Re: [Sursound] Recorder for ORTF-3D OUTDOOR SET
On Wed, Oct 21, 2020 at 02:37:39PM +0100, Augustine Leudar wrote: > So if you > had say, 8 ambisonics mics pointed in 8 different directions ,in order to > record that small 8th of a sphere (or in this case cube) in the direction > they are pointed in (which is what the ORTF does) - how would this work if > the decoder if a format gives spherical coordinates rather than an 8th of a > sphere/cube (hope this makes sense), and with the capsules pointing in all > directions... ? Sorry, this doesn't make any sense... A decoder doesn't give 'spherical coordinates', it outputs signals. What makes you think that ORTF captures 'a small 8th of a sphere' ?? Each Ambisonic mic, by suitable combination of its capsule signals [1], can provide the same signals as any number of conventional capsules (omni, cardioid, fig-of-eight,...) placed at the same point in space and in any direction. So you can always replace every group of (nearly) coincident conventional capsules (e.g. an M/S pair) by an Ambisonic one and get exactly the same signals. If you use a higher order AMB mic (e.g. an OctoMic) you can even get polar patterns for which no conventional capsule equivalent exists, and which certainly provide an advantage for surround. That's all there is to it. [1] This involves some filtering as well as just summing/subtracting signals, and for good reults it requires calibration of the AMB mic's capsules. If you experimented with Ambisonics in the way you pointed out, it's no surprise you got bad results. As I've stated a number of times before, there is *a lot* of completely bogus information on Ambisonics technology floating around. Some of this stuff is at the same level of intellectual integrity as e.g. flat-earth theories. Most of it is just the results of failing to understand basic things, or of simplifying things to the point that whatever remains is 'not even wrong'. Combine that with some people having their own agenda. Ciao, -- FA ___ 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.
Re: [Sursound] Recorder for ORTF-3D OUTDOOR SET
> What makes you think that ORTF captures > 'a small 8th of a sphere' ?? I don’t.. Maybe I wasn’t clear. What I meant was replacing each ORTF capsule (or M/S pair) with an ambisonic mic, and decoding for the direction it should point. All spaced array setups can use ambisonic mics, as they can output all the polar patterns required. My point was; the polar patterns would be more accurate (for a calibrated mic) and hence the spatial accuracy better. So yes exactly that. Thanks for making it clearer :) Steve > > Sorry, this doesn't make any sense... A decoder doesn't give 'spherical > coordinates', it outputs signals. What makes you think that ORTF captures > 'a small 8th of a sphere' ?? > > Each Ambisonic mic, by suitable combination of its capsule signals [1], > can provide the same signals as any number of conventional capsules > (omni, cardioid, fig-of-eight,...) placed at the same point in space > and in any direction. > > So you can always replace every group of (nearly) coincident conventional > capsules (e.g. an M/S pair) by an Ambisonic one and get exactly the same > signals. > > If you use a higher order AMB mic (e.g. an OctoMic) you can even get > polar patterns for which no conventional capsule equivalent exists, and > which certainly provide an advantage for surround. > > That's all there is to it. > > > [1] This involves some filtering as well as just summing/subtracting > signals, and for good reults it requires calibration of the AMB mic's > capsules. If you experimented with Ambisonics in the way you pointed > out, it's no surprise you got bad results. > > As I've stated a number of times before, there is *a lot* of completely > bogus information on Ambisonics technology floating around. Some of this > stuff is at the same level of intellectual integrity as e.g. flat-earth > theories. Most of it is just the results of failing to understand basic > things, or of simplifying things to the point that whatever remains is > 'not even wrong'. Combine that with some people having their own agenda. > > Ciao, > > -- > FA > > ___ > 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.
