Since Sabine first invented digital feedback control in 1991, FBX Feedback Exterminators have set the standard for transparent and reliable automatic feedback control. Now Sabine is proud to announce the next generation of automatic feedback controllers: The FBX1200 and FBX2400, now with SMARTFilter™ Technology.


The power of the FBX with SMARTFilters lies in its ability to control feedback during the program, not just at setup time. If feedback occurs during that crucial moment of the show, in the middle of the big solo, or just when the worship leader begins the sermon, the FBX places a filter that only kills the feedback, not the sound and power you work so hard to achieve.

Think of the FBX as a very advanced set of automatic parametric filters. If you had the time, the filters, and the test equipment, you could find the feedback frequencies, dial in the precise filter location, and make a very narrow filter, just deep enough to remove the offending tone. The FBX does it all for you auto-matically, and it does it faster than any other method.

How do we do it? First let’s consider just how a superior feedback control filter should behave. Filters can be described by their Speed, Accuracy, Resolution, and Sonic Integrity.

The industry’s best digital signal processors that run the SMARTFilter algorithm give the new FBX1200 and 2400 a distinct speed advantage over all other automatic feedback controllers. And in Setup Mode the speed is increased, so you can complete your entire setup of the FBX in less than 30 seconds. During the show the 24-bit FBX is constantly on the watch for feedback, never allosing it to ruin your show. Filters are placed almost immediately (in 0.4 seconds at 1 KHz.)



This is a big one. Now that we know feedback is happening, we need to target it precisely. Many feedback controllers place their filters in the general vicinity of the feedback and then widen the filters until the feedback goes away. The FBX uses a more sophisticated solution. It centers the filter exactly on the frequency that is feeding back. This unique one-Hertz resolution enables the FBX to control feedback with transparent filters that are ten times narrower than graphic equalizer filters, which can only muster 31 spots to place their very wide filters. Feedback frequencies are single tones, and that means there can be almost 20,000 places for them to occur in the audio spectrum. You can see that using a feedback control device with less resolution is like shooting a fly with a shotgun. You may eventually get that fly, but it will take a lot of shooting and cause a lot of damage!

In contrast, the FBX 1200 and 2400 place these accurately chosen filters with on Hz resolution. this means a direct hit on a single feedback tone - every time.

Filter quality: True Constant Q filters maintain width at any depth when measured at the -3 dB power point. Sabine uses this most rigorous method for computing filter width.

Sabine’s innovative approach to digital filtering is unique in the industry. Our filters just sound better, with far less phase distortion and a smoother response. Sabine filters maintain their integrity at all depths, providing true Constant Q performance.

Some competitors tout the benefits of more filters, but why add more filters than you need? The FBX processor could easily produce 50 filters if we wanted them, but they would only degrade your sound. Our experience proves that twelve feedback filters per channel is the right number. More filters just cut into the quality of your sound.Some competitors tout ever narrower filters. The FBX processor can easily produce filters that are 1/100 of an octave wide, but our experience teaches us that filters narrower than 1/10 of an octave allow the feedback to return with very little provocation. Sabine filters are transparent to the ear and offer the ideal balance of width and protection against feedback under shifting conditions. Making them narrower ultimately degrades their performance, and we won’t do it.

The FBX1200 and 2400 give you the easiest, fastest, and quietest setup procedure. In less than 30 seconds you will be ready to begin your performance, and the whole process is so quiet you can almost do it without anyone knowing it is happening!

Even with all the improvements of SMARTFilters, and the improved specs and audio performance, perhaps the best news is that we lowered the price! And the FBX Feedback Exterminator is made in the USA. Call us or head to your nearest Sabine dealer and try the new FBX for yourself. You will hear your sound and nothing else!

Speed of feedback elimination, shown as amplitude over time: The top chart shows the speed of a competitor. Note slow reaction time and longer time to eliminate the feedback. The bottom section shows the much faster FBX.

Is it music or is it feedback? This is the most difficult question your feedback controller must answer. A wrong decision means you waste filters (less gain for you) and punch unnecessary holes in your sound. The FBX has always excelled in its ability to make the right decision, and the new SMARTFilter technology makes it even better. Less sophisticated feedback controllers place filters on any loud tone, even if it is music, but the FBX uses a patented analysis of the harmonic content of your program material. Because feedback is low in harmonics, and music and speech are rich in harmonics, the FBX is able to make the correct and accurate answer to the music or feedback question.


After the super-fast setup is complete the bright blue LED on the Ready button clearly tells you the show can begin, and you’ve got all the extra gain you need. You have complete control of the mix between filter types (see the Fixed and Dynamic Filter box above), and the bright, three-color LED display shows you your filter status at all times – you can see it from across the room!


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