# CuSnP — Resonant String Audio Unit > Sympathetic string simulation Audio Unit Extension for iOS DAWs. (iPhone/iPad app by Neon Silicon.) - Source: https://appshunter.io/ios/app/cusnp/id1418236738 (this page in markdown: same URL + `.md`) - Developer: [Neon Silicon](https://appshunter.io/developer/1409314093) - Category: Music - Price: Free - Rating: 4.80/5 from 36 App Store ratings · 10 written reviews indexed - Age rating: 4+ - Requires: iOS 11.0 · 9 MB - Languages: American English - Released: 2019-02-07 - Data updated: 2026-07-07 - Monetization: free - User reviews in markdown: https://appshunter.io/ios/app/cusnp/id1418236738/reviews.md ## What is CuSnP? CuSnP is an Audio Unit Extension, or AU, for the iPhone and iPad. This application is simply a container for the AU and serves only as the documentation. CuSnP must be used in some sort of AU host or DAW application. CuSnP is a sympathetic string simulation. Input audio excites the strings and causes them to resonate much like the open strings on a piano will resonate when some other sound source excites them. ## Key features - Sympathetic string simulation - Audio Unit Extension (AU) - Resonates with input audio - Container for AU functionality - Documentation included ## Recent user reviews (10 of 10) All indexed reviews: https://appshunter.io/ios/app/cusnp/id1418236738/reviews.md ### 5/5 — The best *2024-07-04* This is amazing, I like how simple it is to use it but I do have some crazy suggestions: be able to “simulate” more than just 14 strings, you should be able to do 21 or 24. Next: you should be able to simulate audio being passed through piano strings (88 strings), but it would be disabled by default as it would not run well on low end devices, and a 2nd option for simulating all 230 strings. Besides that, 5/5 stars ### 5/5 — Excellent effect *2022-09-06* This a great effect, I love it and use it often on my contrabass. Thank you for your creative work. ### 5/5 — God's own app *2021-07-02* This app is amazing and what id been lookig for a long time. I tried midi guitar and other similar apps, they had good things i liked but lacked the crucial ability to shift the master tuning, theyre all stuck in 440hz which is on its way out and dead sounding after a hundred years of it. so i needed an ability not only to shift master tuning (as Oval synth does admirably with no lag time or reduced quality) but adjust each individual string as I am using a just 432 tuning on guitar and also have to account for intonation issues etc. This app is literally perfect for it, it's really well made and best of all free, which I have lately been thinking is really the sign of the greatest work because it shows it is like a gift of love from the developer, not just a quick buck with a gimmick and flashy write up to sell itself, anything like that is eventually discovered to be tacky and just about useless, because money corrupts, but this unassuming app I actually overlooked months ago, is free and has no adds etc, perfect. THANK YOU to the developer, you are a genius and understand music on a deep level. This has really enriched so much about music for me now. I am still programming in different keys but it's fun to program them in and then turn monitoring and hear it, wow. It also gives enough strings i think i can tune to account for strings varying tuning while playing for example have three strings set to 432,433,434 if that particular string tends to tune up on that note while playin, and if i'm correct it should recognize them specifically and still sound good like guitar. I am also experimenting with this developers chorus and eq plugins, they seem to be amazing too, with the eq in seconds i had better sound than with garageband eq only, even better than garageband + amplitube eq, now i am using amplitube for their compressor and this eq and then the resonant strings. Btw one thing developer might like to know is i overlooked this plugin due to the unremarkable name, CuSnP, i thought what is that, doesnt seem that great (!) and didnt even read the info. Well, now i have and realized it might be exactly what i wanted and it is and more. it's really cool. Thanks again! ### 5/5 — Like this for ‘flattening’ percussive sounds. *2021-04-26, version 1.8* So if a percussive sound hits this, it suddenly flattens and disperses? Just try it, when you want a dramatic change in say, a piano track in your mix. Almost makes it a pad sound. You can remove certain frequencies represented by wires horizontally, and so change the overall character. I suppose it’s like an EQ in that way, but the ‘unseen’ harmonics are removed, or not created, as well. If a certain piece ends up becoming an ambient or drone-type feel, I