Re: [Sursound] Recorder for ORTF-3D OUTDOOR SET
The only problem with using ambisonics mics is the high frequency limit above which they stop working properly. A second order ambi mic reduces this problem, but above about 7Khz the not quite coincident capsules becomes a problem. J On Thu, 22 Oct 2020 at 11:36, Steven Boardman wrote: > > > What makes you think that ORTF captures > > 'a small 8th of a sphere' ?? > > I don’t.. > > Maybe I wasn’t clear. What I meant was replacing each ORTF capsule (or M/S > pair) with an ambisonic mic, and decoding for the direction it should point. > All spaced array setups can use ambisonic mics, as they can output all the > polar patterns required. > My point was; the polar patterns would be more accurate (for a calibrated > mic) and hence the spatial accuracy better. > So yes exactly that. > > Thanks for making it clearer :) > > Steve > > > > > Sorry, this doesn't make any sense... A decoder doesn't give 'spherical > > coordinates', it outputs signals. What makes you think that ORTF captures > > 'a small 8th of a sphere' ?? > > > > Each Ambisonic mic, by suitable combination of its capsule signals [1], > > can provide the same signals as any number of conventional capsules > > (omni, cardioid, fig-of-eight,...) placed at the same point in space > > and in any direction. > > > > So you can always replace every group of (nearly) coincident conventional > > capsules (e.g. an M/S pair) by an Ambisonic one and get exactly the same > > signals. > > > > If you use a higher order AMB mic (e.g. an OctoMic) you can even get > > polar patterns for which no conventional capsule equivalent exists, and > > which certainly provide an advantage for surround. > > > > That's all there is to it. > > > > > > [1] This involves some filtering as well as just summing/subtracting > > signals, and for good reults it requires calibration of the AMB mic's > > capsules. If you experimented with Ambisonics in the way you pointed > > out, it's no surprise you got bad results. > > > > As I've stated a number of times before, there is *a lot* of completely > > bogus information on Ambisonics technology floating around. Some of this > > stuff is at the same level of intellectual integrity as e.g. flat-earth > > theories. Most of it is just the results of failing to understand basic > > things, or of simplifying things to the point that whatever remains is > > 'not even wrong'. Combine that with some people having their own agenda. > > > > Ciao, > > > > -- > > FA > > > > ___ > > 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. > -- 07889727365 02036861372 3 Swimmers Lane Haggerston London E2 8FR www.facebook.com/reynoldsmicrophones www.sohovr.co.uk -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20201022/7b073c79/attachment.htm> ___ 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.
Re: [Sursound] Recorder for ORTF-3D OUTDOOR SET
Hi Jack If the spaced array was only using cardioids, then maybe their patterns would be more stable at higher frequencies, but not for near coincident spurs of mid/side (and the like). As they are even further apart than an ambisonic mic, and they aren’t calibrated together. Steve > On 22 Oct 2020, at 12:36, jack reynolds wrote: > > The only problem with using ambisonics mics is the high frequency limit > above which they stop working properly. A second order ambi mic reduces > this problem, but above about 7Khz the not quite coincident capsules > becomes a problem. > > J ___ 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.
Re: [Sursound] Recorder for ORTF-3D OUTDOOR SET
et > polar patterns for which no conventional capsule equivalent exists, and > which certainly provide an advantage for surround. > > That's all there is to it. > > > [1] This involves some filtering as well as just summing/subtracting > signals, and for good reults it requires calibration of the AMB mic's > capsules. If you experimented with Ambisonics in the way you pointed > out, it's no surprise you got bad results. > > As I've stated a number of times before, there is *a lot* of completely > bogus information on Ambisonics technology floating around. Some of this > stuff is at the same level of intellectual integrity as e.g. flat-earth > theories. Most of it is just the results of failing to understand basic > things, or of simplifying things to the point that whatever remains is > 'not even wrong'. Combine that with some people having their own agenda. > > Ciao, > > -- > FA > > ___ > 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/20201022/f8d9a5f6/attachment.htm> ___ 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.
