not just a display piece

Laying down timing tracks for the new album, finally. I did four and a half tracks yesterday – this is a quick process. None of these recordings will make it onto the final, but it’s a helpful step.

For the moment, the new microphone is living as a display piece in the corner of the room, on the shelf with all the other microphones. Every time I see it, I consider more places I might actually use it on this album. XD

This whole thing got started by looking up how to fake bullhorn vocals, like I needed for the new single, Pee Police (on Bandcamp, YouTube, and Soundcloud). Universally, people said the best way to do it was use a real bullhorn. I mean yes, I’d wanted to build a carbon microphone for a long time. But in terms of actually doing it, this was the prompt.

If you want a specific sound made by a specific thing, the best way to do it is have that thing. $19 in parts later, I have it!

“Starship on Fire” is so far the most likely track to get some carbon mic vocals in the mix. Since it’s told – sung? – from two different viewpoints at once (past character, present character implied), one of those viewpoints having this kind of effect makes storytelling sense. I will at very least try it, and see how it sounds.

I’m going to use the Korra On the Air icon for all the LJ and Dreamwidth crossposts that mention this microphone forever, aren’t I? Yes. Yes, I am.

It’s a long weekend for a lot of people reading this, so – yay! Go have some fun.

a mic of constant sorrow part iv: once upon a time in a catalogue

The last parts for the carbon microphone arrived yesterday! And once I got back to the Lair, I set about adding them to the circuit and building out the final version. Here’s a quick sample recording I’ll talk about more later.

I’m starting with the previously-discussed circuit, now taken out of the test harness and reassembled on one of the small breadboards. The new isolation transformer on the left – basically the outputs of the original circuit are attached to one side, and new outputs picked up off the other. This serves two purposes: first, it eliminates some kinds of hum noise if they start to crop up, and second, combined with 2K of resistance on the other side, brings the line-level(ish) output down to microphone level.

(These are standards which matter in a studio and … not many other places. XD )

The zig-zag in the resistors doesn’t serve any function purpose other than fitting into a smaller space – ideally, I guess I wouldn’t’ve been making needed values out of collections of other values? But I had what I had.

Signal flow is right to left in this photo. Underneath, at the top and bottom of the board, I’ve built wire rails to connect the components. That probably means I’m not really using the breadboard entirely as intended? I don’t even know. It holds everything in place and that’s definitely what I intended. XD

To house all this, I’m using an “experimenter’s case,” which is basically old-radio-speak for a metal box. XD It has soft metal on two sides, easily drillable and workable, and a hard case. I’m using one side for input, the power lamp, and the on/off switch; the other side is for output, or, as it turned out, outputs.

The carbon element (in the can) is connected to the driver/amplifier circuit via a 1/4″ TRS phone jack – like an old large headphone jack – with the two leads to the carbon element being on tip and ring, and the shielding ground being on the sleeve. (Tip, Ring, Sleeve: T R S.) That socket is on the left in the above photo; the middle component is a small LED, to indicate power on/off, and the right is a BIG CHUNKY POWER SWITCH. I love big chunky power switches. CHONK

For output, I quickly realised that I could have both balanced XLR output at microphone level, and line-level output on a phone plug, if I could find a way to isolate the chassis ground from the phone socket’s sleeve connector.

Normally, both being grounds on the same circuit, they’re connected automatically. Finding one that isn’t already connected is actively difficult! But careful use of electric tape did the job; I drilled the mounting hole larger than it needed to be, and basically lined anyplace the case and the socket would touch. Isolation achieved!

If you look for the blue and white wires, you can see where the TS (mono) phone plug is tapping the raw (line-level) amplified mic signal, just before it’s fed into the isolation transformer.

The transformer is really pretty optional – powered carbon circuit signals are pretty high as microphone signals go, and as I mentioned above, we’re actually reducing that signal to create the balanced XLR output on the other side of the transformer. But it’s nice to have the option of using line level, since it already exists. That’s what built-in sound inputs like on your laptop want, too, so there’s a point to it.

And here’s the whole driver/amplifier circuit, with a battery holder made of velcro.

Is that cheating? Holding the battery down with velcro, I mean. totally cheating I’m hoping it works out – I didn’t have a 9v battery case and it seemed excessive to try ordering one.

