Processing
Best Feedback Eliminators for Churches
Quick answer
A feedback eliminator buys roughly 3 to 6 dB of extra gain before feedback, and no more. Moving from a lapel to a headworn microphone buys 6 to 10 dB for less money, so the box is worth buying only after the microphone and the loudspeaker aiming are already right.
This page exists to sell you a box only if you still need one after reading it. A feedback suppressor listens for the sustained ring that precedes howl and drops a very narrow notch filter onto that frequency. It works, it is genuinely useful on a lectern microphone in a hard room, and it is routinely asked to fix problems that are not electrical at all.
What causes feedback is a loop: the microphone hears the loudspeaker, the system amplifies it, the loudspeaker plays it louder, round again. Everything that helps either shortens the loop or reduces its gain. Start with how to eliminate feedback in a church and gain structure for church sound, because both are free.
On this page
What actually buys gain before feedback
Each fix and roughly what it is worth. The figures come from the physics of distance and microphone directivity, not from a product claim.
Halving the distance from the mouth to the microphone is worth about 6 dB, which is more than a feedback eliminator delivers and costs nothing at all.
| Fix | Roughly worth | Cost | Why it works |
|---|---|---|---|
| Halve the mouth to microphone distance | 6 dB | Free | Inverse square law: the wanted signal doubles in level, the room does not |
| Move the microphone behind the loudspeakers | 6 to 10 dB | Free | The microphone stops sitting in the loudspeaker coverage pattern |
| Aim the loudspeakers down at the congregation | 3 to 6 dB | Free | Less energy reaches the platform and the rear wall |
| Lapel to headworn microphone | 6 to 10 dB | About $54 for a capsule | The capsule keeps a fixed short distance from the mouth |
| Cardioid to supercardioid or hypercardioid | 2 to 3 dB | About $70 more | Higher directivity rejects more of the reflected room energy |
| Notch the two or three ringing frequencies by ear | 3 to 6 dB | Free with any EQ | Removes the specific frequencies where the loop gain is highest |
| Automatic feedback suppressor | 3 to 6 dB | $169 to $485 | Finds and notches ringing frequencies faster than a person can |
| Acoustic treatment of the rear wall | 2 to 4 dB | $59 and up | Reduces the reflected energy returning to the microphone |
These gains do not simply add up, because each one changes the conditions for the next. The order matters though: the free fixes are also the largest ones, which is why a church that buys the box first is usually disappointed by it.
What a feedback eliminator will not do
It will not fix a microphone pointed at a loudspeaker. If the lectern sits in front of the mains, the loop gain is so high that the unit will notch filter after filter, and by the time it has enough notches to hold the system quiet the voice sounds hollow and thin. The notches are doing exactly what they were asked to do and the result is still bad.
It will not fix a choir microphone hung too far from the choir. Distance is the enemy here: a hanging condenser three feet above singers needs far less gain than the same microphone six feet above them, and the difference is 6 dB before anything else has been tried. That geometry is the whole of the choir microphone problem.
It will not fix a gain structure problem. If the channel is running at low gain into a fader pushed to the top, the noise floor and the room both come up with the voice. And it will not fix a room. A three second reverberation time in a stone sanctuary means the loop energy stays in the room long enough to build, and that is an acoustic problem addressed in acoustic treatment for churches.
Small church: one persistent problem microphone
The usual small church case is one microphone that rings, normally a lapel on a pastor who walks, or a lectern microphone in a room with a hard rear wall. A cheap dedicated unit on that one channel is a reasonable purchase once the free fixes have been tried. Insert it on the channel rather than across the whole system, so the filters only affect the microphone that needs them.
Behringer FEEDBACK DESTROYER PRO FBQ2496 Automatic and Ultra-Fast Feedback Destroyer/Parametric EQ with 40 FBQ Filters and 96 kHz Audio Performance
$169.00Automatic feedback detection with twenty filters per channel at a fraction of the dedicated dbx price. It works, and it is less transparent than the more expensive units when it is working hard, which matters less on speech than on music.
Best for: One problem microphone and a small budget
Check price on Amazon
Shure PGA31-TQG Wireless Headworn Condenser Microphone
$54.00The headworn capsule from the BLX bodypack sold on its own. Converting a preacher from a lapel to a headworn capsule buys 6 to 10 dB of gain before feedback, which is more than any suppressor on this page, for the price of a cable.
Best for: A church that already owns a wireless bodypack and has a feedback problem
Check price on AmazonWho should not buy this tier: Music channels, where twenty automatic notch filters across a full band mix audibly hollow out the sound.
Mid-size: suppression as part of system processing
In a mid-size church the feedback problem is rarely alone. The same room that rings is usually untuned, uncrossed and unlimited, and a unit that solves all of those at once is better value than a dedicated box. The exception is a church that already owns a processor and needs suppression on specific channels only.
dbx DriveRack PA2 2x6 PA Complete Professional Loudspeaker Management System, Rack Mountable with Android and iOS Control. Black
$426.00 Specs and sizingFeedback suppression alongside crossover, room tuning, delay and limiting in one rack unit. For a church with no processor yet, this costs less than the dedicated feedback unit and solves four more problems.
Best for: A church buying its first system processor
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dbx AFS2 Advanced Feedback Suppression Processor with Full LCD Display
$485.00 Specs and sizingTwo channels with both fixed and live filter modes, so the filters found during a soundcheck stay put and a separate bank remains free to catch something new during the service. That split is the reason to pay for the dedicated box.
Best for: Lapel and lectern microphones in a room with hard surfaces
Check price on AmazonWho should not buy this tier: Churches whose feedback comes from loudspeakers aimed at the platform, which is a placement problem no filter solves.
