Feedback for Flight Simulation – 2020

A Single Amp, Single-Transducer, Haptic Feedback System

 

“Chosen One, break to follow F-16, left downwind runway two one”…

I check left, picking the ‘dainty’ little jet up visually, and reply,

“Chosen One, traffic in sight”.

As we pass abeam, a tiny flick of the wrist brings with it a slight shudder, transmitted directly to my bony backside. Not much, just enough to communicate to the senses that something is happening. Something about the airframe state has changed. Then, with a sturdy pull on the stick, the shudder intensifies until it’s a steady, 3-G rumble. A rumble felt throughout my Little Pink Body (LPB). I know it’s 3-G’s from experience – seat time that is. And I’m there, man!

“Ding, dong”.

“Whaaa…?”.

It’s the doorbell, rudely snatching me from my virtual world of sights, sounds and physical sensations. Surrounded by my imaginary friends.

Let’s Get Physical

Did I say physical sensations? Yes, Virginia, I did. And I’m not talking about force-feedback joysticks here: this is physics-based feedback, distributed about the anterior, posterior (colloquially known as “Seat Shakers”, or “Bass Shakers”) directly from the sim, via my “ejection seat” – an old, beat up, faux-leather office chair in my case. It has become, right behind VR and HOTAS gear, another piece of kit I just can’t go without. Especially in VR!

In 2D I’d say it is, perhaps, nothing more than a neat gizmo (but I’ve not flown in 2D in a couple of years now, so what do I know?). In VR the immersion factor goes up a notch. Notch-and-a-half even. Awareness of the aircraft is more acute and control inputs are smoother. Without it, the sim feels dead to me. Feel, getting it into the sim, is what this is all about.

Intentions

When I first heard about this type of feedback I found the existing information to be somewhat scattered, especially concerning flight simulation. And I had no idea what a transducer was (other than the one on my boat). My intentions here are to:

  • Give a “bump” to this type of feedback in the context of flight simulation; specifically for DCS World (though the principles apply to other sims).
  • Review a DIY solution, with links to required software and hardware options.
  • Cover some settings to tweak the experience.

When properly set up we get a “seat of the pants” feel into our simulated flights. These are of course artificial effects (we are in an ‘artificial’ world remember). Some effects though can be quite convincing: landing gear ‘thumping’ into the wheel wells, cannon fire, stall shudders, etc. Others, notably acceleration (“G”), have no easy (cheap) way of being replicated. Especially in my 6 X 10 foot ‘man cave’ (the uninitiated might call it a closet).

With apologies upfront to Pavlov, perhaps our “G” feedback, as experienced here, is really just conditioned feedback? It lets you know, physically, that you are adding stress to the system – so stop that! In the real world excessive “G” can hurt you. With this system of feedback it is simply an alternative method to clue you in – condition you – to the state of the aircraft. Cost-wise, when compared to VR or HOTAS gear, it’s reasonably inexpensive too. Cheaper than a motion platform for sure (though you could add this to that). Think good “bang for the buck”. Note that you can spend a LOT of money on this, eventually, but it’s really not necessary.

History

This subject falls within the category of: Haptic feedback – the use of touch to communicate with users. Game controllers buzzing, joysticks (of the past anyway) twitching, sim racing wheels vibrating, home audio-visual systems that ‘kick’ your couch when the villain shoots the protagonist; etc. This is not simply the audio of the sim being transmitted though – it’s physical reactions: acceleration (‘G’), guns firing (or hitting you!), stall effects, etc. While simply pumping the audio out to the gear might add to the experience, you’d get everything, including voices (radio transmissions, music, etc). Most importantly, some physical effects might not be audible, or just too weak to be felt. Racing sims have had this for a while (tire grip loss at the wheels for instance) and if you dig around you will find those that have adapted racing sim gear for flight. And thus, here we are…

Overview

Figure 1) High-level view of the effects flow and the basic components required: sim support, interfaces, and hardware.