That LED power indicator? It’s warm white, left over from another project. I was planning on putting in your typical red LED, but realised that if they’d had a power indicator on one of these in 1932 or whenever, it most certainly would’ve been a little incandescent bulb, and it may and may not have had a colour lens. So I went with warm white, because period accuracy! Sort of.

The neat thing about the way this circuit works – and all carbon microphone driver circuits work – is how it points you right at vacuum tubes, and from there transistors, conceptually. It really, really does.

See, in tubes and transistors – which are both signal amplifiers – the input signal is used to create an amplified copy by controlling how much raw input power is let through, from another source. That’s why tubes were called “valves” originally; it’s because they are valves, electrically controlled, and regulating the flow of electricity from an input, just like the valve on your faucet controls the flow of water from the plumbing.

In this case, exactly the same thing happens yet again. But the input signal is sound pressure (how loud the sound is), which is controlling how much electricity is let through from the battery. And those changes in sound pressure – and therefore electrical flow – make the electrical copy of the sound waves.

Neat, huh?

Anyway, that’s the inside. Let’s look at the case!

I really like how chunky and primitive it looks. This is an old experimenter’s case; I’ve had a box of random cases in which I can build things for a while, and I don’t even know where I got this one, or when. If you saw it on the set of a 1950s television SF show, nobody would give it a second glance.

Always document your builds! You never know what might confuse people later. And by people, I mean yourself, after you’ve come down from the science-related memetic disorder high. I want at least the theoretical possibility of using this amp with other carbon elements, so writing down how the interface works is pretty important!

Except for the glare from the power light, I think this would be the Radio Shack Catalogue photo from, say, 1975:


Good, Better, or Best? Probably “Good.” It is just carbon, after all!


Or maybe this is the catalogue shot? Not sure.

Finally, here’s a test recording I made, using both outputs (phone/line level and XLR/balanced mic level) at once, hooked up to two different inputs on my board. I put both recordings in the same mp3; one’s on the left channel, the other’s on the right. The two tracks should be pretty much identical – being the same signal picked up at two different places on the board – and I wanted to see if that actually happened. Fortunately, it did!

Well, eventually it did. This is actually the second time I tried this, because the first time, I discovered that I’d managed to wire the two outputs up as electrical inverses of each other. Playing the two tracks back at the same time resulted in massive waveform cancellation. Which was hilarious, but also a good indicator; they wouldn’t’ve cancelled so well if they weren’t really similar. 😀


EXTREME WAVEFORM CLOSEUP

So that’s about it for this project! I’ll most likely do something to the ring to control the elastic better. And I’ll probably build a case for the whole kit, like I’ve done before – mics should have cases for protection! – but that’s a separate project.

This has been such a fun build, you have no idea. If you have any interest in this kind of DIY audio, I totally recommend this as a fun, easy project. Particularly if you don’t have studio gear, because you can look up the line level part of the output to damn near anything (including a PA system, I might mention) and it’ll work.

As always, more and bigger pictures on my Flickr account. And if you’re out of work, that’s a great time to listen to the new (NSFW lyrics) single! It’s awesome.

understanding something better now

For a long time, there was a… conceit, of sorts, in science fiction, of connecting simple large objects in such a way that produced inexplicable complexity. The sort of thing where the characters would put five or six pieces together, and suddenly have a walking, talking robot.

It never made the least bit of sense, either in reality or to me personally, but that latter is changing. As I’ve been playing around with this carbon microphone (here’s a new test recording from yesterday, using the improved circuit) and along the way reading about things like the early telephone system and early radio and most of all the telegraph – I really start to see how they get there.

Particularly early radio, and even more particularly the telegraph.

The telegraph, I mean, damn. They ran one wire. Not a pair of wires: one. They relied on local grounding at each station; the ‘return’ for the power supply was the planet.

So look at this from a not-really-that-naive point of view, right? You’re a farmer out in the middle of Saskatchewan or something, right? It’s weeks to anywhere. You go into town for your mail every couple of weeks, the nearest neighbour is a mile or two or three away, a big gathering in town is monthly market day. You’re not stupid; you deal with complex machinery pretty regularly as a farmer. You know how this works; you know clocks, you know how complex machines have to be to do even simple things well, you know how they work and now to fix them and how to adapt them to new tasks.

