Hey guys. So I have been texting someone from Germany I met online as he also has a pair of B&W 800 Matrix speakers. He mentioned that he treats his tweeters every so many years with Ferro fluid. It was kinda hard to actually text about it online with someone I just met from another county. I did google it and looked on utube for some videos and there are some. It’s seems it should be done about every 10 years or so. And u actually have to take the tweeter out of the cabinet disassemble / remove the voice coil clean out the old Ferro fluid and add new Ferro fluid. It’s seems to be some kind of a magnetic liquid used in speakers especially tweeters for better clearer sound, highs, voices etc. It really looks like a job for the experienced in rebuilding speakers. Has anyone heard of this or had it done ? I’d really love to know from folks who had experience with this. My speakers are from the 90s and even though they still sound phenomenal I’d really like to know more about this. I do plan on keeping my speakers for the long term. Thanks to all in advance. 

128x128Ag insider logo xs@2xtattooedtrackman

I have changed the ferrofluid in my tweeters.  The ease or difficulty in doing so depends entirely on how hard or easy it is to dissemble the tweeters.  It turns out in my case it was easy to dissemble to tweeter to be able to get to the channel where you wipe out what's left of the old ferrofluid and add the new.

Personally, with nicer speakers like yours I would just send the tweeters to Millersound and have him do the work.  I'm sure it would be quick turnaround (guessing days) and very reasonable and Bill is great to deal with.

Millersound Speaker Refoaming, Speaker Reconing and Repair Services

Regarding "ferrofluid", from the net:

"Ferrofluid cools down the speaker coils which are susceptible to extreme heat. Ferrofluid transfers and dissipates the thermal energy produced by the strong vibration of the moving driver. As magnets increase in temperature, they lose some of their power."


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Unfortunately replacing ferrofluid in tweeters that used them is something you must do ever decade or two.

Thank goodness we have more or less moved away from that.  You might also look at DIYaudio for help.

@timlub @jetter @erik_squires   Thank u all who posted. And thank u jetter for mentioning Bill from Miller sound. I will definitely be calling him about this. I have a couple questions. By cleaning out the old ferro fluid and putting in new what will I really hear if anything. And what if I do not do this. Would it cause any harm to the tweeters since my speakers were built in the 90s ? Also I will be upgrading all my 8 crossovers (4) in ea speaker very soon also. Like it did mention in post I already think they sound phenomenal. But since they are from the 90s and I do plan on not selling I think it’s a good idea for an upgrade on all I can do for them. 

Ok.  So I just got off the phone with Bill from Miller sound. Very nice guy BTW. He said that he definitely does that it is very responsible $105 ea tweeter. But he said to be extremely careful shipping them if I can’t make the 2.5 hr drive to PA from NJ where I am. But —— he said IF I still hear good and loud treble with my tweeters they are definitely still good with the ferro fluid and he advised me not to touch them. BTW last night before I even heard about this Ferro fluid thing I was up in my music room for about 5 hrs enjoying my system and I decided to take all 6 speaker covers off and listen for the rest of the time with them off. And as I was listening to the Cars - Dangerous Type , btw I love the drums thundering and exploding on that song with my speakers. So i definitely heard the great loud detailed treble on both tweeters. So I will definitely take Bills advice and until I hear anything different ( negative) with them I’ll leave them be. Bill also mentioned a place closer to me in NYC that he recommended that does great work on speakers too. It’s called Technetron. That way I could bring them in instead of taking a chance and shipping them and having them get damaged in the mail which I very much appreciated him telling me that also.