Ferrofluid

I have done it many times.... If your listening habits would never strain the tweeter, I would normally remove the fluid rather than replace it. Can sound slightly better, never found it to sound worse.

Ferrofluids main purpose is to dissipate heat. When the coil heats up, it naturally cools within the fluid. I do not drive my speakers crazy hard an have compared sound with and without fluid several times. I always heard a tad more information without fluid, so I normally remove it. I have also measured many tweeters with and without ferrofluid, resonance also goes down a bit when it is removed and don't take this as a recommendation to remove it. I've been building, repairing and modifying speakers for more than 40 years, I would do this to my own, but to someone without personal skills, I would recommend to leave alone until it needs to be done. Ferrofluid  will thicken as it ages, so overtime, it will hinder driver movement and heat transfer 

@tattooedtrackman     Yes,  I do design, build, mod and repair crossovers.  I know what I'm doing and want you to please take to heart what I tell you  here. Your speakers crossovers are well thought, complicated expensive. When I build,  Each woofer, tweeter mid, midbass and each crossover part is hand measured and matched for accuracy. If you want someone to replace caps and resistors, fine, upgraded parts will be audible, but understand, 1 person may say Wow, what a shocking improvement and another may say, well, I can tell its done, but it wasn't much different.  You can spend a ton and not hear alot of difference. With that said, when you replace inductor coils,  you are changing the line impedance sometimes over an ohm on a single part.  If you take off a 3mh ferite core, it may have a resistance of .8 ohms, when you change to a 3mh air core, it could be more than double that.  So you think you have a crossover frequency of say 3000hz, but because you changed the line impedance to that part, you may now be at 2800 or 3200.  On top of that, when I build, I build to have phase and time alignment, when you change parts without a proper plan, you throw that right out the window.  If you want to replace resistors and a few caps, I'm happy to pull schematics and tell you which to change and good idea of what to buy, but unless you are very highly qualified at speaker design, do not change the inductors.  It is alot of work to get this right and it is easy to blow by someone that can solder, but really doesn't know what they are doing,  So EBAY, for me, especially on such a nice speaker, That is a big NO WAY.  

No difference in meter accuracy? You would triamp passive crossovers?

doing nothing is not bad advice, these are nice speakers. 

Also, a trusted ferrofluid might cost $30 to $35.  If you feel that yours is drying up and you don't want just remove ferrofluid, this is still a good option. 

So, I hear you, but again. I would not rebuild those crossovers. A few parts replacements yes, but you would need to measure every inductor for its resistance then figure into the crossover, when the resistance changes on this tweeter, mid etc, how many other parts have to change value to keep the crossover at the same frequency.  When you change coils,  It appears to the other parts in the crossover that you have actually changed the impedance of the driver itself.  So, your speaker goes a little out of whack when you change the parts, a little more on the mid parts and even more on the woofer.  It can change a speaker to being withing 2 % matched parts to being off 20% in matched parts.  I'm being a bit tough with that description, but the point is, the more inductors there are in a design, then the more you change, the more you risk of destroying the original design. 

So, unless you just don't like the original design, I would only do key parts changes. I have not looked at a schematic, I don't know the slopes chosen or the topology of the crossover, butterworth, likwitz etc.  Now parts choice is a can of worms that very few would agree upon in this forum.  Capacitors,   There are more types than this, but in speakers, normally, you have Electrolytic, then step up to mylar/polyester, then poly carb then polypropylene, then polystyrene and lastly teflon. If I recall correctly, B&W used a lot of Solen parts.  I find the Solen parts to be very decent sounding,  they don't get harsh, they may be a little dry, but they don't do anything particularly wrong.  These boutique caps can get very expensive and yes, I can hear a difference between these parts, but for most people, I believe that they would find a nice improvement changing parts, but not night and day. So for my taste, I would take start with the series caps and all resistors.  This should make a nice change, not cost you a second mortgage and no matter who bought your speakers, the main character of your speakers remains intact and you have simply made a true upgrade by anyone's opinion.  The wrong mod can hurt their value.... I hope this makes since,  Tim

I can do the work, if you think that you can pull them and ship,hit me on private message

@katman   You might want to look up his speakers, there are 14 caps in each speaker, not to mention relays, half wave rectifiers and Zeners. The crossover is on multiple circuit boards to handle independent functions, they are not surface soldered and tacked down. I'm not saying that this is a nightmare to do, but you better know what you are tackling.  

