Parallel Passions

       People who are passionate about fine audio and video equipment also tend to be passionate about other fine machines, such as vehicles, cameras, etc. And people who are passionate about good music also tend to be passionate about other cultural aspects, from photography and architecture to fine cuisine, wine, and coffee/tea. We can all share deep pleasure in our appreciation of these many passions of a well rounded cultural life, passions which run parallel to audio, video, and music.
       Here then is a forum for exploring these parallel passions. We'll share with you some of our special discoveries, and we can apply the same discriminating analytic prowess (that we apply to audio, video, and music) to exploring and critiquing just what makes these discoveries so special. And if you would like to share some of your finer discoveries, with your analysis of what makes them special, simply email a letter to the editor at iar-trt@cox.net (be sure to include the word editor in the subject line, so the email spam screening program doesn't put you in junk mail).
       We'll start the ball rolling with discoveries in the field of vehicles. We use vehicles heavily for our extensive scientific research. We need to search out weird parts to construct our unique research experiments in our two lab buildings. With every new research experiment a scientist designs, he is working from scratch in terra incognita. When we need a certain kind of part to construct a research experiment, that part per se does not yet exist, because that research experiment has never been done before. So it takes considerable travel to find and obtain parts (from other random industrial applications) that can be adapted to construct each new scientific experiment that our research leads us to.
       And naturally we constantly need use our vehicles to shuttle research equipment between our two research labs (one facility emphasizes materials research, the other acoustics research, with A/V equipment required at both labs). The Boxster S even managed to haul a monster Plinius Odeon in its front trunk, and the Mercedes SUV truck regularly gets packed to the rafters with staggering amounts of equipment for transport.
       Of course, we also use our vehicles for research into mobile audio/video, and demonstrations thereof to all qualified people. We've been doing this for a long time. Way back in 1964 we experimented with a true hi-fi installation in a car, installing a Scott 310 tube FM tuner slung under the dash, a tube power amplifier in the trunk, a KLH Six loudspeaker in the back seat, and a giant Finco FM4 yagi antenna mounted on a ski rack on the roof. One night, traveling in eastern Massachusetts, we picked up KDKA-FM from Pittsburgh in western Pennsylvania.
       On with the fun and the sharing!

