Archive for the ‘diy’ Category

my real life encounter with the metric inch

Hm. That’s … not a half-bad album title, is it? File that one away… (⌒▽⌒)

Anyway, as you might tell from the last post, I’ve been doing a fair bit of studio maintenance lately, getting rid of redundant/obsolete cabling, finally making second-tier stuff that wasn’t working actually work, all that. And a very small part of that work has been fixing an issue I noticed when I started using the new sound-engineer position that I made viable a few months ago.

It’s not complicated: the studio computer monitors are on a post, mounted to the edge of the desk. It’s been fine. But when the monitors are rotated to face the new engineering location, it tilts a bit, and I’ve been thinking maybe it was tilting more lately. The edge of the desk is sturdy and there’s no damage that I can tell, but there is a gap between the overhang the clamp attaches to and the side of the desk, and what’s happening is that it’s flexing, and over time, it will break.

So the obvious solution is to get some wood to fill the gap. Then the edge won’t be able to flex, and the monitor post will stay straight up.

The funny thing was when I measured the gap, it was just under an inch. That’s a very annoying number for a variety of reasons, but I was like, well, whatever, I’ll sand something down.

And I went down to the shop to find some wood and was poking around seeking something close, when I noticed some old fake-wood recycled-plastic decking samples that I’d got and not used for anything, and when I measured them, they were 25mm exactly – just under an inch.

And measuring it in metric and getting 25mm exactly is what made me realise that it was one metric inch. (TL;DR – it was an old USSR standard for converting stolen technology, particularly computer technology, to make the math easier in conversion to metric. Instead of 25.4mm/inch, it was 25.0mm/inch exactly.)

So I sanded down a bit of the faux woodgrain (not included in the 25mm measurement) and checked the desk again and the gap was, in fact, 25mm, and with a little tapping with a hammer, the fill block I cut fits perfectly.

The post no longer leans, and I now have had a real-life encounter with that historic oddity, the metric inch.

That’s a checkbox item I didn’t even know was on the list and didn’t really need to be checked, but goddamn if I haven’t checked it. Go me. I guess.

more adventures in computing

So, my digital audio workstation. The hub of any small/personal recording studio, the thing what lets you record and multitrack and all that.

I built this machine into an absolutely antique Compaq case, right? It was originally for an HP Compaq Presario SR1010NX, though nothing inside the case is original anymore. I used it because it was what I had and I had zero moneys when I started building this monster, and the studio as a whole. And the front panel USB ports and audio ports haven’t been working for a while.

Part of that has been the nature of the build. The front-panel audio hasn’t worked since I built it; the front-panel USB ports did work, until – for reasons I’ve discussed extensively in the past – I needed to disable the on-motherboard USB, and go with a higher-performance/different-chipset USB card.

I tried connecting one of the front USBs to an internal header on the card, got no result, ran a USB extension cable to the front, and didn’t bother digging further. Similarly, I’m not using the onboard audio for any actual work, so I’ve never bothered addressing that, either, except to run a 3.5mm microphone lead extension cable to the front, similar to the USB port.

And it stayed that way until last night, when I pulled the box out to install a long-cabled USB hub so I could have more than one front-facing port, and was reminded of exactly what a clusterfuck the cabling was back there. The rest of my studio’s cable management is quite tidy, really, but… behind the tower… wow, yeah, no. And when I pushed the machine back in place, I’d lost a monitor and my trackball to cable disconnects.

I’d also recently found a fanless Nvidia 1030 chipset card, which makes gaming on this machine… not an excellent experience, but a functional one. That means getting to more than one USB port started to matter – hence, the new USB hub.

And so, between all that, enough was enough. So I went at fixing the cable mess, got re-annoyed at all those extension cables thanks to 1) that’s just fugly and 2) that’s more cables, and decided I’d just do my damnedest to fix everything.

Cleaning up the cables was – well, tedious, but it let me position a sound baffle better, and that’s always nice. No more cables popping out when I slide the machine around. Problem one sorted.

After digging up more old documentation, I was finally able to get one (1) of the front-panel in-case USB ports going, off an internal header on the card. It turned out there were four(!) ways you could get this silently wrong, and I got it wrong in one of them. Now the upper built-in front port works fine, and – even better – is a true root device.

The second front-facing USB case port, I covered in electrical tape in a way that makes it effectively invisible, which is perfect. And the aforementioned new USB hub – which I plugged into the card, in back – is also up front, and looks much better than a straggly cable connected to the front of the case with endlessly-sticky velcro.

endlessly sticky velcro is just… ugh. i hate it so much.