So, all you need is a $20 meter?  I have 3 LCR's (meters) and a computer that measures capacitance.  I'm lucky to have some reference parts that I have exact measurements for. I don't disagree that on many crossovers, its a fairly simple chore to change caps, but his speakers are complicated and would not want to see them messed up.  Cheap meters can be off quite a bit in their tolerance.  Just don't believe that in this case that you gave the best advice.  

Hi Mike, we'll, I've tried to get ahold of you. Audiogon blocks personal information sharing, I believe that it is to stop sales and transactions outside of Audiogon. I realize that I was just helping you with an issue and you certainly had no ill intent. Overall, it would  be nice if Audiogon created a form or something to share personal info when no one is trying to profit.

Hi @katman well, I do agree that in a perfect world, active crossovers are always better than passive crossovers. There are a few scenarios where they are not, I’ll give you one quick example.

When designing a speaker, I always use the crossover slopes that will achieve the best alignment more the given drivers that I am using.

I have taken drivers and used Linkwitz 12 or 24 and just could not get rid of a hump or a dip or maybe achieve a good phase response, Switch to Butterworth 6/12/18, same, switch to Bessel or Chebechev... yada yada. It can take alot of work to get the best out of a crossover design. I have yet to see a electronic that give the flexibility to change apc/cpc slope types and rolloff.

I believe that there are several threads here that tackle the subject. If you don't find them, you could easily start that thread. 

Again, if all the stars fall into alignment, electronic crossovers are definitely better. I hope this helps. Tim

I'm  in the St. Louis area

@tattooedtrackman sent me a woofer, a mid, both tweeters and his crossovers from his B&W 800 Matrix. He had a crack in his woofer, a nice dent in his mid and complained of harshness in his tweeter.

I repaired the woofer and removed the dustcap for the mid and took out the crimp. Then measured the tweeters. One measured as though it had dried ferrofluid, the second measured as though it was just drying up. I went to remove the ferrofluid and noticed that on 1 tweeter the voice coil gap was a bit off. I removed the ferrofluid. It was overfilled and drying up. I rotated the voice coils and put them back together. FS was cut in half with the old fluid removed, but one was still off a bit, but they still measured a bit better than when I got them overall. I then upgraded Every Cap in the crossover, redesigned the tweeter section to close a sizeable hole between the mid and tweeter and sent them back. Mike’s initial impression was that everything was better, but it wasn’t long before he was feeling that there was a harshness out of one side that wasn’t on the other. He pulled the tweeters and crossovers and sent them back to me. I disassembled the tweeters, the voice coil magnet gap just wasn’t right on one of them. I took a spacer and moved around the gap trying to get in back in round. I soon felt comfortable that there was a clear improvement. I went ahead and measured out just enough ferrofluid to say that it was enough and replaced the coils. this time continually rotating and remeasuring until I got a very close match between tweeters. I then changed added a bit more resistance and changed the inductor coil on the tweeter crossover.. Even though the same 18db per octave slopes were used, the design was a fair bit different than the original. B & W used 18db bessel slopes. The mids were rolling acoustically at 24db per octave, with the hole between mid and tweets, crossover point was 10db down. I lowered the crossover point by 200 hz and I changed the slope on the tweeter from bessel to butterworth. The butterworth slope along with the slightly lower crossover point gave us a linkwitz alignment at 2200 hz. So, the hole was gone, what was a hole is a smooth transition response. Mike has only had these back for a few days, but that is what was done. I really believe all problems were taken care of.