I would love to make a sound do a death spiral motion . With an LFO, on each axis, bit a load of doppler, distance attenuation and filtering, i think i could kill the thread quite quickly....
On Wed, 8 Mar 2023, 17:00 Chris Woolf, <ch...@chriswoolf.co.uk> wrote: > Ta - looks interesting - there's always someone who's been there before;} > > Chris Woolf > > > On 08/03/2023 16:21, Marc Lavallée wrote: > > The article is freely available here: > > https://ntrs.nasa.gov/citations/20080042307 > > > > Marc > > > > Le 2023-03-08 à 11 h 15, Picinali, Lorenzo a écrit : > >> Hello Chris, > >> > >> this might be interesting for you! > >> > >> > https://journals.sagepub.com/doi/pdf/10.1177/154193120805200103?casa_token=CptzIp9vOaQAAAAA:fG10j5X-vgVL92L3YHFjBTRAyYUCHfVpsuYDrU3DcGX4wPgzym4ZZoLHSh2I2AfvIZrEyKpIQ54 > >> > >> > >> I remember they also presented this work at ICAD in Paris in 2008, > >> and if I remember well they won the best paper award! > >> > >> Best > >> Lorenzo > >> > >> > >> > >> -- > >> Lorenzo Picinali > >> Reader in Audio Experience Design<https://www.axdesign.co.uk/> > >> Dyson School of Design Engineering > >> Imperial College London > >> Dyson Building > >> Imperial College Road > >> South Kensington, SW7 2DB, London > >> E: l.picin...@imperial.ac.uk > >> > >> http://www.imperial.ac.uk/people/l.picinali > >> https://www.axdesign.co.uk/ > >> https://www.sonicom.eu/ > >> ________________________________ > >> From: Sursound <sursound-boun...@music.vt.edu> on behalf of Chris > >> Woolf <ch...@chriswoolf.co.uk> > >> Sent: 08 March 2023 16:03 > >> To: sursound@music.vt.edu <sursound@music.vt.edu> > >> Subject: Re: [Sursound] [off-topic] Spirals > >> > >> > >> ******************* > >> This email originates from outside Imperial. Do not click on links > >> and attachments unless you recognise the sender. > >> If you trust the sender, add them to your safe senders list > >> https://spam.ic.ac.uk/SpamConsole/Senders.aspx to disable email > >> stamping for this address. > >> ******************* > >> Bringing things round in a circle (rather than a spiral).... > >> > >> Anyone any ideas how one could provide an audio horizon that could be a > >> mimic of the gyro artificial horizon? That could presumably add an > >> additional warning of unintentional spiralling, and one that would > >> signal a discrepancy between gravitational/centrifugal pull and absolute > >> vertical. > >> > >> I can see the problems of providing a height dimension with headphones, > >> and also a question of what audio signals would have sufficient rate to > >> provide the frequency of stimulus needed. ATC and TCAS would be some > >> help but I think you would need rather more than just that. > >> > >> This is just coffee-time thoughts - I'm not planning to go flying any > >> time soon;} > >> > >> Chris Woolf > >> > >> > >> On 08/03/2023 13:23, t.mich...@posteo.de wrote: > >>> Hi Panos! > >>> > >>> First of all: Welcome! > >>> Second: YES you are definitely in the right place. > >>> Third: If you have any question, feel invite to ask. :-) > >>> > >>> > >>> Take care and stay healthy > >>> Cheers > >>> > >>> Thorsten > >>> > >>> > >>> Am 08.03.2023 00:08 schrieb Panos Kouvelis: > >>>> I recently subscribed to this mailing list for insightful > >>>> discussions on > >>>> surround sound. > >>>> > >>>> Up 'till now, the material I have received is about aviation. > >>>> > >>>> Am I in the wrong place? > >>>> > >>>> :-) > >>>> > >>>> *Pan Athen* > >>>> SoundFellas <https://soundfellas.com/>, *MediaFlake Ltd > >>>> <http://mediaflake.com/>* > >>>> Digital Media Services, Content, and Tools > >>>> > >>>> > >>>> On Wed, Mar 8, 2023 at 1:03 AM Sampo Syreeni <de...@iki.fi> wrote: > >>>> > >>>>> On 2023-02-22, Fons Adriaensen wrote: > >>>>> > >>>>>> And in many cases the aircraft may very well be unstable in that > >>>>> axis: > >>>>>> if left alone, the roll angle will slowly increase. > >>>>> Actually, most modern aircraft are stable in the bank axis as well. > >>>>> Part > >>>>> of why they have swept wings, bent wings and wingtips and the > >>>>> like, is > >>>>> to this regard. (Part of: most of it has to with approaching > >>>>> transonic > >>>>> flight. But not all.) > >>>>> > >>>>> The thing is though, and as you say below, the pilot won't feel > >>>>> anything > >>>>> weird when approaching a spiral. The built in stability of the > >>>>> airplane > >>>>> will keep everybody in their seat at 1g acceleration