Home of some experimental (and not so experimental) musical effects and electronic instruments. Most are one-offs but there will be small purchasable batches available from time to time.
In a couple senses of the term. Not too many updates last year because of a lot of personal stuff. But I have been busy! Especially in the last couple months!
The Hollow Earth
The new version I mean. It's already been posted about (scroll down). I still don't have a video about it, and it's still not ready for release. There's been *one* problem that's keeping it from being accessible. It's a power issue. In some cases, on some amps/guitar/power combinations, it's extremely noisy. I think it's some sort of ground loop or "virtual ground" problem. It's fine and perfect in many situations, but unusable in others. I'm not very knowledgable when it comes to the physics bhind electronics, grounding issues and whatnot, and this seems to be exactly the problem. The physics of it. Thats why it's taking so long (again). I've gone through about 4 revised PCB prototypes so far, still no dice.
On my own amps, on my own guitars and own power supplies, in the electricity in my home, I have no problems whatsoever. It's been so hard figuring this out. What a headache this design has been!
Vibrato
This is a refresh of that vibrato I made! General improvements, including a wet/dry blend for pseudo-chorus, and a blendable crackle/noise/scratch sim (like vinyl). I'm building 10 of these. Unsure whether I should leave the noise blend in or not.
Here's a video: http://www.youtube.com/watch?v=r7az_xhgJcQ I'm kind of terribad at pedal video demos. The second half is better. That's because I let an ebow do all the work.
Is a glitchy "sampling" mode on the new HE better than no "sampling" mode at all? The intent is to have a mode that records sound input and turns it into an envilope. Here's how I'm doing it so far:
20 sub-samples are taken from the input at 5ms intervals, then averaged. the average becomes the main "sample" that lasts 100ms. this occurs 10 times a second.
so it samples at a total of 200hz. the problem is when I hit a note like low E (82-ish hz), or any note really, that the played note will get pretty close in-phase with my sampling frequency from time to time as it "drifts". because of that, for an entire 100-200 milliseconds, it'll only be sampling the "dips" in-between the sound waves and will average close to 0, even though to our ears the note rings loud and clear. as clear as it was when it was sampling at the peaks of the same waves 300ms earlier! the result is a stuttery glitchy envelope instead of smooth envelope following.
adding circuitry is a last resort (there's barely any room left on the PCB). so far I've tried:
1. adding offsets of 2.5ms every 2 samples to try and average an equal number of wave dips and peaks.
2. only keeping the very highest sample out of 20
3. ignoring sudden drops of envelope if the next one goes right back up again (loss of detail)
Increasing the sampling frequency is difficult at the moment since the whole foundation of the bare-bones design is built around 20 sub-samples per "real" sample, because of the interpolation I'm doing. I think I'll try adding a timer interrupt that samples much more/faster and independantly of the rest of the program.
v2.0 prototype. It works really well! Things left to do on firmware is the sample-from-sound-and-turn-into-LFO mode, a dedicated random mode, and some tweaks to the simple random blend you can add to existing LFOs.
Found the time to (mostly) finish the new prototype this weekend. What's left to be done is ironing out the few glitches and adding a couple modes in software. Specifically:
-menu to assign a function to the soft-stomp. between tap tempo, shape record and manually triggered envelope
-a mode where it samples and makes an lfo/envelope based on input sound. could be pretty rad for drum machine stuff!
-I should probably make an option to invert whatever shape
...oh yeah, and definitely what's my densest/most insane PCB layout. It'll take a few weeks to arrive, though.
..though a bunch of it was copy pasted. I figure I'm about 95% done the new hollow earth, at least programming-wise. Hardware-wise, an AVR dev board, a few rotary encoders, a trimpot, an led and a 5x7 led matrix is all I've been staring at these past few weeks.
Four knobs is probably all you'll need! They're all multi-function. Turn for one thing, hold down and turn for another, tap for another, etc.
A bit of tech info. I'm using an atmega644 uC. It's got 64KB program memory but so far I'm using only 17% of it. I needed the 2KB of eeprom it offered for preset storage. When recording custom LFO shapes, it samples at 10 a second for up to 18 seconds. And then it's interpolated times 20 to smooth it out. Speed is full adjustable while recording and after, obviously. 10sps is plenty for slow human hands, but I'll offer the user to fine tune this in a sort of "preferences" mode.