Then, I figured out – with yet more ancient documentation pulled from websites – what the bloody hell was happening with the front audio panel.

So get this: this Compaq case, which shipped in the late 2000s, shipped with a front-facing audio header that used the AC97 header standard. That’s a standard from 1997, a.k.a. the previous century. They did that instead of using the HD Audio spec.

My motherboard, of course, uses the HD Audio spec.

So it’s utterly unsurprising that it never worked. The two are different, even thought the internal connectors are identical!

so mad. But!

There is a hax to deal with literally this, and if you dig enough, you can find it. It’s not even complicated – it’s a single registry edit in Windows 10, basically telling it to ignore the plug detection system because AC97 didn’t have that. But first, you have to figure out what the hell is going on, and that’s not so easy, because nothing in software will tell you what’s happening.

And I set it, now the front panel just works. It’s there, it’s active, and you can use it. Or, well, I can.

Very little of this matters, like, at all, for this machine’s primary uses. I don’t use the onboard audio for anything, really – though that’s changing now that I’ve got some Windows 10-based synth emulators, but even then, the onboard sound would be only for previews, and any music made will be straight to WAV files and imported over into the Linux DAW, never touching the onboard card. Because ugh.

But it’ll sure make BASHY BASHY easier in PC Overwatch, particularly with Overwatch’s weird issues talking to my microphone. I can just plug into the front panel and bypass the problem entirely.

And I think we all know that’s what really matters. (⌒▽⌒)

what even is this

Let’s talk about wifi.

Let’s talk about the wifi in the recording studio.

Historically, I haven’t cared very much about the wifi in my studio. I don’t need it for much. I have a network connection, but it’s always been stupid and kind of broken. Part of that is not being able to put a wifi driver in a low-latency kernel without issues, so instead of a wifi card, I use a corded card and run to a wifi bridge. This shouldn’t be an issue.

The key word being “shouldn’t.”

I have discussed before how completely fucked this building is, on so many levels, when it comes to RF. I have talked about picking up FM radio on house wiring. I have talked about the many ways I have tried – eventually, with reasonable success – to get decent wifi working here at all.

I haven’t talked about the utter shitstorm and freakshow which is the studio space.

Here’s where I’ve historically put my little wifi bridge. (Well, this was after pulling it up for reasons, but basically here. A few centimetres from here.)

I get 0-300KBPS here. That’s garbage. The zero part, particularly. It’s fast enough, as long as you don’t try to move too much data, at which point it throws its hands in the air and surrenders, dropping to zero, where it stays for a while until it rests up and feels like having another go. When I didn’t actually have to use networking for much, that didn’t matter, and I moved large things around by putting them on USB keys and going to my laptop in another room.

That’s no longer quite as viable, with all the Intel CCS foolishness, and running multiple OSes, some of which like their network very much, thank you, and even kind of require it.

(And since I finally got a better graphics card, playing networked games needed some help, too.)

So, while running a very large file transfer that couldn’t be done with sneakernet and was going to take about a week to complete, I started fucking with it. First thing I did was pull the cords out of the baseboard (see above photo) and toss it to the side while I pulled some other wires.

This is when I noticed transfer went from about 80KBPS to 1.3MBPS. Instantly.

It still swung around a lot, but it stayed in a wide band of, oh, 500KBPS to 1.3MBPS as long as it sat there, which is to say, kind of near the door, in the centre of the walkway. And then it’d drop to zero for a while to rest up, but not often, and even with that, everything became dramatically better.

So I pulled cables around more so I could move the bridge a bit and see if I could get something more reasonable that was not in the worst possible place in the room, like, say, over by the couch, less than a metre away.

No.

Okay. How about over by the wall to the left of the door? Let’s test it by…

…no. I see.

I tried a lot of other places. None of them were better. Many were worse. Some much worse.

So let’s recap, shall we?

You can draw a bigger circle around that golden spot and you get basically the same numbers. It got worse moved further away. And those were the best places, other than the original, the Golden Spot, and one place partly down the hall which wouldn’t actually work out.

I have more than one of these bridges, of course. Swapping bridges did not help. Neither did swapping out cables, or power cords. All behaved exactly the same way, and all of these results were eminently duplicable.

So I got a really long pair of cables and ran the bridge to the other side of the couch, across the room, just to see what would happen.

what. the. fuck.

