I just finished my first refoaming exercise, a pair of CX50's with new foams from Good Hifi. Apparently I was successful, the drivers work completely without scratching and don't look too bad either.

The problem is that they sound like crap. Well maybe that is a too strong word, but definitely different and worse than when I started (the old foams had only some cracks). This is not too surprising since the new foams feel much stiffer than the originals. How long am I supposed to play these before I can expect them to perform?

New drivers, £50 and no hassle

Having read previous threads, I expected that from you, Graham

The deal is that I wanted to do this as an exercise for other jobs that can't be sorted with £50 and no hassle. In addition, I have a pair of CX100's waiting, and your solution for all these would've required an additional investment of over 200 euros I'd never get back selling these on if I decide to.

I am in a similar position to you.

My attempt to refoam my CX50's resulted in a trip to King Street for a new set of drive units.

I also have a pair of CX100's in excellent cosmetic condition but foam rot in all the drivers. I have decided to take the plunge and buy new drivers because I know I lack the skills for refoaming. I know I will not get my money back in future if I decide to sell, but that applies to all of the work I have done or had done for me on my old B&O collection!

Simon

wirralsimon:

I am in a similar position to you.

My attempt to refoam my CX50's resulted in a trip to King Street for a new set of drive units.

I'm pretty sure I've done these correctly. Good Hifi FAQ says they make take weeks to begin to sound correct, so I'll give them a little time before getting new drivers... "and you will notice a gain in bass-weight and a less bright delivery of sound after some time" which is just what I'd hope for right now. I may just expect too much since the contrast after plugging them in place of the Pentas was so large.

Anyway, I'm doing the CX100's one speaker (not one pair of drivers) at a time. I'll probably get to assemble the first one tonight and I'll try and compare it to the original before I rip it apart as well.

Hi,

I have refoamed many,many cx's , both cx50 and cx100's without too many problems.

The tolerances are fairly small on these (rather small) drivers and even though they don't seem to scrape at first they still might do so when hitting rumbling lows. I play someting like the song 'Angel' from Massive Attack's 'Mezzanine' Album to discover if there is some distortion or not.

The cx50 are not really the best speakers (they are just cut-down cx100's), though they are sufficient for small spaces and excellent in home-theater use. Not really that great for listening to music. (if compared to Penta's they will for sure dissapoint...)
A sub does (even a little cona like I have) help, but switching to cx100's really is a big improvement (necessity...imho) for listening to music. 

I found changing the cap in crossover does ihelp a bit as well.  The last pair of cx50's I still have now use a new 10$  'generic' kind of crossover from Boston acoustics that really helped to push them a bit further, especially at higher volumes with nicer lows and a fuller midrange.

Yes, they need some time to play and 'loosen up' the refoamed drivers as the Good hifi foams are fairly rubbery. The last pair of cx100 that I refoamed (the chrome-plated ones) are only now coming into their own having lost their intial pitchyness of the bright highs and they have been in use every day. I did try some softer foams from an North-American supplier that turned out to be total crap. They were too small and after finally getting ones that fit, they were so thin they ripped after a month. There is pressure in those cabinets...

Do not forget that the 'new' ones you buy at the B&O store are not necessarily as 'new' as they would like you to think..... spare parts do age as well.

Hope it helps ....

cooldude:

Yes, they need some time to play and 'loosen up' the refoamed drivers as the Good hifi foams are fairly rubbery. The last pair of cx100 that I refoamed (the chrome-plated ones) are only now coming into their own having lost their intial pitchyness of the bright highs and they have been in use every day. I did try some softer foams from an North-American supplier that turned out to be total crap. They were too small and after finally getting ones that fit, they were so thin they ripped after a month. There is pressure in those cabinets...

Do not forget that the 'new' ones you buy at the B&O store are not necessarily as 'new' as they would like you to think..... spare parts do age as well.

Hope it helps ....

Thanks, it did

I got the first CX100 together and compared it to the other one (and the CX50s). It wasn't nearly as disappointing, it might even sound better than the untouched one. That was enough assurance that I got refoaming the other CX100 underway as well.

I'll use them as my main speakers for a while and see how they turn out. I'll connect the CX50s as secondary speakers on my MX6000 so they will also get some playtime without annoying me too much They are so nice externally that they will be worth new drivers if they don't get better.

