OP-1 review

I've decided to start this blog to share my journey on the new OP-1 synthesizer from Teenage Engineering.  The OP-1 is an exciting new instrument that incorporates synthesis, sampling, sequencing, effects, and 4-track recording in a compact, portable keyboard design.  With a reported 16 hour battery life, the OP-1 stands out as the first truly mobile solution for synthesis and recording enthusiasts.

The OP-1 contains 7 varieties of synthesis, some drawing inspiration from classic concepts and instruments, others bringing new ideas to the fold.  The synthesis types available on the OP-1 are Cluster, Digital, Dr Wave, FM, Phase, Pulse, and String, each with brief descriptions below. In addition to the synthesis options detailed below, each synthesizer in the OP-1 has a dedicated amplitude envelope, effects select, and assignable LFO. 

Cluster:  Offers multiple oscillator synthesis.  Cluster offers up to 6 available oscillators that are layered on top of each other with control over spread, unison (unitor), and wave envelope. The wave envelope seems to adjust the "brightness" of the wave, and the time it takes to reach maximum brightness or decay from it.  The spread control differs from the unsion control in that it offsets the waveshape of each stacked oscillator and not merely the relative pitch, which the unison control handles. 

Digital:  Teenage Engineering describes this as "true digital synthesis," but offer little more in terms of explanation.  The controls are waveshaper, octave, detune/ringmod, and digitalness.  The Digital synth engine has quite a wide range, from electric organ sounds to mellow brass, and well out of the range of the ordinary with buzzing, noisy sounds reminiscent of motors, power tools, and even a touch of 8 bit computer noises.

Dr Wave:  Frequency Domain Synthesis.  I'm not educated in acoustic engineering, so if that's not a term Teenage Engineering made up, it's at least one that I'm not familiar with.  The controls are wave type/length, filter, phase, and chorus.  Wave type and length seems to make enough sense in practice, but seems very dependent on the following two controls.  The filter does and does not behave like a traditional filter.  The controls on Dr Wave are a bit difficult to fully grasp because, unlike most other controls on the OP-1, you can endlessly rotate the knobs to move through the full range of values with its parameters.  The filter on Dr Wave, if it borrows the term from common synthesis, must be a type of comb filter, or at least a filter that moves from one type to the next while showcasing different frequency and resonance values between.  The filter helps to hone in on the exact wave type you are searching for (while viewing feedback on the oscilloscope-style screen), but also allows you to clip waves and introduce overtones.  The phase knob is also a bit of a mystery, but at times seems to populate the aural field with more instances of the wave, or perhaps divide the wave into smaller fragments.  This can create complete chaos, or add just enough grime to liven up your sound.  The chorus paramter on Dr Wave sounds, to my ears, to animate the wave similar to PWM more than it  acts like a chorus on the final output of the sound.  Dr Wave is one of the more mysterious synthesis types on the OP-1, but one of the most versatile and capable of achieving completely original sounds.

FM:  This is the popular FM synthesis adapted from the Yamaha DX series.  I honestly think the current online manual has the parameter controls mislabeled, but the idea is there. FM offers control over topology (essentially an algorithm select to borrow terminology from the DX), frequency (which changes both the modulator and carrier frequency, but offers a wide enough range to cover all bases), FM amount (brightness control), and detune.  The FM engine on the OP-1 sounds great and is easy to use, but lacks individual envelope control over the modulator and carrier as you would expect coming from experience with a Yamaha DX synth.  I would also suggest that a shift+knob turn would allow you to select carrier and modulator frequencies separately as it can be a bit of a chore and occasionally taxing on the ears to turn a single knob until the proper relationship is found.  A much more approachable format for FM synthesis in its present state, however, and a fine fit for the four knob interface.

Phase:  Phase Distortion.  This is the type of synthesis best known from the CZ and VZ series Casio synthesizers from the 1980s.  The OP-1 gives control over phase shift, distortion amount, phase filter, and phase tilt.  These controls combine to recreate nearly all of the sounds of the Casio classics, and have a few tricks that expand the sonic potential of the synthesis type.  The phase tilt is of particular interest.  If you ever played with a CZ series keyboard, you will remember that you were given a set number of waves to choose from including several resonant types.  The phase shift on the OP-1's PD synthesis can be thought of as a variable wave select, while the phase tilt introduces resonance.  Together, you are given access to a much broader range of wave images than the handful available on the CZ series. Sadly, however, it is a single oscillator unlike some of the higher end Casios, and there is not an envelope to control the phase filter or distortion.  On the bright side, you are able to use the LFO to modulate any of the synthesis parameters, a trait not shared by the original phase distortion synthesizers of the past.