Disclosure

For this overview I will be dealing primarily with VR-supported titles that I am familiar with: Digital Combat Simulation World (DCSW) and X-Plane (XP). Other titles have support yet they don’t support VR, or I am not familiar enough with them to put forth any useful details. With regards to X-Plane, I’ve decided not to cover much as, using the software I describe herein, there’s nothing to it really. You set it and forget it, and the settings I’ll talk about later apply in the same way. None of the individuals, companies, or organizations have provided me with free software or hardware for this report.

Single Amplifier, Single Transducer System

We’re going to cover a single-amp, single-transducer system. I am not an electrician, audiophile, our sound engineer; this all comes from experimentation over the last year or so for my own personal use. What I put together works well and has for almost two years. My hope is to give you enough background information to branch out, if you wish, and ‘roll your own’ solution.

Also, this system DOES MAKE NOISE. There’s no avoiding it. In the end we’re dealing with vibration, you know, like speakers. Sort of. I can’t give you a decibel level here but it’s really not that bad in my opinion. I’d say that 90% of the output no one will even detect. It really depends on how you set things up. More on this later.

Also, this is not the only way to accomplish this, it’s just how I did it.

NOTE: Links can be found at the end.

Software

Since we are specifically dealing with physical feedback from the sim, we need software that outputs that data directly to our physical devices (and finally to us). DCSW does not output data directly in the manner we need it, so we require something that interprets what DCSW does output, then convert it for our use.

For DCSW my choice is: SimShaker Sound Module (SSM) and SimShaker for Aviators (SSA). Note the latter depends on the former. This is what I use and is the only option that supports DCSW within my personal budget [1]. These two pieces of software support both DCS World and X-Plane as of June 2020.

The sim needs to ‘publish’ a software interface that reports the physics data we’d like to know about. SSM/SSA ‘listens’ for these events and sends sound data – effect signals – to the specified sound card in response. Refer to the instructions with the software for installation and usage. I will have more to say about SSA later in the “Tweaks” section.

[1] There is an option for the following titles: Falcon BMS, War Thunder, AeroFly FS 2, IL-2 Great Battles, Condor 2.

Hardware | Sound Cards

The software needs to send the effect to our hardware, somehow, so we can feel it. Sound is ubiquitous on PC’s – I’ll go out on a limb and state that 99.99% of all PC’s have a sound card. I won’t get into the icky details concerning sound processing, at all, here. Lets just say that sound is analog: we go from digital (an effect/signal) to analog (sound). This all happens via the sound card.

Two Sound Paths, or “Pipes”

As Figure 2) illustrates, we need a path for our feedback system (effects) and we need one for our normal sounds (everything else): we need two paths here, so we need two sound cards.

‘Virtual’ Sound Cards And Latency

So we’ve presumed your PC has a sound card but, what if you don’t? If you don’t, and are playing flight sims, then you may have already noticed an issue: Latency (or a very quiet experience). You may have a “Virtual Sound Card”. Not likely but I thought I’d throw this in, just in case.

Latency is the time it takes for a sound to be generated until you hear it, or feel it. This is important; any delay beyond a certain point feels out of sync. Virtual sound cards can introduce a delay in this processing. That’s latency. We don’t don’t need that and from here on we’ll ignore this situation: you really should get a physical sound card/device. Actually, two of them. You have options here…

Physical Sound Cards (USB, Add-on cards, motherboard ‘chips’)

USB Sound Card

Initially I thought my situation was such that only one sound card existed on my PC. I needed to acquire another (or so I thought). Research led me to USB Sound Cards. These are simple devices, plugged into a USB slot, that act as a sound card – to the system they are sound cards. They are inexpensive too. I found one for $15. At one end you have the USB plug; in the middle some hardware/circuit board gizmo (the ‘gut’s of the sound card I presume); at the other end a 3.5 mm (normally) headset/speaker jack. This is what I used for some time and found it to be acceptable, with little latency. I said a “little” latency because there was just a touch of it.

