Re: [Sursound] [ANN] International Conference on Spatial Audio, Nov 10-13 2011, in Detmold, Germany
Hello Jörn, Website? Joseph Anderson 27 Hungate, Pickering, North Yorkshire, YO18 7DL, UK On 14 Apr 2011, at 5:55 pm, Jörn Nettingsmeier wrote: hi *! i think this announcement will be of interest to sursound patrons, so i'm forwarding it on behalf of the entire organization committee. we're in the early stages of planning, so it might make sense to re-visit the website in a few weeks. best, jörn *.* ICSA 2011 - International Conference on Spatial Audio November 10 - 13, Hochschule für Musik, Detmold Organizers: Verband Deutscher Tonmeister (VDT), in cooperation with Deutsche Gesellschaft für Akustik e.V. (DEGA), and European Acoustics Association (EAA). Contact/Chair: Prof. Dr.-Ing. Malte Kob Erich-Thienhaus-Institut Neustadt 22, 52756 Detmold Mail: icsa2011attonmeister.de Phone: +49-(0)5231-975-644 Fax: +49-(0)5231-975-689 -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20110417/97bc11ca/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] distance perception in virtual environments
Hi, Gavin Kearney et al have presented their work on Depth perception in interactive virtual acoustic environments using higher order ambisonic soundfields at the Ambisonics'11 symposium in Paris; the article is available online at http://ambisonics10.ircam.fr/drupal/?q=proceedings/o6 Best, Markus On 17 avr. 2011, at 19:38, Dave Hunt wrote: Hi, Date: Sun, 17 Apr 2011 09:28:28 +0800 From: Junfeng Li junfeng.li.1...@gmail.com Subject: [Sursound] distance perception in virtual environments Dear list, I am now wondering how to subjectively evaluate distance perception in virtual environments which might be synthesized using WFS or HOA (high-order ambisonics). In my experiments, the sounds were synthesized at different distances and presented to listeners for distance discrimination. However, the listener cannot easily perceive the difference in distance between these sounds. Anyone can share some ideas or experiences in distance perception experiments? or share some references on this issue? Thank you so much. Best regards, Junfeng Change in amplitude with distance should be perceptible fairly easily, but on its own would just sound the same but quieter, or louder. High frequency absorption by the air is only really perceptible when the distance is fairly large, though this effect could be exaggerated for artistic purposes. The lateness of arrival of sound from distant objects is not directly perceptible unless there is something visible (e.g. lightning and thunder). Reverberation definitely gives perceptible distance effects. More distant sources are more reverberant. The amplitude of the direct signal should decrease with distance (inverse square law, or some similar law), while the amplitude of the reflected and reverberant signal would remain fairly constant or decrease less rapidly with distance than that of the direct signal. It is the ratio of direct to reverberant sound that is important. John Chowning's 1971 paper The Simulation of Moving Sound Sources is a good early consideration of how to synthesise distance. Of course the reported result will depend on the listener, who may not be used to analysing sound for these effects. Ciao, Dave ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] rf interference
Hi, Bill - Yep - I skipped the extension cable today and just had the mic go from the breakout cable to the PPAs, and today's recording didn't turn up with any RFI, at least when I played back the first couple of minutes of the test recording. Hopefully the remainder will be RFI-free, as well. Thanks, surround sound list. cheers, j On Apr 16, 2011, at 5:56 PM, Bill de Garis wrote: I have the radio pick up problem with my Tetramic. I find it is better to put the 4 XLR adaptors into my 4x3ft XLR cables and then plug the XLR cables into my MOTU Traveller rather than use one of Lens extension cables and plug the adaptors directly into the Traveller. If I need distance I use a couple of InstaSnakes and shielded CAT5. Radio pickup is still a problem in some locations though. I tried wrapping multiple layers of heavy kitchen aluminium foil over the adapters after zip-tying them to the handle of my Rycote blimp. Worked OK in the kitchen, but nowhere else. :o) Bill On 16/04/2011 12:36 p.m., Jascha Narveson wrote: Hello, once again, surround list - My apologies for the continued emails from my end - as you can tell, I'm trying to muddle through some location recording this weekend, and am running in to things I've never dealt with before. To whit: I've just come back from recording in Times Square and discovered that I was picking up the radio. I'm using a TetraMic, and I'm guessing that the 6' extension cable that goes from the mic to the break-out cable might be the weak link, as it looks rather thin and is probably unshielded. From the PPAs I have four 3-foot XLR cables that are then going in to the 788T, so they might be part of the problem, as well. I know that in picking Times Square as a recording subject I'm walking in to one of the heavier RF zones in the city, but I'm hoping that somebody here might have some tips of things I can try to work around it...? Is there some way I can shield the cables in a d.i.y. fashion, for instance? thanks yet again, - jascha ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] distance perception in virtual environments
