (Moore, Patterson) = are supported mostly by observations obtained using non-spatialized, or dic= hotic, scenes to better reveal mechanisms sorting out the spatial confound.= However, while spatial cues are considered to play a secondary role in sce= ne alaysis, spatial release from masking is, on the other hand, quite impor= tant in partial loudness modeling, at least from the energetic masking poin= t of view and especially for complex sources. This is even more relevant fo= r asymmetric sources distributions. I feel there is much to do before we ca= n address this aspect with confidence, even limiting the scope to non-movin= g sources, but more curiosity with respect to spatial variables may be valu= able when designing listening experiments with natural sounds. <br><i>[If o= ne asks a sound engineer working on a movie soundtrack: "where do you = start form?", he will start talking about panning, to set the scene us= ing his sources (foley, dialogue, music, ...) and **then** adjust levels/eq= ...] <br></i></div><div>=C2=A0</div><div><font color=3D"#444444">Best,<br>= --</font></div><div><font color=3D"#444444">Francesco Tordini</font></div><= div><a href=3D"http://www.cim.mcgill.ca/sre/personnel/" target=3D"_blank"><= font color=3D"#444444">http://www.cim.mcgill.ca/sre/personnel/</font></a><b= r><a href=3D"http://ca.linkedin.com/in/ftordini" target=3D"_blank"><font co= lor=3D"#444444">http://ca.linkedin.com/in/ftordini</font></a><br><br></div>= <div>=C2=A0</div><div>=C2=A0<br><br>>----Messaggio originale----<br>>= Da: <a href=3D"mailto:joshua.reiss@xxxxxxxx" target=3D"_blank">joshua.rei= ss@xxxxxxxx</a><br>>Data: 06/09/2014 13.43<br>>A: "<a href=3D"= mailto:ftordini@xxxxxxxx" target=3D"_blank">ftordini@xxxxxxxx</a>"&l= t;<a href=3D"mailto:ftordini@xxxxxxxx" target=3D"_blank">ftordini@xxxxxxxx= t</a>>, "<a href=3D"mailto:AUDITORY@xxxxxxxx" target=3D"_bla= nk">AUDITORY@xxxxxxxx</a>"<<a href=3D"mailto:AUDITORY@xxxxxxxx= MCGILL.CA" target=3D"_blank">AUDITORY@xxxxxxxx</a>><br>>Ogg: R= E: RE: perceptual evaluation of cochlear models<br>><br>>Hi Francesco= (and auditory list in case others are interested),<br>>I'm glad to = hear that you've been following the intelligent mixing research.<br>>= ;<br>>I'll rephrase your email as a set of related questions...<br>&= gt;<br>>1. Should we extend the concepts of loudness and partial loudnes= s to complex material? - Yes, we should. Otherwise, what is it good for? Th= at is, what does it matter if we can accurately predict perceived loudness = of a pure tone, or the just noticeable differences between pedestal increme= nts for white or pink noise, or the partial loudness of a tone in the prese= nce of noise, etc., if we can't predict loudness outside artificial lab= oratory conditions. I suppose it works as validation of an auditory model, = but its still very limited.<br>>On the other hand, if we can extend the = model to complex sounds like music, conversations, environmental sounds, et= c., then we provide robust validation a general model of human loudness per= ception. The model can then be applied to metering systems, audio productio= n, broadcast standards, improved hearing aid design and so on.<br>><br>&= gt;2. Can we extend the concepts of loudness and partial loudness to comple= x material? - Yes, I think so. Despite all the issues and complexity, there= 's a tremendous amount of consistency in perception of loudness, especi= ally when one considers relative rather than absolute perception. Take a TV= show and the associated adverts. The soundtracks of both may have dialogue= , foley, ambience, music,..., all with levels over time. Yet consistently p= eople can identify when the adverts are louder than the show. Same is true = when someone changes radio stations, and in music production, sound enginee= rs are always identifying and dealing with masking when there are multiple = simultaneous sources.<br>>I think the issues that many issues relating t= o complex material may have a big effect on perception of timbre or extract= ion of meaning or emotion, but only a minor effect on loudness.<br>><br>= >3. Can we extend current auditory models of loudness and partial loudne= ss to complex material? - Hard to say. The state of the art in those based = on deep understanding of the human hearing system (Glasberg, Moore et al...