The wonderful Bang and Olufsen RL60 Speakers

I just bought some Bang and Olufsen Redline 60 speakers from someone in Oakland using Craiglist to replace the tinny, hollow sounding Sony computer speakers next to my PC monitor.  They came with a Beomaster 5000 amplifier and a non-working B&O remote control the size and weight of a longer Tom Clancy paperback.  It seemed like a pretty good deal for $150 and an hour and half of driving.  Not to mention that I had spent all week bargaining him down from his $275 asking price.

I tried them out at his loft in a bad part of Oakland and they sounded good.  Just a weird clunking sound when I moved the speaker, which the owner explained was a metal plate.  I wasnt’ sure what he meant, but they sounded good and it was a good price.  I got the system down the stairs and into the Saab amid some shifty characters lurking in this industrial part of Oakland.

A 50 minute drive home, and I’m still feeling pretty good about the purchase.  Naturally, the first thing I do when I get them inside is to take them apart to find the source of the clunk.  I discover a loose oval shaped metal place, and a lot of very old brown foam floating around in the speaker’s chassis.

A quick Google and I discover the Beoword.org forums.  It turns out the engineers at Bang and Olufsen employed an ABR (Auxillary Base Radiator) when they designed this first version of the speaker.  Over time (20+ years now) the foam holding the ABR together disintegrates and prevents the ABR from working.

The project: Find some replacement foam, stick it on to the metal pieces of the ABR and put the speaker back together.

The conclusion: A huge improvement.  I’ve replaced the ABR foam on 1 of the 2 speakers and the difference is very noticeable.   I think I have the process down to about 45 minutes for the next one, exlcuding the time it take the glue to dry.

Here’s a picture of the new ABR in place, read on for  the full process.

Replacement foam in place on the RL60, ready for reasembly.

Here’s the finished result, ready for reassembly.  Click below to see the entire process in detail and photos.

Step One:

Take the speaker apart.  There are 3 screws on each side, 2 for the straps and 3 further screws within the connections assembly.  Be careful with the straps, they may be brittle but should come off easily enough with a little care.

The Bang and Olufsen Redline 60 with ABR

Step Two:

Remove the screws and straps holding the two halves together.  Below, the screw holding the wedge which secures 1 of the 2 straps.

The screws behind the B & O Redline 60 speaker

Step Three:

Don’t forget the screw just behind the connections!

Close up of the connections

Step Four:

The inside of the RL60 speaker.  On the right you can see the Auxiliary Base Radiator (ABR) which is in rough shape.  The foam holding the inside (oval) metal piece to the outer loop had disintegrated.  This is the part we’re going to remove, and refoam.  The large oval metal piece was clunking around in the speaker and would have eventually come through the outer fabric, not to mention the huge hole hindering the speaker’s acoustic design.

Inside the RL60 speaker. What's left of the ABR on the right.

Step Five:

Remove the ABR by unscrewing the screw on the outer metal loop.  The inner piece is loose and can be carefully removed.

A close up of the Auxillary Base Radiator on the RL60

Step Six: Close up of the foam material used.  You’ll need to find a replacement as close as possible to this material.

The foam material used by B&O for the RL60

Step Seven: Disintegrating foam after 20+ years of use.  I used carpet underlay as a replacement found at Home Depot.

The foam has completely disintegrated and is very brittle after 20+ years.

Step Eight: Remove and clean the foam and glue from the two pieces of the ABR.  I used a washing up brush and a knife for the glue.

The two metal pieces of the ABR removed and cleaned up.

Step Nine: Use the outer ABR piece as a template on your replacement foam and cut.

The replacement foam read to be cut

Step Ten: Cut and ready to go.  I doubled up on the underlay material to gain thickness.

Replacement foam, ready to go.

Step Eleven: Glue the replacement foam to both metal ABR pieces being careful to space the inside piece equidistant from the outer ring on both sides, top and bottom.  I used Liquid Nails to glue the foam underlay material to the metal.

Replacement foam glued to the metal ABR pieces with Liquid Nails

Step Twelve:

Close up of the ABR with replacement foam.

Step Thirteen: Admiring the speaker, and my work.

A view of the speaker half of the RL60 by B&O

Step Fourteen: Replace the insulting foam of the RL60 speaker and screw the back half back on.  You’re done!

Replace the insulating foam, and screw the back half back on.