Hi All,

Whilst fiddling around today I have noted the following issue with my left speaker / channel and I would like seek some of your expert opinions on this.

What I noted today is that the left woofer when playing at higher volume levels has very little 'travel' especially compared to the right speaker. It seems to only 'vibrate' a little in and out, whereas the right distinctly travels in and out... it appears to be 'tighter'... both speakers had their woofer surround replaced when I purchased them.

At normal listening levels there is no discernable difference in the bass response, however at higher volumes I perceive some imbalance, a little more depth and fullness to the bass on the right speaker,  but not a major difference. So from a listening perspective it is not really a major issue.

Is this a problem? Is this a sign of a developing problem? Will it cause damage to the driver with this restricted movement? 

Another question is this speaker / channel has always experienced a little static upon waking the BM after it has been in standby over night...could this be a related issue? This has continued after capping both the speakers and the BM.

This is all probably me fussing.

Looking forward to your thoughts.

Laurence.

I suppose the first thing I would do is check the cross over - however I wonder if the drive was correctly repaired - if done by an amateur, it may well not have been centred properly.

Thanks Peter,

...very prompt reponse ....Well I assume that the dealer I purchased them from redid the woofers, altho I don't really know for sure.... and the alignment did come to mind, so this was why I was a little concerned that this may affect the driver over time..

What would be the issue with the cross over do you think and what should I look for?

Laurence.

Can you tell if the woofers were also re-shim'ed ?
Check the dustcap, if it's the original one and it looks untouched, they weren't reshim'ed.
Many refoam'ers skip this important step and it does matter over time.

You can also check if the woofers cones will travel equally easy "by hand", note any blockage or roughness.

Martin

Hey Martin,

Thanks for your prompt input as well... I can't really tell regarding the dustcap / re-shim'ed issue... not sure how I would tell if its original? What should I be looking for?

But I will take your advice and do the cone travel test when I get back later today, as I'm about to head out and let you know how it goes ... my gut tells me that it might be an alignment issue as you have both suggested... as this would explain the apparent 'tightness' of this woofer...

Any thoughts on the static issue? My concern was trimpots on that channel which i know you say are always an issue for the 6000..

Thanks again,

Laurence.

Of course its hard to tell if something is original if you haven't got anything to
compare with but if you can show us a photo, I can tell you if it's original.

Another thing is the overload safety switch, that can be reset by a little knob on the front
between the two front cloth panels.
Push and excersize it a little from side to side a couple of times. I've seen these
start to oxidize causing both strange intermittent and more permanent faults.

The static is most likely not caused by the speaker but the Beomaster. Maybe a capacitor
or a small signal transistor "warming up".

Martin

Agree with martin about the overload circuit. My MS150s sounded as if they were blown until the oxidisation was cleaned off - now sound as good as new.

Hi Peter and Martin,

Ok so I had a little time tonight to do a couple of quick tests and I think you are both right on all counts..

First the static, now my speakers don't sound blown like yours Peter, or like Jeff and his MC120's ... I think they sound great (really), but... when I did your wiggling test on the overload button Martin, the following happened.

- normally once the system has been switched on , then you turn it off, then on again, the static will not reoccur, not until another long shutdown (eg. overnight). But when I wiggled the overload button when in standby then power up, static occured.  If I run, put to standby but don't touch the over load, no static. After several rounds this became a pattern.

- Also  on 2 -3 ocassion while wiggling the overload in standby, the static occured... just a faint static fizzling out...

...In summary I think your both right and the overload needs a clean as its causing this static... Martin, your guidance would be appreciated.. 

The woofer, from what I tell has a slight 'scratching' sound when I push gently at the centre line each side of the cone, not everytime, but most times . I checked the right woofer, there was no scratching at centre line, only when off centre. So I think thats spells alignment issue?... Martin I can send you a photo this week, maybe you can confirm condition for me. Given this, the question is do I need to fix this? And I think the best option for me is to just replace the whole woofer ... Martin do you have any in stock?

Thanks for your speedy, assistance both of you!

