Circuits

I have been working on some circuits lately.  I am particularly interested in noise generators or chaotic oscillators.  I like to find something right on the boundary between pure tone and noise.  Some of the circuits I have found are the Lorenz system, reverse bias diode based noise, the Rossler attractor and the TMPP chaotic oscillator (my favorite so far).

To make a circuit takes several steps.  First I try to simulate the circuit using the Falstad circuit simulator:  http://www.falstad.com/circuit/ .  After that I use a bread board to construct the circuit:

After demonstrating the circuit works I do a breadboard layout using ExpressPCB.  I then photo and etch the circuit board, drill the holes and solder the components into place.  I try to find a nice looking case to use for the circuit.  In my search for interesting circuits I found a number of web sites.  Music from Outer Space http://www.musicfromouterspace.com/ has a host of unusual noise makers.  In particular the Weird Sound Generator and the Noise Cornucopia are interesting to me.  I currently have parts on order for the Weird Sound Generator.  The Noise Cornucopia has several interesting types of noise beyond standard white noise including filtered and grainy noise.

My biggest issue with circuits is that usually you have to supply them with at least +/- 9V which requires two 9 V batteries.  That's a lot of voltage for a simple noise box so I usually attempt to rework the circuit to 9V but if I need to I can move up to +/- 9V.  Since I'm not interested in doing power supplies right now, I try to stick with battery power.  Op amps require both a positive and negative voltage and a ground located between them so if I put a couple of caps in series between +9 and 0 on the battery I should get a ground in between them.  I usually put some high resistance resistors in series too, though I'm not sure that is necessary.

I had been searching the web for a while for chaotic oscillators and found the Lorenz system: http://ccreweb.org/documents/physics/chaos/LorenzCircuit3.html which uses the AD633.  The Analog Devices chip enables you to multiply two voltages together as analog signals rather than converting to digital which is an interesting trick.  The AD633 is a bit pricey ($10) and Mouser doesn't stock them though Digikey does.  I found a Ring Modulator that uses this chip which should be quite cool, the WARP 633: http://m.bareille.free.fr/modular1/warp633/warp633.htm

So I was surprised to find the Rossler Attractor on the Falstad circuit simulator: Go to Circuits->Op Amps->Oscillators->Rossler Circuit.d

I built this circuit and replaced some of the resistors with potentiometers and made a video of me playing with the knobs.  The output is not that interesting by itself so I added a delay and phaser to the sound:



After searching the net a bit longer I found "A simple chaotic oscillator for educational purposes" by Tamasevicius et. al.  http://www.df.uba.ar/users/sgil/physics_paper_doc/papers_phys/e&m/A%20simple%20chaotic.pdf

The first thing I did was to load the circuit into the simulator.  This shows some classic chaotic behavior on the scope:

The import code for the Falstad simulator is:

$ 1 5.0E-6 0.30802168489180315 50 5.0 50

a 240 224 352 224 0 15.0 -15.0 1000000.0

d 416 224 352 224 1 0.805904783

r 208 240 208 304 0 495.0

l 304 304 352 304 0 0.1 -4.0766317387341106E-4

c 304 304 256 304 0 1.0E-7 -0.08352313181090625

c 352 224 352 272 0 1.5000000000000002E-8 -0.6182734965994132

w 320 144 352 144 0

w 352 144 352 224 0

w 240 208 240 144 0

w 240 144 256 144 0

w 416 192 416 224 0

w 352 272 352 304 0

w 176 240 176 208 0

g 176 304 176 320 0

g 208 304 208 320 0

w 240 304 240 240 0

w 256 304 240 304 0

w 208 240 240 240 0

w 176 208 240 208 0

R 480 192 512 192 0 0 40.0 20.0 0.0 0.0 0.5

r 176 240 176 304 0 10000.0

r 256 144 320 144 0 10000.0

r 416 192 480 192 0 20000.0

w 352 304 416 304 0

w 416 304 416 224 0

O 352 304 352 336 1

o 25 8 0 34 5.0 9.765625E-5 0 -1

Next I built the circuit but I needed to make some changes.  I wanted to use +/- 9V, 200 mH inductor, 500 ohm resistor, 9 V input, potentiometers and a few other changes.  The first attempt seemed to work OK with some real chaotic regions that transitioned from tone to noise.  I would like to modify this to get more range in the chaotic regions.  I think need to get some different value potentiometers to implement this.