perpendicular to > >>>>> the floor, evenas the airplane banks to something approaching 90 > >>>>> degrees, and loses all of its lift. Then it just falls, sideways. > >>>>> > >>>>> When that happens, you're in what's called a "death spiral", because > >>>>> it's extremely difficult to recover from the condition, and you > >>>>> typically don't even know you've entered one. When you do, you as a > >>>>> pilot are already in a state of spatial disorientation; you > >>>>> *literally* > >>>>> don't know which way is up and which down, and since the plane is by > >>>>> now > >>>>> basically half-way inverted, with now absolutely no lift, losing > >>>>> altitude like a falling rock, you as the pilot have very little > >>>>> possibility of correcting. > >>>>> > >>>>> *Technically*, in *theory*, you often *could* recover, if you have > >>>>> enough altitude, speed and sturdiness of airframe; even I have run it > >>>>> through in a game. But in practice, recovery from a well developed > >>>>> death > >>>>> spiral is mostly beyond human ability. Especially once you lose > >>>>> height, > >>>>> because at low altitudes, already going nose down, you can't even > >>>>> convert high air speed/energy into a corrective manoeuvre before you > >>>>> hit > >>>>> the terrain, and there will only be seconds to lose. > >>>>> > >>>>> This is then why the pilot flying is supposed to only look at the > >>>>> instrumentation, and why there are auditory warnings about bank > >>>>> angle on > >>>>> the modern jets. The Swedish commercial midsize Boeing pilot, > >>>>> Mentour, > >>>>> on YouTube, is first rate in explaining all of this stuff. > >>>>> > >>>>> Okay, so, finally, how would you recover from a well developed death > >>>>> spiral, presuming you realized you were in one? Well, the optimum way > >>>>> would be to use all of the airfoils at the pilot's control at the > >>>>> same > >>>>> time to convert kinetic and potential energy of the frame into > >>>>> first 1) > >>>>> orientation, and then 2) into safe height in level flight. > >>>>> > >>>>> The optimum control trajectory going there is universally wild, so > >>>>> that > >>>>> you can't even practice for it in a simulator. It can even be > >>>>> chaotic, > >>>>> in the true mathematical sense. Many of the attempts at automated > >>>>> recovery I known of literally crashed on that point; you can't do > >>>>> optimum control here, because it leads you into an unstable > >>>>> calculation. > >>>>> Instead, you have to have your algoritm flying off the optimum > >>>>> path, in > >>>>> order to keep a stability margin. (Knowing how much off the optimum > >>>>> path > >>>>> it should be, and what a stability margin even *is*, is to date an > >>>>> unknown as well. It's difficult to quantify.) > >>>>> > >>>>> So, how would I fly out of a death spiral, suddenly and against > >>>>> expectation fully knowing I was in one? Fully knowing which way, how > >>>>> fast, at which height, I and my aeroplane was going? Well, > >>>>> obviously, I > >>>>> would have to regain lift, evenas I was falling. I'd use ailerons to > >>>>> gain "level flight" evenwhile falling. While that was done, I'd yoke > >>>>> up, > >>>>> no matter the orientation of the airframe (assuming I wasn't > >>>>> downright > >>>>> inverted), in order to gain altitude and *true* level flight. I'd put > >>>>> the engines in idle and maybe spoil the airfoil, for want of > >>>>> structurally sound airspeed and the g-forces which necessarily come > >>>>> after a recovery from a spiral. Something like that. > >>>>> > >>>>> Even if I did all of that *just* right, I'd probably contact terrain. > >>>>> All on-board would be lost. Because recovering from a death spiral, > >>>>> once > >>>>> it's started and developed well, is pretty much an inhuman feat. It's > >>>>> almost impossible for a computer to do, as well. The many algorithms > >>>>> which have been tried out, taking control away from the human pilot, > >>>>> none of them have been shown to do any good either. > >>>>> > >>>>> Fons, this is one of the other things I follow. Amateurishly, but I > >>>>> still do. > >>>>> > >>>>> https://www.youtube.com/watch?v=b7t4IR-3mSo > >>>>> https://www.youtube.com/watch?v=JhzaogGQNFU&t=1056s > >>>>> https://www.youtube.com/watch?v=o7N0pshAC0k > >>>>> > >>>>> Now the fun thing is, as my pilot friends say, you can actually > >>>>> *even* > >>>>> do a full, level, aileron roll on all of the AirBus