# Kuvert - Swedish Envelopes > Audio manipulation app with five drawable, looping envelopes for effect control. (iPhone/iPad app by Klevgränd produkter AB.) - Source: https://appshunter.io/ios/app/kuvert-swedish-envelopes/id1052691394 (this page in markdown: same URL + `.md`) - Developer: [Klevgränd produkter AB](https://appshunter.io/developer/1118902192) - Category: Music - Price: $9.99 - Rating: 3.70/5 from 19 App Store ratings · 15 written reviews indexed - Age rating: 4+ - Requires: iOS 7.0 · 9 MB - Languages: American English - Released: 2015-11-20 - Data updated: 2026-08-19 - Monetization: paid - User reviews in markdown: https://appshunter.io/ios/app/kuvert-swedish-envelopes/id1052691394/reviews.md ## What is Kuvert? Kuvert 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, while the incoming audio isn’t (unless you’re feeding it looped material of course). This is a powerful & fun way of altering your sounds to a whole new level, sometimes not even recognizable! Thanks to the looping nature of the plug-in, it will fit very well into any musical context. One way of using it would be to revitalize any looped material within a few seconds. Noteworthy features: • 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) Check out the product web page for a video demo. Feedback or suggestions? Drop us a mail: support(at)klevgrand.se or @klevgrand on Twitter ## Key features - Five drawable envelopes - Volume control - Filter envelopes - Glitch/timing alteration - Delay send control - MIDI clock sync - Preset saving ## Recent user reviews (10 of 15) All indexed reviews: https://appshunter.io/ios/app/kuvert-swedish-envelopes/id1052691394/reviews.md ### 5/5 — For this Price 👍 *2025-10-12, version 1.0* Even if IAA seems to be a Little old fashioned, this app is very intuitiv und interaktiv to create stunning drumlike patterns with. It is something of its own and should be maintained —-> AUV3 ### 1/5 — Works in Audiobus, but not in AUM *2023-09-27, version 1.0* Does what it says! Just make sure to use midi clocking, when using Kuvert for ex. in AUM. You can even use AUM's built in midi clock to start/stop Kuvert (via play button overlay) when using it in an fx chain etc. Very good tool! 2 years later: Not en par anymore, completely OUTDATED. 2023: Even more outdated, no AUv3. Uninstalled since years... ### 3/5 — Could be a 5 star app *2020-09-14, version 1.0* If this were an audio unit it would be one of the apps I’d use the most, but it’s not and I never use it, I bought the IPad version because I tried the desktop demo and thought I could use it as an audio unit like with the desktop version, guess I should have been more thorough when reading the description for the iPad version. If I’m being honest, not making this an audio just isn’t smart at all. ### 3/5 — AuV3 = * * * * * *2019-10-22, version 1.0* AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * AuV3 = * * * * * ### 4/5 — A sonic delight, but where is AU3? *2019-07-08, version 1.0* Beautifully designed, this is an elegant, easy to use and highly effective app for manipulating sound in subtle or not so subtle ways. It would benefit from a few decent presets, and an upgrade to AU4. Nic ### 1/5 — Doesn’t Work *2018-05-27, version 1.0* Running it in Cubasis through IAA on my fully updated iPad Pro. Does not work at all. It’s a shame because their other apps, especially Korvpressor, are great. ### 3/5 — Updated review *2018-03-08, version 1.0* This app works great now as IAA. This would be top notch as an au. Request to developer, please implement a gate mode triggered by midi notes. ### 5/5 — Pleasure, Principally *2017-06-27, version 1.0* Klevgr.'s effect apps have given me, as a noise generating techno thug, unbeforehad sound generating possibilities. Swedish Envelopes? It's Pandora's box of twisted perfection for the sound manipulater with a certain ear. ### 3/5 — A Few Issues... *2016-05-24, version 1.0* As another reviewer has