Now take this metal rope, attach it to a bit of wound-up metal thread and a lever and a spring, and suddenly you can talk to Vancouver. Sure, you need to learn a code, but that’s easy, and suddenly there’s impossible spooky action at a distance – a really big distance.

Then there’s radio. Even crazier. Take another metal rope, and another bit of wound-up metal thread, and a tiny bit of inexpensive crystal, and this thing you put in your ear that you ordered by post (which is not more than a magnet and some more metal thread and a piece of paper) and suddenly you have news from Toronto in your house.

To the observer at the time, it is intense complexity from small numbers of simple parts. Sure, most of the complexity comes from the humans at the far end of each connection, but it’d take a good bit of sorting out to get that really parsed, and in the meantime, the reaction is more along the lines of:

     What magical fuckery is this?!

Suddenly the whole “small numbers of simple objects producing combinations of intense complexity” makes a lot more sense. They’d seen it multiple times in their lives, so… let’s make a robot with eight vacuum tubes, a motor, and a bunch of metal tubes? SURE, WHO EVEN KNOWS – THAT OTHER SHIT WORKED, WHY NOT THIS? How is an empty metal tube supposed to do anything? I dunno, I didn’t expect this metal rope to do anything either, but now it’s 8pm and dark since 4pm and I’m snowed in on the cold cold plains in January, and before going to bed I’m listening to a jazz band playing right now in the Savoy Hotel in New York City.

Impossible madness, from small numbers of simple parts.

Really, if anything, it’s surprising those decades weren’t even goofier.

anna won’t let me play this either

I have a song I call “Missing Home Row,” which is Great Big Sea’s “Goin’ Up” but all the chords – none of which are bar chords – played one fret too high.

The effect is remarkably similar to this:

mmmmmmmmmmmmmm musical supervillainy mmmmmmmmmmmmmm

building the “can” – the carbon element mount

My carbon microphone is actually in a can now! I’m super happy with it, and yes, it works, even if most of the circuit is still in a test harness. The can itself does not contain anything important in the way of circuitry, though it does contain quite a bit of grounded shielding which is very important, and that shielding is carried forward out the cable, which is a TRS phone plug.

I made the decision to put the support circuitry in a separate box for a couple of reasons. First, the signal level is pretty high, so a decently-shielded cable should prevent most issues from being actual issues. Second, the support circuitry for these things tended to be external in the originals, so it’s period-accurate. Third, opening the can to replace a battery every 15 hours of use or so was going to be annoying; much easier to do it an an external experimenter’s cabinet.

And yeah, one of the downsides of this mic is the high power consumption. I thought about trying to tap phantom power, but from what I can tell reading up on it, the amount of power actually supplied – voltage aside – is dramatically lower than a battery’s supply and is not well defined, by which I mean is not defined, so… yeah. Batteries it is.

Anyway! I decided to make it look like a vintage carbon-element microphone of its era, only using elastic instead of springs. Springs look cool, but they’re also noisy as hell and create other issues, and it’s easy to tell that they would’ve used elastic if they’d had it just by how quickly they changed to using elastics as soon as they had elastics to use.

BUT SOLARBIRD, HOW DID YOU DO IT?

Well, first, let’s ask the eternal question: ah, junk shop, is there any build problem you can’t solve?


No. No, there is not.

If you’re wondering, that’s a vaguely-20s-looking kind of drink can holder in the middle, and I believe a hand towel holder designed to hang from the top of a door.

My only worry was whether the towel ring assembly was just screwed into the plate, or bolted to it; most excellently, it turned out to have been attached with a screw. So I just separated the ring from the existing base, sanded the attachment point down a bit to make it nice and flat, and attached it to a small metal L, using a rubber plumbing washer to make up the extra space.

Attaching to a standard microphone stand attachment is just as easy; unscrew one of those infinite number of cheap mic clips that are floating around every studio ever, toss the bit that holds the mic, drill out the hole in the L metal to be large enough, and pad with more plumbing washers.


Result!

Now the ring is ready to attach to any standard microphone stand.

