Cassette Recorder Audio Processor - Number Two!

April 1st, 2016

Now Available in teh pr0p Shopz

The Cassette Recorder Audio Processor Rack Extension is back and better than before! This time we bring you the more Pro Version with L0-f1 Dolphonics™ Processing! We listened to everyone who loved the classic tape sound of the original C.R.A.P.Re, and added more controls for even worser tones. It’s guaranteed to make things sound warm and fuzzy and buzzy and hummy and munchy. It’s like the Original Crapre, but with more Number Two!

lopassholes at robotspeak

March 29th, 2016

Jordan Ginsburg and I perform as a modular synth duo under the moniker, “Lopassholes”. Here’s a recording of our set in San Francisco from last week.

DSI/Oberheim OB-6 Sound Design

February 18th, 2016

One of the exciting surprises of NAMM 2016 was the announcement of the Oberheim OB-6, a collaboration between Tom Oberheim and Dave Smith. Once again I find myself immersed in analog glory as part of the sound design team developing presets.

The profile of this keyboard is the same as the DSI/Sequential Prophet 6, and uses similar technology for the general interface and control architecture, however the voices are akin to the Oberheim SEM and have the inimitable SEM filter flavor. Because the 12db/oct filter architecture is different than say a moog ladder or the Prophet6 24db/oct filter, developing a diverse range of unique sounds poses a little challenge, but using oscillator detune approaches and frequency modulation (X-mod) opens up a really amazing range of timbral combinations.

Here is a demonstration of the patches I’ve contributed to the team. Some of these may or may not have been included in the final release:

DSI/Sequential-Oberheim OB-6

DSI/Sequential Prophet 6 Sound Design

May 15th, 2015

Once again, it’s an honor to have been asked to be on the sound design team for Dave Smith Instruments. Having regained the old “Sequential Circuits” moniker, the company is now DSI/Sequential! It’s only fitting that the new synthesizer is a six voice polyphonic instrument dubbed the Prophet 6! Synth legend, John Bowen, is also part of the sound design team and is recreating many of the classic patches that he created for the Sequential Circuits Prophet 5. More information is available on the DSI/Sequential Website

Unlike the previous sound design projects for the Prophet 12 and Pro 2 which are based on digital oscillators, the Prophet 6 has an analog voice architecture with digital control over the various parameters. Like it’s original namesake, the Prophet 6 has two oscillators with saw, triangle, and pulse waveforms, noise source, as well as the remake of the classic curtis low pass filter. The P6 includes some variations of the old poly-mod of the Prophet 5 which allows for some FM and wave shape modulations.

Having spent so much time in the world of modular synthesizers where routing possibilities are unhindered, sound design on the fixed architecture of the Prophet 6 has been an interesting test of mod routings. At the same time, this is a keyboard instrument, and voicing patches should also respect the format for people who are great players. I’ve found myself first reverting to the sound of a classic six voice Roland Juno or the Prophet 5 as a base of inspiration, and then working with sequences to build up a voice that complements the envelope timings. Afterwards, I would apply the onboard effects to round off the patch. Actually Dave Smith’s philosophy is that a patch should sound good without effects so that the instrument could be tracked without fx cluttering a mix.

The following example is a recording of my programs (including the built-in sequences) being submitted to the project for consideration as factory presets:

Buchla 208 Music Easel - Slider Cleaning!

April 15th, 2015

While vintage synthesizers are amazingly good fun for the sound and historic value, they do require a lot of care. I’ve owned this vintage Buchla system for nearly 25 years, and it was finally time to take on the daunting task of servicing the sliders. The controls were sticking and at certain points and other points would lose contact, so the instrument was “partially” usable.

I missed the opportunity to get a set of new sliders from Luther, and I asked around the vintage easel network to see if anyone had spares. Unfortunately, none are available. As a last resort, I decided to take on the task of cleaning each slider individually.

