Things I’ve learned, published for the public benefit
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Does listening to a 40 Hz tone “clean up” the brain in Alzheimer’s patients?

In 2012, I made a Web-based tone generator with the goal of helping tinnitus patients determine the frequency of their tinnitus to better target therapy. Since then, I have heard from people using my generator to teach physics, practice violin, drive away carpenter bees, tune DIY speakers, analyze room acoustics, calibrate vintage synthesizers, cause mischief in class with frequencies the teacher can’t hear, and even open a portal to Sedona, AZ. Far be it from me to take away from all these worthwhile applications, but last week, I got a message from Dennis Tuffin (of Devon, England), describing a new use for my generator which may very well trump everything else:

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Review of the Steelcase Please (v2) chair

Photo of the Steelcase Please chair

This review is part of my series of reviews of ergonomic office chairs. People have wildly varying opinions when it comes to chairs, and you should always test a chair for a few days in your own work environment before buying it. (See more advice on how to buy a good chair.) Don’t use my reviews to decide which chair to buy; use them as a starting point for your own testing.

In my review of the Steelcase Think chair, I wrote that it is a chair that doesn’t get the attention it deserves. This goes double for the Steelcase Please, which is a model that is almost absent from online reviews, most likely because it is only available in Europe. This lack of online prominence does not mean that it doesn’t have its ardent fans. I’ve dealt with two salesmen at my local Steelcase dealer – both told me outright that they prefer the Please to all other Steelcase chairs, despite the fact that its current version turned 14 years old this year, and, in theory, should have been superseded by newer offerings like the Leap v2 and Gesture.

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Review of the Steelcase Think (v2) chair

Photo of the Steelcase Think chair

This review is part of my series of reviews of ergonomic office chairs. People have wildly varying opinions when it comes to chairs, and you should always test a chair for a few days in your own work environment before buying it. (See more advice on how to buy a good chair.) Don’t use my reviews to decide which chair to buy; use them as a starting point for your own testing.

After test-driving the Herman Miller Embody and the Steelcase Gesture, I felt a bit down. I had just tried out two top-of-the-line models from the two most renowned high-end chair manufacturers and neither was good enough. Would I ever find a suitable chair for myself? As it happened, my next candidate, the Steelcase Think, restored my faith in ergonomic chairs.

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Review of the Herman Miller Embody chair

Photo of the Herman Miller Embody chair

This review is part of my series of reviews of ergonomic office chairs. People have wildly varying opinions when it comes to chairs, and you should always test a chair for a few days in your own work environment before buying it. (See more advice on how to buy a good chair.) Don’t use my reviews to decide which chair to buy; use them as a starting point for your own testing.

Let me tell you about effect the Embody has on people. I went into the showroom of my local office furniture dealer with a budget of about €800, stretchable to a non-negotiable limit of €1,000. With a price starting at €1,400, the Embody was strictly out of the question. But there it was – sitting there with that skeletal backrest and gorgeous design, like some prop from Star Trek that accidentally ended up among regular chairs. It would have been a shame not to try it out, if only out of curiosity.

As the flexible backrest cradled my back and the plastic “pixels” massaged my muscles, I started gently rocking back and forth, trying to think about how to drag out the conversation with the salesman to avoid having to get up. “Come to think about it”, I thought, “perhaps I could add €400 to my budget. After all, an ergonomic chair is an investment in health. You can’t put a price on that!” The salesman must have noticed my reluctance to get up. “People look at various chairs, but everybody always ends up on the Embody”, he mused. A couple days later, I was test-driving the Embody in my room.

The Embody seems to take a page out of Apple’s playbook – not just in terms of the design (it could have been designed by Jony Ive), but also the hard-to-justify price. There is no denying that it is a beautiful piece of industrial design, far better looking than the much-touted Aeron. I really can’t think of many chairs whose design is in the same league as the Embody – perhaps the Steelcase Think or Gesture, but that’s it.

