Kuvert Lets You Create Complex Envelope-Controlled Rhythmic Effects


Klevgränd Produktion AB has introduced Kuvert – the ‘Swedish Envelope app’.

Kurvert allows you to draw five different envelopes. These envelopes control different effect parameters, and can be drawn freely or onto a grid. The envelopes are looped, letting you create complex rhythmic effects synced to your music.

Here’s a video intro:



  • Volume envelope
  • Low cut filter envelope (with resonance)
  • High cut filter envelope (with resonance)
  • “Glitch” envelope (alters timing)
  • Delay send envelope (with tempo synchronised time, filter and feedback
  • IAA (With tempo sync if host sends it)
  • MIDI clock sync
  • Load / Save presets
  • Audiobus
  • Documentation (on the product web page)

Kuvert is available now for US $4.99 in the App Store.

18 thoughts on “Kuvert Lets You Create Complex Envelope-Controlled Rhythmic Effects

  1. This one is really, REALLY good .. (actually Forking Fantastic).

    As is par for Klevgrand the UI is a masterpiece and the app hits several sweet spots in one go.

    I’ve gone in for both the iOS and AU versions and Kuvert continues to surprise and delight.

  2. How is this easier or better than using an envelope editor in Ableton Live against whatever effects you choose? And I don’t mean the question to be snarky at all; I have seen so many of these enveloped multi-effects being sold and I wonder where the market is.

  3. $9.99 for the VST version, here is the link. http://klevgrand.se/products/kuvert/
    This is like LFO tool but cheaper–it loops the effects, ableton doesn’t have any similar offering without digging into
    clip automation (only affects that clip in particular and often leaves undesired settings when you go to the next clip…)or drawing tons of envelopes in arrangement view.

  4. I never really understood the place an ios app would have in the workflow chain of a music production studio. putting it behind the microphone to control the envelope would be a shitty idea because it fucks up the signal (ipad converters!?!?!?! really???) and using it post on a drum loop must be awkward and time consuming, having to upload it to your ipad, edit it and transfer it back to your workstation. ipads are not meant for a studio. plus, the effects demonstrated in this video can be easily replicated using automation and step sequencer-controlled filters. cubase has a step-controlled filter built-in. you can also use guitar rig with way more powerful options. again, this app is missing its point. maybe for live performances but then again, how is this going to work if you want to combine it with other loops and effects? the sheer absurdity of these ios audio apps amazes me.

    1. I totally agree. By extension I have never really understood the place a computer has in the workflow of a professional studio. Everything you can do with a computer you can do with outboard gear and tape. And say you do something worthwhile on a computer – crazy talk, right? – how are you going to get it over to tape? Transfer it through the awful converters in the computer? Really? The sheer absurdity of computer music programs astounds me.

      Computers and iPads are not meant for the studio!

      1. Ya, and what the hell is up with this electricity thing?? Sounds was never meant to travelling in anything other than a gaseous medium.

    2. It makes sense if you are making music entirely with your iOS device (which many do). Until recently, there was really no traditional “VST” as it were, for iOS apps. So the workflow is that you route things through other things. Like you route your synth/drum machine through FX (like this) to whatever app you are recording to. Also, now with things like Audiomux, you can literally route audio on your mac through your iPad with just a simple lightning cable, essentially turning your iPad into a sort of VST plugin.

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