Sonoconnect Ø 160 MM Per meter

Insulated ventilation ducting of 160 mm, by the metre. The inner hose is micro-perforated and sits inside a layer of glass wool with a laminate sleeve around it.

Why the inner hose has holes in it

That looks like a mistake: an air duct with perforations. Yet it is exactly where this ducting gets its effect, and it explains the difference from ducting that is merely thicker.

Sound is a pressure wave in air. A solid, hard wall reflects that wave back into the duct, where it simply travels on. You have contained it but not lost it: it still emerges at the end of the run.

The perforations let the pressure wave through instead, into the glass wool. There the air squeezes between the fibres, and that friction turns the wave's energy into a tiny amount of heat. The sound is absorbed rather than reflected, and what is absorbed does not come out anywhere.

It is also why this works best on mid and high tones: short waves fit easily into the fibre structure. The low hum of a heavy fan has longer waves and is harder to catch in a blanket of glass wool.

The holes cost you no air, incidentally. The film around them seals the duct, so sound passes through and air does not.

Technical Specifications:

• Duct type: flexible insulated ventilation ducting
• Acoustic insulation: 25 mm glass wool blanket
• Inner hose: micro-perforated aluminium laminate
• Sleeve: multi-layer aluminium or polyester laminate
• Bore: 160 mm
• Sold: by the metre

Frequently asked questions

Does air leak through the perforations?
No. A closed film sits directly around the inner hose, so the duct stays airtight.

Does it work against low hum?
Less well than against higher tones. For low frequency hum, decoupling the fan itself does more.

Do the perforations clog up?
Dust can settle in them. That is one reason to keep the intake clean.