FAO: B&W 685 Owners

JonnyGLC

JonnyGLC

JonnyGLC

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Joined
7 Oct 2004
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Manchester
Long story short, i bought a pair second hand the other day but i'm unsure if the drivers have been blown.

If you could listen to the start of this song:

http://www.youtube.com/watch?v=P7nz6-UVrmU

With the start of the song, with the speakers at a reasonable level with the bass slightly up, it sounds like something is catching on the driver?

Just wondering if this is a trait of the 685's or if I've bought a duff set!

Cheers
 
The actual track's just one he made for one of the twilight films, it was off the new moon album i think.

Pretty gutted about this :(
 
Not a 685 owner, but the sound at the start of that track isn't a clean bass tone anyhow. I wouldn't say it sounded like rubbing or any mechanical issue, it just sounds like a filtered square wave synth.

If you want to be sure you'll need a source of clean sine wave bass tones. There are test tracks on Youtube, but a better option would be to download this:

http://www.linearteam.dk/default.aspx?pageid=winisdpro

and play with the included signal generator. Play some tones around 30-40Hz, but be careful not to do it too loudly.

If with those tones it still sounds unclean, then there is an issue, most probably a deformed voice coil from overheating, caused by a previous owner overpowering them. Irregardless of the speaker model, those tones should sound clean up to reasonable levels.

Good luck! :)
 
I cant hear it as Im on a laptop but it may be worth taking the cone out (unscrew from cabinet) and taking a look behind to see if the wire that is connecting the cone (voice coil) to the terminals on the speakers frame is not hitting the back of the cone when under maximum excursion.

If not, give the cone a shake when you have unscrewed it from the cabinet as I have had a case of poor construction and within the unit, there was a small ball of solder that was causing a rattling when being driven
 
Even getting the noise from about 75hz with that generator, and it's definitely more prominent on the left speaker than the right.

Gona try my best to get these back to him, argj.
 
:(

Hope you manage to sort it.


I thought I'd run the generator on my speakers to check them, unbelievably there is an issue on my right one too! They are DIY so it's a fault with the driver on mine which I sort of noticed before installing it but didn't think too much of. Sounds like a tiny bit of wire hitting the rear of the cone, but the tinsel leads are stiched into the spider. I'll have to check that out now, argh :mad:
 
Ok got a step further now.... This might sound weird but if i bung the bass holes the noise totally dissapears? No matter how loud i turn the volume up or how much i drive them?

It seems the sound i'm hearing is of the air escaping through the hole between the driver and the bullet?
 
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This happens on both speakers then? But it is suspicious it would happen more on one than another.

Blocking the port will reduce cone movement in any case, so a reduction in any rubbing sound may be attributed to this. Ports can make a 'chuffing' sound at higher levels, but it should be sufficiently sized and smoothed to not do this, especially at 75Hz. It looks like the 685s use a real phase plug (ie, it doesn't move with the cone. the 602s one did), if it were air escaping through the middle though it should be more noticeable with the port bunged as the pressure would be higher.

Hard to say without hearing the sound (a recording may help?) but it sounds dodgy, mostly as it is more prominent one one speaker than the other and what you're describing sounds more like rubbing than chuffing sort of sounds.
 
Out of curiosity try swapping the speakers over left to right and see if the noise moves with the speaker, that way at least you can tell if it is music based or that particular driver is worse.
 
This probably ain't much help but I have a pair of 685s but I won't be back at uni until Monday to test it for you.
 
Dr.EM said:
This happens on both speakers then? But it is suspicious it would happen more on one than another.

Blocking the port will reduce cone movement in any case, so a reduction in any rubbing sound may be attributed to this. Ports can make a 'chuffing' sound at higher levels, but it should be sufficiently sized and smoothed to not do this, especially at 75Hz. It looks like the 685s use a real phase plug (ie, it doesn't move with the cone. the 602s one did), if it were air escaping through the middle though it should be more noticeable with the port bunged as the pressure would be higher.

Hard to say without hearing the sound (a recording may help?) but it sounds dodgy, mostly as it is more prominent one one speaker than the other and what you're describing sounds more like rubbing than chuffing sort of sounds.
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The drivers move more when the bass port is bunged up, yet for some reason the noise stops which is why it's confusing me all the more! But then makes me think it is the air trying to escape out of the hole in the driver.

Bear said:
Out of curiosity try swapping the speakers over left to right and see if the noise moves with the speaker, that way at least you can tell if it is music based or that particular driver is worse.
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Already done that, and with the sine wave generator it was the same situation.. More apparent on the left :(

Nanoman said:
This probably ain't much help but I have a pair of 685s but I won't be back at uni until Monday to test it for you.
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Grr :p

The seller has agreed to give me a full refund, but i got suck a cracking deal with them i don't really want to give them back despite the niggle!
 
Just how noticeable is it? It's annoying I can't hear it as it'd be identifiable as a particular issue quite easily from the sound I reckon.


The noise I noticed on mine earlier was never noticed in any music, only on a high level, low frequency test tone, where things like the door rattling are more noticeable really but there's certainly something amiss with it as the left is fine.
 
With rock/indie music it's really not apparent at all which is why at first i didn't notice it. Had a couple of rock filled days and sat gawping at the ridiculous amount of detail they kick out!

But then i moved onto a bit of techno/dnb and it's so annoying that i had to stop listening to them :(
 
A random name said:
But then i moved onto a bit of techno/dnb and it's so annoying that i had to stop listening to them :(
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Well, from that sentance, unless you're cranking them to unreasonable levels, there is a fault. I had the slightly larger and older DM602s for years and never heard any strain from them, things in the house would rattle before this happened and it was rare they'd be used at this volume at all.
 
Dr.EM said:
Well, from that sentance, unless you're cranking them to unreasonable levels, there is a fault. I had the slightly larger and older DM602s for years and never heard any strain from them, things in the house would rattle before this happened and it was rare they'd be used at this volume at all.
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Yeah that's what worried me, they weren't at unreasonable volumes at all, infact with that genre of music it's apparent from very low volumes! Gona just get a refund from the guy :(
 
Normally if there is voice coil damage, gently pushing the woofer inwards to the end of its normal range of travel will either feel rough, make an audible rasping sound, or both (push linearly, evenly distributing the load). If there is any difference in feel between the two speakers, then there's certainly a problem.

It's difficult to explain exactly what I mean, but you get the idea. Although, if you say there are weird noises at certain frequencies, and you can get it to 'follow' one speaker by swapping them, then you've found that there's a problem anyway!
 
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If you need to get them fixed, this is the number to call:
01903 221700

It is the B&W repair number. I had to call them when I damaged the tweeter when cleaning my 685 with a vacuum cleaner. I do not know what i was thinking lol
 
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