Review – Curve 2.5 by Cableguys


New features that provide an edge in sound design throw the competition a “curve” ball.  With its easy to use waveform design, Curve 2 is powerful and intuitive.


by Rob Mitchell, July 2017


Even though I have reviewed many other music software plugins in my time with SoundBytes, I have had my eye on one plugin for a while. That plugin is Cableguys’ Curve 2.5. I guess it almost went under my radar, but when I heard many others mentioning its high-quality sound and easy to use interface, I thought it was time to check it out in detail. I will just refer to it as Curve hereafter.

Cableguys started out in 2007, and besides creating Curve they are the producers of many other music software plugins. Some of those include Timeshaper, PanCake, and MidiShaper. Located in Hamburg and Berlin, they continue to push the envelope in the creation of music software.

Curve is a three oscillator subtractive synth plugin with customizable waveforms, 7-voice unison, an easy-to-use interface, and high-quality sound. Curve is available in 32-bit or 64-bit for PC (VST) and Mac (VST and AU). It runs on Windows 7 and higher, and for the Mac it runs on OS X 10.6 or later. A 2 GHz CPU is recommended. Curve uses a license file for its copy protection.


The Browser


When you first load Curve, you might want to listen to some of its presets. To get to the browser, click on the Library tab towards the top of the display. It has a good number of presets to get you going, but if you use the Sync feature (in the menu at the top-right), it will automatically download a huge number of presets from various designers from around the world. At first there were five pages of presets from which to choose, but after running Sync, I found that I had 225 pages of presets on board. It can take a few minutes to download them all from the Cableguys server, and you can choose if you want to share your own presets as well. If you do, your presets will be uploaded when you run the Sync operation, and will be on their server for all the other Curve users. You are able to select which ones you wish to share, so it won’t just grab all of your creations and upload them.

Having so many presets is nice, but it can also be a bit overwhelming. Thankfully, this browser makes it easy to navigate through them, and get you headed in the right direction. The presets can be rated using a star system, and you can search (by Author or Name) through the presets using the menus over on the right side. You’re able to view just certain types, such as Leads or Pads, etc. Other choices include viewing all the presets that are available, approved presets, or just your creations. “Approved” means Cableguys went through those and decided they have a good volume level and play-ability.  When I switched to the Approved presets, I noticed it went from 225 pages of presets all the way down to 47 pages. You’re also able to see information about the preset and the designer in the lower-right. Some macro controls are here as well, which can be assigned to as many as eight different targets (per knob) for modulation.


Oscillators and Filters


Over on the left are the three oscillators, each of which can have two wave shapes. Crossfading is possible between the two shapes using the Crossfade control. This can be modulated in the modulation matrix, which I will get to later in the review. Other controls for the oscillators are Pitch, Detune, Pan and Volume. You can create up to ten wave shapes, and switch between them using drop-down menus. Besides the ten wave shapes, Noise is also available. You could (for instance) have a wave shape set up, but instead of another shape to crossfade to, you could have the Noise selected if you’d like.

Clicking the magnifying glass on each wave’s label will show that wave’s shape in the display up above for some detailed editing. Nodes in the display let you bend the shape the way you want (click/drag), and clicking in the display will add a new node for further manipulation. When you click the arrows at the upper-right of the wave display, it opens it up to a larger display making it easier to edit. You can use the various tools (Step Drawing, Snap to Grid, Note Grid, Randomize) to draw the shape you want, but there are standard preset shapes as well. These are located in the lower-right of the wave shape display and include Sine, Saw, Square, and Triangle. Undo and Redo controls are also available. As you change the shape, you will also see the harmonics that are displayed behind it. The harmonics can’t be edited directly, but it is useful to see what is going on with those while you’re in the editing process.

Each oscillator can be fed to the two filters in a few different ways: Filter 1 to Filter 2 (Series), Filter 1 only, Filter 2 only,  Filter 1+2 (Parallel), Filter 1+2 L+R (Filter 1 in left channel and Filter 2 in the right), or Bypass/Off. The two filters are identical, and there are several types to choose from: 6dB Clean Low and High Pass, 12dB Clean Low/Band/High Pass, Peak and Notch, 24dB Clean Low/Band/High Pass, 12dB and 24dB Sallen Key Low/Band/High Pass, and Notch. Standard cutoff and resonance controls are here, as well as Drive for saturated/distorting effects. A “Resonance Distortion” setting can be enabled with a Soft or Hard setting. The Soft setting sounds like it has a rounded, warmer edge to it, while the Hard setting can be very sharp and louder, especially with the resonance turned up.