The backrest on the Embody is a very flexible sheet of plastic supported by a matrix of loosely connected H-shaped “pixels”. As I mentioned above, the feeling you get when resting against it is that of being cradled and massaged at the same time. I didn’t make a video, so here’s a clip from TheTechReviewer’s review:

The thing about the backrest is that the flexibility is all in the upper torso. In the lumbosacral region, the chair is quite rigid. After 2 hours of sitting, I noticed my sacrum started getting sore from the plastic pegs digging into my spine. I am not the only one who’s run into this issue – one of my friends felt the same way, and there are a lot of online reviews which include the same complaint.

Whether or not you find the Embody uncomfortable in the sacral area, you will probably agree that it is not a “comfy” chair. It does cradle your back, and it does massage it, but it is a rather firm massage. If you want a feeling of induldgent comfiness as you settle into your chair after a long session at the gym, look elsewhere.

The shape of the backrest on the Embody can be adjusted with that knob on the right you can see in the above clip. This is similar to the “lower back firmness control” on the Steelcase Leap. What this does is change the shape from more of an S shape to a straight I shape, or vice versa. If your back is more curved, you need more of an S shape (the lower curve of the S fills in your lumbar region). I was able to mitigate the sacral discomfort by straightening the backrest, but then the upper curve of the S also became straighter and started pushing my upper torso forward in an uncomfortable way. Because the knob controls two sections of the backrest at the same time, there was no way to adjust it to fit the shape of my back. Perhaps the sacral part of the backrest could be made more comfortable by adding some foam in the right place, but I didn’t have the time to test it – plus there’s the question of whether you should have to do that kind of thing on a €1,400 chair.

The innovative backrest is attached to a standard “smooth” synchro-tilt mechanism. This forces you to sit in what is essentially one position – you can recline a bit if you exert your back and thigh muscles, but the resistance rises quickly and you won’t be able to hold the position for any significant length of time. There’s a knob to adjust the resistance, but you cannot use it every time you want to change your position because you’ll go crazy trying to find the right setting for relaxing, and then the right setting for working, every single time. (The knob is continuous – there is no visual or tactile feedback as you turn it, so good luck getting back to your optimal working resistance if you change it.)

There is a trick that lets you recline without using your muscles – you can shift your body weight by putting your arms behind you like so – but then you can’t operate your mouse, so you cannot, for example, do casual browsing in a reclined position. Another way is to make the backrest resistance very low (so you can achieve a good recline angle for an extended period) and, when you want to do some serious typing, engage the tilt limiter to keep yourself (near-)upright. The tilt limiter then acts as a switch for changing position from upright to reclined, and vice versa.

Making heavy use of the tilt limiter is the best solution – though I should probably call it the “least bad” solution because it has some disadvantages. First, the Embody’s backrest doesn’t have a lot of inherent springiness, so when you hit the limit, it’s not exactly super-comfortable (see below clip from bkwtang’s epic review).

Second, if you’re being kept upright by the tilt limiter, you can no longer rock on the chair, and rocking is good for you.

Third, the tilt limiter control itself does not lend itself to frequent use. You have to move the tilt limiter lever by two stops to go from a near-upright position (tilt lock 2 – 112° hip angle) to a reclined position (tilt lock 4 – 127° hip angle), which is somewhat annoying. What’s worse, the lever is positioned at the very back, under the seatpan – hardly the most convenient location for a control that you’re supposed to use many times a day. (On the plus side, it looks like you don’t have to take your weight off the backrest in order to go from one tilt lock setting to another, like on the Aeron. But I’m going by the linked video here, so don’t take my word for it.)

Changing your position frequently is vitally important from the point of view of ergonomics, and your chair should encourage you, not discourage you from doing so. I feel that any chair that doesn’t let you easily switch from a near-upright (110–120°) “typing” position to a highly reclined “thinking / casual browsing” position (around 130°) cannot be called truly ergonomic. (I am well aware that, by this measure, the vast majority of office chairs are not ergonomic.)

The maximum hip angle on the Embody is around 127°, which is similar to the Steelcase Amia and considerably less than on the Leap or Gesture. That’s not a great result – I would like to see at least 130°.

In the upright position, the seat is tilted forward rather than flat, which is an unusual design. It would tend to open your hip angle (good for the lumbar spine) at the cost of putting a bit more load on your knees.

