Tag Archives: audio

First experiments with an Instamic

New toy! I bought an Instamic: a tiny voice recorder that I wanted to use in situations where conventional microphones might be difficult or a nuisance, especially when I’m recording with my GoPro Max, which has no facility to take an external mic input.

Here’s my quick first test on yesterday’s dog-walk, in case it’s of interest!

The Modern Lab Notebook

I’ve just uploaded my longest YouTube video yet!

Entitled The Modern Lab Notebook: Scientific computing with Jupyter and Python, it’s a two-and-a-quarter hour blockbuster! But you can think of it as three or four tutorial seminars rolled into one: no need to watch it in one sitting, and no need to watch it all! It starts with the basics, and builds up from there.

It’s intended for people who have some Python programming experience, but know little about the libraries that have become so popular recently in numerical analysis and data science. Or for people who may even have used them — pasted some code into a Jupyter notebook as part of a college exercise, say — but not really understood what was going on behind the scenes.

This is for you. I hope you find it useful!

Watch it full-screen, and turn the resolution up 🙂

Also available on Vimeo.

Speaking to the future?

speakerconesFrom the “Things I should patent but probably won’t” department…

Predictive Loudspeakers

Yesterday, I was talking to a loudspeaker designer, who was describing the mechanical limitations of speaker cones. One of the key problems is that a loudspeaker cone is basically a mass on a spring. Once you give it an impulse, it will then rebound to its original location with a velocity and momentum, and these will all affect the sound that comes immediately afterwards. It also, of course, has its own resonant frequencies. And these factors mean that people have spent a lot of time trying to minimise the mass and resonance of loudspeaker cones or replacing them with complex electrostatic devices, or vibrating ribbons, or whatever.

Now, it occurred to me that as we start to get digital linkups to loudspeakers, we can do something we could never do before: we can predict the future.

At least, we can buffer the digital signals for a while as they come into the loudspeaker. As long as we do this for all of our channels equally, the delay is not usually a problem. (I am thinking primarily about listening to music at home or in a studio; if this was audio for a movie, you’d need to delay the image by the same amount, and it wouldn’t work at all for live PA systems, but bear with me…) We could then look ahead in that buffer and provide an impulse to the loudspeaker cone now based not just on what we want now, but on what we are going to want a few milliseconds down the line. The signal you feed to the speaker would then be the first derivative, or the Laplace transform, or something, of the sound you actually want to come out once delays, masses and spring co-efficients are taken into account.

Now, I’m not a control systems expert, and I don’t know how difficult constructing a dynamic PID-feedback system would be, but this is at least a very controlled environment, and the system could, if needed, be self-monitoring and adapt over time.

Such analysis could, of course, already have been done in other places that have access to the digital stream – like the CD/DVD player – but the earlier stages will not typically have much information about the amps and speakers. Now, however, the trend is towards active speakers which include their own carefully-matched amps, and for digital, even wireless, links replacing the old analog cables. So this becomes quite possible, and the market is ready.

What do you think? Anyone want to invest huge amounts of capital and help me make the speakers of the future? Or is this already available?

Toss me a mike…

I think CatchBox is a great idea! A soft, chuckable microphone that you can throw to an audience member who wants to ask a question.


It’s like a conch, but less fragile, which is also good for maintaining civilised discussions…

Thanks to Adrian Higgs for the link.

Cast your net a little wider

A phenomenon that has transformed my life in recent years is the ready availability of audiobooks and podcasts. When I’m shaving, driving, or walking the dog, I’m usually also reading a book, learning something new, keeping up with technology news, or sometimes just being entertained. My iPhone/iPods are used for speech much more than for music, and my bluetooth headset and car hands-free kit are seldom used for actual phone calls! Travelling time, in particular, I no longer think of as ‘wasted time’.

On the audiobook front, the only way to do this is to subscribe to Audible.co.uk (or your country’s variant). Audiobooks can be fairly pricey if you buy them individually — longer ones, in particular, can run to £20–40 — but an £8 monthly subscription will get you a book each month. I ‘read’ many more books now while walking across fields than I used to get through by turning a page or two in the last few minutes before I fell asleep. I use the Audible iPhone app for downloading and listening to them.

For podcasts, my first recommendation is not to try and listen to them using iTunes or Apple’s Podcast apps. Far better is to get a third-party app designed for the purpose, (unless you have an old-style iPod which can only be managed in iTunes). My current favourite is Downcast, which will do things like keep your current listening progress in sync across multiple devices, and let you skip backwards and forwards (e.g. to jump advertisments) using easy swipe gestures. Instacast is also a worthy contender.

Anyway, the main reason for this post was to recommend two podcasts that I’ve found consistently interesting and of high quality.

Mac Power Users

The first is Mac Power Users. Now, you might assume from the title that this weekly programme is all about obscure command-line incantations and developer toolkits, but on the contrary, it’s for normal humans, by normal humans; David and Katie are practising lawyers who just have an interest in getting the most out of their technology, and talking to other guests about how they do the same. And while most of it is definitely for Mac users, some episodes, like this excellent discussions with Fraser Speirs about technology in education, are of more general interest. Sometimes they’ll dive deep into a favourite utility, like Hazel, or a topic, like ‘Geek Fitness’. And at other times, such as when interviewing Alex Lindsay, they end up talking more about efficient ways to get through airport security than about the Apple gear they’re carrying! Unlike many of the podcasts I subscribe to, this one is not primarily about technology news, and I like David and Katie’s relaxed but professional approach.


The Skeptics’ Guide to the Universe, known as ‘SGU’ to its numerous fans, is a discussion of recent and historical science news hosted by some very smart people — Steven Novella, for example, is a neurologist at Yale — who try to separate fact from fiction. They do a lot of background research on stuff that has recently made media headlines, and present the results in an interesting and entertaining way. Recommended if you want to keep your head when all around you are losing theirs.

Both of these should be easy to find using your podcatcher of choice – just search for the names.

© Copyright Quentin Stafford-Fraser