Filterjam, developed by AudioThing Ltd., is a free iPhone application that offers a unique and versatile multi-band resonant filter. With Filterjam, users can create weird ringmod-like filtered sounds by dividing the input signal into four bands and then summing or multiplying them together based on the selected mode.

Whether you're looking to add a touch of brightness or depth to synth sounds or completely mangle acoustic sources, Filterjam provides a range of possibilities. Its intuitive interface allows users to easily tweak the filter parameters and experiment with different settings to achieve their desired sound.

With its ability to deliver both harsh and gentle filtering effects, Filterjam is a powerful tool for musicians, sound designers, and anyone looking to explore new sonic territories. Whether you're a beginner or an experienced user, Filterjam offers a straightforward and accessible way to create unique filtered sounds on your iPhone.