On most good chairs, when you recline, the seat tilts a little bit back, but does not move forward or backward. On the Embody, the seat actually travels a fair distance backward (see video), following the backrest. In this way, the Embody is the opposite of the Leap, which slides the seat forward as you recline. The effect is also exactly opposite: it nearly eliminates lumbar gap. Your lower back remains well-supported across the whole range of motion.

But that’s not all. The Embody’s seatpan actually changes its curvature. The rear part of the seat is attached to the backrest at a more or less constant angle, which would mean it works like the Aeron, i.e. it doesn’t allow you to open up your hip angle. However, the front part of the seat tilts at an angle which is smaller than that of the backrest. The net effect seems to be that you can open up your hip angle well enough, but as you recline, more and more of your weight rests on your thighs rather than your butt.

If the smooth backrest makes it hard to switch between two positions, at least it gives you the ability to rock back and forth around your normal position, which is fun and probably good for your health (though less important than frequent position changes). However, if you use the tilt limiter as described above, you will obviously lose “rockability” in the near-upright position.

Photo showing the construction of the seat on the Embody chair

The bottom of the seat on the Embody

The thermal performance on the Embody is excellent. Your back rests on a porous fabric and the flexible plastic backrest, which has tiny ventilation slits. There is no foam in between. The seat is foam-free as well – it’s built like a mattress, with a layer of plastic hexagons on top of plastic springs on top of metal(?) strings. It’s a brilliant design that provides 30–50% better cooling (subjectively) than foam without sacrificing too much comfort. During long sitting sessions in an ambient temperature of 25 °C or higher, the Embody is much cooler than foam-based chairs.

As expected on a Herman Miller chair, the armrests are nothing to write home about. I found them hard to use because they’re a bit too long and there is no back–front adjustment. As a result, they kept bumping against the edge of my desk as I tried to move closer to my keyboard and monitor. About an inch shorter would have been perfect for me. Your mileage may of course vary.

I was able to adjust the armrest width so that I could use them to support my forearms when typing. The in–out adjustment of the armrests is achieved in an unusual way (again, I’m borrowing from TheTechReviewer here):

The result is that if you adjust the armrests inward for typing, they will also have a bit of a slope, which may make it harder to reach for the mouse because your forearm has to “climb the slope”.

A bigger issue is that the armrests tilt back as you recline, taking your arms away from your desk. This is a problem, because you cannot, for example, read something in the reclined position while using the mouse to scroll the page. Here’s how the Embody compares with the Steelcase Gesture (which has very level armrests):

Two photos showing the reclined armrest angle on the Gesture and the Embody.

Armrest angle on the Gesture and the Embody at the same recline angle (Embody’s maximum recline). Source: bkwtang’s long review.

It’s impossible to review the Embody without talking about the price. This is one heck of an expensive chair. The base price in the US is $1260, but Herman Miller will charge you an extra $40 for the better-looking white frame, and (outrageously) an extra $200 for the softer, more breathable Balance fabric (highly recommended given how hard the backrest is), bringing the total to $1400.

The Tom Test

  • Easy changing between at least two positions (near-upright and reclined): I’m not sure if it’s a pass or a fail. You can use the tilt limiter as an “upright/recline switch”, but the lever is hard to reach, and then the backrest becomes a bit too stiff in the upright position. The reclined position is not very reclined.
  • Open hip angle in the reclined position: Pass. Much better than the Aeron.
  • Lumbar support: Pass.
  • Backrest should adapt to your back: I’m not sure. The backrest is flexible in the upper body, but the lumbosacral part can be hard and unforgiving. Could be a pass for you, depending on your back shape.
  • Seatpan must not be too long: Pass.
  • Micromovements: Pass. You can rock on this chair, as long as you don’t use the tilt limiter.
  • Armrests (if you care about them): Fail. They don’t stay level, are a bit too long, and the “sloping” width adjustment is not well-designed.
  • Annoyances: Other than what I’ve listed above, none.