= ; Fastl, Zwicker, et al...) were not developed with complex material in mi= nd, though when used with complex material, researchers have reported good = but far from great agreement with perception. Modification, though still in= agreement with auditory knowledge, shows improvement, but more research is= needed.<br>>On the other hand, we have models based mostly on listening= test data, but incorporating little auditory knowledge. I'm thinking h= ere of the EBU/ITU loudness standards. They are based largely on Gilbert So= ulodre's excellent listening test results <br>>(G. Soulodre, Evaluat= ion of Objective Loudness Meters, 116th AES Convention, 2004.), and represe= nt a big improvement on say, just applying a loudness contour to signal RMS= . But they are generally for a fixed listening level, may overfit the data,= difficult to generalise, and rarely give deeper insight into the auditory = system. Furthermore, like Moore's model, these have also shown some ina= dequacies when dealing with a wider range of content (Pestana, Reiss & = Barbosa, "Loudness Measurement of Multitrack Audio Content Using Modif= ications of ITU-R BS.1770," 134th AES Convention, 2013).<br>>So I t= hink rather than just extend, we may need to modify, improve, and go back t= o the drawing board on some aspects.<br>><br>>4. How could one develo= p an auditory model of loudness and partial loudness for complex material?<= br>>- Incorporate the validated aspects from prior models, but reassess = any compromises.<br>>- Use listening test results from a wide range of c= omplex material. Perhaps a metastudy could be performed, taking listening t= est results from many publications for both model creation and validation.<= br>>- Build in known aspects of loudness perception that were left out o= f existing models due to resources and the fact that they were built for la= b scenarios (pure tones, pink noise, sine sweeps...). In particular, I'= m thinking forward and backward masking.<br>><br>>5. What about JND? = - I would stay clear of this. I'm not even aware of anecdotal evidence = suggesting consistency in just noticeable differences for say, a small chan= ge in the level of one source in a mix. And I think one can be trained to i= dentify small partial loudness differences. I've had conversations with= professional mixing engineers who detect a problem with a mix that I don&#= 39;t notice until they point it out. But the concept of extending JND model= s to complex material is certainly very interesting.<br>><br>>_______= _________________________________<br>>From: <a href=3D"mailto:ftordini@xxxxxxxx= ibero.it" target=3D"_blank">ftordini@xxxxxxxx</a> <<a href=3D"mailto:ft= ordini@xxxxxxxx" target=3D"_blank">ftordini@xxxxxxxx</a>><br>>Sent:= 04 September 2014 15:45<br>>To: Joshua Reiss<br>>Subject: R: RE: per= ceptual evaluation of cochlear models<br>><br>>Hello Joshua,<br>>I= nteresting, indeed. Thank you.<br>><br>>So the question is - to what = extent can we stretch the concepts of loudness<br>>and partial loudness = for complex material such as meaningful noise (aka music),<br>>where att= ention and preference is likely to play a role as opposed to beeps and<br>&= gt;sweeps ? That is - would you feel comfortable to give a rule of a thumb = for a<br>>JND for partial loudness, to safely rule out other factors whe= n mixing?<br>><br>>I was following your intelligent mixing thread - a= lthough I've missed the<br>>recent one you sent me - and my question= above relates to the possibility to<br>>actually "design" the= fore-background perception when you do automatic mixing<br>>using real = sounds...<br>>I would greatly appreciate any comment form your side.