Noise reduction for existing air bricks

[speedyegg]

Hello all,
I have a number of air bricks in the house - in particular all the bedrooms have a vent at high level.
One thing that is very noticeable is how the noise from the street (and next door!) travels through the vents very well.

I have just had cavity wall insulation installed, so the interior sides of the vents are currently off the wall.
Can anyone recommend a solution to retrofit in to the space to provide better acoustic isolation whilst still allowing ventilation?

I have seen the standard products that are offered as the entire solution (eg http://www.airtechenvironmental.co.uk/pages/vapourvent.html ), but does anyone know of any products - for instance I guess acoustic permeable membranes? that would be suitable to retrofit in to the void that I already have (which, typically, are all different shapes once you get the vent off the wall)


Thanks all!

 

[Symptoms]

egg - BES do draughtbuster vents - they contain an accoustic baffle. Also available from them are cowls to fit over existing airbricks to reduce noise.

www.bes.co.uk