jumbojets. > >>>>> Definitely not recommended, might lose your licence, and you'd > >>>>> have to > >>>>> disengage a number of safety systems, then flying by eye and touch > >>>>> alone. But I'm told all of them *can* do showflying manoeuvres if > >>>>> need > >>>>> be. My nerd friends even claim to me, if need be, the things might be > >>>>> capable of autonomous inverted flight; I'm not too sure if any flight > >>>>> manufacturer actually ever went so far, but if one did, it surely > >>>>> would > >>>>> be AirBus. Damn, woman, stop it right *here*! > >>>>> > >>>>>> A non-zero roll angle means that part of the lift force generated by > >>>>>> the wings is now sideways. > >>>>> Now, once we've handled conventional aircrafts, let's take on fighter > >>>>> aircraft. The fifth generation ones, like the F22 and the F35. Their > >>>>> fly-by-wire flight control surface work in concert, and often in a > >>>>> fully > >>>>> different way. For example, instead of there being separate > >>>>> spoilers, in > >>>>> order to introduce a limited airfoil separation/stall, the primary > >>>>> control surfaces introduce a time-limited and measured stall in a > >>>>> servo > >>>>> loop. And then not, again. > >>>>> > >>>>> Those things basically fly themselves, strategically stalling some of > >>>>> the control surfaces when need be. For example, in order to > >>>>> automatically come back from a leftward death spiral, the fighter > >>>>> will > >>>>> make its right back control surface stall, losing lift > >>>>> momentarily, and > >>>>> so roll the aircraft as well as make it pitch up, lose airspeed > >>>>> because > >>>>> of the increased drag, and so gain an amount of lift. > >>>>> > >>>>> Fons, I like this kind of analysis. Optimum control, and where its > >>>>> limits lay. This stuff is *fun*! > >>>>> > >>>>>> That - and not the rudder - is what makes the aircraft make a turn. > >>>>> The rudder is also a fun turn — pun intended. It's even "fun" in the > >>>>> death spiral recovery manoeuvre. Because you cannot efficiently come > >>>>> out > >>>>> of a spiral using only ailerons. While coming down, in order to > >>>>> rectify > >>>>> the spiral, you actually have to apply a lot of rudder as well. > >>>>> Otherwise you'll end up a whole lot more down, with disastrous > >>>>> airspeed. > >>>>> > >>>>>> The vertical component of lift is reduced, and a pitch-stable > >>>>> aircraft > >>>>>> will just by itself increase its airspeed to restore it. It can do > >>>>>> that only by going down at that same time. > >>>>> True. > >>>>> > >>>>>> Unless you watch the horizon or the attitude indicator, you will > >>>>>> not be aware that this is happening. > >>>>> True. Whence the 178 seconds above. Also, "spatial disorientation in > >>>>> aviation". This Youtube channel of mine, "Mentour", has done quite a > >>>>> number of features on just this thing. He's a commercial pilot, and > >>>>> even > >>>>> has access to flight simulators. See above even for him inverting his > >>>>> native 737 in one. > >>>>> > >>>>>> As the roll angle increases, the g-force will apparently remain > >>>>>> vertical (relative to the aircraft) but increase as well. > >>>>> Actually the g-force does not increase at all. That's why the death > >>>>> spiral is so nasty: you don't feel anything at *all*, evenwhile > >>>>> you're > >>>>> going nose down into the ground. > >>>>> > >>>>> Much of that is because of the intrinsic stability of the aircraft. > >>>>> Because the stability means the craft wants to stay at 1g towards the > >>>>> floor. While it stays that way — no matter its actual attitude — you > >>>>> won't feel anything off even if the thing is inverted in a barrel > >>>>> roll — > >>>>> a nice and harmless aerobatic movement — or in a death spiral — with > >>>>> at most two seconds to die. > >>>>> > >>>>>> And at some point you will notice that you are pinned down in your > >>>>>> seat and unable to move - you are effectively in a centrifuge, way > >>>>> too > >>>>>> fast, going down, and the g-forces will be so high that they can > >>>>> break > >>>>>> up the aircraft. > >>>>> This only happens once you gained too much airspeed and try to > >>>>> recover > >>>>> by pulling up on the yoke. True, if you're already there, not much > >>>>> can > >>>>> be done to recover. But at least don't then pull up the yoke too > >>>>> fast in > >>>>> order to break the airframe. At max do something like a "gentle" 5g > >>>>> curve, and