Mind you, that’s a second Golden Spot. I can move it round there and get worse numbers again, but they’re all dramatically better than the original spot or anywhere near it. In no cases do I get the kind of garbage I was getting on the other side of the room. But I could find – within half a metre – consistent 500-700KBPS, 1.5MBPS(ish), and so on. This was solid transmission numbers without data flooding issues (no buggering off for breaks), with very low packet loss rates. Still more packet loss than there should be, but it’s low enough you don’t really notice.

(Before you ask: this is further from the wifi hub, which is one floor below.)

So.

I kind of have this sorted. Heavy traffic no longer shuts down the connection, and ping times are sane – good, even, a mere 1-5ms to local servers, usually 1-3ms.

But

come

on.

Who designed this place, Ivo Shandor?

found speakers, improving same

I got a pair of abandonware speakers, so I’m making them better. They’re going to end up as another musician’s monitors – I can’t make them true reference, but I can make them a lot closer – and better – pretty cheaply, basically by adding a tiny dome tweeter and a crossover circuit.

I ran a frequency sweep through the factory stock speaker (one on the left is still factory) and found that the single driver started dropping off pretty naturally at around 6000hz, so set the crossover there, first. That didn’t sound quite right so I moved it down to 5000hz so it wouldn’t have to strain, and that was much better.

(For the geeky: single-stage crossover, 7.8uF film cap on the tweeter, .27uH inductor for the primary driver. Sound is… it reminds me of an upgraded Minimus 7, with more low end.)

This is just a phone recording, so don’t expect much – it’s real light on bass, it recorded some, but not much of it, and not well – but still, it’s a before and after and at least gives you some idea about how much these things opened up.

Recording starts with “before” (factory stock) and after several seconds swithces to “after” (added tweeter and crossover circuit), then proceeds to alternate between the two.

wow it’s been a while since I posted here

Hiya!

Wow, it’s been a while since I’ve posted here, hasn’t it? Well, it’s been that kind of year. I warned everyone that the band blog would get a lot more political, but instead, I haven’t even had time to write political posts. Take political actions, yes. (And also, write a lot of short fiction about assassins. One takes one’s stress relief where one finds it.)

But posts? No. And this isn’t one, either. This is about music stuff!

When I was Festival Mémoire et Racines in Quebec this year, I picked up a cute little noisemaker. It reminds me a little of a kokiriko, but much simpler and smaller, and played very differently. But it was radically underengineered, and the two small dowels used as spacers between clackers were absolutely not going to last – one even broke before I could get it back home.

Which is where attoparsec comes in. Matthew said he could totally make replacements out of brass for me, and that he’d actually kind of enjoy doing such a simple project to unreasonably unnecessary degrees of precision.

To wit:

Looks great, doesn’t it? The metal bits make it look so much more like an actual non-toy effects toy, rather than the Can$10 bit of fluff it is.

So… yeah! Not something I made or even fixed but something which someone fixed for me. Yay! Thanks. ^_^

hey linux networking peeps

I’m finally getting back to working on a new gateway/router server and I’m basically setting up this old-school sort of DMZ, with the rest of our servers hanging off one card, and our internal LAN/DHCP/NAT side hanging off the other. (Using ISC, which Debian seems to like.) And all of that seems to be right from the new server’s perspective, which is yay!

Except there’s no packet forwarding from the DHCP side even though it’s enabled and I’m sure I enabled it and yes the kernel thinks its enabled but it isn’t happening.

Any ideas where to start?

show this thursday!

I’m playing with Leannan Sidhe and we’re doing some of my material this Thursday at Shoreline Community College. We’re the 1pm band at SunFest 2017, at the Rock River outdoor theatre, on campus, near Building 1600.

While this is largely a campus event, there is bus service (331 from North King County, the 5 from the south, also… something like the 342 from Northgate?), and also visitor parking on the south side of campus, which it’s not expensive, and some street parking, which is free if you can get it.

Hope to see some of you there!

it’s the latest issue!

I’ve updated the Kitting Out Cheap guide to building your home recording environment on a low budget. New additions include short commentary on kit microphones, updated interface information, and pointing out that hey, guess what – USB chipsets matter!

So, hiya, Home Recording panel attendees – here y’go!

Project Kohaku A-B-C

I made another thing! A magnetic (electric) Irish bouzouki pickup, the kind used on electric guitars, but with some extra features. I retconned a project name for it (Kohaku A-B-C) because it has three primary modes – “single coil,” “humbucker,” and “electric/acoustic mix,” which to be honest is kind of two modes depending upon the single coil vs. humbucker setting, but Kohaku A-B-C-D is too long and didn’t sound enough like a JDF anti-Godzilla plan.

Sounds!