stated, this doesn't work smoothly with Audiobus. Also, it doesn't fill the screen on my (large) iPad Pro; it just occupies the top left corner. This is annoying, but not the end of the world. It's frustrating that Klevgränd haven't updated this app since launch and made what I'm sure are fairly easy fixes. ### 4/5 — Nincompoops need not buy... *2016-04-15, version 1.0* ...this is brilliant. If I can find one fault it's the name. That's how good this is. Beautifully elegant interface with simple design. Load a piece of music (you'd own or not?) and mangle it. And have great control over the mangleability. Another of my made up words but you get it. You should get this app as well. ## Frequently asked questions about Kuvert ### What is Kuvert? Kuvert is an audio manipulation application that allows users to draw five different envelopes to control various effect parameters like volume, filters, and timing. It's designed to creatively alter sounds for music production. ### What devices does Kuvert support? Kuvert is currently supported on iPad devices. It was released on November 20, 2015, and its latest version is 1.0. ### How much does Kuvert cost? Kuvert is a paid application and costs $9.99. There are no in-app purchases or subscriptions associated with this app. ### Does Kuvert have ads? No, Kuvert does not contain advertisements. As a paid application, it offers an ad-free experience. ### What kind of effects can I create with Kuvert? You can create a wide range of effects, including volume shaping, filter sweeps with resonance, timing alterations for glitch effects, and tempo-synchronized delay sends. The looping nature of the envelopes allows for dynamic and evolving soundscapes. ### Can Kuvert sync with other music apps? Yes, Kuvert supports IAA (Inter-App Audio) with tempo sync if the host sends it, and MIDI clock sync. This allows it to integrate with other compatible music production applications on your device. ### What is the age rating for Kuvert? Kuvert has an age rating of 4+, making it suitable for a broad audience. The app focuses on creative audio manipulation tools. ### How often is Kuvert updated? The latest update for Kuvert was on November 20, 2015, with version 1.0. As of the provided data, there have been no subsequent updates. ## Version history (last 1 release) ### 1.0 — 2015-11-20 This app has been updated by Apple to display the Apple Watch app icon. ## Apps similar to Kuvert | App | Rating | Price | Category | | --- | --- | --- | --- | | [Kebarp AUv3 MIDI Arpeggiator](https://appshunter.io/ios/app/kebarp-auv3-midi-arpeggiator/id6479562640) | 4.8 (12) | $5.99 | Music | | [Async Sampler](https://appshunter.io/ios/app/async-sampler/id6453162970) | 4.5 (18) | $14.99 | Music | | [TAIP - Baby Audio](https://appshunter.io/ios/app/taip-baby-audio/id6446287957) | 5.0 (5) | $12.99 | Music | | [GSDSP Quantum Distortion](https://appshunter.io/ios/app/gsdsp-quantum-distortion/id6476145487) | 5.0 (10) | $14.99 | Music | | [spectwhirl](https://appshunter.io/ios/app/spectwhirl/id6471030896) | 4.0 (5) | $4.99 | Music | | [Mazetools Soniface Pro](https://appshunter.io/ios/app/mazetools-soniface-pro/id1232018647) | 4.7 (24) | $12.99 | Music | ## More apps by Klevgränd produkter AB - [SquashIt multiband distortion](https://appshunter.io/ios/app/squashit-multiband-distortion/id796836524) - [R0Verb multi delay-line space machine](https://appshunter.io/ios/app/r0verb-multi-delay-line-space-machine/id937195891) - [Svep - phaser, flanger, chorus](https://appshunter.io/ios/app/svep-phaser-flanger-chorus/id940079014) - [Enkl - monophonic synthesizer](https://appshunter.io/ios/app/enkl-monophonic-synthesizer/id968693910) - [Korvpressor](https://appshunter.io/ios/app/korvpressor/id995163144) - [Esspresso](https://appshunter.io/ios/app/esspresso/id1037999669) All apps by Klevgränd produkter AB: https://appshunter.io/developer/1118902192 --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-19.*