Now, the can itself was a little more of a trick. This is all mechanical construction, not circuitry, since all that will be in an external box. But! There is some electrics, because given my particular… affinity… with RF (and radiating it, hi, it’s solarbird for a reason), I wanted a good heavily-shielded pickup enclosure.

Did you know you can buy adhesive tape made of copper? With conductive adhesive? It’s made exactly for this purpose. I love it. I started by lining the back, and peeling excess up the sides a bit intentionally. You want a good amount of overlap with this tape.

Lining the sides involves another ring of copper metal tape, with – again – overlapping tabs made of the excess height. Getting the height right is really simple – just put the tape in and cut inwards, using any common scissors – this may be metal tape, but it’s pretty thin, and no special tools are required.

After I took that photo, I realised I needed smaller tabs, so I went through and made another set of cuts, halfway between each existing cut.

Once you’ve fiddled around with it a bit, you’ll end up with something that looks like this:

Make sure the copper is well rubbed down against each other, so the conductive adhesive can really carry current without adding any resistance. Again, no special tools, a fingernail is fine – but make sure it’s well stuck down.

You might also notice in that photo, a small black line – I broke the tape, and fixed it with just a small piece to cover the gap. As long as you have well-connected metal throughout, you’ll be fine. We’re talking very low power with RF noise, in most circumstances, so you don’t have to worry about carrying power or anything like that.

Unless you have a tesla coil, maybe. That’s different.

Now, I also needed a grill for the microphone, and – importantly – it had to be a conductive grill, because I need that RF blocking all around the carbon element. I know, I know, some of you are going, “it’s a carbon element how are you doing anything to it?!” and all I can say is I have recordings and I have to ground myself with a wrist strap if I’m using AKG microphones, and again, supervillain.

Fortunately, a material that serves this purpose quite well is common and cheap: aluminium window screening! I’m kind of annoyed with myself, because I threw away a bunch two weeks ago – used but still clean and good – because I had no thoughts I’d need it. What was wrong with me? I can’t even tell you. Moods. So I had to stealbuy some. Fortunately, it’s pretty much dirt cheap.

I got a ring of heavy flexible rubberised foam to make a structural ring, and measured the right size just by pushing the screening into the bottom of the can until I had good edges. Since it is window screening, it has a lot of room to compress, and that helped. You want that excess screening material, for reasons which should be obvious momentarily.

In the above photo, I’ve sized the screening material, and am getting ready to make a ring of copper tape to surround both the inner and outer layers of the support ring. This is partly structural – you can see that my support ring is not a single loop, but a bent straight piece – and partly to help make sure of good, solid contact between the metal screening, through copper tape, to the interior copper shielding of the can. Make this part a little too large, if anything, and you end up with a solid pressure-contact connection.


Swaaaaank

Holding the carbon element in place is also a job for foam. In this case, I have some high-density impact-absorbing foam left over from my case making projects earlier, so I just used that. It can be a very rough cut, as long as it’s just a tad bigger than the ring it’s going into. It’ll compress, and that provides a little more outward pressure to make the grounding contact between the grille and the interior shielding better.

You’ll also note inside the can, against the back, I’ve placed a spacer ring. This keeps the grille’s support ring from going too far into the can; it’s just a physical element, since you want the carbon element nice and forward, and not sinking into the can where sound would get echoey.

What you can’t see is an important step I … didn’t remember to photograph. Sorry! And that’s drilling a hole for the cable. The cable is three-conductor; two signal leads (which connect to the two contact points of the carbon element) and one shield ground. The shield ground gets soldered directly to the copper tape, which is why you use copper metal tape instead of some other metal. This is a little tricker than you might expect, mechanically; I had to use higher temperature on the soldering iron. I think it mostly has to do with soldering wire (physically complex, wicks well) to a flat surface (physically simple, does not wick well). Just take that part as read.


[Win95TADA.wav]

Some of you might be looking at this picture and going, “…wait. The carbon element is right up against the grill. It’s touching, and metal, and isn’t that a problem?”

Well spotted, you! It would indeed be a problem! I solved it by cutting out a couple more layers of plastic window screening – also left from another project – to provide an insulation barrier between the metal screening and the actual pickup element. If you don’t have any of that, hosary would do fine – the same material used in pop filters. Acoustic transparency is important here, of course, but to be frank – less so than usual.