I’ll tweet my progress:

DSI Pro 2 Patches

February 17th, 2015

Programming the Dave Smith Instruments Pro 2 synthesizer can be a fairly labor intensive task. While I am compelled to use the [Latch 1] + [Hold] patch reset shortcut and start a new sound from scratch, I find myself creating up the same types of patches. As a time saving measure I’ve made a set of templates that cover basic types of sounds including basses, leads, drums, paraphonic patches, sound effects, and sequences. These patches serve as a starting point for further tweaking and embellishment. The file (linked below) contains a sysex dump of User Bank 2 which contains 97 templates and a couple of extra patches. Documentation on each patch is also provided with recommended parameter changes and application of the sounds.

Pro 2 Patch Templates Archive

On occasion, there’s a request for a list of my patches included in the Pro 2 factory banks. The following file is a sysex dump of user bank 3 (99 Patches) which includes the patches submitted as well as new ones:


Tracking Session

February 4th, 2015

A rough mix of a tracking session from earlier this week. Tim Bulkley on Drums and Art Hirahara on Rhodes engaged in a jazz improv session. Placed a C12 VR out in the middle of the hall to capture the natural reflections of this big warm sounding space. There are 7 mics running through a Metric Halo into Reason. I’ve posted the track on propellerhead’s Discover service, primarily because the compression algorithm sounds better than soundcloud.

Reason Inducted into the NAMM TEC Hall of Fame

January 26th, 2015

While everyone was busy drooling over all of the new gear and modular synthesizers on the main floor of the NAMM tradeshow, A group of manufacturers were meeting upstairs to receive special honors, and this particular group included the crew from Propellerhead Software! The NAMM TEC Awards, “recognizes the individuals, companies and technical innovations behind the sound of recordings, live performances, films, television, video games, and other media.” In 2015, the TEC Awards have inducted Propellerhead Reason into the Hall of Fame, alongside with some other iconic bits of gear including: Scotch Magnetic Tape, The Fender Rhodes, The ARP 2600 Synth, Empirical Labs Distressor, and others (full list here). Below is a video of the introduction from George Peterson:

Remembering David Wessel

October 17th, 2014

It was deeply saddening to hear about the passing of David Wessel. Professor Wessel was one of the important pillars of the academic community for his contributions towards the advancement of computer music technology. During the 1970s and early 80s, he was involved with IRCAM (Institut de Recherche et Coordination Acoustique/Musique), and eventually took a position as Director of the Center for New Music and Audio Technologies and Professor of Music at UC Berkeley.

I had the pleasure of taking a summer course at CNMAT where I met Professor Wessel in 2001. This was about the time when Open Sound Control (OSC) was being developed, and I vividly recall his presentation on gestural control systems and the musical application of expressive real-time control of computer generated audio. At a time when most people were still working with traditional systems of sequencing, recording and synthesis in computers, CNMAT, under Wessel’s direction, was pioneering the future of electronic music technology.

Professor Wessel had a natural gift of explaining rather complex concepts of max/msp and his pedagogical technique inspired the methodology behind the many bits of content I’ve developed over the years. For this, I will be forever grateful. Thank you Professor Wessel for pushing the weirdness envelope, and showing us the way.

Dave Smith Instruments Pro 2

July 14th, 2014

The Pro 2 Synthesizer is part of the new generation of keyboards from Dave Smith Instruments. Partly inspired by the classic Sequential Circuits Pro-One, and using the technology of the DSI Prophet 12, the Pro 2 is a monophonic instrument that can be a center of a synth production studio, but also has the capabilities to integrate with an analog modular synthesizer system. It’s been an honor to be asked back to the DSI sound design team to work on the Pro2. Over the course of the week of work, I archived some of the sounds to instagram and have collected the snippets here.

I couldn’t really wait to try the CV/Gate i/o features of the Pro 2, and hooked it up to the Make Noise system with triggers coming off maths. Not surprisingly, the integration is pretty tight. There are some calibration controls on the Pro 2 which had to first be adjusted, but then it was nothing but pure fun routing to and from the modular system.