Motherboard Sound Card  – “Sound Chips”

I hate to admit it but, after a few months of ignorance, I decided to go spelunking into Device Manager. Guess what I found? A motherboard sound chip! I could have saved myself $15 bucks as I already had two sound cards in my system! Moral of this story: dig around and see if you have the same setup: an add-on sound card (Creative, ASUS, EGA, etc), and a motherboard sound chip. Your first clue (should have been mine, but I didn’t look) is multiple headset/speaker jacks. Note that it is possible these are still ‘connected’ to a single hardware sound device. You’ll just have to test this.

Add-on Sound Card

You could go out and purchase another add-on sound card (again from Creative, ASUS, EGA, etc) but they will cost more – from 3 to 20 times more. In my opinion this isn’t necessary to get you started, so I recommend the USB card option if purchasing new and you’re on a budget.

Hardware | Amplifier and Transducer

Now we get more into the meat of things; we have the ability to get a signal (effect) from the sim to a sound card. Next is to do something useful – dare I say ‘stimulating’ – with that signal. We need a Transducer – a converter of this signal into sound ‘energy’.

Amplifier

Before we get to the transducer however we need to understand that the signal being transferred from the sound card is too weak to be of much use. We need to amplify that signal and, as with home stereo systems, we need an amp. This whole audio thing, to me, is a bit of a jumble of different terms and confusing definitions – because it seems to be defined inconsistently between manufacturers of audio equipment. We are essentially working within the audio world at this stage in our system.

The amp linked to below. Note that I have used the output wires (to the transducer) on the back of this unit. Some amps are different. I could have used the “Speaker” connections also but the back output is for low-level signals – most of our signals are low frequency yet still (barely) audible, so either works.

Matching Ohm’s

This is where things start to get tricky. You see a transducer (see below) is akin to a speaker, without the ‘cone’ to generate actual sound waves (that would be picked up by your ear). And like a normal speaker these transducers need to be matched to output from an amplifier. It’s an “ohm’s” thing. Watts too, but that’s coming…

We’re going to keep things really simple for this overview though and stick with a single amp and single transducer [2]. This makes it easier to build. What we want is an n-ohm amplifier, matched to an n-ohm transducer, typically 4 ohm’s for both. Things get finicky if you don’t match the ohm’s here but, since we’re simplifying things with a 1:1 match-up it’s not a big deal.

For example: I started with a 4 to 8 ohm, 45 Watt amplifier, matched to a 4-ohm transducer at 50 watts. Actually, that’s not quite true…

NOTICE – I really started with a ‘package’ deal that came with an Amp and Transducer (2 Ohm transducer), matched from the factory. Allegedly. I ended up not using this system because, well, the amp ‘fried’ itself. I won’t go into the gory details but after a month it smoked, sparked, and literally went down in flames. Not good. My guess was cheap parts in the amp.

So, in “rolling our own” system we have a bit more control, and we can build it for the same, and likely, lower cost. I like that part! (just ignore the little detail where I spent about $200 buck’s only to see it go up in flames – my goal is to save you that trouble).

Back to ohm’s and stuff. Please, follow this link for a more in-depth explanation. The most important part of that article boils down to:

  • Don’t use a transducer (speaker) with an impedance (ohm’s) LESS than the ohm’s supported by the amp, example:

Transducer @ 2 ohm’s using an amp @ 4+ ohms is BAD: 2 < 4

Transducer @ 4 ohm’s using an amp @ 4+ ohms is GOOD: 4 = 4!

See, a 4 ohm amp will try to drive a 2 ohm transducer, but since it can’t it will heat up or the safety circuits will shut it down. Not what we want. My experience is that not all amps have this safety feature? Make sure yours does! This seems to be a common feature however but double-check.