That's as far as I have so far.

Blog out,

Plasma Portal

Metabolomics 2a

I have been working on a new piece that follows the style of Tangerine Dream and some others based on  arpeggiated synth lines.  Metabolomics 2a:

Metabolomics 2a by Hans Mikelson

I started this piece by searching through some patches until I found one I liked in Dune (analog modeling software synth).  This fades in around 0:10.  I modified it a bit until I liked it more.  It has a bit of a brass sound to it.  I then added a pad track with Morpheus (additive synthesis).  This is the sound that fades in at around 1:00.  This was a good start.  I originally set up in A minor apparently, then for some reason added F so that pushes into more of a D minor vibe?

I wanted to make use of some Native Instruments stuff since I had bought the "Lite" version and one of the instruments generates some ambient noise (Metaphysical Function).  Searched around until I found one that sounded decent.   This sound can be heard mixed with the droning sample at the beginning of the song and can also be heard around fading in around 4:50.

I also used the NI drum machine (Aerobic) and scrolled through until I found a patch that worked with the piece.  Tweaked it a bit.  These fade in gradually between 1:00 and 2:00.

Next I added some samples from one of my other pieces (Dark Quanta).  I pitch shifted this to approximate C and D# tones (at this time thinking the piece was in C minor).  Tried a few effects on it such as high pass filter but ended up just using an auto panner (Luxonix).  This starts out the piece. 0:00 to 0:10 or so and shows up again near the end.

Added another Dune synth with a pulsing modulated filter.  This comes in at 2:00.

Added another track using Dune for a chorus sound.  I checked the Dune ARP and thought it was in C minor but I forgot that it is shifted based on the midi note so it was really in A minor so I created this part in C minor.  This is the part that comes in around 3:30.

I wanted to liven up the rhythm section a bit so I added some acoustic and analog synth percussion samples to a track.  I then used a granular/glitch tool to randomly envelope and repeat them (Michael Norris: Grain  Streamer) ((Free))  This makes the insect like sounds beginning around 1:22.

I routed everything to a master reverb in Reaper (AUMatrixreverb Small Room)  Added some fades and pans and that got it to its present state.  Finished it off with Voxengo Elephant Ultrasmooth 3 dB (compressor).

So at this point the piece was sounding pretty good in the form that you can listen to above, but I thought it could use some analog synth like Moog part around 4:00 or so.  I went down to record it thinking the piece was in C minor at this time and found out that it was closer to D minor.  I haven't got the part recorded yet.

So then I went back and changed everything to all be in A minor (except the F note in the one pad) and now I'm trying to decide if that will make the whole song sounds more sterile maybe it was better before?  OK, so this is still something of a work in progress but I like the way it is coming around.  Currently the drums seem to be going on for too long but I fade them out a bit in the latest version that isn't up yet.

Blog out
Plasma Portal

Democracy 2.0 (Live)

For a while I have been trying to take my studio productions and perform them live.  I have been working on this song for a while now.  This song started out as a preset on the Korg EMX-1.  Based on that I did the song "The Legend of Andromeda Gulch."  I later used the same bass and kick part for my song "Democracy" based on the protests in Madison, WI.  Awhile ago I had started performing with the Moog Little Phatty arpeggiator.  I originally started out with an extended jam on the Little Phatty that I would do with a delay pedal.  The LP has a great sound but without effects it sounds a little too dry.  A delay is all it needs to liven it up.  I had worked up this LP routine over a few weeks and then didn't do anything with it for a few months.

Next I started taking the electribe (EMX1) out to the open mics again.  I wanted to use the same beat I had used with Democracy but without the political commentary.  At first I did an intro with the Theremin and a combined jam with Theremin and electribe.  The next week I switched to the LP, doing my original LP Arp jam and also added the KP3 Kaoss pad using the synth sounds.  I added a few samples and came up with the following set piece.  This only uses three instruments (LP, EMX1, KP3) and was performed as in a live setting (so although I did it in the studio I did it all as a single stereo track recording, I also used Voxengo Elephant for post production.)  The LP is processed through the EMX1 and I use MIDI sync to sync the LP and KP3 to the EMX1.