Tires

Toyo Open Country A/T

50,000 Mile Test Report

       For all you SUV owners (and light truck owners), we've found an amazing tire. The Toyo Open Country A/T is a miracle of tire engineering.
       Engineering is in general the art of skilful compromise among competing physical factors. The tradeoffs in tire engineering are especially unforgiving, especially for multi-purpose tires, such as all-terrain models. But somehow, Toyo's engineers have managed to create a brilliant design that gives us the best of many worlds, instead of the compromised mediocrity you find from other A/T tires.
       In the past, for our research and demonstration SUVs, we've worked with diverse A/T tire designs from Michelin, Goodyear, etc. - and they evince the mediocrity common to A/T tires. As soon as you put big, deep lugs on a tread pattern, to give a tire off-road capability, you're asking for compromise and mediocrity in many performance factors. The tall lugs flex, making transient handling performance sloppy, mushy, sluggish, and unpredictable  (when you give a steering input, the lugs flex first, so there's a time delay before the tire body and vehicle react, and later there's a delayed rebound effect when the flexed lugs spring back with their own time constant, and yet later there's a squirmy oscillation as the rebounding lugs evince overshoot and lingering ringing, thus continuing to counteract and confuse your steering input). The coarse tread pattern usually makes the ride noisy and harsh with vibration, even on the smooth pavement where SUVs spend 90% of their mileage. The deep cross channels lessen the contact surface area, which degrades braking and cornering performance. And, with less contact surface area, wear is increased, which degrades tread life. If the tread compound is made softer to provide a smoother and quieter ride, or to improve road grip, then tread life is made even worse. That's the usual scenario of compromised performance that we've come to expect and accept, just to get off-road capability.
       The Toyo Open Country A/T changes this whole equation. First, and most important to us, its transient handling response is precise, quick, and predictable. This is crucial for safety (accident avoidance in traffic) and for driving enjoyment on winding country roads (being able to adjust your line in the middle of a new, unknown road curve). Second, its ride is quiet; in fact, on smooth blacktop, it is dead silent (on California freeways, the rain groove pavement pattern interacts with the parallel tire tread grooves to produce resonating air channels which yield a smooth whirring sound). Third, its ride is very smooth and unfatiguing - free of harsh vibration and very effective at absorbing small road irregularities. Yet this tire still communicates very well with the vehicle suspension, so it can do its work and so you can get accurate feedback of road feel at the steering wheel.
       The icing on the cake is that the Toyo Open Country A/T boasts an amazing 500 tread wear rating -- much higher than other off-road tires, indeed higher than most highway tires. And the proof is indeed in the pudding. We have put over 50,000 miles on these tires, including some grueling off roading, and a tread depth measurement shows that only one third of the tread depth has been consumed, so more than half the useful tread life still remains (still allowing for the legal tread depth that must be left over at the end).
       How can the Toyo Open Country A/T deliver better handling performance than other A/T tires, in the face of the limitations imposed by the tall lugs and deep channels that all A/T tires must have for their off-road capability? The answer is some very clever design work by the Toyo engineers. For example, in the design of the tread pattern alone we see three factors that provide this tire's superior handling performance -- especially its precise, quick, and predictable transient response in the lateral (steering) direction that we value so highly for safety and for driving enjoyment on curvy roads.
       First, the tread blocks or lugs each have a large land area, and are especially wide in the lateral direction (across the tire). This makes each tread block much stiffer, especially to forces in the lateral direction needed for steering and handling. This stiffness is further improved by the hardness of the Toyo's tread compound (the same hardness that yields the superior 500 tread wear rating). The tread blocks or lugs of other A/T tires bend or flex more easily in the lateral direction. That lug bending makes those tires' steering and handling response more sluggish (since those tires' first reaction to the lateral forces of your transient steering command is for the lugs to bend, while the tire carcass and your vehicle have not yet moved relative to the road, thereby delaying those tires' response to your steering commands); vague and less precise (since both the physical amount of lug bending and the temporal delay of the lugs' bending and of the lugs' later elastic snap-back are variable, depending on conditions); and unpredictable (since you cannot predict, anticipate, and compensate for the complex variables dictating the lugs' initial bending and later elastic snap-back).
       Second, the deep channels or voids between tread blocks run in a striking diagonal across the tread. This makes the walls of each large tread block diagonal to rather than orthogonal to the lateral forces imposed by your handling commands. That in turn makes each tread block much stiffer yet, and less likely to flex or bend, in response to your steering inputs. When a wall is orthogonal to the direction you're pushing, you can push the wall over relatively easily, because the piece of wall you're pushing at is backed up only by empty space. But when a wall is diagonal to the direction you're pushing, it's much, much harder for you to push over that wall, because the piece of wall you're pushing at is partially backed up by another piece of wall, and that other piece is partially backed up by yet another piece, etc.
       Third, the channels follow a pronounced zig-zag pattern across the tread face. This means that adjacent circumferential rows of tread blocks are staggered, so the large tread blocks overlap heavily as you look across the tire (the tread block of one row begins before the tread block of the adjacent row stops). This in turn means that, as you travel across the contact patch between tire and road, there is always, at every instant, a relatively constant amount of stiff tread block surface area available to deliver lateral forces to the road, which further contributes toward making this tire's transient handling response precise, quick, and predictable. In most other A/T tires, channels or voids in the tread pattern run pretty straight across the tread, which means that the critical edges of the contact patch (which afford the best torque) alternate between being voids and tread blocks (at one instant they are voids, the next instead tread blocks). If they are voids at the instant you give a transient steering command, then for a split second you'd get little handling response, then a split second later more handling response (again, the vague, sluggish, unpredictable transient handling typical of off-road tread patterns). However, with the Toyo tread design there is always, at every instant, a pretty constant amount of tread block area in contact across the contact patch, so you always have at your command, at every instant, the same transient handling response available at the edges of (and throughout) the contact patch.
       The precise, quick, and predictable transient handling response of the Toyo Open Country A/T has saved my bacon more than once. For instance, when a truck ahead of me unpredictably came to a sudden halt, I was able to execute a drastic precision swerve to the next lane with our tall, heavy SUV that the Porsche would have been proud of.