throw this in if there’s an instrument I want to knock the percussion, sudden-ness out of. It’s something I try quite a lot, and decide whether the song takes to the whole new character of the sound, or not. Also, the original source is still there in character, to an extent. I don’t think I tried it on drums, but that would be the ultimate percussive change, must at least try this! ### 5/5 — Genius concept *2020-08-24* I had no idea how much I needed this till I found it. Love how it can make midi instruments sound so much more like live instruments ### 5/5 — A gem! *2020-03-27, version 1.6* This a brilliant little app that will work magic in almost any mix where you want to add real character to sounds. Get it. ### 5/5 — Modulate subtlety, or total weirdness. *2019-07-09* I utilize this app in so many unorthodox ways. It creates some very unique morphing possibilities. ### 5/5 — Run anything and everything through it! *2019-05-02* I like it. And this devs other apps. Get them all! ### 5/5 — Pseudo guitar synth *2019-02-21* Or a resonant Indian type pad thing to play over. I think this is epic and amazing technology. You can pick the harmonic idea or not it sounds neat either way, hails. ### 5/5 — Nice effect *2019-02-06, version 1.0* Thank you what a loverly little app for adding a harmonic edge to piano strings and pads. It’s free it sounds good and I’m pleased to give it 5 stars. ## Frequently asked questions about CuSnP ### What is CuSnP? CuSnP is an Audio Unit Extension (AU) for iPhone and iPad that simulates sympathetic strings. It requires a host application like a DAW to be used. ### How does CuSnP work? Input audio excites the simulated strings within CuSnP, causing them to resonate. This creates a sympathetic resonance effect similar to open piano strings vibrating with other sounds. ### Can I use CuSnP on its own? No, CuSnP is a container for an Audio Unit Extension and must be used within another AU host or Digital Audio Workstation (DAW) application on your iPhone or iPad. ### What devices does CuSnP support? CuSnP is supported on iPhone, iPad, and iPod devices, running on iOS. ### Is CuSnP free to use? Yes, CuSnP is available for free. There are no in-app purchases or subscription fees associated with this application. ### How often is CuSnP updated? The latest version of CuSnP is 1.8, released on April 13, 2021. Updates are provided by the developer, Neon Silicon. ### What is the age rating for CuSnP? CuSnP has an age rating of 4+, making it suitable for a wide range of users. ### Does CuSnP have ads? No, CuSnP does not contain advertisements. It is a free application without any ad interruptions. ## Version history (last 5 releases) ### 1.8 — 2021-04-13 Added support for running on macOS Fixed a bug that could cause a crash when dragging a preset file onto the presets panel. Fixed a bug that could cause a crash when an AU host deleted a preset. Fixed a bug that caused issues with loading user presets on some hosts. Added support for exporting presets to the macOS version of CuSnP. ### 1.7 — 2020-09-20 Added support to allow Audio Unit hosts to access and store user presets in CuSnP. ### 1.6 — 2019-10-23 Added the ability to set the string frequency using MIDI note and pitch bend. Please see the documentation in the app for how to use this new feature. ### 1.5 — 2019-08-19 Added support for basic parameter automation and MIDI automation. Some enhancements to support user presets. ### 1.4 — 2019-05-13 Memory usage optimizations. Fixes for potential memory leaks. ## Apps similar to CuSnP | App | Rating | Price | Category | | --- | --- | --- | --- | | [Zero Reverb](https://appshunter.io/ios/app/zero-reverb/id1051938245) | 3.3 (45) | Free | Music | | [TB GonioMeter](https://appshunter.io/ios/app/tb-goniometer/id6444903624) | 4.8 (22) | Free | Music | | [Zero Chorus](https://appshunter.io/ios/app/zero-chorus/id1056863629) | 4.2 (21) | Free | Music | | [Viking Synth](https://appshunter.io/ios/app/viking-synth/id1085274012) | 4.7 (39) | Free | Music | | [GSDSP MMM](https://appshunter.io/ios/app/gsdsp-mmm/id6443846329) | 4.8 (34) | Free | Music | | [skippodisk](https://appshunter.io/ios/app/skippodisk/id6449685454) | 4.9 (10) | Free | Music | ## More apps by Neon Silicon - [LRC5](https://appshunter.io/ios/app/lrc5/id1418930761) - [GyroVibe](https://appshunter.io/ios/app/gyrovibe/id1461657653) - [PhaseDelayArray](https://appshunter.io/ios/app/phasedelayarray/id1472910992) - [NeSi xTrem](https://appshunter.io/ios/app/nesi-xtrem/id1553303748) - [LRC7](https://appshunter.io/ios/app/lrc7/id1562010770) All apps by Neon Silicon: https://appshunter.io/developer/1409314093 --- *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 2026-07-07.*