Re: [Sursound] Recorder for ORTF-3D OUTDOOR SET
This is an especially annoying problem when you consider hi frequencies are what we localise best On Thu, 22 Oct 2020 at 12:37, jack reynolds wrote: > The only problem with using ambisonics mics is the high frequency limit > above which they stop working properly. A second order ambi mic reduces > this problem, but above about 7Khz the not quite coincident capsules > becomes a problem. > > J > > On Thu, 22 Oct 2020 at 11:36, Steven Boardman > wrote: > > > > > > What makes you think that ORTF captures > > > 'a small 8th of a sphere' ?? > > > > I don’t.. > > > > Maybe I wasn’t clear. What I meant was replacing each ORTF capsule (or > M/S > > pair) with an ambisonic mic, and decoding for the direction it should > point. > > All spaced array setups can use ambisonic mics, as they can output all > the > > polar patterns required. > > My point was; the polar patterns would be more accurate (for a calibrated > > mic) and hence the spatial accuracy better. > > So yes exactly that. > > > > Thanks for making it clearer :) > > > > Steve > > > > > > > > Sorry, this doesn't make any sense... A decoder doesn't give 'spherical > > > coordinates', it outputs signals. What makes you think that ORTF > captures > > > 'a small 8th of a sphere' ?? > > > > > > Each Ambisonic mic, by suitable combination of its capsule signals [1], > > > can provide the same signals as any number of conventional capsules > > > (omni, cardioid, fig-of-eight,...) placed at the same point in space > > > and in any direction. > > > > > > So you can always replace every group of (nearly) coincident > conventional > > > capsules (e.g. an M/S pair) by an Ambisonic one and get exactly the > same > > > signals. > > > > > > If you use a higher order AMB mic (e.g. an OctoMic) you can even get > > > polar patterns for which no conventional capsule equivalent exists, and > > > which certainly provide an advantage for surround. > > > > > > That's all there is to it. > > > > > > > > > [1] This involves some filtering as well as just summing/subtracting > > > signals, and for good reults it requires calibration of the AMB mic's > > > capsules. If you experimented with Ambisonics in the way you pointed > > > out, it's no surprise you got bad results. > > > > > > As I've stated a number of times before, there is *a lot* of completely > > > bogus information on Ambisonics technology floating around. Some of > this > > > stuff is at the same level of intellectual integrity as e.g. flat-earth > > > theories. Most of it is just the results of failing to understand basic > > > things, or of simplifying things to the point that whatever remains is > > > 'not even wrong'. Combine that with some people having their own > agenda. > > > > > > Ciao, > > > > > > -- > > > FA > > > > > > ___ > > > 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. > > > > > -- > > 07889727365 > > 02036861372 > > 3 Swimmers Lane > Haggerston > London > E2 8FR > > > www.facebook.com/reynoldsmicrophones > > www.sohovr.co.uk > -- next part -- > An HTML attachment was scrubbed... > URL: < > https://mail.music.vt.edu/mailman/private/sursound/attachments/20201022/7b073c79/attachment.htm > > > ___ > 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. > -- Artist website: www.augustineleudar.com Business website: www.magikdoor.net -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20201022/3854d48b/attachment.htm> ___ 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.
Re: [Sursound] Recorder for ORTF-3D OUTDOOR SET
regarding sound quality: i had my hand only at an sennheiser ambeo. did an A/B comparison with Schoeps DMS setup. while the drums i recorded sounded like drums via the Schoeps, they sounded like cardboard boxes via the ambeo. or are other ambisonic mics comparable to e.g. a ccm4 or mkh8020 ? spatial resolution: don/t you get better resolution with a spaced array especially in the diffuse field. (and rainforest has a lot of diffuse field) in other words: is the coincidence route (ms, dms, ambisonics) really good for field recording in terms of sound quality ? in the end one could produce b-format also out of the discrete signals of a spaced array... On Thu, Oct 22, 2020 at 12:36 PM Steven Boardman wrote: > > > What makes you think that ORTF captures > > 'a small 8th of a sphere' ?? > > I don’t.. > > Maybe I wasn’t clear. What I meant was replacing each ORTF capsule (or M/S > pair) with an ambisonic mic, and decoding for the direction it should point. > All spaced array setups can use ambisonic mics, as they can output all the > polar patterns required. > My point was; the polar patterns would be more accurate (for a calibrated > mic) and hence the spatial accuracy better. > So