Let's see, checklist. What's done, and to-do..
(software) -expressive display -hook up PWM output (with freq doubling) -do custom LFO record/playback -x20 interpolation! -speed control -tap-tempo -depth control -random blend -preset saving/loading -square/triangle/ramp/sine/saw hard preset LFOs -shape edit -trigger mode -multimode tap footswitch -preferences/options
clicky encoders are annoying. ordered some non-clicky ones.
with the push-for-secondary-function knobs and the display now offering an expressive level of visual feedback, I've been able to simplify the next hollow earth pedal to just 4 push-knobs and one toggle at the back of the enclosure!
this was a huge priority because it means I can PCB mount everything on a single board this time!
So I got myself a couple tiny 5x7 LED matrix displays to tinker around with. I thought they might be a nice replacement to 7-segment displays. On the new Hollow Earth, I'm using a microcontroller with a greater number of pins, so I think it's doable. Might make for some neat animation, too!
Then my mind caved in at the thought of manually typing binary data for each PIXEL. It's pretty daunting to do by hand, because each LED in the matrix does NOT have its own pin. Instead it's a row and column array where you have to carefully "render" the LEDs, line by line, applying positive power to cathodes where you *don't* want pixels, and so on. Arrrrghhhhhhhhhhhhhhhhhh..........
Too much, I said, so what do I do? I install something I haven't used in like ten years, Visual Basic 4.0.
An hour later, I have made an app where I can draw a number, letter or graphic just by clicking on squares, and then automagically spits out code and/or raw binary data I can simply paste in my micro!
Whatta time saver!
Writing a program that writes code for you. How zen!
I've started a complete Hollow Earth redesign. I really want to see it being sold again and the old design was just so difficult. Being on two PCBs, socketed ribbon cables, wired switches, hacks and tricks giving each build it's own little quirks. I've had enough of all that. The old one was designed when I was just beginning to understand microcontrollers almost two years ago and I've learned a lot since. Time to do it right, this time.
Instead: -single PCB design -everything PCB mounted, except jacks -rotary encoders instead of pots, with double functions (turn does one thing, push and turn does another, or just push, like tapping the speed knob for tap tempo) -less parts (no "shape" stompswitch for one) -in-program interpolation, no more smooth knob -and so on
Probably no more vactrols either. They were a pain to bias properly so that CV-out and the actual tremolo effect played nicely together. Gonna try digital potentiometers instead.
UPDATE: I'm afraid trigger mode will probably go the way of the dodo. It never worked THAT great, and it's one of the major roadblocks in my simplifying.
I've finished a new website for my various musical projects (not really DIY-related). So now instead of pointing people to a myspace, I can just send them to this:
This is something I've been working on (on-and-off) since january or febuary of '10. For DIYers, looping is usually restricted to ISD sound recorder chips. They are neat but don't offer a whole lot of flexibility. I wanted totally random access to individual samples for some pseudo-granular drones so I saw what I could do with microcontrollers. Initially I had started learning dsPICs, but later put it aside and went with what I knew, the 8bit AVR.
I'm using SPI RAM which isn't the fastest solution but I just wanted to see if my ideas could be done. Fidelity was secondary. I went with the ATMEGA328 which is the chip with the most amount of internal RAM in DIP format. I didn't want to use the larger 40-pin DIPs.
I wanted to be able to ping-pong the "playback head" in as little time as a 1ms sample window, define start and end loop points, among other things. That meant quite a bit more code that simple record and playback. Keeping it tight, I still manage up to 12KHz sampling on the 8-bit uC. Considering there's a lot of SPI communication with both RAM chips and the DAC, I don't think that's too bad. Stuff like LED updates and potentiometer sampling only happen around 20 times a second. I use an additional uC (atmega88) on a daughter board for the 16 LEDs. It serves as a 4-to-16 decoder.
On the less technical side, sound-wise it is pretty lofi. It doesn't handle complex recordings well. Stuff like full chords, mixed-down songs, things with a lot of harmonic detail and smooth volume dynamics. Some complex things work, most don't. What it does handle well is individual monophonic instruments (or picking single strings on a guitar), some vocals, cicuit bend noises, and it handles electronic beats really well!
