I worked in an ethnomusicology archive in India for over forty years, and retired in 2015. In that period I have overseen the transition for spool based analog archive to an all digital archive. The spools that we recorded, and the spools we received recorded, are still preserved, though there are now 24 bit digital copies.
One rule I have always observed: make the best copy you can, but do not apply any ‘improvements’ (noise reduction comes to mind). If the recordings came as MP3s. we preserve them as MP3s, alongside a Wave file. If the recording is 44.1 k sampling rate, we do not upgrade to 48 kHz, nor do we convert 16 bit files to 24 bit. In the last few years, I have deposited first order Ambisonic recordings in the archive, both as A format and B format. You need the B format because it is always possible something in the conversion chain will get lost – the filtermatrix, the processing software. I will soon be depositing eight channel recordings done with Brahma-8. They will be encoded to 2nd order B format, and SPS, and the originals will also be preserved. Hopefully, there will be 12 channel MEMs based all digital recordings. The same rules apply. These rules are the result of many years of discussion with archivists around the world. umashankar Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10 ________________________________ From: Sursound <sursound-boun...@music.vt.edu> on behalf of Stefan Schreiber <st...@mail.telepac.pt> Sent: Sunday, February 24, 2019 7:28:25 PM To: Surround Sound discussion group Subject: Re: [Sursound] Enquiry on upmixing from 1st order ambisonics to 3rd order ambisonics. Citando Dave Hunt <davehuntau...@btinternet.com>: >> From: Politis Archontis <archontis.poli...@aalto.fi> >> Subject: Re: [Sursound] Enquiry on upmixing from 1st order >> ambisonics to 3rd order ambisonics. >> Date: 22 February 2019 18:15:00 GMT >> To: Surround Sound discussion group <sursound@music.vt.edu> >> >> >> Hi David, >> >> These upmixing methods extract a lot of information from the FOA >> recording that is then re-used to essentially “synthesize" the HOA >> signals, with a spatial resolution that would not be possible with >> the FOA recordings. They are “active” in that sense, and >> signal-dependent, compared to the “passive" classical ambisonic >> decoding. Their success depends of course on how effective is their >> underlying model and how robustly they are implemented. >> >> In that sense there isn’t necessarily a large benefit in parametric >> upmixing from FOA to 3rd-order, compared to parametric decoding for >> playback, since these methods can also upmix directly from FOA to, >> say, 40 speakers or headphones, with their maximum sharpness. >> However, the HOA upmixing could be useful for people that are >> working with a HOA processing pipeline, and they want to integrate >> FOA or lower-order material seamlessly. >> >> Regards, >> Archontis Politis > > > Very few people have access to microphones beyond FOA, so that in a > live recording a number of close microphones could be mixed in third > order, with a FOA microphone as a "room" mic. I don't understand these permanent "objections". The Octomic and the Zylia ZM-1 microphones are available and well priced. Why not just doing some investment (for a longer time), and just buy one of these? COMPASS seems to be able to upsample 2nd and 3rd order to higher, so you seem to have always some advantage. (To be confirmed after COMPASS gets available, of course.) From persons claiming to be professional recordists I would actually expect to use up-to-date equipment. (The mentioned microphones don't cost more or much more than some professional cameras - just to compare. I expect that a real photographer... you know what I mean.) Best, Stefan Schreiber > > For location recording, the FOA mic options are more robust, with > better weather protection, and more practical than any higher order > option. > > In a "synthesised" third order sound field, FOA recordings could be > used as more "ambient" stems. > > The up-mix is a re-coder, FOA to third order. What would follow it > is a third order mixer and a decoder to loudspeaker feeds. Other > third order sounds could be mixed into the decoder. More than one > FOA signal could be mixed into the re-coder. Whether it is better > that each FOA signal has its own re-coder is debatable. > > If the re-coder includes its own identical decoder, which cannot be > bypassed, the two (or more) sets of third order decoder loudspeaker > outputs could be mixed together. The availability of an identical > decoder, and a suitable mixer might be problematic. > > > Ciao, > > Dave Hunt > _______________________________________________ Sursound mailing list Sursound@music.vt.edu https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fmail.music.vt.edu%2Fmailman%2Flistinfo%2Fsursound&data=02%7C01%7C%7C6c9ca6d8c0d9462f1bdf08d69a603044%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636866135247033978&sdata=pviNVKjfdeiRa0fCdxCRKgBMIuQ5VULCOdOJbjqHMWc%3D&reserved=0 - unsubscribe here, edit account or options, view archives and so on. -------------- next part -------------- An HTML attachment was scrubbed... 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