if you then manage to not crash into the terrain, level > >>>>> off > >>>>> and apply some spoiling. > >>>>> > >>>>> Ah, you too think about this. Hmm. 8) > >>>>> > >>>>>> To recover: > > 1. Reduce power to idle. > >>>>> Preferably as soon as you know you're losing altitude. Because > >>>>> you'll be > >>>>> trading potential energy for kinetic energy/speed from the get go. > >>>>> This > >>>>> is also why I mentioned fighter jets and dog fighting from the get > >>>>> go: > >>>>> that energy count-down (or up) is how dogfighting has been counted > >>>>> from > >>>>> the start. It's how dogfights are won, and the energy management is > >>>>> also > >>>>> how planes are either crashed or landed safely. > >>>>> > >>>>>>> 2. Bring the wings level. This has to be done gently, to avoid even > >>>>>>> more mechanical stress. > >>>>> Yes. However, this is difficult to do once you went into spatial > >>>>> disorientation, your synthetic horizon is at something like 120 > >>>>> degrees, > >>>>> and you descend at a about a five kilometres per minute, from an > >>>>> altitude of, say, a generous ten thousand feet. Within a thick cloud > >>>>> cover, with all of your instruments yelling at you at the same time. > >>>>> > >>>>>>> 3. As the wings return to level, the excessive speed will put the > >>>>>>> aircraft into a steep climb. > >>>>> What is "level", here? In a death spiral, the optimum recovery will > >>>>> take > >>>>> you through a route where you'll *definitely* not be level. Your nose > >>>>> will be looking down, at an airspeed which is *way* over your craft's > >>>>> design limits. That will also take place well after you can > >>>>> laterally, > >>>>> in ailerons, balance the aircraft; as such, even a very little > >>>>> take on > >>>>> the ailerons, or the rudder, the yoke, would immediately either stall > >>>>> some control surface, or made better, tear each of them apart. And > >>>>> you > >>>>> don't really know what is "level" hear, either; even your > >>>>> instrumentation is probably fucked up already; believe you me, no > >>>>> inertial thingy ever survives the kind of vibration an aircraft > >>>>> induces > >>>>> on itself when put into a multiple g's acceleration, combined with a > >>>>> wide stall. > >>>>> > >>>>>>> Let it happen but keep the pitch angle under control. > >>>>> Exactly so. "Let it happen." Many of the worst accidents on record > >>>>> have > >>>>> happened because pilots fought their planes, instead of "going > >>>>> with the > >>>>> flow" which a plane, designed to be statically stable from the start, > >>>>> would have done by itself. For example, (ya'll, prolly not Fons) > >>>>> take a > >>>>> look at: https://en.wikipedia.org/wiki/Pilot-induced_oscillation . > >>>>> > >>>>>>> You will regain some of the lost altitude, and airspeed will > >>>>>>> decrease. > >>>>> Recovery from a near miss death spiral is still more involved. > >>>>> Because > >>>>> you might have to operate the aircraft at structural load, and do a > >>>>> recovery from a prolonged stall over all of the airframe. You might > >>>>> actually have to "fly" your airframe over a minute in a full stall > >>>>> over > >>>>> every part of it, and then try to regain aerodynamic control. "After > >>>>> sinking, flying, and shaking like a rock from a cannon." > >>>>> > >>>>> It can be done. But nobody teaches you how to do this, and in fact, I > >>>>> don't know of *one* algorithm which has flown this route. > >>>>> > >>>>>> 4. As you approach normal airspeed, bring back power and level off. > >>>>> That should be obvious, then. It's that third stage before "Profit" > >>>>> which always slights the eye. ;) > >>>>> > >>>>>> Ciao, > >>>>> Moro. > >>>>> -- > >>>>> Sampo Syreeni, aka decoy - de...@iki.fi, http://decoy.iki.fi/front > >>>>> +358-40-3751464 <http://decoy.iki.fi/front+358-40-3751464>, 025E > D175 > >>>>> ABE5 027C 9494 EEB0 E090 8BA9 0509 85C2 > >>>>> _______________________________________________ > >>>>> 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/20230308/988a2b84/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. > >>> _______________________________________________ > >>> 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/20230308/3142cd19/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. > > _______________________________________________ > > 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... 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