Review – Linplug’s Spectral

Linplug says that Spectral is the “result of fourteen years of synthesizer building experience”. Our reviewer thinks those fourteen years were well spent resulting in an innovative and elegant product.

by Warren Burt, Jan. 2014

Linplug Spectral: A Synth to Help Change Your Mind

Linplug’s Spectral is their latest offering ( – 149 US$/119 Euro – 32 and 64 bit versions available – AU and VST plugins for Mac or PC).  They describe it as the “result of 14 years of synthesizer building experience,” and on the basis of this innovative and well thought out product, those 14 years were well spent. 

I’ve been a happy Linplug user for many years, so when I found out that they were releasing Spectral, I didn’t hesitate to buy it.  Spectral is a semi-modular softsynth that combines elements of both additive and subtractive synthesis, but in a really unique way.  Each timbre can be made up of 1-4 oscillators, each of which can have its own (custom-drawn) waveform, and each of which can have its own (custom drawn) filter.  So far, so normal (except maybe for the custom drawing bit).  But it’s the many features of those oscillators and filters, and how they can modulate each other that are the first point of difference and where a lot of the charm of Spectral lies.  Each oscillator has two waveforms, which can be morphed between.  Each oscillator has its own envelope, and auxiliary envelopes and LFOs can control the morphing, as well as anything else.  The waveform drawing is done by changing a graph of strengths of harmonics.  There is a large editor window for this with lots of ways of drawing and changing waveforms.  The filter drawing also is done on a large editor window with again, many options for changing filter shapes.  There are also many preset filter and waveform shapes and the user can save their own as well.

Each oscillator, on its own, or processed through its associated filter can then be sent to any other oscillator or filter to either amplitude modulate (AM), frequency modulate (FM), or phase modulate (PM) any other oscillator or filter.  Each oscillator and filter has 2 modulation inputs for a total of 4 ways to modulate each oscillator/filter pair.  And each of these controls has a knob which can control the input amplitude of the oscillator or osc/filter pair. Given that one can set up multiple feedback patterns with the oscillators and the filters, the possibilities implied here are truly immense.

Many people investigate a new synthesizer to find out what premade sounds it has.  Spectral has about 850 presets many of which are lovely.  For many people, this may be the reason they’ll buy this synth, but I’m not one of those.  After 45 years of playing with synthesizers, I want machines that give me sound making structures I haven’t encountered before and ways of making sounds that will encourage me to try things I haven’t tried before.  I want a machine to help me change my mind.  Spectral is one of those machines.  The possibilities for oscillator/filter inter-modulation, combined with the means of drawing both waveforms and filter curves, and the ability to do real-time timbre modification on the oscillators, makes this a very powerful machine.

And then, like all LinPlug products, it takes TUN files (from the free Scala program), so that all that timbral power can be played microtonally.  So now we’re talking about incredible pitch power combined with the timbral resources of the machine.   AND, in addition to the modulation power of all the envelopes and LFOs, with the ECS feature, you can make anything on the front panel externally controllable through MIDI.  I’ve been playing a lot with Spectral over the past few weeks – going slowly through the manual, feature by feature, and every day I’m more and more impressed.  Although you can just load it up and play the excellent presets, that’s really just scratching the surface of this synth powerhouse.  I really do strongly recommend that, as I did, you go through the manual slowly and carefully – there are too many neat features that could be overlooked otherwise, each of which provides more resources and compositional ideas. 

The machine is a very powerful one and it needs CPU power to match it.  Working on an i3 processor laptop computer, with simpler sounds, I found that without the “Spread” control on the oscillators, I had all the CPU power I needed – unless I was using a sound with a long decay and fast arpeggiation.  With some of the presets however, ones that used all four oscillators with “Spread” control on in some of them, I ran out of CPU power very quickly – a sustained five voice chord could easily push the CPU meter into the red.  I fared better on a Dell Optimax 990 with an i5 processor.  With that I was able to have 8 voice arpeggios where all the voices had long decays (more than 5 seconds) and only use 55% of the CPU power.  That said, the spread control is a pretty wonderful beast.  On each individual oscillator, you can have up to six copies of any oscillator, spread through a band of ± 50 cents.  That’s enough of a spread to create all sorts of slippery, beating sounds from your original timbre.  And your voices can have a variety of stereo spreads, which can also be controlled from an envelope or LFO.  If you have a computer powerful enough to handle the demands of multiple oscillators with Spread on, you’re going to have a lot of fun.

Being LinPlug, of course, there is also a very powerful Mod Matrix with 35 sources and more than 100 destinations.  Each modulation can be scaled positively or negatively, of course.  And the Modulation depth of any slot can also be controlled, either with internal signals, or with external MIDI through the ECS.

I’m usually not all that interested in arpeggiators, but the one on Spectral really excites me.  It has up to 32 steps, and for each steps 5 parameters can be adjusted: transposition, note velocity (or rest or tie), note force (where a particular member of the incoming chord will always be played), glide, and note duration.  Overall control of tempo, kind of arpeggiation, number of steps, number of octaves in the arpeggio, and swing are all able to be externally MIDI controlled.  LinPlug has always had powerful arpeggiators in their earlier synths, but this puts all the good features together in a way that makes something that is more like a powerful interactive composing environment than a simple arpeggiator.

There are 14 effects in the machine which, like the oscillators and filters, are capable of a wide range of parallel and serial patching.  And again, all the parameters of those are controllable either internally or by external MIDI.

Spectral also comes with the standard LinPlug “Chord Memory” feature – which again, will add to the power of the Arpeggiator – and an “Exact” control.  Moving this away from 100% introduces irregularities into the sound, for those who want the warmth of old-style analog. 

There are a couple of “gotchas” I’ve found with the machine.  The “Main Envelope” which controls the volume of all the mixed oscillators is easy to overlook.  It’s very near the bottom of the envelope selection list, so when you can’t get the envelope you want despite how many of the individual oscillator and filter envelopes you’ve adjusted, check the “Main Envelope.”  Adjusting that will probably give you the overall shape you want.  Also, when adjusting the ECS to add external MIDI control, be sure to turn it off after adding your desired controls, or you’ll end up with all sorts of things controlled you didn’t want.

The above are learning-curve things, of course.   Spectral is a very powerful synthesizer (reasonably priced, too!) with a huge range of resources and possibilities.  Learn it slowly – it will provide you with many years of composing and timbral exploration discoveries.  I know that I’ll be devoting a lot of my time to exploring it.

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