I recently repaired my Beolab 8000 and took the rotten foam out in the process. Do you think it is worth it to buy new OEM foam or is simply stuffing some aftermarket acoustic foam in the cabinet enough? What actually is the function of the foam ( I guess minimizing reflection from the cabinet)? Can there be too much foam in the enclosure?
As always, thank you for your help!
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Beolab 8000 Foam - is it worth it to invest in new OEM parts?
11 replies
I'm using rockwool, 32 kg/m3 type, in my BL8000 cabinets and the result is great.
Yes, there is a point where too much material degrates the sound if you block the air flow through the bass pipe.
I bought foam, not OEM, but I matched the thickness etc to the original. I also measured and cut it to the original size. I couldn't believe the improvement in the sound afterwards. Made a huge difference.
I just checked out some pictures of the foam. I figure it effectively creates a space in the collum from the bottom woofer up to the start of the bass reflex tube (sealing around the bass reflex tube). This should be easy to reproduce.
Would you mind please sharing some pictures of the work as I’m about to do the same?
Location: Brittany - France
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Just a general heads-up: Mineral wool / fibreglass insulation / Rockwool (whatever name you use where you live) is an excellent choice generally as a material for acoustic absorption that doesn't break the budget. However, if you use it in an area where the air velocity is high (like around the port of a ported loudspeaker), you risk blowing glass fibres out into the air. This is probably bad for human lungs. This is one of the reasons why, when it's used inside loudspeakers, its typical "gift-wrapped" in fabric. (The other good reason is to keep the glass fibres out of the fingers and lungs of the people building and fixing the speaker...)
To answer part of the original question, the purpose of putting acoustic absorption inside a loudspeaker cabinet is to reduce the velocity of the air inside it, thus attenuating the internal modes (or "standing waves").
Cheers
-g
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Thanks
-geoff
The newer type of foam provides a piece which prevents the bass pipe for (audible) resonating.
Just keep it as original as possible.
Location: Utrecht
Quite a challenge to achieve "Less is More" while having the Beovirus.
Login to view imageThis is my result. I think I got pretty close to the OEM foam.
Dear BeoSince,
Just to be sure, something I like to check.
I see two separator pieces of foam. The one that is at the bottom of the bas reflex pipe ... I guess that one has a hole?
Location: The Netherlands
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