Inspiration

Sometimes I find myself searching for inspiration when creating music.  I want to make some music but I'm not sure what to do.  I think everyone has this problem from time to time, staring at a blank page.  In this article I'll describe some sources of inspiration that you might want to try.

Patch it

Synthesizer patches or presets can often be a source for inspiration.  I hate to use someone else's patch directly but they can often inspire me in a piece.  Often times a patch can suggest a certain mood or type of piece.  Or it may inspire me to create a similar patch.  One cool source of patch inspiration is the randomize feature.  My Waldorf Pulse analog synth has a random patch generator.  This is a really cool feature for patch inspiration without having to worry about copying someone else's work.  You can keep generating random patches until you find something that sound really cool, then tweak it a little bit to make it more usable.  I notice some software synthesizers have this randomize feature and I wish others would included it.  You can also get some inspiration from a new plug-in.

Got Rhythm

I'm not a drummer and I must confess I don't have great drum intuition which is probably OK for working with ambient sound but hurts quite a bit when I want to make some techno.  One technique I found is to find a piece of music with a similar style to what I want to make, then focus on just the kick.  I try to match the kick pattern, not necessarily the kick sound.  I don't have to match the pattern precisely because I really don't want to match the pattern precisely.  I just want to have a nice sounding unique kick pattern.  Sometimes once I have the kick pattern I can add the rest of the percussion sounds myself.  The second drum I usually add is the snare.  I may also base the snare pattern on another track if I need to.  The next pattern to add is the high hat pattern.  Then add other sounds.  I also like to mix acoustic and electronic drum sounds to provide more depth.

Sacred Chord

Stealing a kick pattern from another song is OK for inspiration, why not some chords.  Of course you probably wouldn't want to steal all of the chords for a song, then you would just have someone else's song, but there are some other ways to do this.  I have a large number of music books.  Sometimes times I like to browse through them and play certain chord progressions, ignoring the rest of the music, just jamming on the chord progressions to see if I can find a groove I like.  So even if the progression was originally from a country ballad or a classical piece it may end up in a bit of my electronic music.  Beethoven and Mozart were great at putting together chords.

Another variation on this is to take a certain artist and try to integrate their overall sound.  I'm a big fan of Pink Floyd and I like to make music with a bit of a Floyd vibe but I wouldn't want to copy their music directly.  So I studied how they bring their chords together, the types of chords they use.  Then use similar chord structures to make original songs.

Limit Your Palette

I have a lot of equipment but sometimes have too many options works against you.  I sometimes like to stick with just one instrument or a pair of instruments.  Once I tried to do a whole piece with just software synthesizers.  After you get a good sound going you can always fill it out with other sounds.

Beauty

A beautiful landscape, a beautiful person or feeling can also be the source of inspiration.  Don't forget those.

Hopefully you may find this information helpful when you are seeking to stimulate your muse.

Remixing Part 2

I was working on a remix of my friend Brian Bethke's song Red Window.  This song works really well for a remix because it does not have a complex bass part, so I could just low shelf filter the bass out of the song and work from there.  Here is my original remix:

Red Window (Plasma Remix 1)

At this point I like to take a little time and listen to the song.  I usually burn it to disk and listen to it in my car to make sure everything sounds balanced etc.  I wanted to make the break a little more interesting too.  I worked some more on it and added some new parts.  I think I increased the length of the breaks a bit.  After that this is the version I came up with:

Red Window (Plasma Remix 2)

I then posted both copies for Brian to review.  I also asked a DJ friend of mine, Alex, to review the songs.  Alex had some great suggestions on how to build energy and I did a third version of the song based on those suggestions.

Red Window (Plasma Remix 3)

At this point I am planning on giving this project a rest for a while and work on some other projects.  I may come back to it later but the remix is pretty good as it is.

Blog out,
Plasma Portal

Remixing

I decided that a good way to get into music production would be to do a remix.  I contacted a friend who had written a song with a bit of an electronica vibe to it about doing a remix of the song and he was happy to agree to it.  He even volunteered to send me some files. To get started I ripped a copy of his song from a CD and loaded it into Audacity.  The next thing I needed to do was to figure out the tempo of the song.  Let's say a four beat measure is 1.845 seconds.

BPM = 4 beats /1.845 s x 60 s/min = 130 bpm.

