---
title: "Low-frequency acoustic cleaner"
description: "A low-frequency acoustic cleaner is an industrial sonic horn whose fundamental frequency sits in the 60–250 Hz band. The long acoustic wavelength — between 1.4 and 5.7 metres in air — projects further from the bell horn than higher-frequency designs, fills large open vessels more uniformly and is the default choice for cleaning bulky industrial equipment."
canonical_url: "https://sylio.co/glossary/low-frequency-acoustic-cleaner"
last_updated: "2026-06-28T02:29:29.383Z"
---

A **low-frequency acoustic cleaner** is an industrial [sonic horn](/glossary/sonic-horn) whose fundamental frequency sits in the 60–250 Hz band. The long acoustic wavelength — between 1.4 and 5.7 metres in air — projects further from the [bell horn](/glossary/bell-horn) than higher-frequency designs, fills large open vessels more uniformly and is the default choice for cleaning bulky industrial equipment.

## Why frequency choice matters

Acoustic energy at long wavelengths diffracts around obstructions (tube banks, electrode rows, baffles) instead of being absorbed or scattered. That makes low-frequency horns the appropriate selection where the cleaning target is several metres deep and partly obstructed — most large industrial vessels fall into this category. Higher-frequency horns concentrate more energy per unit volume but lose effectiveness in deep cavities; see [high-frequency acoustic cleaner](/glossary/high-frequency-acoustic-cleaner) for the complementary case.

## Typical applications

- [Electrostatic precipitators](/glossary/electrostatic-precipitator) — collecting-plate cleaning, hopper de-bridging
- [Preheater cyclones](/glossary/preheater-cyclone) and [calciners](/glossary/calciner) in cement plants
- [Kraft recovery boilers](/glossary/recovery-boiler) — superheaters, [generating banks](/glossary/generating-bank), economisers
- [Air heater](/glossary/air-heater) cold-end basket cleaning
- Large [fly-ash hoppers](/glossary/fly-ash-hopper), [silos](/glossary/silo) and [bunkers](/glossary/bunker-coal-bunker)
- [HRSG harp-tube banks](/glossary/heat-recovery-steam-generator) in combined-cycle plants

## Indicative selection bands

<table>
<thead>
  <tr>
    <th>
      Band
    </th>
    
    <th>
      Wavelength in air at 20 °C
    </th>
    
    <th>
      Typical use
    </th>
  </tr>
</thead>

<tbody>
  <tr>
    <td>
      60 Hz
    </td>
    
    <td>
      ~5.7 m
    </td>
    
    <td>
      Very large ESPs, recovery boilers, deep silos
    </td>
  </tr>
  
  <tr>
    <td>
      75 Hz
    </td>
    
    <td>
      ~4.6 m
    </td>
    
    <td>
      ESPs, preheater cyclones, large hoppers
    </td>
  </tr>
  
  <tr>
    <td>
      125 Hz
    </td>
    
    <td>
      ~2.7 m
    </td>
    
    <td>
      Mid-size ESPs, baghouse compartments, calciners
    </td>
  </tr>
  
  <tr>
    <td>
      230 Hz
    </td>
    
    <td>
      ~1.5 m
    </td>
    
    <td>
      Boiler convective passes, smaller hoppers, baghouses
    </td>
  </tr>
</tbody>
</table>

## Related terms

- [Sonic horn](/glossary/sonic-horn)
- [Acoustic cleaner](/glossary/acoustic-cleaner)
- [High-frequency acoustic cleaner](/glossary/high-frequency-acoustic-cleaner)
- [Infrasonic cleaner](/glossary/infrasonic-cleaner)
- [Bell horn](/glossary/bell-horn)