Hello all,

Looks like I have a pair of S45s with blown woofers. Probably the voice coils are bad. The big magnet is loose on one of them. The midranges are active, seem fine. What are my options?

Can someone suggest replacement woofers?

Peter

P.S. I just had a look at this thread and got a bad feeling:

http://forum.beoworld.org/forums/p/21962/164350.aspx#164350

Peter

Martin Olsen may have spare drivers - Martin, are you here?

I understand that the voice coils are burnt, so you definitely need new drivers.

If all else fails, check these 8" drivers Peerless 830869  HDS-205 Nomex, and the Monacor SPH-200KE.

 EDIT - Actually the SLS 830667 looks like a better fit.

Before buying, check the dimensions really well, especially the basket diameter and depth, to make sure they fit perfectly in the weird S45 woofer mounting place.

Menahem

You can try to send them somewhere to have them re-coned, which will involve the tedious process of re-centering the magnet structure. If you don't want to go that route, then you can wait for a good set of woofers, or cheap complete S45's, to come up for sale. If you use a different kind of driver, all bets will then be off. It may sound good, it may not, but it'll never sound like an original S45 again.

My MS150's were delivered with 3 out of 4 bass drivers damaged with this same problem. I lucked out and found a pair of the OEM 8" woofers, and for the 10" subwoofers, I used a pair of the new Peerless 10" SLS drivers. Comparing the two side-by-side (one speaker with the OEM 10", and the other with the Peerless SLS 10"), they sound quite similar actually - the modern drivers being a bit cleaner and more dynamic. I like the MS150's better with the newer Peerless SLS drivers I put in them.

One person on here used the 8" Peerless SLS for replacing the woofers in his S120's. I acquired a pair and tried them in my S80.2's, and it was definitely an improvement to my ear (not having measured anything before or after); a more sensitive driver, with a much richer bass sound, and I didn't hear anything objectionable in the midrange, so I assume it didn't mess with it too much. I might leave them in permanently, haven't decided yet...

You might luck out and get something better, but if you don't want to research and experiment, or if you're a stickler for OEM (which isn't a bad thing, I understand how that is), I'd find a quality re-coning place. It'll cost as much as, if not a bit more than, new woofers though, just so you know.

Jon

Looking at online sources, the Monacors are more expensive than the Peerless'. Silly question: does that mean they're 'better'?

The Monacors are Oriental, marketed by a German company. The Peerless are European designed, but no idea where they're made. I'd prefer the Peerless, if they fit.

Both Peerless and Vifa are now made in China. However, I would expect that they still have excellent quality control, and the two Peerless drivers I mentioned are indeed built very nicely. Yeah, I bought Peerless partly because I wanted to keep it Danish, but apparently they had moved production by the time I got mine. If you want to keep it truly Danish, find something comparable to the S45 woofers (I take it you found the T/S parameters?) from Scan-Speak - they make more or less the best drivers in the world, but you will pay anywhere from a little more to alot (ALOT!!!) more, more than your speakers might be worth.

Jon

P.S. - Also consider SEAS drivers - their quality control and consistency is the best of the best. They are all made in Norway.

petergutierrez:

Silly question: does that mean they're 'better'?

That is the million dollar question.

Generally speaking, the more expensive a driver is the better it is likely to be and that is where the problems start with Beovox speakers. Many enthusiastic amateurs have replaced original drivers with upgraded units & ended up with speakers that sound terrible. The problem is that the drivers are designed specifically for these speakers so "better" specified drivers can actually sound worse when installed.

I would certainly consider any drivers that are recommended via this forum though as these will be from the results of plenty of trial & error.

The short answer is that the most expensive won't neccessarily be the best option. Refoaming the originals is definately the best way forward but yours appear to need prohibitively expensive remedial work, not just the cones but the coils & magnets - I personally would go that route.

Chris.

I'll say one more thing here. Speakerbuilding is one of my hobbies, and I know not everyone cares to get as wrapped up in it as I do, but hopefully this will be beneficial to you.

I would re-cone your OEM drivers if I were you. B&O Uniphase speakers are designed a particular way - to have as small an amount of phase shift as is possible (all frequencies reach the listening position at the same time, ideally). The merits of this design are debated regularly, but this is how the speakers are designed, and this is what you have, so keep it like that.