The other way to do this is to load the sample into Reaper and modify the tempo until the song matches up with the measure lines in Reaper.  This is probably the best time to do any time stretching to the entire file if you intend to change the original tempo of the song since the next step is to chop up individual pieces of the song to prepare for remixing.  Changing the time often results in artifacts so its best not to do it if you don't have to.  In this case I did not want to change the time.  Both Audacity and Reaper have time stretch/pitch shift capabilities if you want to change the key or tempo of the song.  I suggest auditioning them all to see which one sounds the best.

I did not need to make any real modifications in Audacity except to save it as a wav to a new directory that would hold all of the remix files for this song.  I then went through the song and isolated different song sections.  There was an intro with some reversed instrument sounds that lasted about a measure, the outro was nearly identical.  There were a couple of two measure sections of groove.  There were longer sections of verse and chorus.  There was a short two measure instrument break with just the basic groove.  There was a bridge for a few measures.  There was an electric guitar solo at the end of the song for a few measures.  I used Audacity to create a separate sample for each of these sections and saved them in the remix directory.  In some cases I broke the section down to a single measure and in other cases I saved several measures.  You can do some of this inside of Reaper but I wanted to have easy access to these files.  When I get a little further I may ask my friend for a separate track with just the vocals, just non-percussion instruments, bass & kick and other percussion as separate tracks.  Actually as long as I have vocals on a separate track compared to the other instruments I would be in pretty good shape.

I then opened up Reaper added a new track and loaded this song as a media file into the first track. The first thing I wanted to do with this track was to add a 808/909 kick to it.  It had an acoustic sounding kick that was set far in the background so I wanted to spice up the kick for a dance groove.  The first think I did was to apply an FFT based low shelf filter to filter the lows rolling off around 150 Hz down to zero.  This took much of the bass from the keyboards and drums.  This opened up some space for me to add the drum machine kick and the synth bass.

I really like the Dune software synthesizer plug-in.  I have tried a few others but this one seems to have the best sound.  For this type of work it is probably good to start with MIDI and a software synth.  I can always go to MIDI analog synth later or record digital audio on an acoustic or analog electronic instrument later.

I first added a basic kick drum sound, with the intention of modifying it later to make it more complex (or simpler).  I used Dune and MIDI to create the kick sound.  I then copied the MIDI file to an identical file.  I modifed the copied file to actually remove some of the drum beats.  I used this as a small intro for the kick drum.  I repeated copying and modifying the kick MIDI part to create some more drum variation through out the song.

I next added a bass part.  I auditioned a variety of synth basses until I found one in Dune that I liked and worked with the song.  I created a simple bass part to underscore the melody.  I had to figure out what chords were in the song at this point.  It turned out to be basically a Bb minor song.  I added the bass notes using an Akai mpk mini.  I then went into the MIDI file and quantized the notes manually.  I then added some envelopes and applied one to the amplitude and the other to the filter cut-off so I could fade in the bass and sweep the filter during the part.

I thought the song could use a clap and I added this with Dune as well.  I added an amplitude envelope to fade in the claps over time.

After the first chorus there was a single measure of groove before the next verse so I split the song sample at that point and added a few extra measures from the sample sections I had saved earlier.

In this part I added some strings.  I auditioned a few different strings and although Dune has nice strings I went with Komplete elements strings that I had just bought and added the Guitar Rig Phasor from NI to achieve a phased string effect.  I then played in a string part starting with a lower line then adding a second line about one octave higher.  I copied the string phrase to a few different places throughout the song once I had a part that I liked.  To get a good part I played back the song main line and improvised string harmonies along with it  until I ended up with a nice sounding part.  I added volume envelopes to the sound arranged the fading.

I had learned from reading some articles to always mix at a low volume.  I find this technique works really well.  You know you can almost always hear a part with the volume cranked but can you hear it at low volumes?  When I do a mix I always turn the volume down to a low level and bring each instrument down until you can't really hear it then gradually bring it up until it sounds balanced.  I do this with each different part one at a time.  After I think I have a good mix I turn up the volume and verify that no parts need to be adjusted.

After this I saved a mix to disk brought it into Audacity and used Voxengo Elephant for compression (Master's punch) finally saving to MP3.  I burned the original song and the new mix to CD so I could listen in my car.  I have quite a bit of car time so I like to listen to mixes in the car.  It also helps me understand if it is a good mix if it sounds good in a car with all of the traffic noise.