“That’s not like you.” Yes. But think about it, I mean, what’s a telephone use? Oh yeah, THICK PLASTIC WITH SOME HOLES IN. Does it hurt the sound? NOT VERY MUCH, because it’s a carbon element with a range of around 300hz to 3500hz, maybe. So you can afford some loss in the high end, because what you don’t lose, the mic will lose for you. And this screen material is plenty acoustically transparent for these circumstances. So would be hosary, or the right foam, or all sorts of other things. Just, you know, use good judgement.

Anyway, the build stuck on hold – ON HOLD! HA! – for a couple of days as I wait for the 600ohm isolation transformers to arrive. They aren’t essential, necessarily, but do reduce RF noise and hum in some circumstances, so I’m going to use one. I’ll post more when I’ve got more done. I’m really pleased with how it’s coming along; this is fun.

Bigger pictures on Flickr, as usual.

ps: People were asking for a sound sample. This is from the test harness, before I built the ‘can.’ New recording sample next time.

a waveform sung into a can

I have a waveform! I did a bunch of testing of various parts and such, discovering that the carbon transmitter (microphone) I had was indeed fully functional, and really, it came down to “not enough voltage.” 1.5v is pretty borderline for carbon microphone power, so that’s fine.

The waveform is kind of lopsided, but that’s because this test harness doesn’t have the balanced output yet; I’ve ordered the balanced transformer, and that should help. It’s also a bit noisy – here’s a sample – which is partly related to SHIELDING WHAT IS SHIELDING because it’s a test harness.

Talking of, here’s what version one looked like:

This is a direct implementation of the first half of the circuit described in this instructable, which runs off a 9V battery. Once the rest of the circuit is added, it’ll have balanced output, which is pretty snazzy.

This is a closer view, and also after I added an LED, because hey, LEDs!

After that, I tried a smaller capacitor, and that’s working fine – mostly, I’m just picking from what I’ve got, which goes along with what the circuit designer described.

I’m going to play more with the circuit a bit, pending getting the matching transformer. And some shielding.

And, of course, the can. 😀

ps: this harmonica “bullet mic” looks pretty cool too.

a mic of constant sorrow

I’ve been trying to build a carbon microphone. Why? Well, partly, because I can, and partly, because if you want that “telephone” sort of sound, the best way to do it is to use a telephone element rather than fake it later (see also: BULLHORN), and partly because I want to be able to sing into a can, like them fellers at the radio station.


A Microphone of Constant Sorrow

And this should be – electrically, at least – very simple. Small power supply – battery is fine – resistor or two, capacitor. Done. Very simple circuit.

But it isn’t working, and I have absolutely no idea why, and I’m highly frustrated. I’m going to try a higher-voltage circuit, which I’ve been avoiding for no good reason other than it shouldn’t help, but I’m starting to think the carbon element I got new-old-stock off eBay isn’t up to snuff.

Anybody else built one of these monsters before? I have actually managed to get extremely-low-volume recordings out of it a couple of times – far too low level to be useful, I’m afraid – so I don’t think the element is actually dead. But honestly, I have no idea.

eta: GUESS WHO HAS A WAVEFORM 😀


A WAV of Constant Sorrow

the new single has lyrics

I was asked to post the lyrics to the new single (Bandcamp, YouTube, Soundcloud), so sure, I can do that!

The copyright says Crime and the Forces of Evil, of course, but this is very much what I think of as a Mary Kaye and the Cosmetics song – my all-girl hardcore punk band that plays exclusively Hello Kitty-branded instruments. And I would love to play a MKatC gig, but so far, really, that’s mostly My Girlfriend, Sad Muppet, Get Out, and this. We almost have enough music for a 20-minute mini-set, though!

