The Marani DFP-225 Professional Digital Feedback Eliminator is a 1 rack unit device that utilizes two distinct approaches to managing feedback. The first approach utilizes dynamic band scanning and the placement of automatic high precision notch filters to cancel audio feedback in musical applications. The unit analyzes the frequencies in the signal, determines which frequencies are causing feedback, and uses 25 real time notch filters per channel in adjustable steps to attenuate the feedback by up to -45 dB. The settings of the notch filters are automatically stored in EEprom memory and must be saved to one of the device's 16 user presets for future use before powering off the device. The unit also has 4 factory presets.
The second approach is to avoid feedback altogether by utilizing a frequency shift mode. In this mode, the entire frequency spectrum is shifted by an adjustable 1 to 4.5 Hz across the spectrum to avoid any frequencies from feeding back while retaining the original harmonic ratios of the signal. The frequency shift mode slightly changes the tone of the signal band and is useful for vocal applications.
The feedback eliminator can operate in dual channel, stereo, or mono mode, and includes an analog bypass circuit for easily removing it from the signal chain. It accepts both line level and microphone inputs, and includes selectable +48V phantom power. For I/O, the device uses both balanced XLR and balanced 1/4" TRS connectors for both channels of the input and output.
- To prevent clipping, the device includes a built-in limiter
- For time alignment of different speakers, the device includes an adjustable digital delay between 000.0000 ms to 848.9984 ms in steps of 1 ms or 20.8 μs
- Analog Bypass Circuit
- You can easily remove the feedback eliminator from the signal chain by engaging the devices analog bypass circuit
- USB Control
- All device presets and feedback parameters can be controlled over USB from a computer running the Marani control software for Windows, which you can download for free from the Marani website