Michael Zucchi

 B.E. (Comp. Sys. Eng.)


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Friday, 28 December 2018, 08:46

Speaker Boxes and Music Players

I finally got around to mostly finishing the speakers I was making out of recovered drivers. Here's a bit of a photo-diary of the final stages.

Here we have the completed woodwork. It has been glued and sanded square. I'm mostly happy with how it turned out but I could have done a bit more sanding; I was over it by then. In each case I pretty much practiced on one and got better on the other one, hence a few differences here and there. The one on the left is unpainted and the one on the right has a coat of sanding sealer and also the binding post mounting mechanism.

Three undercoats, lots of sanding and two overcoats and it's ready to be put together.

Given the paint was so expensive ($90) I did a bit of a shit job in the end; I just got sick of dealing with everything. First I had a cheap throwaway brush which I should've just thrown away before I even started. Then the paint was too thick for the weather and needed more thinning, then I tried using a small roller - but again i got some cheap junk which left behind piles of dust and shit, and because I hadn't used a roller before I didn't apply it as well as I might have.

The next shot just shows the mounting point for the binding posts.

Even this I kinda fucked up. I tried using the drill press to drill the screw holes to mount it but to avoid scratching the paint I had it on a small block of foam. It moved when I wasn't looking and I drilled it in the wrong spot. It's hidden but I know it's there.

Soldering the wires.

Completed binding posts.

Connecting the driver.

Inserting the acoustic foam. I have 25mm at the read and 12.5mm down the sides - about as much as could fit in the small box.

A completed speaker (so far). The screws (all 24 of them) for the box are really only aesthetic as the box is very well glued. They did help when setting the glue though.

The pair. I've only redone the rubber surround on the right one so far, the one on the left is still a bit scratchy with high volume as a result. The mounting rubber washers/etc is still work in progress.

I'm still yet to get some fabric for the grilles. I did a quick peruse through lincraft but couldn't find any suitable, next time i'll ask and there's a couple of other places to try.

And finally a shot in testing. The plan is to put the electronics in another box with a battery pack. I've got the bits for the battery but am still working on the mechanics.

How do they sound? Well ok. They're not going to break any technical records; there's no engineering behind the boxes other than being a sealed box with a bit of foam in it. Each only has a woofer so the top-end is very retarded. The bottom end isn't too bad but it does have an echoey effect with some mid-tones, then again so do any other small speakers i've tried (including the $1000/pair units I just installed in the dining room). Quite ok for a bit of outside doof though!

It's been a good little project to get away from the screen so far, although finishing it off will not be.

Electronics and Software

I was looking around for hardware for the player but since I have the mele doing nothing I thought I may as well use that. Most of the other prototyping boards around now are either too high powered or missing some necessary bits; although the nanopi boards look quite attractive (on a side-note I can't believe how expensive raspberry pi shit is in australia). As this is nominally a 'portable' system based on recycled speakers (with no tweeters!) the audio quality isn't terribly important, the on-board dac/codec sounds good enough to me. I'm also considering an old phone or an old 7" tablet I have, although it's far less attractive to me if they can only run android (fuck that shit; yeah fuck you too google).

After spending most of a day on it I managed to get debian running on the mele. I tried the sunxi wiki and building my own kernel and bootloader but without any debug console I couldn't tell if it was working or not. I got this server image to work in the end, using the jessie image.

While trying to build using the sunxi instructions I discovered that the ubuntu maintainers have a really broken idea about what a cross-compiler should do. And they're really quite rude about it, hiding their rudeness behind the `code of conduct'.

To avoid dragging in gobs of junk and other poettering snot I built a basic SDL (1.2) and a cut-down ffmpeg (1.0) from source and have a basic console music player working. With a little more work I can control it with the mele airmouse although without a screen it's going to be difficult to do too many interesting things. Something to poke about with.

Tagged hacking, linux, workshop.
Friday, 17 November 2017, 22:02

Silent Spring

Well I finally got tired of Slackware64 - it worked quite well until I upgraded it to 14.2 some weeks ago, and then too much stuff broke - all I could get working was the VESA driver which meant I was back to a single screen, no opencl either. I ended up putting in xubuntu lts (16.4).