That's about as far as I have gotten in the remix process so far.  Some of the next steps are to expand some of the other non vocal parts and add some solo synth instruments.  I'm thinking of adding a more complex sound to the intro or possibly the outro.  I may want to capture some of the original kick rhythm, use some extreme filtering or effects on some of the original tracks.  I have to add some sweeps, ramps, splashes and rolls to improve the transitions.

The second aspect of remixing was to review some remixes that I liked.  I read the Wikipedia entry on remixing: http://en.wikipedia.org/wiki/Remix and then found several of the suggested remixes on Youtube and listened to them so I could get a feel for the history of the remix.  I also found a number of remixes in my song collection and listened to them to see how they handled it.  I also listened to some of my favorite electronic artists to study how they put their songs together so I could use similar techniques.

Blog out,
Plasma Portal

Green Bullet Repair

Soldering iron with high wattage button on the side, electrical solder, flux, damp sponge, de-soldering braid.

My green bullet microphone was having some problems cutting out when I would move the cord so I thought I would try to repair it.  I searched the internet for a while but could not find very much information on repairing green bullet mics.  I suspected there was something wrong with the cable near the spring because when I moved that part of the cable it sometimes caused the mic to make a loud click or cut out.

Used an allen wrench to remove the set screw on the cable and used a screwdriver to remove the two small screws on the screen on the front of the mic.

The mic has a rubber seal around the transducer element.  I didn't see any problem with that part.

Here is a close-up of the transducer element.  I had originally thought that maybe some wires had worn through their insulation and it was making contact with the case of the mic but I could not see any evidence of that.  The wires, solder joints and heat shrink all seemed intact.

I then disassembled the cable with the spring.  This was interesting.  A bit of copper braid is soldered to the top of the spring that is then forced into the opening and held in place with a set screw.  I still could not see anything wrong and since it is soldered in place I had to use some copper braid to de-solder it.

Once I got it de-soldered I found another interesting feature.  the braid had broken from the solder point.  I suspected this is what was causing the problem.

I decided I needed to attach a conductor from the braid near the spring to the braid near the mic case.  It seemed too short to reach this distance.  I first tried some fine wire but that didn't seem to work.  I then tried a short piece of desoldering braid.  I thought this might work perfectly.  So I tinned it by heating the braid and coating it with solder.  Then I soldered it into place on the mic cable.

Put the spring back into place and screwed the set screw back.  So far this repair has been successful.  The cut out is gone and the mic seems to work fine.

For a bit of the history behind the green bullet visit:

http://www.greenbulletmics.com/

I have been gigging with this repair for several months now and it still works great.

Update: Patching this with de-solder braid is not the best way to do this.  This eventually did fail.  Better to redo this with the shielding mesh.

Blog out,

Hans Mikelson

Plasma Portal

Welcome to the Portal Blog

Welcome to the Plasma Portal blog.  I decided to start this blog to discuss my musical creation efforts and other related interests.  Plasma Portal is the name of my band consisting of one member (myself) but occasionally I have had guest musicians join me.  I am planning to move some of my other music related blogging activities here from my MySpace site: http://www.myspace.com/hans_mikelson/blog.  My main music distribution site is through reverbnation: http://www.reverbnation.com/plasmaportal.  On that site you can check out some of my latest music.  I previously used MySpace for Plasma Portal: http://www.myspace.com/plasmaportal .

I'll provide a bit of background to get you started.  I had been fascinated with electronic music since the 1970s or earlier with musicians such as Tomita and ELP.  I started getting into synthesizers in the 1980s with a Yamaha CS01, DX100 and Casio SK1.  This began my synthesizer collection which has grown to include many more synths over the years.  I became involved with Csound in the mid 1990s and produced a large collection of software Csound effects and instruments many are still available from Rick Boulanger's site: http://www.csounds.com/.  I also became involved on mp3.com during this time and published most of my songs to mp3.com on the album Teknology World.  Mp3.com used to be a site where anyone could join and post music similar to what Reverbnation does now.  You can find out about it here: http://en.wikipedia.org/wiki/MP3.com.

A few years ago I started going to open mics and jams and started getting back into music again.  I usually play harmonica with Phil Circle when he appears in Eau Claire http://www.philcirclemusic.com/.