The Pro2 has four oscillators and two analog filters. There’s a feature to route two of the oscillators to the Prophet 5 style low pass filter, and the other two oscillators to the Oberheim SEM style State Variable Filter. Using this routing feature, i’ve recreated a classic synth riff and sweep effect from Pink Floyd’s Dark Side of the Moon.

The Two Filter sections can run in series or parallel or mixed in-between. Series is when the oscillator is routed first to the Low Pass filter and then into the State Variable Filter, Parallel is when the oscillator output feeds equally to both filters and the outputs are mixed.

The four digital oscillators can be used as modulation sources or targets. In this patch, amplitude modulation and frequency modulation are intermixed to create tones that resemble classic Buchla tones.

The Oscillator is digital and modulating the wavetables and processing it with the digital and analog distortion sections will get you some very brash and punchy bass tones.

FM modulation of oscillators is initiated when you hit the pitch bend on this patch… that adds the growl to the screaming cat tone. Otherwise it’s just a funky filtered lead sound.

The 32 Step Sequencer is pretty powerful and with some careful programming, you can make drum loops. The Reset button on the sequencer is used as a loop retrigger while various parameters are tweaked in real-time. Unfortunately I didn’t have time to tap the full power of this feature.

The four oscillators can be split out in Paraphonic Mode. You can play four different notes on the keyboard but all four voices share the filter bank section. A bouncy part like this New Order riff sounds like it’s coming from a true polysynth.

Most people would expect the Van Halen, Jump synth riff… sorry to disappoint. After a week of non stop patch programming the brain does weird things…

The internal feedback routing from the Prophet 12 is also available in the Pro 2. Along with some non-standard key tracking modulation and synced filter effects rendered this IDM fill sound.

Gotta Have More Cowbell! This patch uses the Roland TR-808 approach of specifically tuned pulse waves to create the ringing effect.

In this video, the Pro 2 sequencer is sending CV/Gate signals to the Moog Werkstatt. The Audio from the Werkstatt is routed back to the Pro 2 audio input and processed with the bit crusher effect and filters.

The Pro 2 Sequencer tracks can be routed to four different CV out sockets. Here the minimoog model D is being triggered and sequenced by the Pro 2. Users of Propellerhead Thor Polysonic Synthesizer will notice that the modulation matrix looks very familiar!

Moog Werkstatt-Ø1

June 20th, 2014

The Werkstatt-Ø1 is a monophonic analog synthesizer with with a single VCO, resonant low pass ladder filter, LFO, envelope generator, one octave keyboard, and mini patch bay. Using jumper wires, you can experiment with different patch routings. While it’s a fun unit on it’s own, the circuit board has a section designed specifically for experimenting, and clear points that allow you to make modifications.

The Werkstatt was introduced at Moogfest 2014 as part of a special engineering workshop in the Moog factory, and I was quite fortunate to be among the first group to build this synthesizer. We were provided the tools to solder in a few dozen components (approximately 200 solder joints) to a partially populated circuit board. Under the guidance of Werkstatt designer, Steve Dunnington, and the Moog engineering staff, all of us had our new synths up and running by the end of the first day!

I borrowed this TT-303 Bass Bot (TB-303 Clone) to take to Asheville. Like the TB-303, the TT has CV/Gate outputs. I was hoping to punch some holes and add 3.5mm jacks during the workshop, but had to settle on making a couple patch cords. The TT-303 CV out is connected to the Werkstatt VCO, and the 303 Gate out is connected to the Werkstatt VCA.

Werkstatt as a Synth Module

The Werkstatt design is ‘somewhat’ influenced by the Eurorack modular format. It has a height of 3U, so it has the same vertical dimension of a Eurorack module. It runs off a 12V DC supply voltage, and so it can be powered from a Eurorack supply. Despite these commonalities, it would be difficult to convert the Werkstatt to a Eurorack module without considerable hacking. The 1/4” audio output jack and the power connector jack are situated right on the edge of the PCB, which is already too large to fit between Euro mounting rails. If someone were to fit this in modular case, they would have to customize the space to accommodate the entire box.

