Aqeel Aadam Sightlines: A Harmonic Filter You Can Play
Aqeel Aadam Sightlines is a playable harmonic filter for Mac, Windows and iOS. Eight tuned bandpass filters, three voice modes and deep modulation, from $20.
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Small developers keep finding fresh corners of synthesis. Aqeel Aadam Sound has staked out an interesting one. Released on September 3, 2026, Sightlines is a playable harmonic filter that behaves like an instrument one minute and an effect the next. It is built around a bank of resonant bandpass filters tuned to the harmonic series, and it runs on Mac, Windows and iOS from an introductory price of 20 USD.
At a glance: A harmonic filter plugin and instrument. Up to eight tuned resonant bandpass filters, three voice modes, and a full modulation matrix. It loads as an instrument or an effect, and quantizes to musical scales. Introductory price is 20 USD (regular 30 USD) on desktop and 7.99 USD on iOS, with a free 7-day trial. Formats are VST3, AU, AAX and AUv3.
What is Sightlines?
Most filters cut or boost a range and get out of the way. Sightlines does the opposite: it uses filtering as the sound source. Its engine is a bank of up to eight resonant bandpass filters, each tuned to a partial in the harmonic series, the way the overtones of a plucked string stack above a fundamental. Turn up a band and that overtone rings out. Set the resonance and feedback high and the filters start to sing on their own, like a struck or bowed object.
That places it next to physical-modeling and resonator tools such as Chromaphone 3 and sequenced resonators like Audio Damage Tessera, but Sightlines takes a simpler, more playable route. The filterbank first appeared inside the developer's Outgrowth instrument, and here it becomes a dedicated tool. It's the kind of instrument that draws from the same curiosity as granular boxes like Output Portal or the chance sampler in Chopgrid, where the fun is in shaping raw material rather than recalling a patch.
What Sightlines does
Instrument or effect, from one plugin
Sightlines loads two ways. As an instrument, it filters an internal source into new tones and plays across the keyboard over MIDI. As an effect, you drop it on a channel and it adds movement, resonance and tonality to whatever audio passes through. Tuned to a fixed frequency, it acts like a resonator; played over MIDI, it becomes a pitched voice. The same engine covers both jobs, which is a lot of range for one inexpensive plugin.
Eight tuned bands you shape by hand
The heart of it is the harmonic filterbank. Each of the up-to-eight bandpass filters has its own volume, so you sculpt a custom harmonic profile the way you would draw a spectrum. You can stretch and warp the harmonic series away from strict integer overtones for inharmonic, bell-like or metallic results, and quantize the whole set to musical scales so it stays in key. Resonance and feedback in the tuning section push the bands from gentle coloration into self-oscillating tones.
Three voice modes
As an instrument, Sightlines feeds its filters from one of three sources. A noise generator gives the filters raw material to carve into pitched tones. A sample player with repitch lets you run your own audio through the bank, and it reads WAV, AIFF, FLAC, OGG and MP3 files. A waveshaper synth adds a more traditional oscillator voice. Each mode changes the character of what the harmonic bands are resonating.
Deep modulation
None of this is static. A full modulation matrix drives any control from multiple LFOs, sequencers and smooth random sources, so bands can swell, retune and morph over time. Performance effects round out the signal on the way out. A sibling app called Waymaker extends this further with sequencing and pitch control over the output.
Sightlines specifications
| Spec | Detail |
|---|---|
| Type | Harmonic filter, playable as instrument or effect |
| Engine | Up to 8 resonant bandpass filters tuned to the harmonic series |
| Voice modes | Noise generator, sample player with repitch, waveshaper synth |
| Tuning | Per-band volume, harmonic warp/stretch, scale quantize, resonance, feedback |
| Modulation | Multiple LFOs, sequencers, smooth random sources, full mod matrix |
| Audio import | WAV, AIFF, FLAC, OGG, MP3 |
| Formats | VST3, AU (Mac), AAX, AUv3 (iOS) |
| Desktop OS | macOS 10.13+ (Intel and Apple Silicon), Windows 10+ (64-bit) |
| Mobile | iPad and iPhone (standalone and AUv3) |
| Trial | Free 7-day trial (no preset saving) |
Sightlines vs Chromaphone 3
The closest reference point is Chromaphone 3, Applied Acoustics' physical-modeling instrument. Both build sound from resonance rather than samples, but they aim at different users.
| Sightlines | Chromaphone 3 | |
|---|---|---|
| Price | 20 USD intro / 30 USD | 199 USD |
| Engine | Harmonic bandpass filterbank | Physical modeling of acoustic objects |
| Role | Instrument and audio effect | Instrument (percussion and mallet focus) |
| Platforms | Mac, Windows, iOS | Mac, Windows |
| Learning curve | Open-ended, patch-it-yourself | Preset-rich, guided |
Chromaphone 3 is the deeper, more finished instrument with a huge preset library and a decade of refinement, and it's the pick if you want realistic struck and plucked bodies out of the box. Sightlines costs a tenth as much, works as an effect as well as an instrument, and travels to iOS. If you like designing your own resonances and want the tool on a tablet, Sightlines earns its place. For a filter-first take on this territory, u-he Filterscape is another reference worth knowing.
Who Sightlines is for
Sightlines suits sound designers, ambient and experimental producers, and anyone who enjoys building textures from scratch. The instrument-or-effect flexibility means it is as useful on a drone patch as it is reshaping a vocal or a field recording. The low price and iOS build make it an easy tool to keep around for sketching ideas away from the studio.
It's a weaker fit if you want a synth that sounds complete the moment you load a preset, or if you already own a resonator you know inside out. This is a tool that gives back what you put into it.
How much does Sightlines cost?
Sightlines launched at an introductory 20 USD, up to a regular 30 USD, with the intro price running for a limited window after release. The iOS version is 7.99 USD on the App Store. A free 7-day trial unlocks every feature except preset saving, so you can test the workflow before buying. It's sold directly through the official Aqeel Aadam Sound page.
FAQ
Is Sightlines an instrument or an effect?
Both. The same plugin loads as a MIDI-playable instrument that filters an internal source, or as an audio effect that adds resonance and tonality to incoming audio. You choose the role when you insert it.
What are the system requirements for Sightlines?
On desktop it needs macOS 10.13 or later (Intel or Apple Silicon) or Windows 10 or later, 64-bit, in VST3, AU or AAX. There is also an iOS version for iPad and iPhone that runs standalone and as an AUv3 plugin.
How is Sightlines different from a normal filter or synth?
A normal filter shapes a sound that already exists. Sightlines uses a bank of harmonically tuned resonant filters as the sound source itself, so you play and modulate the overtones directly. It can quantize those overtones to scales and warp them away from strict harmonics for inharmonic tones.
Can I use my own samples in Sightlines?
Yes. The sample player voice mode repitches your own audio through the filterbank and reads WAV, AIFF, FLAC, OGG and MP3 files.
Verdict
Sightlines is a small plugin with a genuinely fresh idea: play the overtones, not just filter them. The eight tuned bands, three voice modes and deep modulation give it real range, and the instrument-or-effect design makes it useful far beyond one job. It asks you to experiment rather than lean on presets, which won't suit everyone. But at 20 USD, with an iOS build in the box, it's one of the most rewarding sound-design buys of the month.