[2] In the sim racing world things go way beyond what I’m describing here: I’ve seen sim racing rigs with transducers on each of the four corners of a sim ‘platform’, one per wheel (and another under the seat even). That’s FIVE transducers and, assuming they want a unique effect for each wheel, and the seat, they need 5 separate ‘paths’. It’s complicated. And it requires more complicated software and hardware. We’re not going there but feel free, once you think you’ve understood all this, to explore. At this stage I don’t feel it’s necessary, or even supported; the sim would have to provide data output for, say, both wings (or multiple points of ‘interest’ in this context) and to my knowledge this doesn’t exist. More on this later.

Output Signals and Sub-Amplifiers

The output sounds from this system are all of lower frequency. Like, really low. Ideally less than 80Hz. If the frequency is too high it will start to ‘buzz’ – you’ll be able to hear it from the transducer even. However most amps in our price range won’t go below around 20Hz. The SSA software actually uses WAV files – same as music. WAV files can store data down to 1Hz but the less expensive system we’ll describe can’t go that low. Our setup will use the SSM WAV files which appear to be in the range: 20-80Hz, which works for us.

The amp I use comes with both ‘normal’ input/output and low-level input/output (see link below). We plug the sound card into the Low-Level Input jack(s) on the amp, then connect the (subwoofer) output on the back of the amp to the transducer and we’re good. However you don’t strictly need a subamp here; the SSM’s WAV files should still work even if your transducer is wired into the normal speaker output connections.

Watts

More electronics and audiophile stuff? Just a tiny bit. I’ll keep this one simple too: there’s no need to get crazy with the power output (watts) on your amplifier. Besides, they tend to get more expensive as they get more powerful. It should be equal or greater than what the transducer is rated for however. A rule-of-thumb is the amp wattage should be 2X the speaker/transducer watt rating. Just notice that you may not be able to crank it to full volume. In general, with our 1-Transducer and 1-Amp system, if the amp wattage is less than the rated watts for the transducer we are limiting what our transducer can give us – the ‘oomph’ if you will.

Let’s take ‘G’ for example since we’re talking about flight simulation. Say your transducer is rated for 50 watts of power but our amp can only deliver 25 watts. If we have the amp at full volume/gain then our 9-G  “Bat-Turn” will feel a little anemic. And it’s likely we won’t get anything at all – the amp will be working itself into a lather but the transducer is ignorant of its efforts.

If we reverse that then at about 4.5-G the transducer will “max out”; we won’t feel anymore “G” beyond that: 9-G will still feel like 4.5 G. It might even lock up inside the transducer housing, doing nothing until the power to it is reduced or amp is reset.

Also please note that we’re not building a “premium” setup here. There will be limits based on, primarily:

  • Source software: what physics info does it ‘expose’ and the sample ‘sound’ data
  • Quality and power of amplifier
  • The ”mass’ of our transducer (related to power)

That is extremely simplified. Note that, if we have a 1000 watt amp and a 50 watt transducer it may still work – just don’t put the volume/gain at 100%! Start at about 5% in this example and work up from there. It seems amps, and likely cheaper ones, don’t really give you the stated wattage except under ideal circumstances, if then.

You only need a 1-channel amplifier also; our simple system only has one transducer anyway so there’s no need for stereo output. And they are cheaper.

Hardware | Transducer

Okay, here’s where the rubber meets the road, so to speak. The transducer takes a signal from the amp and, basically, vibrates. The ‘mass’ of the transducer matters here (as well as the aforementioned ohm’s and watts).

Inside a transducer is, usually, a hunk of metal suspended in a magnetic field [3]. The signal sent will vary this field causing that chunk of metal to move. That’s where the magic happens. A larger transducer (that piece of metal inside is often referred to as a ‘puck’) can really rock our world if it’s big enough. The benefit to larger pucks (and they make 1 POUNDERS or more! – but they are expensive) might be a wider range of ‘feel’. Or it may just work better for BIG effects like “G” and stalls. Of course you have to scale everything else with it.

I have noticed that smaller transducers work better for higher-pitched effects in the system described here (flaps extension for example), while larger (more ‘mass’-ive) ones really kick with deeper, bigger, effects (G-feel and stall).