Final words

Like most chairs with smooth backrests, the Embody is primarily a chair for sitting in one position – the “intensive working” position. You can try to make it do two positions, but it will make you feel it wasn’t really designed with that in mind: the tilt limiter makes the back a bit too stiff, the mechanics of switching from one position to another are a bit too cumbersome, and the limited recline angle does not let you truly relax your lumbar spine. In terms of allowing easy upright/reclined changes, it’s really not that different from your average $200 office chair with a synchro-tilt mechanism.

Since I consider changing your position to be an ergonomic priority, a chair that gets a mediocre grade in that area cannot get a great overall grade, even if it is perfect in all other ways (and, to be clear, the Embody isn’t).

Although the top part of the backrest feels amazing thanks to the innovative “pixel matrix”, the sacral section is quite hard and eventually caused soreness for me, my friend, and at least some other people (judging from online reviews). In my case, it would have been enough to send the chair back, but it could be absolutely fine for you, as long as you don’t mind firmness.

This is not a chair for armrest-lovers. Although they’re an improvement over the Aeron, a gaping chasm separates them from the best efforts from Steelcase.

I did not buy the Herman Miller Embody and I cannot recommend it, but it is a great-looking chair with some intriguing features. I would very much like to see some of the innovations used in it – particularly the pixelated back and the mattress-like seatpan – make their way into other chairs.

 

Thanks to Kornak Meble in Wroclaw, Poland for letting me try out the Embody and a few other chairs.

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Review of the Humanscale Liberty chair

Photo of the Humanscale Liberty task chair

This review is part of my series of reviews of ergonomic office chairs. People have wildly varying opinions when it comes to chairs, and you should always test a chair for a few days in your own work environment before buying it. (See more advice on how to buy a good chair.) Don’t use my reviews to decide which chair to buy; use them as a starting point for your own testing.

What does sitting in a Humanscale Liberty chair feel like? Let me put it this way. If, one day, I wake up and every chair in every waiting room in the world is a Liberty, I will know I’m in heaven. The comfort level of the backrest is off the chart. The three-part mesh adapts to the shape of your back without making you feel like you’re falling in. It has the perfect amount of “give”.

The backrest is mounted on a hinge located at the height of your lumbar spine. That is a beautiful, beautiful thing, to quote everybody’s favorite U.S. President. When you push on the top part of the backrest, the bottom part pushes back, filling in your entire lower back, down to the sacral area. In combination with the mesh, this creates a quite unique feeling of your entire back being cradled in a uniform way. It feels a bit like floating in air. Actually, the level of support is not uniform – 60-70% of the support is in the lumbosacral area, which helps maintain a healthy lumbar curve.

In addition to the hinge, the whole backrest tilts back as you recline. This is achieved by means of a counterweight mechanism, which means there is no way to adjust the resistance – the resistance is always proportional to the weight placed on the seat.

The Liberty has a kind of default position you naturally adopt when you sit in it (see photo below). In theory, the counterweight mechanism should ensure that the standard position is the same for every user (regardless of body weight). In practice, there are slight differences due to anatomy – for example, if your upper body is 75% of your total weight, while my upper body is 70% of my total weight, you will be sitting at a larger recline angle.

The backrest is not “springy” – the resistance goes up as you recline, but not sharply. If you want to recline further, you only have to put a bit more pressure and it will stay in that reclined position. And it reclines incredibly far:

Photo showing the default position and the maximally reclined position on the Humanscale Liberty chair.

The “default position” and the maximally reclined position on the Humanscale Liberty task chair.

So reclining is not a problem (other than the fact that if you stay in that position for a long time, you’ll kill your neck). What is a problem is sitting upright. You cannot really sit more upright than the default position. And you will probably want to, since the default position on the Liberty is quite reclined.

Let me explain what I mean by “you can’t sit upright”: You can use your abdominal muscles to pull your torso forward to achieve a more upright position, but the backrest won’t give you enough support to maintain that position for any length of time. The other option is to push your lower back out. The backrest has a hinge, so if you push the bottom section back, the top section will tilt forward, making you more upright. Problem solved? Unfortunately, pushing your lower back out is the single most harmful thing you can do to your back while sitting. You want to maintain a healthy curve in your lower back (that’s what lumbar supports are for). I fear Liberty users who want to sit more upright (for example, people who type a lot), will end up hurting their spines.