The CX100 cones were much harder to clean. Maybe they hadn't rotted long enough or the manufacturer used a different glue at that time - it just stretched and stretched without giving up, whereas the on the 50s the old stuff mostly just pulled off leaving an almost clean cardboard after a wipe with isopropanol...

tournedos:

 

Thanks, it did

I got the first CX100 together and compared it to the other one (and the CX50s). It wasn't nearly as disappointing, it might even sound better than the untouched one. That was enough assurance that I got refoaming the other CX100 underway as well.

I have found that the cx100's also benefit considerably from changing the caps in the cross-overs (I changed mine altogether) 

I'll use them as my main speakers for a while and see how they turn out. I'll connect the CX50s as secondary speakers on my MX6000 so they will also get some playtime without annoying me too much They are so nice externally that they will be worth new drivers if they don't get better.

I used to have 5 cx50's as home theater ( driven by an B&O AV7000 and MCL2P amps) which worked really well in that setup. Now I have cx100's which work just as well for watching movies, but are so much better for listening to music in regular 2 speaker stereo. I also found that people get used to the sound of their speakers with broken surrounds and sometimes find it strange to hear them fixed up .... Give the cx's a couple of weeks of workouts and listen again before you make up your mind to put in new drivers.

The CX100 cones were much harder to clean. Maybe they hadn't rotted long enough or the manufacturer used a different glue at that time - it just stretched and stretched without giving up, whereas the on the 50s the old stuff mostly just pulled off leaving an almost clean cardboard after a wipe with isopropanol...

Age and environment sure make a difference in the life expectancy of these drivers. I have had really bad ones with almost no surounds left to surrounds that were (Almost) intact..... The cleanup of the drivers is the worst part of the job

So they arrived today in the rotted out condition I expected. 

I didnt pay too much for them.

I have more than just a simple refoam job planned for these guys.

They look remarkably simlar to the pair I bought a couple of weeks ago and will be tackling shortly!

I would be very interested to see how you get on.

Simon

Eugene1960:

So they arrived today in the rotted out condition I expected. 

I didnt pay too much for them.

I have more than just a simple refoam job planned for these guys.

Hi Eugene,

Let us know what you have planned for these ?

I am currently doing a pair in really bad shape. They will be refoamed and get an all new updated cross-over.
Because the metal is in such bad shape I will fill it with car body filler and then put some nice rosewood veneer on them to match the amp it will be used with..

Regards 

My thinking is to strip them to aluminum and go from there. If the aluminum is in good enough shap I will shine them up. If not = Paint- not black.

I am tossing back and forth between rubber or foam. I am inching towards rubber.

Heres the deal. I have another set of CX-100's that ewere refoamed in february. The metal is in good shape. Problem is they are black and I dont really want black speakers. The sound out of this pair is outstanding. So I would have something to compare against if I choose rubber.

My own ears are really the only judge that matters.

I want a bare metal pair snd another color Crimson Red or perhaps Lime green, or white with black frets. Heck maybe black with sivery gray freys would be OK. Anything but basic black.

But either way  a set of polished aluminum is what I am after.

Problem on eBay is the few Aluminum sets that come up get bid way up even if the surrounds are trashed. At least here in the US they are, My good black set ran me 129 and some change as I recall. with the seller providing detail photos of the drivers and a copy of the refoam recept. 

129 wouldnt get you anywhere near an Aluminum set right now.

it's true that Alu finished ones are very hard to find on ebay.  And for me too : anything but the basic black ...

I do have a pair that I had repolished.... It's quite a bit of work to get to a nice shine on these...
But they look stunning with my stacked beosystem 7000!!!!  

If you need any info, let me know. In the meantime, good luck with your project , and let us know on how you decide to finish them.

This is a pic of my polished cx100's  before/after 

sorry double post 

I'm pretty much torn (pardon the pun) with what to do with my CX's as well. The white CX50s will definitely need new frets (the old, sticky surrounds had stuck on them and show through to the front!). I'd perhaps like something else than pure white, but can't think of any other colour that would work, except black of course.

And the CX100's are all black. The frets are OK but maybe could be some other colour... I've been thinking red as those RLs of yours, Eugene, looked really great!

Ah, I just now realized that I can probably mix & match the white and black frets on these to see how they would look. I suppose even the treble frets are the same size on both?

