Wedding Venue: Feedback Problem Solved with RTA

The Challenge: Every Wedding, Every Time

The Granary, a converted stone barn in the English countryside, had become one of the region's most sought-after wedding venues. The rustic charm of exposed stone walls, oak beams, and flagstone floors created an Instagram-worthy setting. But behind the beautiful photos lay an audio nightmare that plagued every event.

The venue's sound engineer reported that acoustic feedback occurred at every wedding during speeches. The wireless handheld microphone would begin howling within seconds of being turned up to a comfortable speech level. The engineer had resorted to keeping the system gain so low that guests in the back rows could barely hear the best man's toast. Complaints had started affecting bookings.

Measurement: RTA Ring-Out Analysis

Using the SonaVyx real-time analyser, the engineer performed a controlled ring-out test with the venue empty. Starting from a low level, the system gain was gradually increased while monitoring the RTA display for emerging peaks.

The SonaVyx problem detector flagged three feedback frequencies in order of onset:

• 2.4 kHz: First to ring, Q factor estimated at 15, -6 dB relative to stable broadband level
• 1.1 kHz: Second frequency, onset at +2 dB above 2.4 kHz threshold
• 680 Hz: Third frequency, onset at +4 dB above 2.4 kHz threshold

The gain-before-feedback at the primary mic position was measured at -6 dB relative to the target speech level of 85 dBA at the back row. This meant the system could never deliver adequate speech levels without feedback.

Diagnosis: Reflection Hotspot

The impulse response measurement revealed the mechanism. Strong early reflections from the stone side walls arrived at the microphone position within 5 to 8 milliseconds. These reflections were only 3 to 6 dB below the direct sound level, effectively creating a secondary sound source aimed directly at the microphone.

The AI diagnostic identified that the microphone was positioned at the intersection of two strong first-order reflections from the left and right stone walls. This was the worst possible position for feedback susceptibility.

Solution: Notch Filters and Microphone Repositioning

Two complementary interventions were applied:

1. Three narrow notch filters in the system DSP:
   • 2.4 kHz: -9 dB, Q = 12 (bandwidth approximately 200 Hz)
   • 1.1 kHz: -6 dB, Q = 12 (bandwidth approximately 92 Hz)
   • 680 Hz: -6 dB, Q = 12 (bandwidth approximately 57 Hz)
2. Microphone position moved 40 cm forward from the original speech position at the head table, relocating it out of the reflection hotspot identified by the impulse response analysis

The narrow Q values ensured minimal impact on overall sound quality while providing maximum feedback suppression at the problematic frequencies.

Results: 18 dB More Usable Gain

Before/after measurement quantified the improvement:

Metric	Before	After
Gain-before-feedback	-6 dB	+12 dB
GBF improvement	—	+18 dB
Speech level at back row	72 dBA	90 dBA (clean)
Feedback incidents per event	3 to 5	Zero
Guest complaint rate	40%	0%

The 18 dB improvement meant the system could deliver speech at 95 dBA without any feedback. The sound engineer reported that the first wedding after the fix was the first event in two years without a single feedback incident. The venue manager noted that audio quality complaints had been completely eliminated from post-event surveys.

Lessons Learned

• Microphone position is as important as EQ: The 40 cm repositioning contributed approximately 6 dB of the total 18 dB GBF improvement.
• Narrow notch filters preserve quality: With Q = 12, the three notch filters affected less than 2% of the audible spectrum. Broader parametric cuts would have degraded the tonal quality significantly.
• The problem detector automates ring-out analysis: What traditionally requires an experienced engineer's ear can now be performed objectively with SonaVyx problem detection, documenting the exact frequencies for repeatable results.
• Stone venues need measurement, not guesswork: Every stone building has unique reflection patterns that change with microphone and speaker placement. The RTA provides the objective data needed to solve each venue's specific feedback pattern.