Another thing that I consider dangerous is that the hard metal edges of the backrest are positioned right behind the soft part of your elbows when you’re typing. It might not be an issue if you have a wide build, but for me, the only way to avoid constantly bumping my elbows on the frame (and irritating my ulnar nerve) was to sit much further from my desk than I like to. The root of the problem is the concave shape of the backrest, with the sides sticking forward.

As I described in another post, repetitive pressure on the ulnar nerve is no joke. It can result in permanent disability. In truth, just that problem alone is enough for me to disqualify the Liberty as a chair for computer work. I’m just not prepared to take the risk. Here’s a photo I made to demonstrate the issue (notice where my right elbow is resting):

Photo showing the author sitting on the Liberty chair

The hard backrest edges on the Liberty can put pressure on your ulnar nerve. Notice the position of my right elbow as I type.

In addition to being extremely comfortable (in the default position), the Liberty is an admirably cool chair. The mesh, predictably, ensures excellent airflow around your back. The real positive surprise is the gel seatpan. It conducts heat away from your bottom much better than typical foam, without compromising on comfort. To my knowledge, Humanscale is the only major ergonomic chair brand that uses gel seats. The idea offers such clear advantages that I cannot fathom why other manufacturers don’t do it. Steelcase, hello? Why do you insist that my butt has to be on a material that’s used for thermal insulation? Anyway, potential buyers should note that the gel seat is not a standard feature on the Liberty – you have to ask for that option.

The one knock against the Liberty’s seatpan is that it doesn’t tilt back when you recline (it only goes up, which is a natural side-effect of the counterweight mechanism). This goes against standard ergonomic guidelines for chairs. In combination with the slightly slippery fabric on my demo chair, it sometimes made me slide a bit forward when I reclined (depending on what pants I was wearing). If you plan on getting the Liberty, I would recommend choosing high-friction upholstery.

The armrests on the Humanscale Liberty are quite useless:

  • The only adjustment you can make is change the height
  • I found they’re set too wide (48 cm) to enable me to rest my forearms while typing (they may be OK for very wide users)
  • They extend a bit too far – as a result, they made me sit a bit too close to my desk than I found comfortable.
  • They tilt together with the backrest, so if you recline beyond the “default position”, they tear your hands off the desk (but they’re too wide anyway, so it doesn’t really matter)

In general, I preferred working with the armrests lowered out of the way.

One final thing before I move on to the wrap-up: I have seen an unusually high number of complaints on Amazon about the build quality of the Liberty – armrests falling off, that kind of thing. That sort of thing shouldn’t happen on a $1000 chair, though it should also be noted that Humanscale offers a generous 15-year warranty.

The Tom Test

How does the Liberty fare on my checklist? Let’s see:

  • Easy changing between at least two positions (near-upright and reclined): Fail, because there is no truly upright (or near-upright) position. You can be reclined or more reclined.
  • Open hip angle in the reclined position: Pass.
  • Lumbar support: Pass. The hinged backrest does wonders here.
  • Backrest should adapt to your back: Pass. The hinge + mesh cradles your back brilliantly.
  • Seatpan must not be too long: Pass.
  • Micromovements: Not great. You can move the backrest back and forth, but there’s no springiness that would encourage micromovements.
  • Armrests (if you care about them): Fail. See above.
  • Annoyances: Hard backrest edge may hurt your elbows.

Final words

As I hinted in the introduction, the Humanscale Liberty is a fantastic chair for waiting rooms. It can be a great chair for workers who sit behind a desk, but use a computer only occasionally – in fact, I have met office workers who wouldn’t give up their Liberty for the world. It can be an outstanding chair for relaxing, watching a movie on your computer, maybe playing a videogame. It’s likely the most comfortable office chair you’ve ever sat in, and that’s no small thing. Everyone should try sitting on it at least once.

However, the Liberty is just not a good chair to operate a computer from. You cannot really sit upright (= more upright than 120°) in it, and the unfortunate shape of the frame will likely pose a risk for your ulnar nerve.

 

Thanks to Kornak Meble in Wroclaw, Poland for letting me try out the Liberty and a few other chairs.

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