I have 2x ceiling speaker boxes made of MDF and plasterboard for my KEF Ci160QR speakers.
I read it's a good idea to stuff the boxes but I'm not sure if I should be 'loosely' filling it with polyfill or lining the cabinet with polyester wadding?
I don't wish to use anything like rockwool or fibreglass which would pose a respiratory risk.
What is ideal here?
Thanks.
I would fill the back box with fire retardant open cell acoustic foam.
See third down (Acoustic foam flat sheet) on the list here: https://www.efoam.co.uk/acoustic-soundproofing-foam.php
See third down (Acoustic foam flat sheet) on the list here: https://www.efoam.co.uk/acoustic-soundproofing-foam.php
It would be convenient to line the box with self-adhesive foam of an appropriate thickness to suit the box dimensions.
The foam on the rear wall of the back box can fall short of touching the magnet assembly. That way, it will not be compressed when fitting the driver.
The fire retardant foam in my link is quite expensive so you may have to compromise on thickness depending on how deep your pockets are!
The foam on the rear wall of the back box can fall short of touching the magnet assembly. That way, it will not be compressed when fitting the driver.
The fire retardant foam in my link is quite expensive so you may have to compromise on thickness depending on how deep your pockets are!
The plasterboard lining in the back box is included for its fire resistant properties.
By the same token the lining should have fire retardant properties.
A fire in the listening room should not easily spread into the loft area or upper story via the speaker cone and back box.
It's in the building regulations.
By the same token the lining should have fire retardant properties.
A fire in the listening room should not easily spread into the loft area or upper story via the speaker cone and back box.
It's in the building regulations.
It's not very big if I'm honest. The inner dimensions are 24 x 24 x 13 cm
I could get either the 1/2 inch (12.7mm) or 1 inch (25mm) thickness foam - both will fit - acoustically what is likely to be a 'better' option?
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That is way too small. Mount the loudspeaker in the ceiling without that box.
The Ci160QR does require a minimum volume of 17 litres for "Reasonable LF Response". The constructed box is only 7.5 litres.
https://images.salsify.com/image/upload/s--GDv-E_Eu--/ef7178dd21cf9ce0933c1dadcb864a0a25b7329b.pdf
One would still have to comply with building regulations by mounting the driver within a fire resistant box.
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I don't know the building regulations in the OP's country, but that kind of ceiling is simply one (very) big fire-resistant box (if the real ceiling above it is fire-resistant - as it should be).
I spoke to KEF about this - they said I would lose some low end but the speaker would still be fine.
I will do this later at some point. I'll probably just use a firehood as an enclosure.
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what size is the firehood?
like Kef told you'll lose low end if it's to small.
personally i think there's to much ado about fire resistance when it seems all your questions about "best" are concerns about final sonic performance. only you can make the determination as to whether what ever you implement will satisfy you.
https://firetopper.co.uk/firetopper-pro-acoustic-speaker-fire-hood/
At present the plasterboard satisfies 30 min fire rating.
Of course I can only buy the inner lining one - so not sure if it is better to go for 12.5mm or 25mm thickness for the acoustic foam.
The ceiling speakers will only be used for Atmos purposes only in a 5.1.2 setup and will be crossed over at 100hz so I'm not concerned about losing 'low end'.