[3] I suspect some transducer manufacturers have different internal mechanisms but this is the one I’m somewhat familiar with.

Adding Additional Transducers

This, of course, goes beyond our 1-Amp to 1-Transducer plan but, to hopefully get you looking in the right place, start with this link as it explains it well enough. The important part is how you wire your transducers together – it’s not obvious.

This link is another good one that will give more insight into how the transducers might be wired based on the ohms of each, together with how it might affect your amplification.

Mounting | A Custom Solution Required

Where you put your transducer is important. For our one transducer system we want to mount it to our chair as securely as possible. While the mechanism is supposed to vibrate, we don’t want any ‘flex’ here. This will require some thought as each chair is different – you may have to fabricate your own mounting system. Some ‘kits’ come with mounting hardware but may still require you to fabricate something; possibly drill holes even but, as I explain in my example later, maybe not. Did I mention there’s going to be some Arts & Crafts today? The aforementioned ‘kit’ that I originally purchased took care of this for me but, well, you know how that went.

So, here’s how I did it:

On the bottom of my office chair there are four bolts that hold the seat to the bottom (legs and swivel). I purchased a piece of scrap aluminum from a local fabricator (actually since it was scrap he gave it to me for free, a 12″ x 12″ piece right out of his trash can). Some slightly longer bolts of the same thread were needed as the aluminum plate ended up being 1/8″ thick (1/16th is common). This may not be required.

Aluminum is soft enough for standard tools to work it with (jigsaw, electric drill, etc). I simply measured it all so it would fit, cut the metal to size, and drilled holes for the transducer mounting screws and the seat bolts, etc. Again, I can’t really give you specifics here because your seating will likely be different.

The important bits are: 1) it is mounted securely and, 2) there’s no flex in the system (you can get away with a little here). We’re trying to get our chair to “Be the Transducer”. If there is flex then you lessen the vibration that is transmitted through to you. Imagine the transducer on a 10 foot, flimsy, rod (that is also attached to your chair). Bear with me here; the transducer will vibrate but all that flex in our imaginary pole will absorb a lot of that vibration. We want to lessen that.

Here is a simple diagram of how I did it:

Isolation

We want vibration – that’s what we feel after all, but we want to contain it. We need to isolate the chair from the rest of the house too. You want as much of the vibration to go, not into the floor but into, well, you. If we could, we’d somehow suspend the chair in mid-air (perhaps in it’s own magnetic field? Maybe?). But we can’t, so we get a piece (or 4) of rubber/hard foam matting to go between the chair and the floor. Some of this will depend on your flooring. This is all good for your neighbors (living below you), or your spouse in the next room. These rubber mats are pretty cheap; I purchased a pack of 4 (each 3 x 3 feet) at my local home improvement store for under $25.

Tweaking

Alright, if you’ve made it this far then I assume you’ve tried it all out and love it. Maybe?

Effect “Clamping” and “Washout”

I’ve taken liberties here and made up the above terms in an attempt to explain settings in SSM/SSA, primarily. In the SSA software, once you are up and flying in the cockpit, you can adjust the values of the output effects (flap travel, G-feel, motor rumble, etc), all from  0-100. As I understand it, all of these effects are summed up (that’s kind of how sound works): Let’s say our system can only handle 100 ‘units’, and each effect can equal 100 units individually. We can’t throw 50 units of engine rumble, plus 50 units of G-Feel, plus 50 units of stall into our “pipe” at the same time. Our total limit is 100 units – thus the system will ‘clamp’ it to this. Even with only one effect it would be clamped if it’s too loud/intense for our system. This may, or not, be intuitive.

Take for example force-feedback (FFB) steering wheels in racing sims: if you try to throw too many effects into the system  – at too high a level – you are going to reach a limit beyond which you won’t “feel” any more effect. There are even plug-ins that will display this to help you adjust your FFB output.

In our three-effect example (engine/G-forces/stall) they will of course all ‘mush’ together, covering each other over to some degree – washout.