That's an interesting question. The environment you're working in for synthesis could matter quite a bit. That is, if your working in, or simulating, an environment with little reverberation it is harder to judge distance since direct-to-reflected energy ratio is an important cue. The other important cue is timbre detail - especially high frequencies. But this requires the listener be familiar with the sound source to be able to discriminate. Try testing with spoken voice. I can't think of any research of the top of my head (especially for multi-channel environments). It is certainly well known that controlling high frequencies and direct/reflected ratio is important for distance perception in stereo mixing - but even there that's usually a relative, or comparative judgment, of one sound source appear vaguely 'behind' another. Not so much an absolute judgment that you might want for a virtual environment. jim On Sat, Apr 16, 2011 at 9:28 PM, Junfeng Li junfeng.li.1...@gmail.comwrote: Dear list, I am now wondering how to subjectively evaluate distance perception in virtual environments which might be synthesized using WFS or HOA (high-order ambisonics). In my experiments, the sounds were synthesized at different distances and presented to listeners for distance discrimination. However, the listener cannot easily perceive the difference in distance between these sounds. Anyone can share some ideas or experiences in distance perception experiments? or share some references on this issue? Thank you so much. Best regards, Junfeng -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20110417/64a7d936/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound -- Jim Moses Technical Director/Lecturer Brown University Music Department and M.E.M.E. (Multimedia and Electronic Music Experiments) -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20110417/5157390f/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] rf interference
Hi, David - I was using the 6-foot extension cable yesterday. I didn't try it today, so I can't comment on whether swapping out the cable today affected the RFI, or if was just a different day and wouldn't've happened in any case. cheers, j On Apr 17, 2011, at 5:10 PM, David Worrall wrote: Hi Jascha, What length extension cable were you using? And does anyone have any experience of the comparative differences between the the different lengths? David On 18/04/2011, at 6:30 AM, Jascha Narveson wrote: Hi, Bill - Yep - I skipped the extension cable today and just had the mic go from the breakout cable to the PPAs, and today's recording didn't turn up with any RFI, at least when I played back the first couple of minutes of the test recording. Hopefully the remainder will be RFI-free, as well. Thanks, surround sound list. cheers, j On Apr 16, 2011, at 5:56 PM, Bill de Garis wrote: I have the radio pick up problem with my Tetramic. I find it is better to put the 4 XLR adaptors into my 4x3ft XLR cables and then plug the XLR cables into my MOTU Traveller rather than use one of Lens extension cables and plug the adaptors directly into the Traveller. If I need distance I use a couple of InstaSnakes and shielded CAT5. Radio pickup is still a problem in some locations though. I tried wrapping multiple layers of heavy kitchen aluminium foil over the adapters after zip-tying them to the handle of my Rycote blimp. Worked OK in the kitchen, but nowhere else. :o) Bill On 16/04/2011 12:36 p.m., Jascha Narveson wrote: Hello, once again, surround list - My apologies for the continued emails from my end - as you can tell, I'm trying to muddle through some location recording this weekend, and am running in to things I've never dealt with before. To whit: I've just come back from recording in Times Square and discovered that I was picking up the radio. I'm using a TetraMic, and I'm guessing that the 6' extension cable that goes from the mic to the break-out cable might be the weak link, as it looks rather thin and is probably unshielded. From the PPAs I have four 3-foot XLR cables that are then going in to the 788T, so they might be part of the problem, as well. I know that in picking Times Square as a recording subject I'm walking in to one of the heavier RF zones in the city, but I'm hoping that somebody here might have some tips of things I can try to work around it...? Is there some way I can shield the cables in a d.i.y. fashion, for instance? thanks yet again, - jascha Dr David Worrall Adjunct Research Fellow, Australian National University david.worr...@anu.edu.au Board Member, International Community for Auditory Display Regional Editor, Organised Sound (CUP) Projects Officer, Music Council of Australia worrall.avatar.com.au sonification.com.au mca.org.aumusicforum.org.au -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20110418/32331e84/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] distance perception in virtual environments
