Logos-Hope on Madprof's workshop

Hello, WordPress, hello Logos Hope

Sat, 14 Mar 2015 14:51:23 +0000

I use WordPress at work, it’s the engine behind fr.om.org, transform.om.org and most of the other sites that we run for clients.

I’m in two minds as to whether I like it or not. Some things are great. For users (content authors, the people writing blog posts or static pages), it’s fine. Easy to understand and use. For writing plugins and templates, it’s… Well, kind of messy and ugly, but doable. For instance, rather than have 1 HTML template “base” file, with a block saying, “put posts here, and wrap each one in x,y,z”, you have a header.php which has only the start of all the HTML, and a footer.php which closes it all, and a content.php, a content-post.php, and so on, and you have to keep them all synced up. Also, since it’s designed for running on old PHP, it doesn’t use namespaces or other ways of keeping code clean, so all functions in all plugins and all templates are all global scope, so to avoid bumping in to each other, you have to name all your functions stuff like, “madprofs_teapot_plugin_get_resource() and similar. Then at the same time, Wordpress has multiple global functions of its own, some called things like, the_post(), others like wp_get_cached(), (so prefixed with wp_), and others in other styles. Messy.

Still, it gets the job done.

So when I wanted to update and clean up the brummie@sea blog, I thought I’d just stick with blogger. It works, it’s what I already had. But then, accidentally, while trying to update it, I lost the entire design, and putting it back together was this awful mess of Google-XML/HTML confusion, I thought, “you know, stuff it, I’ll just use WordPress.” So I span up a site on the server (in about 2 minutes), pointed the blogger importer at brummieatsea.blogspot.com, let it chug away for a few minutes, and here we are.

I’m just using a very simple built in design for now, (with my own background), but it seems to work. I now don’t have to worry about Google turning off blogger like they did with Reader and GoogleCode, and since I use Wordpress at work, I understand what’s going on pretty well.

That all said, we’re now on the ship, trying to settle in. We have a really nice cabin. Jet lag wasn’t fun, especially with the baby, but we’ll get through it. Yesterday Becky drank a big milky drink by accident - we thought it wasn’t cows milk but plant based, and last night and tonight David has been awful - screaming for ages and refusing to be comforted or to sleep lying down in his bed. So that does seem to confirm that maybe it is a lactose intolerance at the moment - hopefully he’s back to normal in a day or so.

Work so far is just cleaning the various venues. We’ve not even begun to start installing new equipment or doing anything really technical. We’ve got the lights out of their bags and air-blasted them all, cleaned many surfaces and TVs and vacuumed and dusted. It’s going alright. Still sooo much to do.

Documentation, and how balanced audio cables work.

Thu, 07 Feb 2013 08:39:00 +0000

I finally had a bit more time this morning to write a bit more in the A/V manual. There’s lots of bits and pieces of documentation on board, but no comprehensive single getting started manual. So I’m writing one, bring together bits and pieces from all over the place, sorting out what documentation there is, updating schematics, etc.

Anyway, here’s the rough version on the article I just wrote about how balanced sound cables work. It’s pretty much my standard explanation of Balanced Audio, and aimed at people coming to A/V from a non-techy musical background, rather than for Electronics Engineers.
You may find it interesting. Then again, you may not.

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Sound is basically vibrations in the air.

TODO: more details, pingpong ball analogy?

Inside an (SM57) Microphone head.
That is the bit of plastic and the coils!This translates really easily into an analogue electrical signal: you simply turn the air vibrations into voltage vibrations.A Dynamic microphone does this by having a small bit of paper (or plastic) which vibrates with the air around it, and pushes against a very small copper coil which, moving inside a magnetic coil itself, generates a very-very-very small amount of electrical current.

TODO: more pictures.

This gets dumped down a wire, which gets amplified by (you guessed it) an amplifier into a very big amount of electrical current, which then drives a big electromagnet inside a speaker, which pushes another copper coil around, which is attached to another big bit of paper (the speaker cone), which causes the air around the speaker to vibrate – with the same vibrations that the microphone vibrated with, just bigger.

Simple, isn’t it? (well. Kind of.)

Balanced Audio Cabling

The trouble with simply dumping an audio signal down a cable, and picking it up at the other end is that your signal line, and return (usually ground) will pick up noise (say from A/C mains electricity, fluorescent lights, dimmers, mobile phones, etc) along the way.

Here’s an original signal:

And here’s some noise:

And the result:

This is a Bad Thing™.

So some clever engineers, back in the deep recesses of time figured out the following:You could take a signal, and before sending down the wire where it could pick up noise, invert it:

If we add the signal to the inverse, you get a grand result of nothing (e.g. -3 + 3 = 0).

Now, if we throw these two signals down a pair of very similar cables twisted round and round each other like crazy, then they’ll both pick up noise pretty much the same as each other:

Note that 3 (the original) + 1 noise = 4,
while -3 (the inverse) + 1 noise = -2. NOT -4!

This is really cool, because if we add these two signals together, we don’t get 0 anymore, we get no original signal, but you do get the noise (doubled).

So we’ll use our amazing maths skills again, and divide this doubled noise in half. (2/2 = 1).