The solution? A bigger “pipe”? A more powerful system with a larger (mass) transducer? Perhaps a hardware setup that could handle 150 units in this example? That might allow us, in theory, to feel more of an effect at a lower volume yes. This really doesn’t solve it though. In other words, with a single-amp/single-transducer system our effects will always share the same “pipe” (we may however rattle our tooth fillings out).

In the end though I’m not sure “washout” matters: if we really were in a jet, and stalling, hard, would we really feel the flaps extending? Both are there but one is overriding, washing out, the other, depending on the output levels of each (and the recording sample ‘volume’). Our brain would prioritize things based on experience I’m sure; in this example the flap extension buzz I don’t notice so much, but that stalling rumble I sure do – because it means I’m about to get in trouble.

With my dual transducer system (I’ve gone a wee bit beyond this simple system), a full blown, hard yank on the stick (in the DCS Hornet), below about 250 knots or less, and the stall shudder feels kinda like rumble strips on the sides of the road (at least here in the United States). Maybe 60-70% of that but it depends on your car’s suspension I suppose. It gets my attention.

Interestingly, again in DCSW, in the Viper with a full loadout and a CAT III setting, I don’t notice the stall buffet nearly as much as in a clean configuration at CAT I when I yank back hard on the stick. This makes sense, to me, because the simulated fly-by-wire system is limiting the jet and preventing us from ‘breaking things’. It was neat to feel this demonstrated with my haptic system.

The SSA software might be written to prioritize things but I’ve not heard so. I doubt it – that might be a nice feature to add.

SSA Level Settings

That’s probably what the level settings are for: if you put Cannon at 100 and G-Feel and Stall at 10 units each, well, when you crank on the stick, while firing the cannon, guess which one you’ll feel the most? Yup, cannon. Okay if that’s your thing…Brrrrrrrpptt…for you A-10 people!

I won’t get into it here but there is the issue of how many simultaneous sounds can be played by your sound card and the simulation. Also I’m just not sure how SSA was written and I’ve only given the WAV files a cursory looksee. And of course how are the sound samples recorded? At what level for instance? So we gotta ‘mess with it’…

Here’s what I do, for DCSW and jets:

My priorities are for Stall effects, followed closely by G-feel. I initially set Stall at 75 and G-Feel at 50 – remember you have a volume knob on your amp, too. Notice with these values, the ‘sum’ is over 100. My reasoning here is that if I’m out of energy I have no available “G” anyway – I’m more likely to be stalling. Conversely, if I’m smokin’ along at the speed of heat I’ll get the max G-feel if I get heavy-handed with the stick – we’re in no danger of stalling in this condition. Therefore these two effects can be set fairly high and with less chance of them washing each other out. It would be impossible to completely eliminate this in our 1-transducer system.

For those of you not familiar, SSM/SSA use effects that ‘feel’ different; the WAV samples are different frequencies for example. These values require some tweaking to taste as your system and the WAV files have a say in this. You’d think a 50/50 mix, of these two, would make more sense but in my system the stall effect isn’t as defined, to me, at equal values.

All other effects, except for the Engine Rumble, are what I think of as ‘transient effects’; they only occur occasionally and are short-lived. Dropping a bomb, touching the runway, etc. As for Engine Rumble well, it’s kind of a mood thing; sometimes I’ll turn it on, sometimes not. Depends somewhat on the aircraft. If I select Engine Rumble then I’ll set it such that I can just barely detect it on the ground, engines at idle. This is a long-running, constant effect (if you’re not out of gas), and having it too high will ‘eat’ into others anyway (washout).