For relatively nearby distance detection such as the buzzing bee or whispering or conversation (versus more distant sources such as in a concert hall), one needs to deliver interaural level differences on the order of 10 ot 20 dB with the corresponding ITD of up to 700 microseconds. (If the sources and speakers are relatively centered then we can ignore the pinna distance detection problem.) At the moment I believe only the Choueiri BACCH dummy head recording and crosstalk cancellation method can routinely deliver this magnitude of ILD over the full range of frequencies. If you are synthesizing the ILD in your virtual signals then you don't need to use a dummy head or an Ambiophone. Of course, this ILD seems to apply only for distances to sources at the sides of the head but in practice extreme XTC and thus real binaural ITD provides for proximity at all frontal angles in the horizontal plane as in everyday hearing. RACE, if carefully implemented with directional nearfield speakers, can get up to about 10 dB or more ILD and you might try this since it is easier (cheaper) than using any of the other crosstalk cancelling or WFS or HOA methods. There is no question that Ambiophonic users report enhanced depth perception when listening to ordinary music or the commercially available earphone type binaural recordings but you may want more than this for what you are doing so you should tweak the normal Ambiophonic methodology to optimize ILD capture and reproduction. Ralph Glasgal www.ambiophonics.org From: Junfeng Li junfeng.li.1...@gmail.com To: Surround Sound discussion group sursound@music.vt.edu Sent: Saturday, April 16, 2011 9:28 PM Subject: [Sursound] distance perception in virtual environments Dear list, I am now wondering how to subjectively evaluate distance perception in virtual environments which might be synthesized using WFS or HOA (high-order ambisonics). In my experiments, the sounds were synthesized at different distances and presented to listeners for distance discrimination. However, the listener cannot easily perceive the difference in distance between these sounds. Anyone can share some ideas or experiences in distance perception experiments? or share some references on this issue? Thank you so much. Best regards, Junfeng -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20110417/64a7d936/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20110417/da4e9255/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Powering the DR-680
David, The DR-680 is powered either by eight AA cells, or via a 12v DC input from a wall-wart PSU or an external battery back. The pack I'm using provides 12 volts, so just plugs straight in. Regards, John On 18 Apr 2011, at 01:24, David Worrall wrote: Hi John, Does this unit plug into the AC socket on the DR-680 or how? ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Powering the DR-680
Thanks John, I see. so it plugs into the power socket. (I've just purchased a DR-680 in anticipation of getting a couple of Len's Little Marvels for field recording, so was wondering.) Neat machine! David On 18/04/2011, at 10:41 AM, John Leonard wrote: David, The DR-680 is powered either by eight AA cells, or via a 12v DC input from a wall-wart PSU or an external battery back. The pack I'm using provides 12 volts, so just plugs straight in. Regards, John On 18 Apr 2011, at 01:24, David Worrall wrote: Hi John, Does this unit plug into the AC socket on the DR-680 or how? ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound _ Dr David Worrall Experimental Composer, Polymedia Adjunct Research Fellow, Australian National University david.worr...@anu.edu.au Board Member, International Community for Auditory Display Regional Editor, Organised Sound (CUP) IT Project Manager, Music Council of Australia worrall.avatar.com.au sonification.com.au mca.org.au musicforum.org.au T : +61 (0)2 61.61.95.22M: +61 (0)4.02.28.36.90 -- next part -- An HTML attachment was scrubbed... URL: https://mail.music.vt.edu/mailman/private/sursound/attachments/20110418/587dbc0e/attachment.html ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
[Sursound] distance perception in virtual environments
You must simulate at least 2 things. At close range, you must simulate the curvature of the soundfield. This is simply proximity for 1st order and the effect is, if anything, exaggerated. see the Appendix of Is My Decoder Ambisonic, Heller et al, AES San Francisco 1980 aka BLaH3 See Daniel for HOA You have to simulate early reflections and a reverb pattern appropriate to source distance. MAG has a paper on this under Distance Panners from an idea by Peter Craven. Real Life Distance Perception is TERRIBLE under (near) anechoic conditions. I recorded Paul Robinson's band at the IMAX theatre in Bradford. They were providing music for a festival of silent movies. Even after 5 days, we still found it disconcerting in that very dead environment. Someone would call you from the door 20m away and you thought they were beside you. ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
[Sursound] distance perception in virtual environments
I hope you have a control where you measure real distance perception too. Not having a real control is a fault in many localisation experiments. ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