Large room or multi-campus: fix the source instead
Large churches with persistent feedback almost never solve it with another processor. They solve it with the microphone, because the source is where the ratio of wanted signal to room energy is set. A directional headworn capsule at an inch from the mouth in a 1,000 seat room is a different problem from a lapel at eight inches, and no box closes that gap. These are the purchases that actually end the problem.
Sennheiser EW-D ME3 Dynamic Headset SET (R1-6)
$669.86 Specs and sizingA cardioid headworn capsule on a digital wireless platform with a 56 MHz tuning range. The directional pattern plus a fixed short mouth distance is the most feedback-resistant combination a preacher can wear, and there is no compander and no gain knob to set wrongly.
Best for: High ceilings, hard surfaces and a wireless preaching microphone
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Countryman E6 Directional Earset Microphone for Vocals with 2mm Cable and TA4F Connector for Shure Wireless - Light Beig
$511.13 Specs and sizingA directional earset that is nearly invisible on camera, which matters on a livestreamed platform. The directional version is the one to buy for a church: the omnidirectional variant gives away most of the advantage.
Best for: Preaching that must look clean on camera and survive a loud room
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dbx 286s Microphone Processor.
$345.00A microphone preamp with compression, de-essing and an expander gate. The gate is the piece that helps here: it closes the channel when nobody is speaking, which removes the open microphone from the feedback loop between sentences.
Best for: One channel, the preaching microphone, especially for a speaker who paces
Check price on AmazonWho should not buy this tier: Do not buy this tier as a feedback fix for a small church with a single wired microphone at a lectern. At that scale the money is far better spent on a headworn capsule and on aiming the loudspeakers properly, and a premium earset for a room that holds eighty people is a solution looking for its problem.
The feedback units compared
| Model | Price | Video inputs | Video outputs | Rack space | Onboard DSP |
|---|---|---|---|---|---|
| dbx AFS2 Advanced Feedback Suppression Processor with Full LCD Display | $485.00 | 2 | 2 | 1U | Yes |
| Behringer FEEDBACK DESTROYER PRO FBQ2496 Automatic and Ultra-Fast Feedback Destroyer/Parametric EQ with 40 FBQ Filters and 96 kHz Audio Performance | $169.00 | 2 | 2 | 1U | Yes |
| dbx DriveRack PA2 2x6 PA Complete Professional Loudspeaker Management System, Rack Mountable with Android and iOS Control. Black | $426.00 | 2 | 6 | 1U | Yes |
How we chose
We did not test these products in person and we never claim to. Picks are researched from manufacturer specification sheets and operator manuals, FCC rules where spectrum is involved, published standards, warranty terms, and the recurring themes in verified owner reviews. Every pick is matched to a real room size, seat count or input list rather than to a price bracket, and it is placed in the tier where its capability actually belongs. Where a product is wrong for most churches we say so on the page.
Sources
- Manufacturer published specifications for each suppressor listed
- Microphone directivity factors as published by the manufacturers
- Consensus of verified owner reviews across major retailers
Frequently asked questions
Do feedback eliminators actually work?
Yes, within a narrow scope. They find the frequency that is ringing and drop a very narrow filter on it, typically recovering 3 to 6 dB of usable gain. That is a real improvement on a lectern or lapel channel. It is also less than you get from moving the microphone closer to the mouth or out of the loudspeaker coverage, both of which cost nothing.
Why does our church microphone feed back at the same pitch every week?
Because the room has a mode, or the loudspeaker and microphone geometry has a resonance, at that frequency, and it is the first place the loop gain reaches unity. A fixed notch filter at that frequency, set once during a quiet weekday, solves that specific ring permanently. If a new pitch appears after the first is notched, you are close to the limit of what the geometry allows.
Should a feedback suppressor go on the main output or on a channel?
On the channel that has the problem, wherever the console allows it. Filters on the main output affect the whole mix, including music, which is where automatic notching sounds worst. Inserting on the lapel or lectern channel alone keeps the filters where they are needed and leaves the band untouched, and it is also why a two channel unit is enough for most churches.
Will a better microphone stop feedback?
Often, yes, more than any processor. A supercardioid or hypercardioid pattern rejects more reflected room energy than a cardioid, worth roughly 2 to 3 dB. A headworn capsule an inch from the mouth instead of a lapel eight inches away is worth 6 to 10 dB, because the wanted signal is much stronger while the room is unchanged. That is the largest single improvement available.
Can acoustic treatment reduce feedback?
It helps, indirectly. Absorption reduces the reflected energy returning to the open microphone, which lowers the loop gain and typically buys 2 to 4 dB in a hard room. It also improves speech intelligibility, which is usually the real complaint underneath a feedback complaint. Corner bass traps and rear wall panels do more than scattered foam squares.
Is a gate the same as a feedback eliminator?
No. A gate closes a channel when nobody is speaking, which removes that microphone from the feedback loop between sentences and reduces the total number of open microphones. That helps, and it does nothing about a ring while someone is talking. They solve different halves of the problem, and on a preaching channel both are worth having.
Researched, not professional advice. This page is compiled from published manufacturer specifications, operator manuals, FCC rules, published standards and owner-review consensus, not hands-on testing. Sound system design, rigging loudspeakers overhead, and any electrical work are jobs for a qualified professional: have flown loudspeakers and their attachment points signed off by a structural engineer or a certified rigger, and have all wiring done by a licensed electrician to your local code. Wireless microphone rules change, so confirm the current FCC position before buying. As an Amazon Associate we earn from qualifying purchases.