Special Options | G-Feel Feeling

There’s a separate setting for “G-onset”, if you will, in SSA (2nd tab). It lets you adjust when the G-feel starts (a side for negative and a side for positive -G). This one is only a little tricky, but the important point, to me, is to set it and forget it. Once you find a starting point (I use around 0.4, which really means I start to feel it at 1.4-G) don’t mess with it too much. If you keep changing what a given “G” feels like then your feel for that point isn’t consistent. And note that this is constant across all aircraft. All I can add to this is: if you set it too low then it will be giving you G-feel when you might not want it [4]. It all depends on your overall system. However I’ve gotten to where I prefer it lower than higher, but not too low – things just feel more responsive to me. With this responsiveness though comes a loss in high-G ‘fidelity’; above about 4 – 5 G and it all feels the same. That’s where a BIGGER transducer system might come in handy. Hmmm…

[4] I will admit that, when I first played with this I set it to 0.0 (so basically I was feeling some “G” all the time – then when I’d ‘nose it over’ the feeling vanished. Cool feeling of 0-G there. In the end it just interfered with other effects that way.  Also, some aircraft (Tomcat), if out of trim, may be ‘applying’ some G all of the time.]

 

SimShaker Sound Module (SSM) | Limiting Compressor (LC)

Having said all that, SSM (not SSA) does come with a feature called “Limiting Compressor”. An explanation from the developer can be found here (this also contains a How-To edit your own WAV files). To summarize, as best I can, the LC will limit/reduce more intense effects (I notice this in G-Feel and stall) when we have multiple effects going through at the same time, e.g., if we’re hauling on the stick at 500 knots in the Viper this will cause the flaps/slats to ‘do stuff’ – the G-feel will be limited so we have a better chance of feeling the flaps/slats move.

Some Experimentation Is Required

There are a lot of variables when setting this all up, a short list:

  • Your Amplifier
    • What gain/volume your amp is set at
    • Frequency cutoff settings of the amp (if any)
  • Transducer
    • How big it is – mass
    • How many you have
  • Settings in SSM/SSA

Here’s an example of a quick sortie I flew in the Viper to tweak my Stall feeling…

From level flight at about 250 knots, I reduced throttle to idle, pitching the nose up to about 30 degrees. As the speed dropped off I held pitch to keep the nose up. At some point it started to shake, just a little, as it was trying to stall. You could see this, even in VR – the cockpit was visually starting to ‘shimmy’. I tweaked my Stall setting so that I would feel the effect at/near that moment. As it is maxed out (horn going off, visible shaking increased) I wanted to feel it as much as possible without any [perceived] clamping or rattling [5]. In my system, when it was really ‘mushing’ (below 100 knots) I felt a definite ‘thumping’ under my thighs (I have a slightly more advanced system, with 2 transducers of different sizes).

It’s an iterative process. My suggestion is to start out with all SSA settings at 50% (it defaults to this), turning off (un-checking) all but the effect you want to work on (you can do this while in flight).  Start with the big effects first, like G-Feel and Stall. These are universal/constants, if you will. As you play with these adjust your amp gain/volume too. Once you get that set note the gain on your amp and use that as your maximum reference. Then leave it there. Then work through all the other settings. Yes, this will take some time. Darn it, another excuse to go sim flying..!

[5] Some transducers will rattle when they really get moving. I find this slightly annoying, and the only real obnoxious noise this system produces. The limiting compressor (see above) may help here too.

The Future and Expansion

Once we get stimulation from our simulation, we get to the point of…I want more! It’s a flight sim thing. Other than purchasing my own centrifuge and mounting my PC inside it, what more can I do? I don’t have the room for even a simple motion simulator.

Ideally we’d have a separate ‘path’ for each effect that is most important to us: one for G-feeling; one for Stall; one for cannons; bomb release; etc., but that would require: a) more sophisticated software (this data has to be segregated somewhere), and b) separate sound outputs (sound cards, amps, transducers) for each effect.

My “reasonable” ideal setup would include 3 pipes: Stall, G-Feel, and then everything else: Think one transducer for G on the lower back of my chair; one for Stall under the seat; and one for everything else, oh, say high on the seat back. It depends on your chair of course. And you’d need a sound card for each (and/or more sophisticated software).

The SimShaker Sound Module software doesn’t support multiple sound cards however, so we’re left with tweaking values and hardware. So we’re done, for now.

