Graham states in his 2006 ICMC paper (http://www.mat.ucsb.edu/~wakefield/pubs/06_Wakefield_ICMC_HOAMax.pdf) that
"Beneficially, both the ICST externals and those described in this paper can be used together within the same application." However, he also states "Several different encoding conventions exist to scale Ambisonic signals at various orders. The original B-Format definition specified a scalar of √2 for the W channel, while the Furse-Malham set (Malham 1999) scales second-order signals to achieve normalized values in the Ambisonic domain, and Daniel (2000) specified up to third order without normalizing weights except for the original √2 W channel. In the presented Max/MSP externals the author opted to employ the same convention as presented by Daniel (2000)" which is a little confusing since firstly the weighting of the W channel is actually 1/√2 and secondly Jerome Daniel states in his thesis that he prefers SN3D weighting and in table 3.3 on page 156 of the thesis he shows this as a necessary conversion factor from SN3D to FuMa (which is the same as original B format for W, X,Y and Z). It would be good if someone who has actually used the two together could confirm that they are indeed fully interoperable. Even if they aren't fully compatible out of the box, it should be easy to make them so as it is likely it's just a matter of channel weightings and writing a small subpatch to do the conversions should be easy. Dave On 9 June 2012 00:45, SERO SERO <[email protected]> wrote: > Hello again Dave, > I am sorry I was incorrect, ICST tool do not have a soundfield rotation > object while Graham Wakefield AMbisonics external do. > > So I am not sure the two are compatible. > Do you have any tips? > > Thank you > > Regards, > > Sero > > On Wed, Jun 6, 2012 at 3:57 PM, SERO SERO <[email protected]> wrote: > >> Hello All, >> >> thank you very much for your responses, very much appreciated. >> >> Dave - Thank you for the links and the ideas regarding the application of >> delay effect to the B-foramt signal; one thing is not clear to me yet is >> the following and I would be very grateful if you can expand further for me: >> >> I have a mono source that is encoded in B-format and already include the >> rotational information in the encoder (current ICST encoder is an encoder >> from mono to B-format + panner) so if I apply delay to the B-format signal >> I am assuming I will already have the system responding to source rotation >> when I rotate my source without further panning the fx soundfield. >> Am I correct or I do need to rotate the delay fx soundfield as well >> according to the source rotation? >> >> Both solution are possible as I will use a typical send/return fx path >> (%wet) for the fx. >> >> Gus - Thank you for the link, Cannot check now in the office but will have >> a look one evening. >> I am definitely up for sharing ideas and patches. Please feel free to >> write on my sursound email for any personal communication. >> >> Very grateful for all the help from the list. >> >> Thankyou >> >> Sero >> >> >>> >>> Message: 3 >>> Date: Sun, 3 Jun 2012 21:33:58 +0100 >>> From: Dave Malham <[email protected]> >>> Subject: Re: [Sursound] B- Format to A-format conversion for an >>> ambisonics fx >>> To: Surround Sound discussion group <[email protected]> >>> Message-ID: >>> < >>> capw+1zrn0w_5hdrbxpss60oy_z7_pgrwjlez_ogyjmpmzxp...@mail.gmail.com> >>> Content-Type: text/plain; charset=UTF-8 >>> >>> Hi Sero, >>> Although there are times that processing A format may be be useful >>> in compositional terms (see Jo Anderson's work) it isn't necessary to >>> change to A format for applying general effects like delay, eq or >>> gain, even if it involves phase shifts - so long as there are no >>> differences between channels in the B Format. So, if all channels have >>> the same delay, no matter what it is. It is entirely possible to >>> provide a B format feedback path via delays which incorporate >>> rotations to increase the complexity of the final soundfield. Dylan >>> Menzies