Pulse:  A pulse wave synthesizer with a filter.  There are two pulses, and controls to set the distance between them.  This works like an envelope controlling pulse width, however you determine a difference between an initial pulse and a second pulse to achieve an enveloped sound.  There is also a filter which is great for basses, but always seems to have a positive decay making it less usable for pads and other sounds.  Modulation is also available for subtle, classic PWM sounds and far beyond.  This has been one of my favorite bass instruments on the OP-1, but sadly seems to be a little limited in doing anything else.  I'm still learning, though.

String:  String modeling synthesis.  Controls are tension, impulse decay, detune, and impulse type.  Impulse decay is the length of time the string is contacted to make sound, while the impulse type is roughly the hardness of what strikes the string.  A low impulse type with high impulse decay will give the impression of a bow on strings, for example.  This is a surprisingly good acoustic model given the lack of controls, with fairly convincing recreations of guitars, harpsichords, contrabass, and violin sounds.

The synthesis options are plentiful on the OP-1, offering an incredibly diverse range of sounds.  As my attempt to describe some of the functions may have shown, Teenage Engineering keeps things vague.  Complicated when it comes time to describe them to others, but in the end the OP-1 accomplishes its goal of forcing users to experiment and use their ears to find sounds.  It can be a challenge to the experienced synthesist to sit down with a sound in mind and craft it right away on the OP-1, but one might stumble upon something entirely different and equally pleasing to what they had in mind.  The color-coded knob and screen relationship also makes it tremendously easy to see what you are doing, even if you don't fully understand it.  Overall, the synthesis options are quite versatile and powerful, and being a young machine we might just get to see a few more with future OS releases.

The other main sound generation tools within the OP-1 are its samplers.  The OP-1 has two kinds of sampling: a synthesizer sampler and a drum sampler.  The synthesizer sampler can record up to six seconds of audio and play it back scaled across the keys. The synthesizer sampler has controls for start point, end point, loop start and end points, gain, and playback direction.  The drum sampler is a little more advanced, and allows for up to twelve seconds of sampling.  Once recorded, the audio clip is spread across the two octave keyboard with each key playing a designated fragment of the audio.  If you wanted to create a basic drum kit, for example, you could record a break off of a vinyl, or a 'demo' passage from another drum machine and then set the in and out points for each heard instrument on a per key basis.  Kick on G, snare on E, hi hat on F, etc...  Each key has independent pitch, gain, playback direction, and play types which include normal, play-to-end (one shot), and loop.  There can also be overlap between keys.  So say you have only a single tom sound in your twelve second recording but want to have three in the beat you are composing.  You can use the same region of audio multiple times with each instance possessing its own parameter settings.  One tom can easily be separated to three keys with different pitch settings.

The audio sources available for the samplers are line-in, a built in FM radio, built-in microphone, or sections of audio "lifted" from the four-track tape recorder.  Using sections of tape with the synthesizer sampler can be used to great effect by overdubbing multiple layers or octaves onto tape and then importing them to the sampler for a more complex patch. The built-in FM radio is also a great source for mangling material.

The samplers have access to the same effects, envelope, and LFO as the synthesis engines.  The drum sampler has an envelope specifically tailored to percussion sounds.

The OP-1 presently offers one of five effects per patch, and one of the same five plus a dynamics processor and EQ for the final output.  The effects are delay (a tape-style delay), grid (three-dimensional feedback plate), phone (pitch/telematic/ lo-fi), punch (lowpass filter), and spring (spring reverb).  All effects are of good quality and, true to the OP-1's design, can be pushed into unknown territory.  The punch or filter effect is another example of Teenage Engineering simplifying things and basing them around graphics rather than standard synthesis terminology.  Again, helpful to encourage use of the ears, but a sidestep for experienced programmers.  The filter also lacks a dedicated envelope (although some but not all synthesis engines compensate).