The Werkstatt has the potential to complement a modular rig, but the header patch bay lacks a common grounding point, making direct connections with outside gear a little more difficult. For basic routing, I’ve made jumper cables that have a 3.5mm plug and terminate with a patch pin. Grounding is achieved by routing the Werkstatt audio output to a mixer/vca module in Eurorack system (1/4” to 3.5mm mono patch cord). This is probably the easiest (and least destructive) way to interface the Werkstatt with modular gear.

In this photo, the TB-303 CV/Gate outputs are patched to the Werkstatt VCO EXT In and VCA In using the 3.5mm to single pin patch cables. Common ground between the 303 and the Werkstatt is established by connecting the audio to the 303 Mix input. This is important because if there’s no ground reference, the CV/Gate signals will not control the Werkstatt.

The kit includes a few patch jumpers (3M - part number 924962). You can find other brands of leads designed for arduino experimenter kits that connect into 0.025” headers. I found these jumpers by Osepp, (part number LS-MMPJ-6) and soldered the ends to a mono patch cord. The joint is a little delicate, so it’s important to use some shrink tubing to insulate and reinforce the connection.

VCO CV Calibration

On the patching header, there is an input called “VCO EXP In” which is the oscillator pitch control that can be modulated from a step sequencer. The Werkstatt follows the tuning convention of 1 volt per octave, and will interface with Eurorack sequencers. If you are using a module that outputs quantized voltage values like the Make Noise Rene, this input may require calibration.

The VCO EXP TRIM knob is VR5, located right below the “moog” logo on the circuit board. Basically you send 1 Volt DC values into the VCO EXP In pin, and adjust the VR5 using a small screwdriver until you hear octave divisions playing from the Werkstatt. Adjusting this control will not affect the keyboard tuning, only incoming pitch cv scaling. We were told that Bob Moog always used a frequency counter to calibrate synths, but you can adjust it manually by using another oscillator as a reference. Once the VCO EXP TRIM adjustment is accurately calibrated, the Werkstatt should track perfectly with a CV keyboard or sequencer.


Using a 500k potentiometer and a couple of jumper leads, a simple attenuator can be incorporated between routings. You can patch the VCO into the VCF and control the intensity of the cutoff frequency modulation. 500k is just enough resistance to scale the keyboard control voltage to the LFO, and this allows you to have two tuned oscillators by patching the LFO out to the Audio input.

With a little extra work, you can mount the potentiometer in an enclosure, and then add your favorite style of knob! In the photo below, i’ve mounted the potentiometer (alpha part RV16AF-10-15R1-B500K) in a Bud Industries, die cast enclosure (part CU-123) with a Davies knob.

Modding the Werkstatt

Most of us who built the Moogfest Werkstatts have contemplated whether or not to apply drastic modifications to these units. They are are the first batch to come out of the factory which already has a special significance, and it would be a shame to butcher the unit. Lately I’ve been tossing around the thought “What would Bob Moog do?” And the answer i keep coming up with is that Bob would probably mod it :-) Below are a few modification ideas. Some are original and others are ideas passed on from Steve Dunnington during the Moogfest workshop.

White Keys

The easiest mod is changing out the keyboard buttons and replacing the whole note keys with white button caps. The added contrast makes it easier to find your position along the scale and gives it an overall cooler look. The tact switch key caps come in a range of colors and are available from the major online electronic component suppliers. I’m using the Mountain Switch 101-0209-EV. Be careful when removing the old key caps so that you don’t break a solder joint. They should pop off by hand without too much effort.

Envelope Trigger Input

One mod that I’ve been obsessing over is an Envelope Trigger input. While you can apply an external envelope signal to the VCA or VCF input patch points, there is no way to actually trigger the envelope except through the note buttons.