Enjoy your evenings..

Laurence..

Hi All,

After many months of not having time to get back to this problem, this evening I was listening to a track which has a very unique, clean, starting bass line, and what I could hear was a very distinct vibration during the play. Investigation showed this only occurs on the left channel. I think a definite confirmation I have an alignment issue with this left woofer.

So I'm thinking I should just change it for a Peerless P830667 as John used in his 120's. Will this be Ok for the S80? I'm also debating whether to change out both when I do it, as both the woofers have had the surrounds changed .. thoughts? I'm concerned the speakers bass will become unbalanced if I do only one.

Thoughts appreciated.

Laurence.

So it wasn't realigned and shim'ed.
Sad case but probably repairable.

Keep the speakers as a matched pair. Don't just change one woofer.
If the other woofer is good and they are still the original ones, I recommend
you get the bad one repaired rather than buy a modern "substitute".
That will probably also be the cheapest solution.

I have refoam'ed countless woofers, B&O and also others.
I have had many requests for refoam kits but I won't sell any.
Reason is that, despite many people stating that it's sooo easy, several still
manage to get it all wrong. I know because many end up here afterwards, the owners
sometimes blaming the kit seller for their mishap and I don't want that to be me.
Some DIY'ers manage to stop while a repair is still possible, others don't...
Re-alinging and re-shim'ing etc. are important steps that most DIY'ers and
even some so-called prof. refoam'ers skip. Most refoam kit sellers
never speak about realigning, claiming that it's not needed. One wonders if
they know what they are talking about at all (?).
Some drivers have incredibly tight tolerances, some even require a custom gig to
hold things in place to get it precise enough.

Martin

Hi Martin,

As usual thanks for your quick reply. Yes sad, but as you say we can sort it out. And to be frank only becomes an issue at high volumes with heavy bass...

Will get you all an update once i get it sorted.

Martin I have sent you a PM also.

Thanks again, have a great weekend everyone.

Laurence.

This story continued like this:
Laurence trusted me his S80.2 woofers for a couple of days as I
was very eager to look into this case;

The mounted rubber surrounds look fine, seems to be a fairly good DIY job.
Generally I think, I would have chosen a type with a little longer
throw but for use in Beovox S80/S80.2 these ones will be fine, I'm sure.

The coil on one woofer was binding heavily to the magnet. Not the way it would
do because of bad alignment however, and at first I thought the coil had
burned, introducing deformation to the thin aluminum coil former as it got hot
but a closer inspection revealed the problem to be that of contamination.
The dustcaps had indeed been removed (the same ones mounted again, quite a
dangerous way to do this as a DIY job when you think of the thin coil
leads passing under the dustcap lip) and I'm sure that re-shim'ing etc. was
done properly, at least that part feels good, but remains of the old and
rotted surround had found its way down the side of the coil former while
the dustcap was removed.
The tolerances are pretty tight so there's no room for anything down there.
As they rot, and especially if worked and squeez'ed, the old surrounds become
sticky and will make quite a mess, hard to get off fingers and tools, and this
had also happened here, only inside the woofer ...
An area of about 2 sq/cm was one large sticky mess on the inside of the
coil, binding to the side of the chassis centerpiece.
A quick check off the "good" woofer revealed the same problem, only not as
progressed.

All in all a typical example of a DIY job that almost went well.
Surrounds are nice, mounting and alignment all very good and even
the choice of glue seems fine but the attention towards old foam debris
was lacking.

The woofers were both cleaned, got new dustcaps and was returned to the owner
and I've heard that they are doing fine back in Singapore. 

Martin

Hi Martin,

Firstly a very big thank you!

Thank you for finishing the storey for me in such detail, I think your discovery here will assist many others in avoiding this pitfall! 

i really can't say enough how glad I am that I made the decision to send the woofers to you, I'm very sure you have saved them from any further damage. You went above and beyond during the whole process keeping me informed of what was wrong. Not to mention how quickly you fixed them for me...

Thank you again.

Laurence.