Each patch (drum or synthesis) in the OP-1 contains one of four varieties of low frequency oscillator, or LFO.  Starting with the most basic is the tremolo LFO which also includes vibrato.  Tremolo and vibrato amounts can be set independently, but share LFO speed.  The tremolo LFO also has an envelope to control the attack or decay of the modulation.  Next is the random LFO which lets you target a destination page (synthesis, envelope, FX) and will randomly modulate all four parameters to the speed and depth you determine.  This LFO also has a simple envelope.  The value LFO is perhaps the most usable.  It allows you to choose one specific parameter to modulate, including the shift+knob functions of the various pages. The value LFO also lets you select from a retrigging LFO and a fixed LFO that constantly cycles in the background.  Sadly, these first three LFO types only operate with a sine shape.  The last LFO type is called element.  There are two sources for the element LFO: the g-force sensor and the line input.  The destinations for the element LFO are volume, synthesis, FX, and envelope.  With the g-force sensor enabled as the source, the position of the OP-1 itself controls the selected destination parameter.  Literally waving your expensive toy around in the air could control the filter frequency, for example.  The line input source for the element sequencer allows you to use the microphone, FM radio, or a connected device as your modulation source.  You could tune the FM radio to a static station for something along the lines of sample and hold, or tune it to talk or music for modulation with more rhythm.  The LFO section could stand more options in the way of waveshapes, but is fairly well-rounded.  This is the section where I could see putting in a second, assignable envelope to be used in lieu of an LFO.

Three sequencer types are available from the traditional to something entirely new.  Pattern is a 16 step grid sequencer typical of vintage drum machines, but with a few surprises.  Notes can be entered either 'live' as the sequencer runs, or by using a knob to advance the on-screen cursor.  Sequences in this mode are limited to just 16 steps, but once recorded there are several things you can do to squeeze more life out of them.  In addition to standard play mode, there is a reverse play mode, and a back and forth play mode.  Swing is also available on the pattern sequencer to create groove.  One of the more interesting tricks with the pattern sequencer is the ability to move notes within the sequence.  This can be helpful if you've tapped out a rhythm live and want to move the start point, but can be put to more creative uses as well.  Another control changes the end point of the sequence allowing you to repeat shorter sections or work in different time signatures.  Playing with the playback types, sequence end, and rotate note controls together makes for a fresh grid sequencing experience with entertaining results.

The endless sequencer allows up to 256 events to be entered in a linear fashion and played back with the keyboard.  The shift button is held when entering events to free the keyboard for transposed playback of your composition.  These sequences can be played backwards or random in addition to forwards, and a numeric display tells you which step of the sequence is being heard.  Selections for this sequencer include clock divisions, swing, and a pattern mask that inserts skips and rests over the sequence.

The last sequencer is called the tombola.  The tombola is a hexagon that can be spun in either direction at varying speeds.  Notes from the synthesizers or samplers are then dropped in and sound as dots that represent them hit the moving walls of the hexagon.  A knob allows the walls to be opened up to allow notes to escape, or to be left only partially open so the tombola has a temporary effect.  The gravity within the tombola as well as the mass of the notes dropped in it can be changed too.  I've had a lot of fun goofing around with this dropping vocal samples in, but was more pleased with the results I attained when using "electronic wind chime" sounds.  The tombola sequencer might not have a place in more structured music, but several tasteful layers of its output can create their own wonderful ambient soundscapes.

The final element that makes the OP-1 a proper standalone instrument is the 4-track tape recorder emulation, complete with editing functions.  Tape tracks are six minutes long at standard speed and record in mono.  Teenage Engineering have gone to a lot of effort to make the tape recorder resemble proper 4-tracks from the past.  The ease-of-use factor from those machines is the first thing you will notice as holding 'record' and pressing 'play' is all that is required to initiate a recording.  Beat-matching can also be turned on, so the tape will have visual markers at each measure and the sequencers will play in time with the tape. With this mode enabled, you can also hold 'record' and then press a note to initiate recording precisely at a beat marker.

Navigating the tape has been made easier than on the real thing.  In addition to simply holding fast forward or rewind (which audibly scrubs through your recorded audio), you can use the shift button with left or right arrows to move in full measure increments, or the stop button and left or right to move to the beginning or end of a tape track.  Loop points can also be set to work on specific pieces of your composition.

Track editing is carried out exactly as it would have been on a real tape machine, but thankfully Teenage Engineering have allowed for modern conveniences.  Dedicated buttons facilitate lifting and dropping sections of track up to 90 seconds, while another button allows to splice and rejoin sections.  All four sections of tape can be lifted and dropped simultaneously if the sections are under 22 seconds.