If you put in any other driver, it will have a different amplitude response and electrical characteristics that may not (and probably won't) match up well with the rest of the speaker.

As an example, SEAS makes some very expensive metal-coned drivers that have very, very low distortion in their operating range, but above their operating range, they ring like a bell. You'd have to specifically design a crossover network, and choose your other drivers based on that characteristic, in order to filter that ringing out and work around it.

B&O Uniphase speakers usually have a symmetrical 2nd order acoustic rolloff rate for their woofers and tweeters, with the phase-link driver's passband being across a very narrow range filling in where the woofer and tweeter crossover to each other. I don't know how familiar you are with speaker design, but you can google any of this to see what I'm talking about - it's easy info to obtain. 2nd order (falling off at 12dB per octave) acoustic slopes are very hard to manage, and to do this, a driver has to have a very smooth, extended response. This is why B&O usually used speaker drivers with soft domes and paper and plastic cones. More energy storage, more distortion, but way smoother response. (Everything is a tradeoff, and I prefer this sound to metal cones and domes, personally.)

Anyway, say you pick up the latest ultra-low-distortion, mega-expensive driver from SEAS or Scan-Speak or whatever. Sure, it has the potential to sound mind-blowing, but not in that B&O speaker. Why? Because the elements that make up the Beovox S45 require that the driver have a certain frequency response, and certain elctrical characteristics, that the other drivers can't replicate. So, a $60 re-cone, in this way, will far outperform a $300 Scan-Speak.

In my MS150's, response wasn't nearly as much of an issue, because of the low crossover point. All the midrange signal they recieve is farther down in level, so I concentrated on electrical characteristics, and box tuning. That's also why I said I didn't hear anything wrong with the 8" SLS in the Beovox S80.2's. Just because I can't hear it, doesn't mean it's not there, but I don't have the equipment to measure it, so I don't know for sure. It definitely doesn't sound the same, but I do like it better I think.

You might luck out with getting a new driver, but you definitely can't go wrong with getting the originals re-coned. You just have to find the right person who can re-attach the magnets straight (not all re-coning places do that).

Anyway, food for thought hopefully. Sorry I like talking about speakers so much - it's my thing. :)

Jon

I agree, the original woofers are the best. They are not off-the-shelf types and if any specs could
have been changed to make them better, B&O would have ordered them differently.
Please confirm that we are talking about Beovox S45 (or S45-2) type 6302 or 6312, that is the woofers with
rubber surrounds.

Martin

These are 6302s.

I have read all of the replies with great interest and have decided to try out the Peerless woofers recommended by some of you. I do have a second pair of S45s with original woofers in working order, so I will be able to compare them side-by-side. I am also going to replace the caps on all four.

I will report back once the experiment is completed (this could take me a while).

If I am not happy with the results, I will remove the Peerless' and try the re-coning route.

By the way, Menahem's trick of spraying the grill nubs with silicon lubricant works great. Grills go on and off now with no stress.

Just happened to see this on Ebay, don't know if it's the right one, but if it is...:

http://cgi.ebay.com/Woofer-from-a-Bang-Olufsen-Beovox-S45-Speaker-System_W0QQitemZ190371198438QQcmdZViewItemQQptZSpeakers_Subwoofers?hash=item2c5301f5e6&BackToListReferer=http%3A%2F%2Fmy.ebay.com%2Fws%2FeBayISAPI.dll%3FMyEbayBeta

I am the Beoworlder mentioned who replaced the 8 inch woofers from some MC120.2s with new Peerless ones. I would have refoamed the originals, but as one of the voice coils was fried anyway, I was in the market for at least one replacement woofer and thought what the heck and just bought two brand new ones. They sound great and took about an hour to replace from start to finish. What's not to like?

I've restored my 4 S45's (6302), and having had them since almost new (demo's from a B&O dealer in 1977), and they have been well taken care of.

If I had to replace them, I would be very careful when buying second-hand drivers, and I wouldn't pay very much for them, unless they were from someone I could trust, like a fellow BeoWorld member, with a solid reputation. Ebay is not a place I generally trust - there are too many junk-dealer charlatans masquerading as sellers.

Failing that, I would definitely go for a new replacement driver, according to the recommendations of fellow members who have already done the honest legwork of trying them out.

In this case, the abovementioned Peerless SLS has a solid recommendation from another member, and according to the factory diagram should fit perfectly.