The machine is kinda busted anyway one of the DIMM slots doesn't work - the BIOS detects it but Linux throws the memory away for some reason. This happened months ago but I thought i'd give it another go but of course made no progress. Before it vanished it would sometimes show up and then crash if I used too much memory so I think the motherboard slot is shot (either DIMM works ok in slot 0, neither in 1). I'm in no rush to replace it, although 4G is a bit tight at times but it's not like I do much on it other than waste my life browsing shit I don't care about, with the occasional bit of pointless coding thrown in.

I probably wouldn't have bothered with unbuntu (and i really don't like it or other debians as a whole) but I somehow corrupted the BTRFS filesystem (I think modifying it from a live boot ubuntu which necessarily has a different build - it's been solid for years) and completely lost it. Well I was modifying it throwing away junk before I backed it up so I had just backed it up. I think that's my last experiment with BTRFS, i'm back to jfs now.

At least ubuntu installed quickly and easily and all, not too much hassle apart from the boot config. I setup an EFI boot partition which ubuntu automatically placed in /boot/efi but I didn't create a /boot partition where grub expects everything like the jfs module it needs to read the modules directory on the root partition. Sigh. Well after multiple attempts (easily enough booting via the live usb stick) I eventually worked out the grub command lines to install everything in the /boot/efi partition and have it work (I haven't used grub in years and that was pre-grub 2).

Then I had to go through the ritual of removing all the junk and installing useful stuff. Fuckoff pulseaudio, networkmanager, gnome-software (I mean what the fuck is this shit?), the auto updater, install emacs and dev packages, jvm's, netbeans. Then had to go through and fix the colours and fonts in the tools I use, fix the WM theme, etc. Fortunately i've installed 2 other machines not too long ago so it wasn't so painful this time.

And the stupid gtk3 scrollbars - something I noticed earlier but thought was just firefox at fault. Apparently scrollbars are hard to get right. I can only imagine that being the case if you also have trouble putting underpants on in the morning.

Firefox 57 is kinda shit. Infact I'm having to use `Midori' to write this because I can't even login to google from firefox because the login window simply doesn't work. And with the new plugin system it means my most useful plugin - one that toggles the javascript enable flag - is broken. You can get sort of get the same functionality from the new plugins but because of the way it works any site still thinks javascript is still available so might present a different page than if it wasn't; i.e. it just breaks more shit. I dunno, i'll see on that one, i'm reading less and less lately anyway so it might not matter. The whole browser is pretty bloody fugly too, like someone published and early mockup made in a spreadsheet tool.

And apparently firefox dropped alsa support some time ago, I thought the upgrade to Slackware64 14.2 had just broken something else. Actually I kind of like that computers just shut the fuck up (and don't catch you out by going beep) unless they're asked to make noise so it's no big deal. youtube is a bit crap, and particularly shit in a browser, and there isn't really any other valid reason for sound out of a browser.

The only reason I stick with firefox is because you can override the default colours and fonts completely (black on white gives me a fucking headache, as doe tiny or shitty typefaces - black on grey, DejaVu @ 9+ pix everywhere please), and disable javascript (it just makes so much of the web so much cleaner and faster). It also used to work well enough on the few sites I regularly use.

Sigh, i've had a troubled week.

Tagged linux, rants.
Thursday, 01 April 2010, 10:00

CentOS isn't worth the paper ... oh hang on

After a few more hiccups I finally gave up on CentOS on my workstation last week - I don't mean to diss on the CentOS project and people as such, but I have to say I had a pretty negative experience with it and probably wont be considering it again (there just isn't any need). I hadn't tried it before, and thought i'd give it a go, mostly because I was expecting simple reliability.

Unfortunately not.