yes exactly that. > > Thanks for making it clearer :) > > Steve > > > > > Sorry, this doesn't make any sense... A decoder doesn't give 'spherical > > coordinates', it outputs signals. What makes you think that ORTF captures > > 'a small 8th of a sphere' ?? > > > > Each Ambisonic mic, by suitable combination of its capsule signals [1], > > can provide the same signals as any number of conventional capsules > > (omni, cardioid, fig-of-eight,...) placed at the same point in space > > and in any direction. > > > > So you can always replace every group of (nearly) coincident conventional > > capsules (e.g. an M/S pair) by an Ambisonic one and get exactly the same > > signals. > > > > If you use a higher order AMB mic (e.g. an OctoMic) you can even get > > polar patterns for which no conventional capsule equivalent exists, and > > which certainly provide an advantage for surround. > > > > That's all there is to it. > > > > > > [1] This involves some filtering as well as just summing/subtracting > > signals, and for good reults it requires calibration of the AMB mic's > > capsules. If you experimented with Ambisonics in the way you pointed > > out, it's no surprise you got bad results. > > > > As I've stated a number of times before, there is *a lot* of completely > > bogus information on Ambisonics technology floating around. Some of this > > stuff is at the same level of intellectual integrity as e.g. flat-earth > > theories. Most of it is just the results of failing to understand basic > > things, or of simplifying things to the point that whatever remains is > > 'not even wrong'. Combine that with some people having their own agenda. > > > > Ciao, > > > > -- > > FA > > > > ___ > > 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/20201022/22c62b1d/attachment.htm> ___ 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.
Re: [Sursound] Recorder for ORTF-3D OUTDOOR SET
> On 22 Oct 2020, at 13:19, michael strohmann wrote: > > regarding sound quality: i had my hand only at an sennheiser ambeo. did an > A/B comparison with Schoeps DMS setup. while the drums i recorded sounded > like drums via the Schoeps, they sounded like cardboard boxes via the ambeo. > or are other ambisonic mics comparable to e.g. a ccm4 or mkh8020 ? I had an Ambeo and got rid of it for this reason. It sucked compared to my Schoeps ccm4/ccm2/ccm8, and Senheiser MKH20/30/40. But my Soundfield ST350 I love, and the Schoepss and Senheisers sit very nicely with it. I also have a Tetramic which I like too, mainly because it is small, and sits under/over a 360 camera well… I won’t part with my ST350, unless it’s to get a ST450 :) It is fab for music, especially in conjunction with the mono mics above. Steve ___ 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.
Re: [Sursound] Recorder for ORTF-3D OUTDOOR SET
On Thu, Oct 22, 2020 at 12:36:38PM +0100, jack reynolds wrote: > The only problem with using ambisonics mics is the high frequency limit > above which they stop working properly. A second order ambi mic reduces > this problem, but above about 7Khz the not quite coincident capsules > becomes a problem. First order responses from an OctoMic are near perfect up to 11 kHz or so, and not perfect but still very usable even at 15 kHz. I doubt very much if there is any 'real' cardioid' doing better at that frequency and above. Certainly not if you take diffraction / reflection from the mic body and clamp into account. Anyway, have you ever considered the sort of frequency and polar response you get by combining signals from capsules spaced more than 10 cm apart ? You'll find they look quite horrible if you care to compute or measure them. You could of course object that those should never be combined, just each one sent to its own speaker. But that would mean that such a one to one mapping is the only possible way to use such signals if you want to preserve sound quality. No downmixing or anything similar (e.g. binaural) allowed. But we all know that this is not true, we all have heard very nice music recordings done with spaced mics. Even those in theory horrible frequency or polar responses resulting from spaced mics can sound quite well. Wich in turn means that this whole 'imperfect polar responses' debate is mostly academic if not irrelevant. Ciao, -- FA ___ 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.
Re: [Sursound] Recorder for ORTF-3D OUTDOOR SET
On Thu, Oct 22, 2020 at 01:38:49PM +0100, Steven Boardman wrote: > I had an Ambeo and got rid of it for this reason. The A/B processing provided by Sennheiser sucks. It gets a lot better with a proper A/B processor computed from actual measurements. Ciao, -- FA ___ 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.
