Beovox s45-2 woofer replacement

[jonnym_ch]

hi all,
based in europe and looking to replace the 8" woofer on my s45-2 speaker. the speaker coil is rubbing and it's unlistenable.
can anyone recommend a suitable replacement and, given that the speaker shows it's impedance as 4-8 ohms, does this mean that both the 4 and the 8 will work fine ?
also, should i replace both woofers at the same time ?
thanks in advance,
jonny

 

[homebrew]

I'd pull the woofer and see if there's a manufacturer's tag with a model number. Possibly a SEAS, Scanspeak, or Peerless. They may have been modified for use by Beovox, so finding an off-the-shelf replacement might not be possible. I'd guess the used market might be the way to go. But if you do find exact replacements, by all means I'd replace both woofers. Since impedance varies with frequency, the 4-8 ohm rating is just nominal.

 

[jonnym_ch]

Hi homebrew,
Thanks for the reply. There is only a model number, 801023, on the speaker, but I have read that they are peerless.
I am based in Switzerland and have found nothing in the used market so was thinking of a modern replacement. I am not an audiophile and these aren't audiophile speakers so something that could provide a nice warm sound was what I was hoping for ... is that even possible ?
They are playing through my hk 430 twin powered amp/receiver.
Any help would be greatly appreciated.
Thanks again,
Jonny

 

[swechsler]

Welcome to AK. Unfortunately, dropping in a woofer isn't a simple matter; you have to allow for enclosure size, enclosure type, impedance, sensitivity and crossover design. This is why woofers have many parameters (called Thiele/Small parameters). These are sealed boxes, which makes the selection a little easier. Whatever you choose, you should replace both, since it's unlikely that the replacement will sound exactly the same. You can approximate the impedance of the original woofer using a multimeter on the ohms setting. This will give you the DC resistance, which is usually around 25% lower than the nominal impedance. So if, for example, it measure 3Ω, it's a 4Ω woofer.

What are your sources for purchasing speaker drivers in Switzerland? That may limit your selection somewhat. On eBay US there is currently a woofer for the original S45; I don't think it's the same as what yours uses, though, since the number is different.

Lastly, have you checked the woofer out to make sure there isn't anything obviously wrong with it? Specifically, make sure the surround, dust cap and spider are all securely attached all around. If not, are there any places around that will repair speakers (I mean other than the obvious just replacing drivers)? This will probably cost less than purchasing two new replacement woofers.

 

[jonnym_ch]

hi swechsler,
many thanks for your reply and for the welcome. i am a total newb but, having read around on the issue, realise that there is a lot more to changing a woofer than simply finding one the same size and dropping it in. in addition, from what i've read, the beovox s45-2 don't have a mid but a crossover that fills in between the woofer and the tweeter (not sure i really understood how this works and what impact this has on the woofer but it's what i read).
i don't have a multimeter unfortunately but, if i changed both woofers, and if the stated tolerance is 4-8 ohms, would it matter ?
i have looked on anibis.ch, ricardo.ch, tutti.ch, marketplace, ebay, amazon and many other sites but nothing second hand unfortunately.
i have taken the woofer out and looked at the superficial aspects and haven't found anything obviously wrong. i have read about issues with this particular speaker where the glue has become loose and the magnet has dislodged in transport however, i see no evidence of this superficially. having said that, i am a newb so wouldn't know what i was looking for.
i have tried to see if the rub is on one side only, to see if inverting the magnet will compensate for any droop due to time. however when i push the paper cone in, it appears as if the rub is all around and not only on one side of the speaker.
based on the size of the speaker (more info here : https://www.beoworld.org/prod_details.asp?pid=666) i was told that the Goldwood 8024 or 8028 would be fine however these are not easily available in europe and was hoping someone would be able to propose an alternative... again i realise that it's not a simple issue !!!
in any case, if anyone can help i would be deeply grateful as these are beautiful speakers and the one that works has a sound that i really like.
best regards,
jonathan

 

[swechsler]

in addition, from what i've read, the beovox s45-2 don't have a mid but a crossover that fills in between the woofer and the tweeter (not sure i really understood how this works and what impact this has on the woofer but it's what i read).

Not sure what this means. The picture in the link you posted clearly shows a 3-way design with a woofer, midrange and tweeter.

i don't have a multimeter unfortunately but, if i changed both woofers, and if the stated tolerance is 4-8 ohms, would it matter ?

Yes, very much. A speaker's crossover is designed specifically with the impedance of the drivers in mind. If you change the impedance, you change the crossover frequencies, which can cause either a "hole" where neither the woofer nor midrange have enough extension to cover certain frequencies between them, or a bump, where both are playing at frequencies where only one should be.

i have read about issues with this particular speaker where the glue has become loose and the magnet has dislodged in transport however, i see no evidence of this superficially. having said that, i am a newb so wouldn't know what i was looking for.

Are you talking about what's discussed in this thread? That sort of thing would probably not be visible without disassembly of the woofer itself. There is where a pro comes in.

i have tried to see if the rub is on one side only, to see if inverting the magnet will compensate for any droop due to time. however when i push the paper cone in, it appears as if the rub is all around and not only on one side of the speaker.

My guess is it's either the glue issue, or the woofer was bottomed out by being played too loud.

It might be worth investigating if there are repair places in your part of the world that you could either bring or send the woofer to.

ETA: I tried to find the thread on Beoworld mentioned in the above linked thread, but they've gone and archived everything, so the link no longer works. The thread's probably there, though, if you can figure out what to search on.

 

[jonnym_ch]

thanks swechsler,

really appreciate your expertise !

Not sure what this means. The picture in the link you posted clearly shows a 3-way design with a woofer, midrange and tweeter.

this is the discussion i found where the mid is referred to as a filler driver that apparently b&o developed (https://www.diyaudio.com/community/threads/bang-olufsen-s-45-2improvement.373862/) though i guess that it is still a mid. again total newb so apologies for misspeaking

There is where a pro comes in.

absolutely !
in the linked post above the impedance is apparently 8ohms, however i will take the speaker to a guy i know to see if it can be salvaged and re-coned or, if not, then have both woofers changed. the problem here in switzerland is that the cost of labour is so high that it will probably be prohibitively expensive to repair and replacement might be the only option.

regarding new speakers, i have read that the Monacor SPH-200KE woofer would be a good replacement ? does anyone have any experience of this ?

once again, many many thanks for your time and experience,

jonny

 

[Beobloke]

I had a rubbing midrange on one of the Beovox RL140s I acquired recently. No sign of damage or distress and the cone looked off-centre in that chassis - i suspect it had been like that from new! I cut the dust-cap off, unstuck the surround from the chassis, re-centred the coil using shims and stuck it back down nice and central. Removed the shims when it dried, stuck the dust cap on and it's been absolutely fine ever since.

If you're confident about giving this a go, it's worth a shot.

 

[jonnym_ch]

hi beobloke,

thanks for the reply. i had looked at re-coning but hadn't thought that it might be salvageable !

even though i suspect that @swechsler might be right in suspecting that it could be the magnet or that it was bottomed out, i might well give fixing it up a try first !

there are some excellent tutorials on re-coning on youtube (including the one by uncle doug which i found through AK) that make me think that it's well within my capabilities, however how were you able to unstick the surround ? did you use something on the glue to loosen it or did you need to cut it ?

thanks for your interest and help.

best regards,

jonny

 

[Beobloke]

Nothing exotic - just a very thin knife blade. The surrounds on my midrange are rubber so they peeled off easily. If yours are foam you may have more of a challenge on your hands!

 

[jonnym_ch]

ok, thanks @Beobloke. much appreciated