General Forum

Re: Red Line 45 help urgently needed

BeoMatt — Wed, 11 Mar 2009 15:44:45 GMT

I have repaired the 45's and placed pictures and text in the workshop area, under

'Bang & Olufsen Red Line Authentic DIY ABR (Auxiliary Bass Radiators) Successful Repair'

thanks to all the advice everyone, Matt

Re: Red Line 45 help urgently needed

BeoMatt — Thu, 05 Mar 2009 14:58:06 GMT

'Passive Radiator' every day is a school day I have just been informed this is it's correct term in the speaker world, so i am going to browse boom box sites and get some ideas !! Matt

Re: Red Line 45 help urgently needed

BeoMatt — Thu, 05 Mar 2009 14:54:22 GMT

Yes indeed I will and a trial and I am sure 'error' list of tested materials, Matt

Re: Red Line 45 help urgently needed

BeoMatt — Thu, 05 Mar 2009 14:52:35 GMT

Indeed you are very wise, rubber ? resonance ? hmmm some hunting I think else the port soloution is my only other option, did B&O use speaker cone material or layered foam ?? Matt

Re: Red Line 45 help urgently needed

Jandyt — Thu, 05 Mar 2009 14:51:57 GMT

Hey Matt.
If you go down the DIY route, would you be kind enough to take step by step photo's?
We love a good photo' thread on here!

Andy T.

Re: Red Line 45 help urgently needed

BeoMatt — Thu, 05 Mar 2009 14:48:02 GMT

Aha !! I have been looking at the site myself just now, I think I may approach this from a diy replacement angle, the metal plates are in A1 condition, I have no idea of the foam used originally apart from bits in the cabinet, did B&O simply suspend them in a foam membrane ?? Perhaps someone has a good set and can post a photo, I could try and obtain some similar material and reproduce them ?? Thanks again Matt

Re: Red Line 45 help urgently needed

Puncher — Thu, 05 Mar 2009 14:47:30 GMT

You can always glue a sheet of rubber across the outer metal frame of the ABR and then glue the mass plate to that - the clever bit is getting a rubber sheet with something like the right compliance to achieve the correct resonant frequency for the ABR.

The tuned port version had the port running parallel to the plate to save space (the speakers aren't that thick). You should find photos of the tuned port conversion plates somewhere among the threads I pointed out - you can maybe estimate the diameter and length of the port from the pictures if you wanted to try that instead of repairing the ABRs.

Of course just about anything will be better than what you have at the moment

Re: Red Line 45 help urgently needed

tournedos — Thu, 05 Mar 2009 14:40:52 GMT

Beomatt:

Thanks a million Puncher, I will have a look perhaps a diy approach may work ?? Matt

Here's one well documented solution, might be helpful!

Re: Red Line 45 help urgently needed

BeoMatt — Thu, 05 Mar 2009 14:30:34 GMT

Thanks a million Puncher, I will have a look perhaps a diy approach may work ?? Matt

Re: Red Line 45 help urgently needed

Puncher — Thu, 05 Mar 2009 14:01:29 GMT

Hi Matt,

This is the same part used in the RL60. It is no longer available from B&O, nor is a repleacement rectangular foam. Member Dillen replaces the foam with a rubber surround, PM him for details if you're interested (note he isn't based in the UK). B&O did at one time supply a bass port conversion plate but there are mixed reports on whether these are still available too.

I suggest you use the search facility at the top of the page and search the entire site for "RL60 ABR" - this should pull up most of the threads where this subject has been covered in the past for RL60 repair, it will apply to your case too.

Have a good read of those and see if your questions are answered there.

Good luck.

Red Line 45 help urgently needed

BeoMatt — Thu, 05 Mar 2009 13:11:15 GMT

I have just aquired a lovely pair of RL 45's but the foam RECTANGLE surrounds have rotted away leaving displaced rectangle metal plates in each cabinet. Can you get replacement foam ?? And can anyone recommend anywhere, I have found normal speaker ROUND foam but no rectangle replacements, perhaps I should make my own ?? Any suggestions welcome, Matt