<br>= ><br>>Best wishes,<br>>Francesco<br>><br>><br>>>----Me= ssaggio originale----<br>>>Da: <a href=3D"mailto:joshua.reiss@xxxxxxxx= .uk" target=3D"_blank">joshua.reiss@xxxxxxxx</a><br>>>Data: 03/09/2= 014 16.00<br>>>A: "<a href=3D"mailto:AUDITORY@xxxxxxxx" t= arget=3D"_blank">AUDITORY@xxxxxxxx</a>"<<a href=3D"mailto:AU= DITORY@xxxxxxxx" target=3D"_blank">AUDITORY@xxxxxxxx</a>>,= "Joachim Thiemann"<br>><<a href=3D"mailto:joachim.thiemann= @xxxxxxxx" target=3D"_blank">joachim.thiemann@xxxxxxxx</a>>, "<a = href=3D"mailto:ftordini@xxxxxxxx" target=3D"_blank">ftordini@xxxxxxxx</a>= "<<a href=3D"mailto:ftordini@xxxxxxxx" target=3D"_blank">ftordini@xxxxxxxx= libero.it</a>><br>>>Ogg: RE: perceptual evaluation of cochlear mod= els<br>>><br>>>Hi Francesco and Joachim,<br>>>I collabora= ted on a paper that involved perceptual evaluation of partial<br>>loudne= ss with real world audio content, where partial loudness is derived from<br= >>the auditory models of Moore, Glasberg et al. It showed that the predi= cted<br>>loudness of tracks in multitrack musical audio disagrees with p= erception, but<br>>that minor modifications to a couple of parameters in= the model would result in<br>>a much closer match to perceptual evaluat= ion results. See<br>>>Z. Ma, J. D. Reiss and D. Black, "Partial = loudness in multitrack mixing," AES<br>>53rd International Conferen= ce on Semantic Audio in London, UK, January 27-29,<br>>2014.<br>>>= <br>>>And in the following paper, there was some informal evaluation = of the use of<br>>Glasberg, Moore et al's auditory model for loudnes= s and/or partial loudness<br>>could be used to mix multitrack musical au= dio. Though the emphasis was on<br>>application rather than evaluation, = it also noticed issues with the model when<br>>applied to real world con= tent. See,<br>>>D. Ward, J. D. Reiss and C. Athwal, "Multitrack = mixing using a model of<br>>loudness and partial loudness," 133rd A= ES Convention, San Francisco, Oct. 26-<br>>29, 2012.<br>>><br>>= >These may not be exactly what you're looking for, but hopefully you= find it<br>>interesting.<br>>>___________________________________= _____<br>>>From: AUDITORY - Research in Auditory Perception <<a hr= ef=3D"mailto:AUDITORY@xxxxxxxx" target=3D"_blank">AUDITORY@xxxxxxxx= ILL.CA</a>><br>>on behalf of Joachim Thiemann <<a href=3D"mailto:j= oachim.thiemann@xxxxxxxx" target=3D"_blank">joachim.thiemann@xxxxxxxx</a>= ><br>>>Sent: 03 September 2014 07:12<br>>>To: <a href=3D"mai= lto:AUDITORY@xxxxxxxx" target=3D"_blank">AUDITORY@xxxxxxxx</a= ><br>>>Subject: Re: perceptual evaluation of cochlear models<div><div= class=3D"h5"><br>>><br>>>Hello Francesco,<br>>><br>>&= gt;McGill alumni here - I did a bit of study in this direction, you can<br>= >>read about it in my thesis:<br>>><a href=3D"http://www-mmsp.e= ce.mcgill.ca/MMSP/Theses/T2011-2013.html#Thiemann" target=3D"_blank">http:/= /www-mmsp.ece.mcgill.ca/MMSP/Theses/T2011-2013.html#Thiemann</a><br>>>= ;<br>>>My argument was that if you have a good auditory model, you sh= ould be<br>>>able to start from only the model parameters and be able= to<br>>>reconstruct the original signal with perceptual transparency= .=C2=A0 I was<br>>>looking at this in the context of perceptual codin= g - a perceptual<br>>>coder minus the entropy stage effectively verif= ies the model.=C2=A0 If<br>>>artefacts do appear, they can (indirectl= y) tell you what you are<br>>>missing.<br>>><br>>>I was s= pecifically looking at gammatone filterbank methods, so there<br>>>is= no comparison to other schemas - but I hope it is a bit in the<br>>>= direction you're looking at.<br>>><br>>>Cheers,<br>>>= Joachim.<br>>><br>>>On 2 September 2014 20:39, <a href=3D"mailt= o:ftordini@xxxxxxxx" target=3D"_blank">ftordini@xxxxxxxx</a> <<a href= =3D"mailto:ftordini@xxxxxxxx" target=3D"_blank">ftordini@xxxxxxxx</a>>= wrote:<br>>>><br>>>> Dear List members,<br>>>> = I am looking for references on perceptual evaluation of cochlear models -<b= r>>>> taken form an analysis-synthesis point of view, alike the wo= rk introduced<br>>in<br>>>> Homann_2002 (Frequency analysis and= synthesis using a Gammatone filterbank,<br>>>> =C2=A74.3).<br>>= ;>><br>>>> Are you aware of any study that tried to assess t= he performance of<br>>>> gammatone-like filterbanks used as a synt= hesis model?=C2=A0=C2=A0 (AKA, what are the<br>>>> advantages over= MPEG-like schemas?)<br>>>><br>>>> All the best,<br>>&= gt;> Francesco<br>>>><br>>>> <a href=3D"http://www.cim= .mcgill.ca/sre/personnel/" target=3D"_blank">http://www.cim.mcgill.ca/sre/p= ersonnel/</a><br>>>> <a href=3D"http://ca.linkedin.com/in/ftordini= " target=3D"_blank">http://ca.linkedin.com/in/ftordini</a><br></div></div><= /div></blockquote></div><br></div> --047d7b15ac6d60873c050464f9f1--