What Little We Can Do

Then there’s the idea of multiple transducers, on the same amp (or possibly multiple amps from one sound card), keeping in mind our ohm and wattage requirements. For starters, perhaps a small one attached to, in my case, the underside of my desk (where my HOTAS is ultimately located). Then I’d feel things in my stick and throttle too; the desk is connected to the HOTAs, the HOTAS is connected to the hands, so forth and so on…

Go beyond this and the wiring gets messy. But what are Man Caves for, eh?

What I’d like to see is more support from the sim developers. DCSW, via SSA, is using LUA (Google it) to extract the info from the sim (I’m not sure how XP does it). This is relatively slow. An API that bypasses LUA – something built into the engine – should be more efficient.

I notice a framerate drop of about 1%, consistently, using SSA. But it’s worth it to me. There may be a setting in SSA’s Export.lua chain, stating the polling rate, if polling is being done (note to self: look this up).

Pros & Cons

Pros

  • At the risk of beating this horse more dead-er; the sim feels, well, DEAD without this. Period. My test mentioned above (stall setting test in the Viper) in VR was a very cool experience. In X-plane this is very nice too.
  • Awareness: I know what the ‘jet’ is doing, or I feel I have a sense for it. During BFM I can tell when I’m getting close to the limit for example. Does it make me the Red Baron? No, but I’m sure it doesn’t hurt.
  • Smoother on the controls: I don’t YANK on the stick so much anymore. A major beef with desk-top flight sims is the lack of feel. Since they don’t sell FFB joysticks anymore, anything that will give me back some feel is good. On this subject I notice:
    • I don’t snap the wings off the Tomcat anymore. I was littering the desert with wingtips there for a while, even with the audible feedback.
    • I think I can feel my “corner speed” better, without peeking. This takes practice for sure.

Cons

Nothing is perfect. I think you’ve probably ascertained some of the cons by now but, to be more complete:

  • Noise: As mentioned up above, this will generate some noise. However, if you’ve taken steps to isolate your chair it really isn’t that much. It’s hard to give an example here but someone ten feet away would hear something, but not much. The best way to describe it is: say you put your phone on vibrate and then set it on your desk. Then you get a call. That’s about how it sounds to someone else (not sitting in your chair). But it can get louder based on how BIG of a system you build.
  • Cost: For what it gives me, personally, I don’t see this as much of a ‘con’ – the value of it is beyond what I paid for it all. Saying that however, you’re looking at around $200 (US) to build this with the gear I’ve linked to below – shipping not included. This doesn’t include the materials needed to mount the transducer as I can’t predict what you’ll require here. Nor do I include the wiring as: a) speaker wire is cheap – you probably have some lying around and, b) the Sound Card to Amp cable can be found for less than $5.

This Is What You Need:

  • Extras sound card (maybe, see above)
  • Amplifier
  • Transducer
  • Software (SimShaker Sound Module – payware) and SimShaker For Aviators (donation-ware)
  • Wiring:
    • 1 cable with a 3.5 mm plug on one end (goes into your headset/speaker jack), RCA jacks on the other end to connect the sound card to the amp.
    • Speaker wire: from the amp to the transducer. Length depends on how far you have to run this.
    • [Optional but nice] Some manner of quick-disconnect connecters on your amp-to-transducer wire; so when you roll/move your chair you don’t yank the amp off the desk!

Links

All prices in US currency, rounded up to the nearest dollar.

USB Sound Card: UGREEN Stereo Sound card – $15

Amplifier: Dayton Audio SA70 – $60.00

Transducer: Dayton Audio BST-1 – $40 – $70 (depends on availability)

Software: SimShaker Sound Module – $25

Alternatives

*Note: I have no experience with any of these items; they are here as alternatives to explore

Earthquake Sound, MQB-1 – Transducer and mount only – $140

Earthquake Sound, Shell Shoxx – $300 – $600 (complete package)

Guest Author – jross @ Mudspike, “Flight Sim Stuff” – You Tube