Lack of packages
Just how limited was a little bit of a shock ... but this was something entirely reasonable and had no major problem with this.
Lack of stability
This was both shocking and surprising. I had a lot of stability issues from day one. Primarily that xterm's constantly locked up when trying to do ordinary things like 'man blah' or 'less foo' (and I need to use the real xterm - the other `desktop project' knockoff's are unusably slow at full screen, and barely usable even at 80x24). I got around it using info, or emacs shell but it got old very fast. Firefox also had a habit of grabbing the pointer if I accidentally dragged something which is too easy to do. For the most part I loathe DnD because generally it's too easy to trigger and used in some really stupid places, and where it could be useful - e.g. dropping files into an application or filename selector, it isn't implemented, sigh. I wish GUI designers of the free `desktops' had a wider GUI experience than just MacOS and Windows 95.
Bloody slow (not just slow)
Ok I'm a bit spoilt with my home workstation and it is decidedly slower hardware, but this was a little ridiculous. I can forgive some of it because I chose to encrypt the home partition, but I really have no feel on how much that makes a difference. I'm sure EXT3 is something to blame here too - if anything demonstrates that the Linux project is no true meritocracy it is that this steaming pile is still the main filesystem of choice when so many more advanced and reliable filesystems have existed for years!
Updates broke it
What finally broke the camel's back was turning it on one morning and having no X any more because the update manager prodded me to install a different Linux and I wasn't paying attention. I am 'partly to blame' because I am using the proprietary nvidia driver (the other one just didn't work, and I need OpenCL/CUDA or something down the line too) from livna or something or other - but I haven't had quite such problems doing similar things in the past that were so difficult to resolve. After mucking about for an hour or two I gave up and just installed Fedora 11 (the newer ones are just fucked up too much to be slavagable within my patience band). That ended up taking the whole day (made a few mistakes along the way), but it was definitely worth it.

Now I don't know how much CentOS differs from RHL, but this doesn't leave a good impression of that either. The whole point of using old software with limited packages is for stability and reliability and it was on those two particular points that I had the most negative experience. Probably the worst I've had with any OS since automated package management existed (~10 years).

I've moved to Fedora 11 and have had no issues since. Faster, more stable, more packages, blah blah blah.

X, Java, Netbeans

Well, while i'm dissing on free software projects ... I don't know what they're doing wrong but OpenJDK has some major performance issues that simply make Java (and anything that uses it) look really bad ( in all fairness I am using Fedora 11, so it is certainly quite an old release ... ). I am doing some stuff in netbeans (6.8) and although usable for the most part, had a decidedly lurcherous gait which only got worse over time till it was barely usable. I resorted to using emacs for editing (it's still a much better basic editor), jumping back to netbeans only to look up methods (JavaDocs as useful as they are are a bit unwieldy to navigate, particularly in a web browser). I suspect it has more to do with something basic like the interaction with X than anything else - and we all know what a mess of The X Windows System that f.d.o are making so it probably isn't entirely `their fault'.

So I finally got sick of that and after a bit of searching on the net and trying "-Dsun.java2d.pmoffscreen=false" to no big effect, the only thing seemed to be to try the Sun JDK. *Cough* Oracle JDK. Apart from a different way of selecting fonts that initially made it look a bit crap, and a generally lighter appearance in the text you'd think I just upgraded the computer to see the difference.

It's like night and day. It might use scads more memory than a C app but it feels just as snappy and responsive (at least in comparison to how it was, hard to guage). The thing is, having such a poor user experience from the OpenJDK just continues to give Java a bad name when it just isn't warranted, and hasn't been for a long time now. I was originally just going to implement a GUI in Java (or maybe just a prototype) but I might try a few tests of the algorithms to see how it compares to the C code - it spends most of it's time in FFTW anyway at present. It's a real pity that it doesn't support a primitive complex type, but that isn't the end of the world. I'm using the Shared Scientific Toolkit at the moment, although mostly just for the arrays and fft ops (that's all the code really needs).


Oh god what is this pain in my head ... yet another messed up build system. One that provides all the craptascialness of Ant for your C++ projects too! Jesus, who comes up with this shit? I had some issues building SST - it turned out I just needed to install the static FFTW library, but along the way I had my first experience of CMake. About the only thing going for it is that it doesn't use XML. What I don't understand is why these things come along and break the whole point of make files? During the build something failed - so I worked out how to manually run the command and the command ran ok. Fine then, just run make and let it continue ... oh no, that would be too fucking simple wouldnt it? It uses some fucked up meta-system for tracking build dependencies, so it just re-builds the whole directory again, again failing on the final link. Then I ran a different make target which built ok ... but wasn't quite what I needed. No problem, try the original build target ... 'target up to date' ... huh?