The controls are really counter-intuitive, and for this reason I won't be building these for anybody just yet. There are some bugs and limitations that I have not been able to fix in the weeks and months of work. The problem is that I designed this back-to-front which is a really bad way of doing things. I started building a looper then later tacked on features. It's all duck-taped and bandaided together with tricks and hacks in the code. What I should of done is figure out my features first, then design around that. Because I did the reverse, fixing the bugs and limitations have been so difficult that I'll have to start over if I intend to sell these. Personally I can live with these quirks, but I can't help but think others would be confused.
The next one will be much better!
A list of features/controls, some more technical information and a video below.
- Input gain (with red clipping LED) - Independent Dry and Wet knobs - Record / Playback toggle switch (with purple rec LED) - Hard bypass toggle switch (with orange LED) - Low pass filter - 16 LED "head" position - Speed, sets the samplerate - Start and End realtime sample trimming - Trim drift/gradual offset - Confusion knob which does ping pong stuff to the "head" - Direction knob sets forward or reverse, or glitchy in-between madness!
Main CPU: ATMEGA328 (overclocked to 12mhz at 3.3v) Secondary CPU: ATMEGA88 (for 16 LEDs only) ADC: internal 8bit DAC: external 12bit MCP4921 RAM: two 23k256 ICs LPF: MAX7403 Programmed in BASCOM
$150 US tracked and insured shipping is around $15 to north america. contact me if elsewhere.
Check the blog post down below. Some samples are there. has samplerate reduction, bitcrushing on an 8-position knob, wet/dry blend and volume. good for lo-fi effects, nintendo/atari sounds, weird digital fuzz, glitches, etc. great on synths and drum machines too! does a good job killing fidelity! when turning up the volume and harshness, with the wet/dry knob all the way "dry", it's not totally dry. more like 96% dry. uses 9v DC standard boss-like adapter. not included. Meant as a non-subtle effect but subtle can sort of be dialed in. Full refund if you dont like it (assuming it's in okay condition, and minus shipping). will try and ship before monday.
I'll have three bitcrushers for sale in a few days.
two samples. both tentatively co-titled the-art-of-dicking-around. I have no idea what I'm doing. I've never been good at recording dirt-only stuff, at least without some kind of backing.
they'll officially go on sale sometime on saturday for $150 US each, but only as of when I update this blog on that day saying so. so please no emails ahead of time. when the time comes, you can reach me at:
Things have been lagging due mostly to demotivation re: the hollow earth. That sucker is tough to build, I mean really tough. it's definatelly not dead, though, and as a way to help kick-start things back up again, I'm selling off a batch of bitcrushers/samplerate reducers with wet/dry blend control. it's an easy build I'll have no trouble building a dozen of, and at the same time it'll help refinance the whole hollow earth gig.
So here's the bitcrusher, called the Moth and does 1-8 bit crushing and samplerate reduction. there's wet/dry blending and volume as well. the graphic will change a little. here's a bad clip. I'll do a youtube once things are orginized.
there will be no reservation list for this one. in a bunch of weeks I'll just announce a day they go on sale and that'll be that. $150 a pop.
in semi related news, the kind folk at Audio Effekte have written a kind word on this project of mine, as well as about montreal assembly!
You should check out Scott's stuff (at mtl assembly). he makes rad effects too and his bitcrushers are way more versatile than mine! face-melting boxes galore!
..I'm thinking of doing a small run (10) of simple samplerate reduction pedals to try and kick things back up again. Two knobs (blend and samplerate), simple circuit, etc. 10x easier than the hollow earth and would help fund/re-enthusiate an eventual hollow earth reincarnation.
Little board I made to help me in developping the programmable synth. Seeing how so many things need to be controlled by DACs (for preset recall and automation), made a little 16-channel multiplexer with sample-and-hold.
Still shopping around for a simple 16-bit DAC. most are either SMD, or are I2S (too slow) instead of SPI. And I can't spare the pins for parallel. Eugh...
