Kreuzberg Audio have recently introduced a plug-in that combines filtering and wavefolding in a way that allows the two processes to complement each other rather than fight against each other. Best of all, it’s also the first of the company’s plug-ins to be offered for free!

The company say that Raspel is not a saturator with a filter bolted on, nor is it a filter with a drive knob that only affects the input. Its Drive control saturates the input of every single filter stage, delivering up to 30dB of boost in front of the filter, which is then attenuated again afterwards. The filter feedback remains linear, while the resonance simply gets ‘thicker’ under saturation rather than becoming unstable, even with Drive being pushed to its limits. The Drive control makes the sound denser rather than just louder, and the plug-in includes automatic gain compensation so that users can easily make their judgements based on character rather than being tricked into preferring the louder option. 

Sitting after the filter is a Character dial, which controls a wavefolder designed to introduce harmonics that allow bass sounds to remain audible on smaller speaker systems. It can also be pushed into more extreme territory: Kreuzberg Audio say that values between 0.1 and 0.3 allow sub-basses to gain some presence without getting thicker; values between 0.4 and 0.6 will start to turn bass sounds into a ‘metallic’ leads; going higher still will deliver aggressive sounds that are well suited to industrial tracks.

• Six filter types: LP2, LP4, LP6, HP2, HP4 and BP4, 20ms crossfade when switching.
• Saturation at the input of every filter stage, linear feedback, automatic gain compensation.
• Character wavefolder after the filter, bit-transparent at 0.
• Modern and Vintage modes.
• 1x, 2x, 4x and 8x Oversampling — 59, 108, 120 and 124 samples of latency at 48kHz.
• Zero-latency mono maker, 20 – 500 Hz
• Time-aligned parallel Mix control with no comb filtering.
• 14 automatable parameters, Smooth from 1 – 100 ms
• 50 factory presets, level matched to within 1dB.

Raspel is supported on PCs running Windows (64-bit, no minimum version specified), Macs running macOS 11 and above, and x86_64 Linux machines running Ubuntu 22.04 or later.

Raspel is available now as a free download.

kreuzberg-audio.com/en/downloads/raspel