Anyway, enjoy:

Pee Police
2016 Crime and the Forces of Evil
ALL CAPS is CRUISE CONTROL for BULLHORN

What the fuck do you think you’re wearing
Why do you think you have the right
You fucking dykes better get with the programme
or there’s gonna be a fight because
we’re gonna bring the law down on you
like we always knew we should
And you’re gonna pay if you look at us funny
Oh it really gives us wood that’s right

‘CAUSE WE’RE THE PEE POLICE
PEE POLICE
GET DOWN ON YOUR FUCKING KNEES
‘CAUSE WE’RE THE PEE POLICE
PEE POLICE
UP AGAINST THE STALL

I don’t care what these bitches are saying
I don’t care if you’re a girl
I’m the cop in charge and I know what I’m doing
and your trousers make me burly now
I can finally strut ’round in here and I can
show you who’s in charge
You better sit your ass down and pay attention
while my lumber’s getting large that’s right

‘CAUSE WE’RE THE PEE POLICE
PEE POLICE
GET DOWN ON YOUR FUCKING KNEES
‘CAUSE WE’RE THE PEE POLICE
PEE POLICE
UP AGAINST THE STALL

No ID? Then you get no peeing
as I slam you to the wall
Jesus says it’s time now to give a beating
and I always give the best of all because
you faggots got to learn one thing and that’s
to bow to my command
If my staff of life doesn’t show you Jesus
My rod will show you god firsthand

‘CAUSE WE’RE THE PEE POLICE
PEE POLICE
GET DOWN ON YOUR FUCKING KNEES
‘CAUSE WE’RE THE PEE POLICE
PEE POLICE
FUCK YOUR NEW ID
WE’RE THE PEE POLICE
PEE POLICE
GET DOWN ON YOUR FUCKING KNEES
‘CAUSE WE’RE THE PEE POLICE
PEE POLICE
GET UP AGAINST THE STALL

ANYBODY ELSE FEELIN’ UPPITY?
I DIDN’T THINK SO

RELEASE: Pee Police

Last month, I saw a horrific video going around, that one of a cop slamming a butch lesbian into a wall and out of a washroom for not performing femininity to his satisfaction. And, after I was done shaking with rage, I wrote this song.

It’s very angry, very political music, with an eye towards bitter humour. Klopfenpop called it “Pete Seeger meets Pussy Riot,” and I have to say, I’m pretty happy with that reaction.

That video I mentioned above was the first of a flood of similar incidents being reported after North Carolina rushed through the anti-TLGB (and safety and child labour law repealing – didn’t know that part, did you?) HB2 in a several-hour-long special session.

Sure, these abuses happened before it became this year’s fundamentalist-button-pushing issue. But the people who get off on this have certainly felt emboldened ever since, to the point of this North Carolina school system voting to let people pepper-spray transgendered students. It’s that fucking bad.

Pee Police lyric video on YouTube

There are several such bills going around, in various permutations, all sourced from the same choose-your-own-oppression master bill by a fundamentalist/rightist organisation. The one offered here puts a $2500 bounty on the heads of transgendered children, targeting the most vulnerable in this particularly vicious hate campaign. The legislative version did not make it out of committee, so they are now gathering signatures to put it onto the ballot. They can’t win, but they can wage hate for months and crank up fundamentalist turnout – and, of course, hurt lots and lots of children.

Pee Police on Soundcloud

Hurting people – particularly very vulnerable people, like kids – is the point, of course. That’s how they get off, and just putting all that out there is the whole point of this new song. Well, okay, they also have the goal of boosting fundamentalist voter turnout. It’s always about that, and if people get hurt along the way – well, so much the better. As long as it’s the right people, like women who don’t know their place.

Din of Thieves will be a lot harder-edged than Bone Walker, and this is part of that aesthetic. I’m not making any guesses about the far end of its range – it won’t be a whole album of this kind of four-chord metal-influenced punk, but I feel like I have some things to prove, and that’ll show. How much, I don’t entirely know. It’s all written, and some of it is the most hopeful stuff I’ve ever written – ask anyone who has heard “Supervillain For I Love You” or – most of all – “We’re Not Friends.”

I guess what I’m saying is: this is a pretty emotional song – one I hope is cathartic – and Din of Thieves will be a pretty emotional album. Because it’s… it’s a pretty damn emotional time.

Pee Police on Bandcamp [Explicit lyrics]

Share it around. Particularly where you think it might do some good.

almost ready

Setting up Bandcamp and working on the a lyrics video for Monday’s release while we have a lovely cool, rainy day outside. <3

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