Re: [Sursound] Ambisonic-Binaural piece using Brahma mic (was Re: Great responses to my post--thanks!)
> Hi Umashankar (and anyone interested), > > Following up on this thread, I just uploaded a soundscape piece I made > using the Brahma mic, presented here in a binaural version. The recordings > were converted from A to B-Format with Tetraproc (thanks to Fons for the > calibrated preset), ambisonic decode with Ambdec (using the extended cube > preset extcube-1h1v, which is a regular cube plus speakers on the centre > of each face) and then binaurally processed with a Max/MSP patch that uses > the IRCAM Spat objects (I also programmed head tracking in this patch). > I > wonder if using that Ambdec preset would be the best for creating BInarual > versions so any comments are welcome. You are almost certainly aware that TetraProc offers two channel outputs ... Fons (some years ago) was quite self-deprecaing about the "Xtalk" option. But I appreciated it. I certainly use them with success for 'stereo', but have little experience with binaural. Michael ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Ambisonic-Binaural piece using Brahma mic (was Re: Great responses to my post--thanks!)
On Wed, Jan 11, 2012 at 12:37:18PM -, Michael Chapman wrote: > You are almost certainly aware that TetraProc offers two channel > outputs ... > Fons (some years ago) was quite self-deprecaing about the > "Xtalk" option. But I appreciated it. It amounts to a first order highpass on the difference channel (L-R). The net result is that at low frequencies there is delayed crosstalk which turns amplitude differences into phase differences - close to the ones that would occur with real sources. It's the inverse operation of zita-bls1, and you can in fact tune zita-bls1 to make it almost cancel the Xtalk option. Ciao, -- FA Vor uns liegt ein weites Tal, die Sonne scheint - ein Glitzerstrahl. ___ Sursound mailing list Sursound@music.vt.edu https://mail.music.vt.edu/mailman/listinfo/sursound
Re: [Sursound] Ambisonic-Binaural piece using Brahma mic (was Re: Great responses to my post--thanks!)
Hi Michael, Yes, I'm aware of that and it's a very nice feature. I also use the VST plugin VVMic for ambisonic to stereo conversion which I'm assuming does something similar to the stereo output in Tetraproc (virtual mics with adjustable polarity and orientation). In this case, of course, I'm attempting full periphonic decode into a binaural sound field. Cheers, Hector On 2012-01-11, at 7:37 AM, Michael Chapman wrote: >> Hi Umashankar (and anyone interested), >> >> Following up on this thread, I just uploaded a soundscape piece I made >> using the Brahma mic, presented here in a binaural version. The recordings >> were converted from A to B-Format with Tetraproc (thanks to Fons for the >> calibrated preset), ambisonic decode with Ambdec (using the extended cube >> preset extcube-1h1v, which is a regular cube plus speakers on the centre >> of each face) and then binaurally processed with a Max/MSP patch that uses >> the IRCAM Spat objects (I also programmed head tracking in this patch). >> I >> wonder if using that Ambdec preset would be the best for creating BInarual >> versions so any comments are welcome. > > You are almost certainly aware that TetraProc offers two channel > outputs ... > Fons (some years ago) was quite self-deprecaing about the > "Xtalk" option. But I appreciated it. > > I certainly use them with success for 'stereo', but have little > experience with binaural. > > Michael > > ___ > 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] Linux help and difficult listening (uploaded wav files)
Hello Jörn, Thanks for writing. Your response isn’t too late, and it may have saved me from potential grief. From what I’ve read, FFADO 2.0 will work with the MOTU Traveler (first generation) and the 896HD. These are the very two MOTU devices that I own. Some years back (prior to learning of Ambisonics), I used Linux because there was a lot of great freeware available for Linux users. I used (and still have) a boxed version of Red Hat Linux 8.0. In the interest of multi-media, I recently downloaded Ubuntu Studio 11.1 for x86 (downloaded as an iso file, and then burned to DVD). Naturally, there is debate as to the “best” Linux for media use. My interest in Linux at this time is because you (and others) had recommended or suggested AmbDec. From what I’ve read thus far, I look forward to trying AmbDec. Chances are, however, I’ll create the requisite audio files using one platform (i.e. Linux) from B-formatted files, and then play them back using a PC-based DAW. The impetus for the PC-based DAW is because I’m using hardware that I designed and built for automating psychoacoustic experiments. In a nutshell, the hardware (photo uploaded) is akin to a voltage-operated surface-controller that works in real time because it gets feedback (based on a listener’s response via a response box) before a subsequent stimulus is presented. My hardware controller works well with Nuendo 4.3 and Audition 2, so I’ll probably stick with these (PC) DAWs. If a dummy driver is needed to create audio files using the AmbDec software, then I imagine JACK or FFADO will work. I have never used JACK; is it similar to ReWire? For my background noise, I have recorded several “representative” establishments/restaurants with noise levels hovering around 60-65 dBA, 70 dBA, and 75-80 dBA. I used a TetraMic connected to a Roland R-4 Pro recorder to make the 4-channel (raw, or A-format recordings). I then used VVMic and the cal (IR) files that came with the TetraMic to obtain the B-format files. A separate audio recorder was used to provide phantom power to my Earthworks (omnidirectional) calibration mic and record SPLs. An acoustic calibrator provided the cal tone and reference level for playing back the background (restaurant) noise at actual levels. To me, recording a single venue and then arbitrarily adjusting the playback level to achieve a particular SNR is not representative of real-world scenarios. Amplifying a quiet coffee house isn’t representative of a “louder” establishment. I don’t think many would disagree with this idea, but most researchers use one source for background noise regardless of the background noise level or desired SNR. Although Ambisonics may not be the ideal way