Re: [Sursound] Recorder for ORTF-3D OUTDOOR SET
I have had great results with a pair of spaced first order ambisonic mics for binaural decoding. Taking the left hemisphere of one of the mics, and right hemisphere of the other, then combining the two. The decorellation does add something nice and spacious to the sound. Sent from my iPhone > On 22 Oct 2020, at 16:32, Fons Adriaensen wrote: > > On Thu, Oct 22, 2020 at 12:36:38PM +0100, jack reynolds wrote: > >> The only problem with using ambisonics mics is the high frequency limit >> above which they stop working properly. A second order ambi mic reduces >> this problem, but above about 7Khz the not quite coincident capsules >> becomes a problem. > > First order responses from an OctoMic are near perfect up to 11 kHz or so, > and not perfect but still very usable even at 15 kHz. I doubt very much > if there is any 'real' cardioid' doing better at that frequency and above. > Certainly not if you take diffraction / reflection from the mic body and > clamp into account. > > Anyway, have you ever considered the sort of frequency and polar response > you get by combining signals from capsules spaced more than 10 cm apart ? > You'll find they look quite horrible if you care to compute or measure > them. > > You could of course object that those should never be combined, just each > one sent to its own speaker. But that would mean that such a one to one > mapping is the only possible way to use such signals if you want to preserve > sound quality. No downmixing or anything similar (e.g. binaural) allowed. > > But we all know that this is not true, we all have heard very nice music > recordings done with spaced mics. Even those in theory horrible frequency > or polar responses resulting from spaced mics can sound quite well. Wich > in turn means that this whole 'imperfect polar responses' debate is mostly > academic if not irrelevant. > > > Ciao, > > -- > FA > > ___ > 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.
Re: [Sursound] Recorder for ORTF-3D OUTDOOR SET
On Thu, Oct 22, 2020 at 04:42:28PM +0100, Jack Reynolds wrote: > I have had great results with a pair of spaced first order ambisonic mics > for binaural decoding. > Taking the left hemisphere of one of the mics, and right hemisphere of the > other How do you obtain only one hemisphere from a first order AMB mic ? By linear processing the only possible way would just be a virtual cardioid or something near. At higher order you could obtain something closer to a hemisphere. So did you use some non-linear process (e.g. Harpex) ? -- FA ___ 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.
Re: [Sursound] Recorder for ORTF-3D OUTDOOR SET
I upmix to third order and then use the Blue Ripple Spotlight plugin to isolate on half of the sound field from each mic and then combine the two into a single third order ambix signal to decode binaurally. It’s sound really nice. I’ll post a session with some files of a dawn chorus recording when I get a chance. J Sent from my iPhone > On 22 Oct 2020, at 17:00, Fons Adriaensen wrote: > > On Thu, Oct 22, 2020 at 04:42:28PM +0100, Jack Reynolds wrote: > >> I have had great results with a pair of spaced first order ambisonic mics >> for binaural decoding. > >> Taking the left hemisphere of one of the mics, and right hemisphere of the >> other > > How do you obtain only one hemisphere from a first order AMB mic ? > By linear processing the only possible way would just be a virtual > cardioid or something near. At higher order you could obtain something > closer to a hemisphere. > So did you use some non-linear process (e.g. Harpex) ? > > -- > FA > > > ___ > 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.
Re: [Sursound] Recorder for ORTF-3D OUTDOOR SET
> > You could of course object that those should never be combined, just each > one sent to its own speaker. But that would mean that such a one to one > mapping is the only possible way to use such signals if you want to > preserve > sound quality. No downmixing or anything similar (e.g. binaural) allowed. > > This is not the case - you just put the hrtf for each speaker position on that track for the binaural remder -- Artist website: www.augustineleudar.com Business website: www.magikdoor.net -- next part -- An HTML attachment was scrubbed... URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20201022/d1149564/attachment.htm> ___ 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.
