[ This text is a revision (August 17th 1993) of the article i posted: Date: Mon, 25 Jan 93 1:03:24 EST From: dionf@ERE.UMontreal.CA (Francois Dion) Message-Id: <9301250603.AA26790@brise.ERE.UMontreal.CA> Subject: Franky in 3D To: Ultrasound Daily Digest I changed it to reflect the new informations i got. Archer did send me this time a nice informational package. ] Well, i think it's time i put my grain of salt on the 3d mania. First of all, even if it is a bit long, i suggest to read it all. And if you dont want to wait for a 3D driver for the GUS, dont forget to read one of my other post in this digest with the subject: Franky in surround. Also found under the filename surround.txt. [Note: 3D drivers are now available for programmers] Now, on with the show: There are several systems that are in use to get 3D sounds on recordings and some have been around since the 50s. Now i wont go into the "how it works" of the more recent ones, but i think this will clear up some confusion. The first part is a "hands-on" experiment, the second is informations, including the address and phone of the owner of the technology that is used with the Gravis Ultrasound. Let's get back to the early days of stereo. One record company (i cant seem to remember) was pushing it, while another (again, blank. anyone?) competed. Interestingly enough, technological development was put on stereo, and not on the first 3D system which was called "binaural recording" and it simply consisted of two microphones placed like the ears. You can try it this way: Go to a hat store and buy an extruded foam mannequin head. You'll then need two microphones. Condenser will do, but you will need to power them if you want to use them with the GUS, since it take a dynamic microphone because it does not supply phantom power like some mixer with XLR plugs. I will post a circuit later for Radio-shack condenser mike unit (a small element that cost about 2$) if there is some interest. (this circuit can be found in the file micro.arj on archive.epas.utoronto.ca. If you dont want to mess with that, go with a cardiod dynamic element. Note that sensitive enough cardiod will cost you a lot, so think about that. You cut holes in the ears of the head, to insert the microphone units (dont forget to make the wires of the elements go inside the head and out the rear (or wherever). Use glue to fill the crack around the mic. Also, the more the ears look like real ears, the better it will work. If you trim the foam, dont forget to use an hairdryer to soften it (it will be more uniform). That's it. Try recording sounds, and you'll be surprised. I was! I did the experiment with a polystyrene head on which i incrusted two PZM microphones. Now that you understand how 3D recording is nothing like stereo recording, we'll see what is accesible presently. First, the gadget we just built in the previous section exist commercially, and is called "Mikey" and is made by Spherical Sound. It's the only system commercialised where the microphones are placed in a head. Another system is made by Virtual Audio and claims to enhance stereo depth, but is not labeled 3D audio. I dont have much more info on it, but from the description it looks like the same thing as the "mikey". A few other systems use less restraining microphones situation and can also be used on any signal because a DSP simulate a 3D signal from parameters entered on the machine. The DSP will calculate filters based on head related transfer functions. To get the parameters for these functions, lots of tests in anechoic chambers had to be done, with frequency, phase and volume information measured in the listeners ears (actually some kind of "mikey" is used to get the measures). QSound (no hyphen) was developped in Alberta, and the inventor sold the concept to another company (Archer Communications). It will not work at all with headphones, or if you are not positionned correctly while listening to it thru speakers and you are not in the soft spot. As for spacial repre- sentation, it cannot recreate a sound behind the listener, but can enhance the virtual representation between the listener and the speakers. And for trivia: Madonna, Sting, Wilson Phillips, Julian Lennon and Paula Abdul to name a few have used the QSound on their latest recordings. You cant buy a Qsound system presently but you can rent one and it is now midi controllable. The Qsound system has been licensed to Creative Labs for inclusion on their SB16asp cards and has also been licensed to Capcom and Analog Devices. Strangeley enough, CDROM titles for Sega home entertainment platform will be released with Qsound, while on this same system you will be able to get a VR helmet *with headphones* (remember, Qsound doesn't support that...). Another variant with a DSP is Roland RSS (Roland Sound Space). It is better (depending on how it is used) than QSound with headphones, but suffers the same faith as QSound when you are listening with speakers. Just move a bit from the soft spot, and suddenly what was in front left is now back left. RSS was used on Suzanne Cianni _Hotel Luna_ album. RSS cost around 40K$ and is midi controllable. I have not seen much things done with it yet, so Qsound and Focal Point seems to be more viable solutions (considering cost!). Another system on which i have zero information is called Audio Cybernetics. I also found out that a company called Sixgraph, from Montreal, QC will release a soundcard for PCs at Comdex in october 93 and from what i was told, they use their own technology for reproducing 3D audio. Then you have the convolvotron, a 300 mips 3D engine for PCs. Used a lot in virtual reality, but can only have 1 3D sound. It is also quite expensive and use more than 2 speakers. A less expensive product from the same company (Crystal river engineering) is the beachtron (around 2000$). They also have a high end 3D audio workstation, rated at 2.5 gips with a price tag almost in the 6 digits! The last technology is called Focal Point 3D Audio. It was developped by Bo Gehring and first used on the Macintosh computers with a modified Audiomedia (Digidesign). It cost around 1400$ in this configuration. Gravis saw that (Focal Point is from Seattle) and it is the system that is now available on the GUS. At a much better price. The system produce the sounds with these parameters: direction, elevation and distance. RSS and Qsound cant accurately represent virtual sound behind the listener, but FP can, which makes it a better choice for virtual reality. However, in the midi implementation Gravis will have to develop a SYSEX command set. We already need it badly, but with 3D, i will shoot myself if i cant control it thru sysex. [Note: it will probably never be implemented to the windows driver, unfortunately]. A more complete description of focal point can be found in the Gravis Ultrasound FAQ. Apparently DOOM will be the first game to support 3D sound on the Gravis (and probably on PCs). Sense8 world builder now has Gravis Ultrasound 3D audio support, and several titles are under work with 3D sound. Several 3D demos are also available. Focal Point(tm) 3D audio 1402 Pine av., #127 Niagara Falls, NY 14301 Voice/fax: 1-416-963-9188 I have found most other addresses and once i have a bunch more info, i will post a totally new article, and hopefully i will have tried all the 3D systems other than Focal point on computers and Qsound and RSS on CDs (plus of course binaural recording). In particular, i am curious about the sixgraph card... Ciao, Francois Dion cism@ere.umontreal.ca dionf@ere.umontreal.ca dionf@nyongwa.cam.org Fido: Francois Dion 1:167/228