I’ve been experimenting with various ways of tapping into the circuit. The envelope generator has two modes: Pulsed and Sustained. When a key is pressed, both a sustained gate and 5ms trigger are generated and sent to a selector switch (SW8). From the switch either the pulse or sustained gate signal passes to the slew circuit. So far using a voltage follower has been the most reliable and way of applying external gates into the envelope. This will ultimately be added to the experimenter section of the circuit board, and it will be necessary to cut a trace to insert this connection.

I’ve breadboarded a voltage follower and patched it into a solder trace on the Werkstatt. An external gate from an XAOC Moskwa sequencer (which can be finicky) runs through the voltage follower and into the envelope generator.


One of the mods suggested in the workshop was adding a diode clipping circuit between the filter and VCA. There’s a jumper on the board where you can insert a passive (or active) distortion circuit for a little extra character. Using a few spare parts I managed to get a nice diode clipping circuit going. It’s a nice mod, but i’m not sure i would always want it active, so part of this plan is to add a switch that will bypass the distortion.

In this photo, the Make Noise Rene is sequencing the Werkstatt. The gate from Rene goes through the voltage follower circuit (on the breadboard) and triggers the envelope generator. The distortion effect is also wired in on the jumper between the VCF and VCA.

Audio Input

The Werkstatt PC Board has a jumper connection that links the output of the oscillator to the filter section, providing an access point to run a signal though the filter alone. You can still modulate the cutoff frequency with the LFO or apply some FM modulation by patching the oscillator to the filter cutoff, and run another audio source like a drum machine or external module though the moog filter. During the Moogfest workshop, Steve Dunnington showed us a prototype mod he applied with an audio input buffer that taps into this point. This mod, however, is destructive and requires the addition of some circuitry and a switching input jack, or a separate switch that disables the oscillator.

3.5mm Jack Panel

Drilling holes into the Werkstatt is ultimately going to be the most daunting task. Having little skill as a machinist, there’s the distinct possibility of messing this up. As a measure of precaution, I’ve decided to have an aluminum panel made by Front Panel Express with the holes precut. Not only will this look neat with clearly engraved labels, it leaves a little room for drilling errors into the Werkstatt itself. There isn’t a lot of vertical clearance between the PCB and the bottom of the case, but as long as the holes are centered along the axis of the existing power and audio jacks (approximately 9.1mm from the bottom of the case), a typical Kobiconn 3.5mm jack will fit (sideways) with a just enough of the bushing to fasten it down.

Since the experimenters pads will be used for the gate buffer and distortion circuits, so I’ve avoided populating that section with jacks. Some of the components may have to be mounted under the PC board, and so the extra clearance is required. The mechanical engineering is something that takes me a little extra time, primarily because I’ve been prone to really dumb mistakes. When completed, I will be able to patch the to and from a modular rig with ease; essentially making the Werkstatt a stand alone module. Hopefully, this will all work out.

Robotspeak Workshops

Robotspeak in San Francisco is a dealer for the new batch of Moog Werkstatt Kits, and I’m going to organize a day or two to talk about using it with other analog gear, build patch jumpers, and work on some of the mods described above. Yes, including the custom patch panel.

A little modular music

June 12th, 2014

idea sketch ES 14.59 from Kurt Kurasaki on Vimeo.

I’ve been creating and archiving quite a few of these little modular pieces for the last year. This is one of the latest patches that utilizes modules from Make Noise, Verbos Electronics, Livewire, and Music Thing / Thonk. The patch is fairly pre-set, relying on a couple of base sequences that are scanned at random rates based on values generated by the Livewire Chaos computer. The oscillators are inter modulating to dynamically change timbre, and one sequence also drives the minimoog model D that provides the backing pad. Most of the build up and breakdown is manual tweaking of dynamic and timbral controls for a sense of live performance, but the notes and sequence themselves are random.