Wed 23 Feb 2011
Posted by andrew under Musings Comments
… a tiny, highly directional speaker that can be used in portable devices like laptops, tablets and mobile handsets.
Given the helpful comments that I got last time I made a wish for a product, directing me to exactly what I was after, I am hoping that I’ll get lucky again. But I’ve searched around, and I fear that it doesn’t (yet?) exist.
Normal speakers in portable devices are unsuited to a shared environment when I’m going about a personal activity. For example, if I want to watch a TV program on my laptop, while my wife watches some video on the iPod on the couch next to me, we are going to interfere with each other, making it difficult for either of us to listen to our shows. Similarly, in an office environment where people are sitting on adjacent desks, it would be great if the sound from any one computer wasn’t audible to the rest of the office. Or alternatively, where many people are on a train and watching video or playing games on their portable devices, reducing the interfering noise would be appreciated.
Headphones are unsuited to both “snacking” type tasks (pick up the device, do something quickly, put it down again) and where a camera is used (as in a video call). If I have to stand up, put down the device, find the headphones, connect them, put them on, then sit back down every time I find I want to watch a video, the result is that I don’t watch videos. And in a video call, while the trend is more and more towards an almost “present” level of quality, seeing the other party wear headphones pretty quickly breaks the illusion. Needing peripherals, such as headphones, usually indicates a compromised experience.
Even if the audio quality is relatively poor, I would still rush out and get a portable device if it had the ability to produce directional audio. I don’t necessarily need high fidelity for watching online video or making a video call.
It appears that the basic technology needed for this sort of speaker is an array of ultrasound generators. You know it has got to be awesome technology if it uses something called ultrasound, right?
From the details on the Explain that Stuff! website, it seems that basically two (ultra) high frequency audio signals are produced, and it is the beat frequency between them that is the actual audio that you hear. Because the frequencies are so high, they are highly directional.
I have found only one product on the market that uses this approach – the American Technology Corporation HSS-H450 – which is a foot long and available for the bargain price of US$1,069.62 (strangely, that’s a UK site). Meanwhile, I have come across a kit that might be used to make your own (if you’re more talented than I am at electronics). Alternatively, there are some less-than-ultrasonic but still directional speakers that I’ve found from Brown Innovations and Dakota Audio. But neither would suit embedding in an iPad, let alone an iPod.
So, I continue to wait and hope…
Tags: directional, future, parametric loudspeaker, speaker, ultrasound, wish
Sun 13 Feb 2011
Posted by andrew under Musings Comments
I was chatting to someone about once-in-a-century events, and I was reminded of a book I read a while back which pointed out that understanding probability is a pretty recent thing. In fact, there haven’t been that many centuries in which people could talk knowledgeably about 1-in-100 years events.
(I should probably put a disclaimer right here that, just as it seems any public post about poor grammar is bound to be riddled with grammatical errors, my post about probability is going to be full of mistakes. So, I promise to fix them, if they are pointed out to me.)
A funny thing about 1-in-100 year events, like 1-in-100 year floods, or storms, or market busts, is that they can appear to come along more frequently than once every hundred years. But it looks like we’re stuck with the name.
A 1-in-100 year event is simply one that has a 1% chance of happening in any particular year, which means that, mathematically, you would “expect” there to be one, on average, every hundred years. But of course, some centuries will have more or less of them.
In fact, (making assumptions about the distribution of events,) you would expect 37% of centuries to never have a particular 1-in-100 year event. You also get exactly one 1-in-100 year event in around 37% of centuries. The rest (26%) have more than one.
While more than a quarter of centuries can see multiple occurrences of a 1-in-100 year event, it’s worth asking: how many times can such an event crop up in a century before you start to wonder if it’s really still a 1-in-100 year event. How many occurrences of 1-in-100 year events should you actually expect?
The answer depends on the threshold for unlikeliness. A reasonable standard might be that anything less than 5% probable is pretty improbable. Back in high-school, playing D&D role-playing games, throwing a 20 sided die and getting a 20 (i.e. a 5% chance) was enough to get you special results. It came up a few times every game, but it was something pretty unlikely indeed. So, let’s use that standard for now. (It’s also common elsewhere.)
So, how many occurrences of a 1-in-100 year event in a single century are needed before we get to a level that’s less than 5% likely (or, you would expect to occur in less than one century out of twenty)?
The answer is 4. It’s only when you get four of a 1-in-100 year event happening in the same century that you might want to start questioning whether something else is going on, because it’s all starting to get a bit improbable. Four or more of such an event should crop up in less than 2% of centuries.
So, in summary, you shouldn’t be shocked to see three of a 1-in-100 year event occur in the last hundred years – it’s perfectly expectable.
Tags: 1-in-100 year, 100 year, probability, risk, statistics
Sun 6 Feb 2011
Posted by andrew under Reviews Comments
Our book-club book for the month is Jasper Fforde‘s most recent novel for adults. Not sure if I’m going to make it to book club this month, but anyway, while the book is still relatively fresh in my mind, I wanted to jot down my thoughts about it here.
An intriguing post-apocalyptic world with some novel ideas
Jasper Fforde is better known for his literary comedy books, which provide a post-modern take on the some traditional genres, like nursery rhymes. This book is a departure from that, so existing fans may not find it quite to their liking. This is, in essence, a science fiction novel: a story set in post-apocalyptic world.
There are still some comedic elements, and there is a hint of romance, but foremost this is a display of Fforde’s inventiveness. For example, in this speculative future, the characters live in a colourtocracy, where association with certain colours relates to a position in the class structure. One might consider the result to be the dystopian love child of George Orwell and Roald Dahl.
While the world itself is fascinating, and learning more about it was the impetus to keep reading, the main character was a bit of an empty shell. I didn’t find anything particularly likeable or admirable about him, nor anything repulsive either – he just stumbles along through the plot, primarily pushed along by other characters’ agendas.
Finally, it is worth noting that this book is the first of a trilogy, and the other books aren’t written yet. This was something not immediately apparent from the cover of the edition that I was reading.
Tags: book, jasper fforde, review, sci-fi, science fiction, shades of grey