incorporated this in his LAmb software >>> (http://www.tech.dmu.ac.uk/~dylan/z/dylan/project/holog/index.html). >>> The same applies to pretty well any effect - if you apply a boost of, >>> say, +2.65dB at 5kHz to the W channel, you must apply an identical >>> boost of+2.65dB at 5kHz to all the other channels. >>> >>> Dave >>> >>> On 3 June 2012 19:53, SERO SERO <[email protected]> wrote: >>> > Hello list, >>> > >>> > This is my first post here so please be patient if I am doing something >>> > wrong with the replies. >>> > >>> > I am working on a patch in MAX 6 for Ambisonics reproduction for a jazz >>> > band and I am looking in creating a series of FX that can be encoded in >>> 3rd >>> > order. >>> > >>> > My main understanding is that for a delay FX type (and any other fx that >>> > affects the phase of the signal) I need to convert the B-format signal >>> to >>> > A-format, then apply the fx I want and then reconvert to B-format. >>> > >>> > Does anyone can point me to any resource I can use to understand both >>> > conversions? >>> > Also can you share a patch u have done in Max (if anyone use it) I can >>> use >>> > as a reference? >>> > >>> > I use the ICST tools in Max 6 for all the ambisonics processing. >>> > >>> > I am already using the trick of applying delay FX to a mono source >>> before >>> > enconding and then use rotation of the sound field to create ping pong >>> like >>> > fx but I would like to do something more creative. >>> > >>> > Thank you very much >>> > >>> > Regards, >>> > Sero >>> > -------------- next part -------------- >>> > An HTML attachment was scrubbed... >>> > URL: < >>> https://mail.music.vt.edu/mailman/private/sursound/attachments/20120603/5b53fa16/attachment.html >>> > >>> > _______________________________________________ >>> > Sursound mailing list >>> > [email protected] >>> > https://mail.music.vt.edu/mailman/listinfo/sursound >>> >>> >>> >>> -- >>> >>> These are my own views and may or may not be shared by my employer >>> >>> Dave Malham >>> Music Research Centre >>> Department of Music >>> The University of York >>> Heslington >>> York YO10 5DD >>> UK >>> Phone 01904 322448 >>> Fax? ?? 01904 322450 >>> 'Ambisonics - Component Imaging for Audio' >>> >>> >>> ------------------------------ >>> >>> Message: 4 >>> Date: Sun, 3 Jun 2012 21:55:37 +0100 >>> From: Augustine Leudar <[email protected]> >>> Subject: Re: [Sursound] B- Format to A-format conversion for an >>> ambisonics fx >>> To: Surround Sound discussion group <[email protected]> >>> Message-ID: >>> < >>> cabx2jupne7q3zozrbybfe4vio+_k6i_-9ymdyxm5w4b1ndk...@mail.gmail.com> >>> Content-Type: text/plain; charset=ISO-8859-1 >>> >>> Hi Sero, >>> I use ICST quite a lot as well - I do as you say and just apply the >>> effects to the signals before sending them into ambipanning~ >>> I'm not sure why converting to from B - format A - format will >>> necessarily allow you more creative possibilities - I'm not really >>> sure why you would do that, A - format as I understand it is just the >>> raw recordings that come out of a microphone ? >>> You can see a patch Ive made here for spatialising audio in 3d with a >>> wii controller (an electroacoustic granular magic wand): >>> >>> http://www.youtube.com/watch?v=7cmodvSM5jE >>> >>> Id be happy to share knowledge patches etc , >>> cheers, >>> Gus >>> >>> >>> >>> >>> > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > <https://mail.music.vt.edu/mailman/private/sursound/attachments/20120609/06b265df/attachment.html> > _______________________________________________ > Sursound mailing list > [email protected] > https://mail.music.vt.edu/mailman/listinfo/sursound -- These are my own views and may or may not be shared by my employer Dave Malham Music Research Centre Department of Music The University of York Heslington York YO10 5DD UK Phone 01904 322448 Fax 01904 322450 'Ambisonics - Component Imaging for Audio' _______________________________________________ Sursound mailing list [email protected] https://mail.music.vt.edu/mailman/listinfo/sursound
