Suggestions needed for NASA project!

[impala454]

I have a small side project I'm going to be working on here at NASA, and it involves giving our sims (I work on the simulators) a little upgrade in sound quality, and actually adding sound to another sim. There's a few things I need to know about that I'm not completely familiar with, and also would love to hear anyone's thoughts regarding choice of speakers/amps/etc. First off I'll list some criteria:

1. These are not going to be playing SACDs. The extent of the sounds would be something you'd hear inside the shuttle cockpit or in the new orion capsule (think Apollo). The majority will be some very low and loud rumbling on ascent, wheels screeching on touchdown, and then while in orbit there will be a lot of jet firing sounds (air jets, thrusters, etc) which would mostly be a kind of high pitched hiss. There may be some others added in later, but for now, it's not going to be extremely demanding as far as getting a flat response curve goes.

2. There are going to be 3-4 cockpits done, each with its own system, but it would be good to keep all 4 with the same setup, for ease of parts and such. The current thinking is 5 or 6 speakers in the cockpit, plus a subwoofer, and I was thinking it might be cool to get a transducer or two to add some shake effect on ascent. I know pretty much nothing about transducers.

3. The source of the sounds will be a PC sound card, and whether we use the built-in or have an aftermarket card, they absolutely must be linux compatible and hopefully programmer friendly.

4. Speakers will need to be fairly small, subwoofer can really be any size as it will be underneath.

If you have any ideas post em quick, I need to build up a parts list quick. Let me know what you guys think!

[audioqueso]

Wow... that sounds really cool. Do you work for NASA full time?

Are you looking for car speakers/in-wall type speakers??? Or bookshelf type?

[Chris D]

Well, I fly simulators fairly often. The key to the sound is really make it diffuse and enveloping. When flying, the sound of both the airplane and the outside environment isn't very directional, it's all around you. So I'd use diffused speakers, with the sound dispersed and reflected off of the walls, not direct radiating.

Yes, transducers would be very cool, and would add to the sensation and overall experience. But maybe 55% of the experience of a real simulator comes from the MOTION of the sim (I don't know if yours are motion... I'm guessing not, because those are mega-mega bucks) 40% comes from the visuals of the sim, which need to be coordinated with the motion to trick the human brain and inner ear into feeling like you are accelerating, climbing, etc, and the remaining 5% is from the vibrations that transducers would add.

Yes, I would use a subwoofer! Tie it in with the transducers.

[impala454]

Yeah I work for NASA full time. The group I'm in does systems engineering & simulation. We have several shuttle sims, one is the forward cockpit, used for ascent/entry sims. There's also two shuttle aft cockpits, used for docking and arm/engineering sims. We've built two new sims for the new orion ship, and have been operating them for a long while, just dont have sound in them yet. So that's a little more of the background.

None of them are motion, most of the work we do is more to help the astronauts with the actual procedures in docking and flying, and for engineering testing (tolerances on the arm or docking ring for various captures and stuff) and all the physics involved.

Some directional is going to be good to have, I think in the end a lot of smaller speakers is going to be the way to go, just curious if anyone has recommendations. I'd like it to be something 2-way as small as possible. As far as subs go, I'd love ot have a friggin earth shaker, but we have several sims all in one large high bay, and can't have them be too terribly loud as to interfere with the other sims, so I'm thinking something that's powered and in the 10"-12" range at most. Does anyone have a transducer recommendation?

[Alaric]

http://www.earthquakesound.com/quake10.htm

[Kevin P]

Sounds like a fun project. As far as sound cards go, Linux supports pretty much all of the common chipsets nowadays, just pick a motherboard or sound card that the reviews say are Linux compatible. Get a card with 5.1/6.1 outputs so you can drive multiple speaker channels with it (most have these nowadays anyway). I've used integrated mobo soundcards (Asus and ASRock mobos) and a cheapo CompUSA sound card with Linux and they work fine. Go to http://www.linuxcompatible.org/compatibility.html to find a comprehensive list of hardware tested with Linux.

As for programming for them, Linux has OSS, ALSA, JACK and PulseAudio standards, and these isolate the applications developer from the nitty gritty details of interfacing to the card (much like Windows drivers do). So, as long as you use one of the standard interfaces (PulseAudio is the newest), you can get by with any card that works in Linux.

I don't know much about transducers, except that you'd basically bolt them to the simulator hull or the bottoms of the seats and drive them from the subwoofer channel. Google for "tactile transducer" or "bass shaker" for more on these. Combine them with 1 or 2 subs inside the simulator to get all the bass/shake you need without going overboard with the SPLs outside the simulator.

[ThomasW]

You'll want to use 'real' tactile transducers as opposed to the cheapie bass shakers. The Clark units are actually 'speakers' that play sounds instead of being just electric 'hammers' like other low bass effects devices (Buttkickers, Earthquake, etc).

Thomas Clark knows this stuff inside and out. He's the man you want to talk with. I know Thomas, he's a nice guy, the factory is about 20 min from my house.

http://www.clarksynthesis.com/military_products.html

http://www.clarksynthesis.com/just_for_fun.html

http://www.clarksynthesis.com/technical_information_support.html

The choice of speakers for the higher frequencies depend on the amount of space available for the boxes holding the drivers and the desired SPL.

[Chris D]

I completely agree that for a theater, you'll want to use real transducers. I had Clarks in my previous theater chairs, and wouldn't use anything else in a theater. Clarks are actually musical, with high fidelity and tactile audio reproduction. In contrast, shakers just convert raw electrical power into strong shaking vibrations.

Honestly, though, if we're talking about a shuttle or rocket simulator, I think all you need is the raw shaking power to simulate vibrations and shaking in the shuttle. For an aircraft that might have different vibrations and sounds at various altitudes, airspeeds, and maneuvers, I think tactile transducers might be more worthwhile.

[David Meek]

I'd like it to be something 2-way as small as possible.

Chuck, for small footprints and decent-to-good sound, check out Gallo Acoustics satellite speakers

[impala454]

I appreciate the suggestions guys!

[Cheaper Wire]

I am going to say it and then run. Why not Bose? Small, comes with a sub that should be easy to hide, and if you get permission, they would probably give you all you need in order to say NASA uses their speakers. Add a few transducers and I think you have a winner.