Peter, we're looking foward to your evaluation and comments after you've got them fitted in one pair, vs your other original pair.

I'm doing some measuring and I don't believe the Peerless SLS-213 (830667) is going to fit into the S45 box. Datasheet for the Peerless' says outside diameter is 213.5mm (http://www.europe-audio.com/document.asp?document_id=1717&link=datasheets\peerless\830667.pdf). I measure the spot in the S45 box at 212mm.

So, I'm still looking. Any other suggestions?

Peter,

I defer to other members on this, but I doubt you're going to find a better fitting driver.

The vast majority of 8" drivers are about 225mm diameter.

I'll let you in to a secret way I've handled this problem in the past - the purists among us will probably shoot me.

You're short of about radius 2mm around the circle.

Mark with white house paint (we call it "base") which is water soluble, and quick dry - a circle 2mm wider than the current cutout.

Then with VERY steady hands, use a NEW grinding wheel on an angle-grinder to score out the extra 2mm, to the same depth as the existing cutout.

Tape off the rest of the speaker, to prevent the black plastic junk touching the other drivers.

Best to do it with a friend holding the main box firmly, or any other method which will give you plenty of physical support.

If you have a carpenter friend with a router, even better.

This method works 100% with no danger to the structure, if you take your time, and do it patiently.

Menahem

Hmm, sounds like something I'd be up to, but I don't have access to those tools.

I think I will check out my options as far as getting the originals refitted by a pro before I do anything else.

By the way, anyone heard of this make?: http://www.usspeaker.com/alpha8-1.htm

Looks like these will fit in the S45 box. Then again, I expect there's a lot of so-so material out there. I'm just not very knowledgable on the subject.

Peter, you definitely do not want that.

There are 2 "types" of woofer drivers out there - bass-woofers (even called sub-woofers), and mid-bass-woofers - this one.

You won't hear any bass from this one - you'd need a separate powered sub-woofer to hear any half-decent bass from your music. This one would probably be best suited as a center speaker in a 7.1 setup.

The first key to determining whether you'll hear any bass at all from the speaker is to look at the Fs parameter of the Thiele-Small numbers. Here it's 73Hz - forget it. For a free-standing full-range speaker like the Beovox's, you want a Fs of around 38Hz or less.

If you have a look at the PDF on this 8" Vifa's page, you'll see the point at which the impedance curve intersects with the frequency reponse curve - that's the Fs, and the impedance is so high, that functionally, you can't hear (or feel) anything below that frequency. On this driver, it's a very respectable 33Hz, but the diameter is way too wide for mounting in the S45.

http://www.parts-express.com/pe/pshowdetl.cfm?&DID=7&Partnumber=264-1104&ctab=2

BTW, another mounting method, if you dont want to grind the cabinet, is to have a carpenter make from MDF, 3mm thick mounting rings which will enable the drivers to be mounted a bit forward, and flush with the black plastic cabinet. The edges of the drivers will overhang the MDF, so it won't be visible.

If you're creative, you can definitely get those Peerless's mounted.

Just so I understand, this one would work too, right? Fs 33Hz:

http://www.madisound.com/catalog/PDF/m8a.pdf

Darn, still would be a tight squeeze in those S45 boxes though.

Yes, that's correct, but of course the actual performance also largely depends on the box it's mounted in. I plugged this M8A's numbers into my software, and it will give very poor performance in the S45's box. Not much bass below 90Hz.

According to the software, the best one in the S45 box is still the Peerless SLS above.

Right. One last question: The problem is that the speaker flange is too big for the box. You're suggesting grinding off a bit of the box. Why not grind off a bit of the flange?

Why not, indeed?

It won't hurt, that's for sure.

Make sure that you tape up COMPLETELY the speaker before grinding - you don't want little metal filings getting into unwanted crevices, and that large magnet is certainly going to pull anything metallic its way.

Depending on how you would grind the metal, I'd be also quite worried about it heating enough to ruin the cone surround or warp the entire basket.

Good point, Mika.

I mentioned patience, and patience is definitely a requirement - gentle grinding at one point on the flange, and moving on before it gets hot. Possibly making 4 or 5 complete 360 degree rotations to do the entire 2mm reduction.

The least invasive procedure would be to make a 3mm thick MDF spacer ring.