Originally I was just going to do a basic wire-up with a level knob, but then I found out that humbucker pickups gave you separate access to both coils, and so can be used as a single-coil pickup as well as in humbucker mode. So that meant adding a switch. Which means it’s probably worth doing a tone knob while I’m at it. And while I was thinking about that I realised there was no reason I couldn’t also build in a tap to the extant acoustic pickup, which means I should also add a little mixer to control relative levels of the two pickups.

So I did! That was a good idea.

The two red knobs are the mini-mixer for the electric (left) and acoustic (right) pickups. Infinite relative levels! Or close enough. The two big black knobs are combined output level (left) and tone (right), the little switch is tone disable switch, the bigger switch changes the pickup mode – humbucker or single-coil.

I’ve had a bunch of those black rocker switches for a while, but I rarely use them because you need to cut a fairly precise rectangle for them to snap in correctly – there’s no screws or anything. Hearing that [CLICK] when you do it right and it pops into place and is straight and not loose at all or anything is so satisfying.

The pickup is held in place in the soundhole basically by foam and friction. Here’s the first test sitting, after I’d added the high-density foam to the pickup itself:

That was almost enough by itself, but not quite. I ended up adding a backplane and some spacer elements, as it had a tendency to rotate in place without those. The hot glue is mostly there to be cable stress relief:

The project box is an old Radio Shack room monitor transmitter – basically, a baby monitor. I don’t remember how I got it or anything. Regardless, I tested it a few years ago and it’d gone bad, so I gutted it and kept the cases for projects. I think it cleaned up well!

I can’t find a picture of a truly unmodified example, but I did find a decent picture with this mod where that modder kept the words “REALISTIC” and “FM WIRELESS ROOM MONITOR” on the box. I’d wanted to keep the REALISTIC logo, too, but I couldn’t – the knobs wouldn’t stay in place flat with the word still there, so I scraped it off with an xacto knife.

I did keep the big TRANSMITTER label though. That seemed important.

Here’s that little rectangular switch. [CLICK] into place. So satisfying. Looks factory. ♥

Here are the large-block components in place, without the wiring, and also without the tone knob bypass switch which was actually a later addition. (One that turned out unnecessary – 800K resistance and infinite resistance are pretty much the same as far as this tone circuit goes.)

The circuit itself is very simple. The larger switch controls which lead from the pickup (humbucker or single-coil) is fed into the electric pickup side of the mixer. The two mixer knobs are just straight-up variable resistance pots, as is the combined-output level control. The tone knob is based on the 1950s-1960s Les Paul-style electric guitar tone knob, only with a smaller capacitor which goes pretty well with the zouk. And the tone-knob enable/disable switch is just a ground lift on the far side of the capacitor and variable resistance pot.

Now I just need to find some way to make the controller stay attached to the face of the zouk (or any part of the zouk really) without making any change to the zouk itself. Maybe a suction cup?

I wasn’t even really thinking about that part when I started this project, past “keep it small so maybe if I want to think about it later, I’ll have the option.”

It almost looks like some kind of foot pedal, doesn’t it? The reason the controls are so large is just so they’re easier to grab without looking. I’m already controlling this thing by feel – if I can come up with some way to attach it, I think it’ll be legitimately viable as a stage device. It’s certainly no fussier than that piezo pickup I made for the octave mandolin, and I’m using that.

So – yeah! Kohaku A-B-C: much more fun than I expected. If you want to make one, Here’s where you can get the pickup bar, the only thing I bought new. The pots are all 1M variable-resistance linear pots, the single coil/humbucker switch is type SPDT and should be pretty clean since the signal goes through it, the capacitor is… 14nF film cap, because I had it and it was handy, and the tone bypass switch isn’t worth doing but if you want to regardless just use anything that’ll let you connect a wire to ground – it’s not in the signal path so you don’t have to worry about quality. The knobs were from the Radio Shack bankruptcy sale at 90% off, and since they’re going through another round of that now, maybe you can get some 90% off too. Or just use the metal posts for an industrial look, it’s not like you need the knobs.

As always, higher-resolution pictures are on Flickr. Have fun, and if you build it, let me know! ^_^

a user interface question

In an audio device with a tone knob, and an on/off switch by that tone knob, which “ON” makes more UI sense?

[poll id=”29″]

This is an honest question. I mean, I’m going to wire it up so that “ON” means “tone knob on,” because that’s how I roll, but I see this go the other way a lot.

(Also in this case “tone knob” means “low pass filter” which means “removes high frequencies” because AND THERE YOU GO. See? SEE?)

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