Re: [Sursound] Recorder for ORTF-3D OUTDOOR SET
< nothing below implies that an Ambisonics microphone is the best solution for all sound capture cases! > On 10/21/20 6:37 AM, Augustine Leudar wrote: Hi Steve, An interesting proposal. You'll excuse perhaps my misunderstanding here, but my understanding was that ambisonics A format consists of a omni plus x,y,z to give 4 signals that are then converted to b format. First order "A format" is just the four signals coming from the four capsules. They are matrixed and filtered to generate the B format signals, which are the equivalent of an omni and three figure of eight at right angles to each other. Ideally the B format polar patterns are frequency independent. In reality this is not the case (for any capsule), but a properly calibrated Ambisonics microphone is very good in that respect, with polar patterns consistent up to very high frequencies (as Fons points out elsewhere in the thread). I built my own ambisonics mic and decoder once a long time ago so perhaps things have changed, I think I put Left + & - right = x Front + & - Back = y Top + & - bottom = z All summed * 0.257 = w into my decoder. Hmmm, just curious, did you also add high frequency non-coincidence compensation filters? A simple add/substract matrix (maybe that is not all you did? - you also say later in the thread you eq'ed the capsules) will work fine for frequencies where the array can be considered small relative to the wavelength in air. The effects of the non-coincidence of the capsules starts to show up at 3Khz or so in my case, exactly where depends on the radius of the array, and needs to be compensated somehow. This is usually done by filtering the B format signals. (see attached graph of unfiltered and filtered response at 0 degrees incidence for my TinySpHEAR mics - these are very old plots but useful anyway as they show the difference those filters make) Best, -- Fernando . Anyway I digress - this basically will give you a sounds position in 3D space , or at least on the surface of a sphere proximity not being so well recreated. So if you had say, 8 ambisonics mics pointed in 8 different directions ,in order to record that small 8th of a sphere (or in this case cube) in the direction they are pointed in (which is what the ORTF does) - how would this work if the decoder if a format gives spherical coordinates rather than an 8th of a sphere/cube (hope this makes sense), and with the capsules pointing in all directions... ? ... -- next part -- A non-text attachment was scrubbed... Name: sphear_raw_0.png Type: image/png Size: 33125 bytes Desc: not available URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20201022/17fb6597/attachment.png> -- next part -- A non-text attachment was scrubbed... Name: sphear_filtered_0.png Type: image/png Size: 26715 bytes Desc: not available URL: <https://mail.music.vt.edu/mailman/private/sursound/attachments/20201022/17fb6597/attachment-0001.png> ___ 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.
Re: [Sursound] Recorder for ORTF-3D OUTDOOR SET
Jack Reynolds wrote > The only problem with using ambisonics mics is the high frequency limit > above which they stop working properly. A second order ambi mic reduces > this problem, but above about 7Khz the not quite coincident capsules > becomes a problem. This isn't correct. Here's OctoMic's omnidirectional directivity graph: https://www.core-sound.com/OctoMic/OM-265-omni.png Here's a well-known German omnidirectional mic's graph: https://schoeps.de/en/products/colette/capsules/omnis/mk-2.html --- Here's the same comparison for cardioid: https://www.core-sound.com/OctoMic/OM-265-cardioid1-log.png Here's the well-known German cardioid mic's graph: https://schoeps.de/en/products/colette/capsules/cardioids/mk-4.html --- You can see more graphs here: www.core-sound.com/OctoMic/2.php Please compare them yourself. Len Moskowitz (mosko...@core-sound.com) Core Sound LLC www.core-sound.com Home of OctoMic and TetraMic ___ 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.
Re: [Sursound] ORTF-3D With Higher-order Ambisonics
Steven Boardman wrote: > Have you tried it with first order? > I would of thought using one Harpexed octomic to synthesise all the spaced > mics, would be a bit blurry, did you try with two? Harpex only operates at first-order. We used OctoMic's first-order B-format as input to Harpex. We've used two OctoMics for ORTF. Since OctoMic's cardioid patterns are so stable and consistent, and because pointing angles can be fine-tuned in post, two OctoMics make probably the world's finest ORTF array. Len Moskowitz (mosko...@panix.com) Core Sound LLC www.core-sound.com Home of OctoMic and TetraMic ___ 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.
