I use an earthworks calibration microphone, but any good quality six mm Omni microphone will be okay. Noise is not important, but flat frequency response is. You could use a tetramic and take the W signal after processing, but it might be overcomplicating things. Coaxial speakers sound ideal, but many of them have problems. A small five inch full range, or 5 inch plus tweeter mounted close together, is best. I use an Adam 5 after first sealing off the bass port. Choice of microphone is more important than the speaker.
umashankar Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10 From: Bo-Erik Sandholm<mailto:bosses...@gmail.com> Sent: Thursday, January 5, 2017 3:31 PM To: sursound<mailto:sursound@music.vt.edu> Subject: Re: [Sursound] [allowed] brahma To get a good calibration, I expect I will need at least one known/reference source or sensor? The reference for me will probably be my coresound Tetramic. I will probably use Kef eggs as speakers as they are coaxial transducers. Only at low frequency will The port be offerter. Have I understood The basics? I will probably measure outside a calibration Day orborrow a anechoic room at swedish radio. Bo-Erik Den 5 jan. 2017 11:53 fm skrev "umashankar manthravadi" < umasha...@hotmail.com>: > Dear fernando > > > > I forwarded your link to marc Lavallée when you first posted them. My > intent is that we should have multiple compatible systems for calibrating A > format mics > > > > Sent from my Windows 10 phone > > > > From: Fernando Lopez-Lezcano<mailto:na...@ccrma.stanford.edu> > Sent: 05 January 2017 00:28 > To: Surround Sound discussion group<mailto:sursound@music.vt.edu>; > glard...@iol.ie<mailto:glard...@iol.ie> > Subject: Re: [Sursound] [allowed] brahma > > > > On 01/02/2017 09:59 PM, Bo-Erik Sandholm wrote: > > Good luck in your continued effekt. > > > > By the way, i have accuired one of your Tetra mic 3d shapeway for 14 mm > > capsules. > > I have not yet assembler it. > > I Wonder is there any software package and description on How to create > > calibration files for The mic? > > I will probably have The possibility to get temporary access to a > anechoic > > room. > > Hi Bo-Erik, > You could take a look at my project here (I posted about this a while > back): > > https://cm-gitlab.stanford.edu/ambisonics/SpHEAR/ > (there is mailing list with 0 posts so far, ha ha..) > > See paper here (been working on this for over a year): > https://ccrma.stanford.edu/~nando/publications/sphear.pdf > > The project includes free software (open source, GPL) that runs in > Matlab and derives a calibration matrix (4x4 matrix of FIR filters) that > can be used directly with TetraProc (by Fons Adriansen) - or any other > software that can run the filters. > > Just a few days ago I _finally_ managed to get the software into > somewhat usable shape in that I think (and I'm pretty much wrong every > time I say this, so...) it is working correctly. The calibration relies > on having 16 measurements (could be 8) in the horizontal plane around > the Ambisonics microphone plus one more of a calibration microphone in > the same exact location. Aliki is used to capture the IRs and edit (trim > and window) them. DRC (Digital Room Correction) is used to equalize the > excitation speaker. Then the software I wrote processes those IRs and > outputs a 4x4 matrix of filters. Many parameters can be tuned. I'll post > a couple of pictures later... > > Documentation (surprise!) is mostly lacking. I hope to remedy that > somewhat soon (at least a list of the sequence of octave function calls > you need to get the job done). > > My latest prototype with 10mm capsules was hastily measured before I > left for "vacation" and the plotted results of the calibration are > looking good. A re-calibration with the latest software of my first > prototype which captured a full concert also sounds fairly decent. > > Anyway, > Good luck! > -- Fernando > > > > > In worst case i Will use the generic calibration from sennheiser :-) > > > > The mechanical size of The tetraeder is about right. > > Bo-Erik > > > > > > > > Den 2 jan. 2017 9:01 em skrev "Gerard Lardner" <glard...@iol.ie>: > > > >> Sorry to hear of the falling-out. I have had some issues with the > >> build-quality of my Brahma, which was made by Embrace Video, but > >> nevertheless it remains my 'go-to' mic for choral recording. > >> > >> With best wishes for 2017, and for your ongoing Ambisonic microphone > >> projects, > >> > >> Gerard > >> > >> > >> On 02/01/2017 06:57, umashankar manthravadi wrote: > >> > >>> This is just an announcement that Nakul Sood and Embrace video will no > >>> longer be manufacturing or selling Brahma ambisonic microphones. Our > very > >>> informal arrangement has come to an end as Nakul Sood demanded 1)I hand > >>> over complete technology and manufacturing protocols, 2) sign a > >>> non-disclosure agreement and 3) sign a non-compete agreement. (there > were > >>> other demands) I have always worked on Brahma as a shared project, with > >>> help from many people and I have no desire to sign a non-disclosure > >>> agreement. > >>> > >>> I had made atleast 20 Brahma microphones before this project began, > and I > >>> will continue to make one off brahmas as demanded (I am currently > making > >>> five second order microphones for Angelo Farina) and I am setting up > fairly > >>> high tech processes in Bangalore where I now live (laser cut microphone > >>> bodies!) > >>> > >>> Umashankar > >>> > >>> > >> -------------- next part -------------- > >> An HTML attachment was scrubbed... > >> URL: <https://mail.music.vt.edu/mailman/private/sursound/attachme > >> nts/20170102/572ce57e/attachment.html> > >> _______________________________________________ > >> Sursound mailing list > >> Sursound@music.vt.edu > >> https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, > >> edit account or options, view archives and so on. > >> > > -------------- next part -------------- > > An HTML attachment was scrubbed... > > URL: <https://mail.music.vt.edu/mailman/private/sursound/ > attachments/20170103/f956a4dd/attachment.html> > > _______________________________________________ > > Sursound mailing list > > Sursound@music.vt.edu > > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, > edit account or options, view archives and so on. > > > > _______________________________________________ > Sursound mailing list > Sursound@music.vt.edu > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, > edit account or options, view archives and so on. > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: <https://mail.music.vt.edu/mailman/private/sursound/ > attachments/20170105/7f2afed4/attachment.html> > _______________________________________________ > Sursound mailing list > Sursound@music.vt.edu > https://mail.music.vt.edu/mailman/listinfo/sursound - unsubscribe here, > edit account or options, view archives and so on. > -------------- next part -------------- An HTML attachment was scrubbed... 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