The one and only point for any make system to exist in the first place is to guarantee your builds are consistent without having to recompile everything every time. For everything else you may as well just use shell scripts - which are conveniently embedded inside a Makefile. I understand CMake does some other stuff, and also provides a `shell script' environment that supports broken operating systems, and that idea has some merit - should you wish to interact with such a broken system at least - but if it can't get the basics right what use is it?

Ant is another nightmare all of its own - not only does it not do any dependency checking whatsoever (one of the most critical features of any build system), simple human readable shell scripting is replaced not only by a disastrous and unparsable XML scripting language but also by dynamically loaded Java modules! I can understand wanting to use your favourite language for everything, but Java is not a scripting language and sometimes there is a right tool for the job.

completely broken ...

... simply worthless.

... CMake ... Ant ...

I consider any tool where you must occasionally `make clean' to get a reliable build to be completely broken and simply worthless. CMake seems to get around this absurdity by abusing 'ccache' - another painful bit of kit that shouldn't need to exist (the limited use-cases for which ccache provides any service can mostly be done in other much simpler ways - assuming you have a reliable dependency mechanism in the first place). And Ant gets around this by the fact the java compiler is quite fast anyway, and already does the dependency checking - but only for the Java sources, and any real project has to do more than just compile objects and link them together. One often has to 'clean and rebuild' in all the GUI IDEs i've used, but there should be no reason to ever need this unless you're manipulating files outside of it.

Idiot. Is this you?

What I find disappointing (vexatious, alarming, and upsetting too) is that people refuse to learn a basic reliable, flexible tool, and then come up with their own which doesn't even solve the original problem. `I can't use an editor to control the tabs in my file' is really an idiotic and puerile argument (if you do think that, then yes i am in fact calling you an idiot. Idiot.) I suspect if they understood the original problem they wouldn't have bothered to inflict all this crap upon themselves or the rest of us in the first place and wouldn't the world would be a better place for that?

I understand some people think make is a bit arcane .. but it isn't. XML is the definition of arcane - lets design a format which makes it easy to write parsers, for developers. You know that tiny bit of code that gets written once and forgotten about because nobody fucking cares once it works. It's not like they even got that bit right - the parsers are large and complex and the code you write using them ends up being large and complex too (and it's all slow). But the real winner is that this then inflicts all the nitty-gritty which makes it 'easy to parse' onto the user for whom it is decidedly not easy to parse, or write, or even design. Now that's arcane.

But I digress.

The auto*tools are a big bit of nasty, but at least it's only one (perhaps broken) system to learn, not 'n' (definitely broken) systems where 'n' is monotonically increasing. And there are plenty of application projects for which it shouldn't be needed (but gets used anyway, sigh).

Woke up too early

Shit, I was supposed to have some bricks delivered this morning - I was up way too late and got little sleep worrying about making sure I tell them to put it in the driveway to avoid 3 hours of back breaking work moving them. I suppose i should go get some groceries, or I might just avoid the shops which turn into a nightmare of panic buying just before Easter since many shops are shut - GOOD HEAVENS - for 2 whole days in a row. How ever will we all survive for so long without being able to buy more shit!

Tagged linux, rants.
Wednesday, 06 January 2010, 20:07

gloat 0.1

I'm sure i'll live to regret this (i can already hear the glee of some kid discovering a buffer over-flow - well, in the unlikely event anybody ever downloads it), but i've uploaded my news snarfer 'gloat' to Google Code.gloat - it's a bit like brag ... err, geddit?

I'm going a bit loopy today. I was up till around 4am working on a 'matrix' clone (C64 - llamasoft), although now i've lost interest in it somewhat. And after a little mucking about in the garden have been solidly stuck behind my machine reading the net, manuals, and poking at bits of code all the way through till nearly 8pm - again. Well I had some lunch and coffee somewhere in all that.

Oh - it was too hot today to do much outside, but I suppose I should be using the weather to go to the beach or do some cycling or something I can't do all the rest of the year.

Tagged gloat, hacking, linux.
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