I think Eugene's red RL looked really good as well.

yes, all the cx frets are the same and are thus interchangable.

It's also easy to change the fabric on them. The fabric is very similar to a polo shirt fabric which can be found in any fabric store in many colors/

The red on polished aluminum is kind of what I would like. I think the black frets against the white look nice. But really any color would work with white.

Guess it just depends on taste and the existing decor. Silver-gray against the black I see working nice.

Recently Lee dolled up a Beolab Sub in Ferrari Red with a black fret. That might look cool in the right location.

So , whats the deal with the generic cross upgrade Cooldude? Rebuilding the existing is easy - 1 cap. But do the BA's make it worth the extra expense to upgrade ?

So far I have peeled the gooey old foam off one set. Was not to difficult. I just foolowed the video instructions from Good Hi- Fi website.

But the final cleanup I used this on an old dish rag to remove the remaining resin. Worked great.

 Sorry Mika for having run amuck on another one of your speakers threads.

Next step is paint removal.

Eugene1960:

The red on polished aluminum is kind of what I would like. I think the black frets against the white look nice. But really any color would work with white.

Totally agree, anything works with white. But as you write everything depends on taste and decor...

Guess it just depends on taste and the existing decor. Silver-gray against the black I see working nice.

So , whats the deal with the generic cross upgrade Cooldude? Rebuilding the existing is easy - 1 cap. But do the BA's make it worth the extra expense to upgrade ?

Usually I just change the one cap. However I use my CX's in combo with a little cona sub. A combo that works well, but I thought sure could be improved on. I have changed the cross-overs in both the sub and the CXs to some that I had left over from a previous project. They are 'generic' cross-over prints used in DIY projects. (I think mine were made by Boston Acoustics and contained decent audio quality caps) I did test them with both the old and new crossover and it sure did help to clean the midrange and push the lows a bit further. I paid about 10$ per cross-over and for me they worth the money. 

So far I have peeled the gooey old foam off one set. Was not to difficult. I just foolowed the video instructions from Good Hi- Fi website.

But the final cleanup I used this on an old dish rag to remove the remaining resin. Worked great.

Goof off is a great product that I use too. It does clean the mess well.

 Sorry Mika for having run amuck on another one of your speakers threads.

Next step is paint removal.

 

My speakers came out of the stripping process quite nicely. Should be OK .

Right now they look a little like yours before you put the final polish on it.

How did you restore the pinstripe? Mine  are pretty much gone. I was thinking stainless wirewheel  brush against the grain.

Mika here is what Black speaker cabinets look like with red frets. 

Stripping the paint wasnt really to tough just a bit time consuming and sticky.

and then there is also some loud purple. Looks cool but doesnt work with my decor.

Eugene1960:

My speakers came out of the stripping process quite nicely. Should be OK .

They look great as they are right now with their grey frets.

Mine were in such bad shape (deep cuts and scratches) that more than just paint stripping was necessary. 
Mine were completely sanded to get most of the scratches and make polishing easier.  It was done on a sort of belt sander with increasingly finer sanding paper on it starting at 300 gritt down to 1200 gritt. Then Polished by hand and finally a coat of protective UV resistant metal finish lacquer.

Right now they look a little like yours before you put the final polish on it.

How did you restore the pinstripe? Mine  are pretty much gone. I was thinking stainless wirewheel  brush against the grain.
I put the pinstripe back on with a couple of coats of satin gloss metal varnish (masking tape and brush) to give it back that almost 3d effect of the original pinstripe. The original alu B&O finished ones had the pinstripes put on in the same way....

Mika here is what Black speaker cabinets look like with red frets. 

Stripping the paint wasnt really to tough just a bit time consuming and sticky.

The paint remover I use is a gel that you put on and they wrap the whole thing with cling film and leave overnight.  Paint almost washes of at that point.

and then there is also some loud purple. Looks cool but doesnt work with my decor.

Oh by the way, when I polished mine, they turned out super shiny (like chrome plate) that we actually had to put them back on the sander to loose some of it in order to better match the finish of my beomaster 7000....  

They are done now and what my ears are telling me is there is no reason not to use rubber surrounds vs original foam.

I really cant tell much difference between the two. I wound up using a poly cap replacement that I had to mount on the side instead of underneath.

Now it's on to stripping the paint off my other set, plus I will also recap and re-cloth them as well.