Above the filters are the four macro controls, which are duplicates of the knobs on the Library page. You can change assignments for these by clicking the magnifying glass. Drag-and-drop functionality lets you select targets for the macros quickly and easily. The first macro is hardwired to the modulation wheel, and the second macro is assigned to aftertouch. The third macro is not assigned to anything in the way the first two are. The fourth macro is normally used to adjust the “Fatness” (various unison settings and volume), but you can reassign those to other targets if you’d like. The macros can all be mapped to knobs on your MIDI keyboard. If you don’t have aftertouch in your keyboard, you’re not out of luck with the second macro control since you can just assign it to whichever MIDI control you want.



Curve has four LFOs, and they are located to the right of the filter and macro sections. For each LFO, you can select from any of the ten wave shapes or choose the Noise. You just select one from the dropdown menu, but it doesn’t show it right away. To see the actual wave shape, you must click the magnifying glass icon. This is also the same way it works with the oscillators. At first I thought this was a little confusing, but once you know to do that, it becomes second nature. After you see it in the display at the top, you can then edit it if needed. Since these aren’t separate from the shapes that are for the oscillators, you have to be mindful that you don’t change them much if you’re using them for one of the oscillators already. I guess most people would just use the first three wave shapes for the oscillators, and the next three for the second wave shape of each oscillator (if needed). That would leave you with four shapes to use with the LFOs.

The rates can be set to Beat (1/8, 1/4, 1/2, 1 bar, 2 bars, etc.) or Hertz, and they can each be set to one of three modes: Synced (to the DAW), Retrigger and One-Shot. The speed of the LFOs can easily get into the audio-rate range. The additional mode called Pitch>Rate can be used for ring modulation, as the note/pitch you play sets the LFO speed. The Level setting controls the depth of the LFO, and the Speed control is for changing the rate when set to Hertz.



In addition to the ten wave shapes you can use, Curve 2 also has standard envelopes as well. These are for the amplitude, and there are two auxiliary envelopes you can use for whatever you’d like. You might assign one of the extra envelopes to filter cutoff, and the other envelope could be for something like the LFO speed. In the lower right, there are buttons to view the stages separately. Attack, Decay, or the Sustain/Loop stages will then have a larger, more precise view for editing. Clicking “All” lets you see the whole envelope once again. Other editing tools include easy presets for making it a linear or exponential envelope.

Just like with the wave shape editing, you can go in to each stage and add curves using nodes, or include some steps where you want. In the lower-right of the synth display are the Attack, Decay, Sustain/Loop and Release controls for the envelopes. One interesting way to use the Sustain/Loop portion of the envelope is to draw in any shape you want for that segment, and it will keep repeating that shape (like an LFO) until you release the keys. You can also use the menu that’s above the Loop control to switch between Beat or Time mode. When using Time mode, you can set the amount of time for the loop section (up to 32 seconds), or turn it off, and it will skip right over that segment. Beat works with settings that are just like the LFO Beat setting (1/4, 1/2, 1 bar, 2 bars, etc.).


Modulation Matrix

In lower part of the screen is the modulation matrix. It has the sources along the left and the targets for modulation at the top. Sources include velocity, envelopes, LFOs, and key tracking. The targets for modulation include LFO speed and level, FM, oscillator pitch, crossfade, volume, and filter settings.

On the right side of the main matrix is a smaller matrix that is for setting up additional FM options between the oscillators. You can also use the two envelopes (EG1 and EG2) to affect the velocity. 

In the OSC section of the matrix, when you hover your mouse over any of the boxes to add a numeric amount, a small popup appears to let you enter an amount for each of the three oscillators separately. This really cuts down the size of the matrix because you are getting three amounts taken care of in the space of each column. Otherwise, that section would be twelve columns across, using up valuable display space. Good idea!

To the right of the matrix sections are the settings for Glide, Unison, Detune, Spread, and Damping (this helps level out more than two unison voices). There are individual glide controls for each oscillator, plus mono, legato, and poly modes you can choose from. In the lower-right of the display you can set the pitch bend range, audio quality, volume level, and the polyphony amount (up to 32 voices).



Curve has numerous creative possibilities with its easily editable wave shapes and simple to use modulation matrix. The only thing I wished it also had was at least one effect to save with my presets; maybe a delay or chorus? Of course, you can just pick from your own effect plug-ins, mixing-and-matching with what you currently use. This works for me at the moment, but I’d like a couple of effects added in a future version.

Besides that small quibble, I really like Curve. It has so much potential with the settings for FM and modulation with the crossfade between wave shapes, it really is just a blast to use. The sonic quality is superb, the price is right, and the wealth of presets will get you started quickly if you aren’t much into preset design yourself.

Curve is available from the Cableguys website for $129 USD, or you can get their bundle deal which includes all their plugins for $179 USD. They have a trial version of Curve and audio examples on their website here:






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