       Ultimate grip on dry pavement of this Toyo is excellent, and amazing for an A/T tire, providing excellent braking and cornering performance. I had to do a full panic stop on a freeway, from 75 to 0, when an inexperienced driver in an adjacent lane suddenly lost it and went careening laterally across my path right in front of me. With most other tires I would have T-boned him or had control problems. But the Toyo Open Country A/T brought me to an amazingly quick stop, with no skidding and no control problems, even on the rain-grooved pavement (which reduces contact area and grip). And, when I simulate a skidpad test by taking these tires around sharp curves (such as cloverleaf on ramps and off ramps) at speed, they show amazing grip, and excellent stability at the limit, which gives me an extra measure of confidence that our SUV can tackle nearly anything with these tires, easily outcornering most cars, even though the SUV is handicapped by greater weight and a higher center of gravity.
       On wet pavement, these Toyos likewise exhibit very good handling and braking. Their deep circumferential channels act as natural rain grooves to shed water, and deep cross channels break up water film to discourage aquaplaning.
       This Toyo A/T also performs very well off-road, especially on all dry, packed terrain. It also does well on packed wet terrain. But of course it is not a deep mud tire or a sand tire, nor is it intended to be. If you're serious about mud or sand, no A/T tire can really satisfy you anyway, and you'll be wanting to get instead a serious mud or sand tire (which of course will be miserable on pavement). I had an unexpected opportunity to test the off road ruggedness of these Toyos on one trip to CES in Las Vegas. Due to ongoing construction, the I-15 was unexpectedly backed up for miles in the middle of the desert. My detailed maps showed some trails across the desert here, so I exited the freeway parking lot in search of an off road adventure that would enable me to make progress toward Las Vegas. The trails turned out to be much worse than the map suggested. Their surface was not dirt or gravel, but instead consisted of large, sharply pointed rocks anchored in the soil. These trails were also frequently punctuated by desert drainage gullies, which were very steep and narrow, and ran perpendicularly across the trail, thereby giving me the ultimate whoop-dee-doo experience. Time after time, the SUV took off and became completely airborne, taking off so violently that it kept banging my head into the ceiling that was far above my head, as my body went flying with negative Gs, in spite of my seat belt harness. Then the SUV came crashing down on the far side of the perpendicular gully, landing hard on another bunch of sharply pointed rocks anchored in the soil. This torture went on for about 2 hours (that's the last time I use these trails as a shortcut to Vegas!). The Toyo Open Country A/T tires handled all this torture without a whimper, and without any damage, even keeping perfect wheel balance for all the highway driving I've done since that episode.
       This Toyo tire furnishes a supple, comfortable ride, much better than you would expect from an A/T tire, especially one with hard rubber tread. The modest 35 psi maximum rated pressure allows the tire sidewall to flex enough to absorb road shock and deliver that supple, comfortable ride. But the Toyo's ride is not mushy soft (tires that are too plush give you no feedback about the road surface, and the first warning they give about the potential for losing optimum grip is only after they've already lost grip, so you can't adjust your driving to safely cope with varying grip conditions until it's too late). The Toyo A/T transmits excellent feedback about the nature of the road surface. It gives you a tactile, direct feel for the texture of the road surface that you can sense in your hands, right through the steering wheel. Thus, you can intelligently adjust your driving to safely optimize grip at all times on all surfaces under all conditions.
       We especially enjoy the ability of the Toyo Open Country A/T to float the vehicle over road irregularities, on everything from washboard roads to minor pavement seams. In a vehicle with competent suspension, you can achieve this float by making your tire relatively hard and stiff, so that high frequency road irregularities are passed on to the suspension to absorb, rather than being absorbed by a softer tire. Feeding high frequency vibrations to your vehicle suspension keeps it energized, and in constant micro-motion. This has the advantage of lessening stiction, and it keeps the suspension active, floating closer to its center, as opposed to passively sitting on its bottom until a big low frequency bump comes along. If you're a sensitive driver, you can feel when you've managed to achieve this ideal state of suspension float. It's a magical, almost ethereal feeling, as if you were floating (even flying) above the road surface. It's similar to the feeling you get when you drive fast enough on a washboard road so that you are flying from crest to crest, with your tires never sinking down into any of the lateral ruts.
       To achieve this magical float, you have to dial in the tire hardness very precisely, so the tire is hard enough to pass high frequency road irregularities on to the suspension, yet is not so hard that your ride becomes harsh. Generally, we have found that the best air pressure to use is the maximum rated cold tire pressure printed on the tire wall (this is usually significantly higher than the vehicle sticker's recommendations for tire pressure). Interestingly, truly magical float is such a subtle, precise phenomenon, that we can tell when our tires have lost merely 1 psi of pressure (as most tires do over time); the vehicle's suspension no longer floats magically, and instead becomes leaden, dead, soggy. It feels as if the vehicle is sinking into each road irregularity, rather than flying over them, and with each upward road bump the vehicles feels more like a heavy truck and less like the buoyant flying machine it did when the tires had merely 1 psi more in them.
       Adding more tire pressure to make the tire harder, in order to achieve this suspension float, actually makes your ride smoother (contrary to the popular belief that lowering tire pressure and softer tires make for a smoother ride). A good suspension can dissipate the energy from road irregularities more quickly than a typical soft tire, which has lingering overhang due to the reactive nature of its compressed air springiness and its hysteresis-rich rubber springiness trading energy back and forth, with long time constants, after the original road irregularity has past. Thus, if you rely on a typical soft tire to absorb a single impulse road irregularity, your seat and body will feel the lingering aftereffects of the road bump long after that bump is past, which magnifies your perception of the bump, and also gives it a leaden, heavy quality (the temporal lingering of the energy is equivalent to adding heavy low frequency booooom to what should have been a quick, sharp, high frequency tick bump). On the other hand, if you can feed that same impulse road irregularity through a harder tire to a good vehicle suspension, that same bump will feel smaller because it is over and done with more quickly, and it will feel lighter because it more accurately retains its high frequency spectral profile, without the added boomy bass heaviness of the long time constant reactive ringing of a soft tire.
       The Toyo is physically a heavy tire, but it feels light as it works with the vehicle suspension over road irregularities. How does it achieve this lightness and float? This tire's tread obviously has a hard rubber compound (to deliver a 500 wear rating), and this combines with its stiff large tread blocks and its sturdy tire walls, to deliver high frequencies to a vehicle's suspension. When these Toyos are inflated to their maximum recommended cold psi, they actually feel pretty light, and

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