of presenting background noise, it has to be a heck of a lot more realistic than methods previously used to test speech comprehension in noise, which are then reported in peer-reviewed literature. To give you an idea of the stimuli being used to evaluate cochlear implants, I have uploaded a few sentences (stimuli) and the respective background noise used by cochlear implant researchers. The first file is a stereo stimulus file and can be downloaded from www.elcaudio.com/examples/ci_stim_stereo.wav Without independently adjusting either the left or right gain, the SNR is 0 dB (silence between sentences was removed to obtain the signal level in dB). If you listen to this first file under headphones, it’s easy to ignore the noise and concentrate on the signal. Things are a little more blurred when listening through loudspeakers. A cochlear implant user doesn’t have the luxury of headphone listening or spatial signal segregation (assume a single implant). For your enjoyment, I also ran the stereo signal through a cochlear implant simulator that generates monaural files. (Note: “stim” in the file names refer to stimulus, whereas “sim” refers to simulation.) A monaural simulation of the above stereo file is here: www.elcaudio.com/examples/ci_sim_mono.wav and a stereo simulation file (noise in one channel and signal in opposite channel, which isn’t spatially realistic) is available here: www.elcaudio.com/examples/ci_sim_L_R.wav Imagine listening to your music (or a conversation) with this much distortion! Mostly, ask whether you believe these wav files, stereo or mono, are representative of real-world listening. This should shed some light on why I wish to improve the methods we use to test and evaluate hearing impaired listeners. Thanks, as always, for your help and insight. Kind regards, Eric -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20120111/99ae4bb7/attachment.html> -- next part -- A non-text attachment was scrubbed... Name: dtlg010.jpg Type: image/jpeg Size: 66729 bytes Desc: not available URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20120111
[Sursound] Motivation for authors
Hello Fons,
Your query ("what motivates authors to make their work available in this way")
made me think of my own situation. Perhaps publishing in peer-reviewed journals
is analogous to receiving Merit Badges in Scouts: In some instances, it’s how
one gets rated, noticed, or makes it to the next level. It seems (at least in
the U.S.) that professors are pressured to publish in professional journals. As
this applies to me, I was told (as a Master’s student) that I’d need at least a
few peer-reviewed articles under my belt in order to get into a doctoral
program of study. There’s a catch, of course, because it’s difficult to do
research in hearing science without university affiliation. At present, I’m
pursuing research while, at the same time, on the lookout for a doctoral
advisor. Doing good deeds and being committed to purposeful work is great, but
I suppose I'm still deficient when it comes to those "Merit Badges."
I have written a couple of noteworthy articles regarding hearing, but only one
appeared in a "peer-reviewed" journal. An earlier article was intended for a
much broader (albeit layman) readership, and it reached people who could truly
benefit from the information contained within the article. Specifically, the
article was about hearing protection and muzzle blasts, and it appeared in
Outdoor Life magazine. Submitting the same article to, for example, Audiology,
might have earned Brownie points needed for admission to grad school, but
submitting an article regarding hearing protection to hearing scientists /
audiologists is simply preaching to the choir. I was happy that the article
found favor with a large readership even though it didn't appear in a
"professional" journal. A second article regarding binaural electronic hearing
protectors found its way to Noise & Health (which IS peer-reviewed), and I was
grateful that they accepted it for publication. I
had previously submitted the article to JASA, and had received a very kind
rejection letter. Some magazines will accept or reject articles because of
reader interest or current research trends. The Journal of the Audio
Engineering Society is known for publishing articles on Ambisonics, but maybe
they rejected a series of related articles, and Acta Acustica united with
Acustica picked them up (?). Once copyrighted, I imagine that the publisher has
exclusive rights to the manuscript, even in derivative form. But how they can
justify high prices certainly eludes me. Downloading single articles from JASA
is kind-of pricey, too. Subscription to AES’s library is reasonable, and you
wonder why others aren’t the same. Furthermore, the AES offers anthologies that
include hard-to-find articles.
I wished I could simply upload research and schematic diagrams to my website
and make them available for good will to all researchers. But unless something
gets published in a professional journal, it may be (mis)construed as
“amateurish” or “unimportant” to those in academia. How unfortunate this is!
Please know that I am grateful to all of you who have freely shared you
insights, expertise, and wisdom, whether you’re an audio professional with
years of experience or a hobbyist with personal opinions on music and
Ambisonics.
Sincerely,
Eric
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Re: [Sursound] Motivation for authors(Robert's off topic rant!)
cey, too. Subscription to AES?s library is reasonable, and you wonder why others aren?t the same. Furthermore, the AES offers anthologies that include hard-to-find articles. I wished I could simply upload research and schematic diagrams to my website and make them available for good will to all researchers. But unless something gets published in a professional journal, it may be (mis)construed as ?amateurish? or ?unimportant? to those in academia. How unfortunate this is! Please know that I am grateful to all of you who have freely shared you insights, expertise, and wisdom, whether you?re an audio professional with years of experience or a hobbyist with personal opinions on music and Ambisonics. Sincerely, Eric -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20120111/f30e268e/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