Four tracks may not seem like a lot to a DAW user, but the OP-1 has a different aesthetic and is frankly quite powerful for a portable instrument anyway.  Overdubbing is available on each track without any noticeable loss in quality, but recordings to the same track are destructive.  Tape tracks can record audio coming out of the main output, so bouncing can be achieved with a free track, but your stereo image will be lost as the tape tracks are each only mono.  You can also bounce between tape and album (the final .aiff rendering of your project) modes, but with the same loss of stereo.  I have found myself treating various sections of tape like I would patterns within a classic sequencer.  I might have a four bar section that I want a melody on, but don't need the pad, so I can record what I need to those four bars and lift and drop them where necessary.  There have also been instances where I might record two instruments on the same section of track, but leave clean versions of each take elsewhere on the tape.

The tape recorder does its job very well, and its simplicity are a breath of fresh air in an era of over-complicated DAWs.  Despite its simplicity and ease of use, though, there are a few interesting ways to exploit the tape recorder.  During playback, the blue knob lets you push the tape forward or pull it back for as long as you move the knob.  Subtle uses of this technique throughout a track can give songs an organic feel, or at least one of a cassette that sat on the dashboard for too long.  Tape speed can also be set in semitone increments from 25-200% of the regular tape speed.  This is a fun way to mess about with already recorded material, but can also be exploited to get more than 6 minutes out of each track.  Teenage Engineering report that higher tape speeds result in higher quality audio, but who's to say that the lower quality might possess a character that is not undesirable?  Holding the shift button while pressing 'play' initiates reverse playback, and material can also be recorded while moving in this direction.  I've made tracks with several passes of the tombola going first one way, and then the other while the first plays back in reverse and then again.  There are likely better uses for this technique, but just know that Teenage Engineering aren't hindering your creativity one bit.  Other dedicated buttons perform "tape tricks" such as break, reverse, and chop.  Break freezes the track with an audible slow down sound, and lets the track continue in time when released.  A very cool feature that will probably be overused by OP-1 owners for a while to come.  Reverse sends the playback backwards for as long as the button is held.  Chop repeats a small section of the track until it is released.

The tape recorder is fed into a final output stage that includes a mixer with level and pan settings, a three band EQ with wet and dry controls, a second instance of the insert effects but designed for stereo, and a stereo compressor.  There are also two buttons labeled 'M1' and 'M2' that each memorize a parameter page in this final output section for instant recall at a press.  Dropping a delay effect in as a fill at the end of the bar or completely killing the bass for a few measures are possible in a live performance context. The compressor has threshold control for both left and right channels as well as drive and release controls.  The drive on the compressor can also create a considerable amount of distortion if that is what you are after.  Finally, the album mode offers two "sides" of six minutes each to which your final stereo mix can be recorded with an additional layer of synthesis, drums, or live input (or all three if you're fast at switching), and all tape tricks.  This can then be easily exported to your computer as can each individual tape track using the on-board mini USB that the unit also uses for charging.

When I first saw the OP-1 on the web a while ago, I was unconvinced.  It was too physically attractive for me to take seriously as an instrument, and too small to command the price people expected to be paying for it.  Well, it is expensive, and it is attractive, but I am now a convert.  I wasn't even fully convinced when I ordered it that it would be just the thing I wanted it to be.  I was skeptical of its synthesis abilities based on the videos and audio clips I could find online.  The OP-1 has a 16 hour battery life, that was the main feature that sold me on it.  This could be my acoustic guitar, the instrument that I can take anywhere and play whenever I want.  Sure, there have been Microkorgs and other instruments before that could run on batteries, but for something like 4 hours and with disposable batteries.  The OP-1 isn't going to replace a Moog, but what will?  What it offers is highly versatile synthesis, dead-easy sampling, and the kind of recording you grew up with made easier all in one box.  It might lack MIDI connections, but I believe that it is more than good enough to use on its own.  It has a sound and character all its own, and its sounds deserve to be recorded to its facsimile of tape with a little warble thrown in here and there.  It covers all the bases while sounding original, and I can come home from the train with a track ready to be dragged onto my computer.  People may complain about the price, but a Korg Microsampler costs just less than the OP-1 and does about a third of what it can do.  I expect the OP-1 to be a polarizing instrument, partially because of its price, partially because of its form, but don't let anyone who hasn't used one make a criticism about its sound and workflow, because they have been thoughtfully crafted with the user in mind and the sum of its parts is beyond comparison.