Part of a long-term project of building a synth. The rough outline is: -3 or 4 oscillators. sine, square, triangle, ramp -2 or 3 LFOs for FM, AM and VCF -1 noise generator -lots of LFO shapes, including "manual" waveshaping -resonant VCF (using SSM2044) -2 ADSRs for amplitude and VCF -programmable delay (based on 2399) -savable patches -real wood enclosure and 2-octave keybed! -some kind of basic arpeggio/sequencer -MIDI-in a big maybe. I haven't looked at MIDI yet
I'm using DSI-type synths (evolver, prophet) as inflluence for the design. Digital control of analog stuff! In the sounds above, I'm using a atmega88 microcontroller to drive an MCP4921 DAC which in turn drives an analog XR2206 function generator. The 12-bit resolution of the DAC gives me a range between 30hz to around 8khz with tolerable drift. The micro has a table of all DAC values for 92 notes. The samples are straight from the oscillator. There's no envelope, filter, LFO or anything. The delay in the first one was added in soundforge for kicks. The "sequencing" is hard-coded in the micro.
The XR2206 is basically a voltage-controlled oscillator with sine/triangle/square outputs, and ramp with a bit of tweaking. It's really simple to use and requires almost no external components!
I'm gonna need a lot of DACs. One for each oscillator, for each LFO/ADSR combo. I intend to do the LFOs and ADSRs in code to make them flexible and as low-part-count as possible! I think I can mix both LFO and ADSR in code and have it use just one DAC.
I'm hoping to make the delay as dynamic as possible! Time and decay modulated by keys and LFOs and whatnot! If I can fit all components for a single "voice" (a dozen chips, I'm guessing) i nsmall-enough space, then I might consider making this a 4-voice synth. The main micro would just have to keep track of which voices are available, and if none are, use the one that was pressed the longest time ago.
I don't know yet if I want to salvage a wooden enclosure from something or just make my own. I haven't done any sort of woodworking since when I was a kid. It's not hard, but I am sort of ill-equipped! I'm not worried for the keybed. Doepfer has some nice OEM ones.
Having major issues with the new batch of PCBs. Can't figure out what it is. If I ever do find out what it is, and if it's serious, then the next batch will be delayed another two months, and a lot of wasted money.
Hi, I am no longer taking orders for the Hollow Earth. I need to get through the current list. This thing has been too much of a time eater, cost and source of stress, and I need to figure out what to do.
4'th revision Hollow Earth PCBs are finally in (7 week wait, ughhh), so I'll get started on builds #12-18 shortly.
fixes include using surface-mount switches instead, some additional noise filtering (not that it was much of a problem before), volume adjustments, and stuff that'll make building them easier for me.
vibrato I built for someone. design similar to the one I made months ago (down the blog) with some improvments/bugfixes.
and yes, still making Hollow Earths. it's just taking time to get through thel ist is all. and yes as of 2010 they will be $275 instead of $200. I underestimated the cost in time and materials when I initially started making them. sorry about that. people on the list have already been informed.
here's a lame-ass demo. I'm playing a discarded umbrella into a TV that's on fire.
It's a bunch of stuff. A bitcrusher, samplerate reducer, a granular sampler/repeater/glitcher, a harsh digital fuzz and noise source. Controls are as follows (left to right):
top: [B]bitdepth[/B]: bitcrush from 8 to 1 bit. things get noisy and ugly and awesome! [B]samplerate[/B]: rate reduction, atari/nintendo-ish sounds, etc [B]tone[/B]: just a big muff tonestack. middle is neutral. right is high boost, left is low boost. [B]blend[/B]: wet-dry blend [B]volume[/B]: makes the pedal vomit kittens
bottom: [B]grain size[/B]: sample size of the granular sampling buffer. [B]grain mod[/B]: modulates the grain sample up or down in pitch [B]glitch 1 and glitch 2[/B]: makes it stutter in different ways. the toggle switch at the top makes the soft-stomp on the right active one or the other of the buttons.
I'm still selling a small handful of these a month, and hopefully I can optimzie production a little to be able to squeeze a few more in that timeframe. Getting through the waitlist, slowly but surely...
I'm building a custom-painted Hollow Earth that I'll be putting on ebay soonish. Hopefully before the end of the week. It's functionally no different from the vanilla ones, but it'll be pretty with swirlies and specks on it. See it as an experiment, testing the auction waters on a custom item.
