As crossovers age...

[JerryLove]

I've noticed some signifigant mid/high harshness in some older speakers that, as far as I can tell should not have it. I'm wondering if one spot I should look should be the crossover network. Are there parts in there that are prone to age-related mis-operation in the 10-20year timeframe? Any suggestions which parts in particular?

 

[highfigh]

I've noticed some signifigant mid/high harshness in some older speakers that, as far as I can tell should not have it. I'm wondering if one spot I should look should be the crossover network. Are there parts in there that are prone to age-related mis-operation in the 10-20year timeframe? Any suggestions which parts in particular?

What make/model are they? In my experience, many of the speakers that were considered "great" or "classic" in the '70s and '80s don't stand up to the test of time very well when compared with newer models. I can't think of a single 6-1/2" woofer that produced the quality of bass as what we have now and many of the tweeters that were considered better than average or great sound less than realistic. Mid-range is an area that some speaker manufacturers seemed to avoid altogether, especially Asian, where "boom/crash" was more common than anything else.

I would suspect the drivers before the caps/coils unless they were exposed to excessive voltage.

 

[JerryLove]

What make/model are they?

B&W 801series2 and (to a lesser extent) B&W 801N.

 

[sparky77]

I would check the capacitors for signs of leaking. Some of the older capacitors will lose there tolerances even without leaking, so a quality replacement might help.

 

[Alex2507]

How about some detailed pic's? I'm sure TLS and Swerd would have some insight. My guess is that you haven't laid eyes on the crossovers yet. I think a visual inspection would be a start and then a replacement of any electrolytic capacitors. But with lots of pic's of course.

 

[TLS Guy]

I've noticed some signifigant mid/high harshness in some older speakers that, as far as I can tell should not have it. I'm wondering if one spot I should look should be the crossover network. Are there parts in there that are prone to age-related mis-operation in the 10-20year timeframe? Any suggestions which parts in particular?

Only electrolytic caps would deteriorate over time, in fact they all do. No decent speaker should have electrolytic caps in the crossover.

I have always polypropylene types and have had no problems over a significant length of time. My surrounds and rear have components 26 years old, with no problems.

 

[TLS Guy]

B&W 801series2 and (to a lesser extent) B&W 801N.

The 801 series two I think do have a harshness in the middle and HF. The 801N is much better, but not as good as the diamond tweeter range.

 

[Swerd]

Only electrolytic caps would deteriorate over time, in fact they all do. No decent speaker should have electrolytic caps in the crossover.

I have always polypropylene types and have had no problems over a significant length of time. My surrounds and rear have components 26 years old, with no problems.

I agree with TLS about aging caps - it only applies to the electrolytic ones. Sometimes they are called NPE for non-polar electrolytic. The polypropylene caps, even the inexpensive ones from Parts Express (Dayton) or Madisound (Bennic), are well made and will never leak or dry out. I would hope that B&W didn't use cheap NPE caps in their 800 series speakers.

I'm not as familiar as TLS is with all the different B&W speaker models, but it has also been my impression that some, but not all models, have harshness in the upper midrange or lower treble. I believe it is caused by crossing over the Kevlar fiber midrange or midwoofer to the tweeter at too high a frequency. Some of them use a 3500 or 4000 Hz crossover point. That won't filter out the break up noise or cone resonance the Kevlar cone makes at these freqs. So it is the fault of the crossover, but it has nothing to do with aged parts.

 

[JerryLove]

How about some detailed pic's? I'm sure TLS and Swerd would have some insight. My guess is that you haven't laid eyes on the crossovers yet. I think a visual inspection would be a start and then a replacement of any electrolytic capacitors. But with lots of pic's of course.

I'll see what I can do. I've certainly stared at the crossover on the S2, but I've not mucked with the N.

 

[JerryLove]

The 801 series two I think do have a harshness in the middle and HF. The 801N is much better, but not as good as the diamond tweeter range.

That's in line with what I'm hearing: but it's still distinct enough that I don't understand how it wouldn't be mentioned on basically every speaker review of the unit.

 

[TLS Guy]

I agree with TLS about aging caps - it only applies to the electrolytic ones. Sometimes they are called NPE for non-polar electrolytic. The polypropylene caps, even the inexpensive ones from Parts Express (Dayton) or Madisound (Bennic), are well made and will never leak or dry out. I would hope that B&W didn't use cheap NPE caps in their 800 series speakers.

I'm not as familiar as TLS is with all the different B&W speaker models, but it has also been my impression that some, but not all models, have harshness in the upper midrange or lower treble. I believe it is caused by crossing over the Kevlar fiber midrange or midwoofer to the tweeter at too high a frequency. Some of them use a 3500 or 4000 Hz crossover point. That won't filter out the break up noise or cone resonance the Kevlar cone makes at these freqs. So it is the fault of the crossover, but it has nothing to do with aged parts.

His series 2 has the older mid range driver. That does have some break up modes.

His later Ns have the midrange driver that is a bend driver by design.

This whole issue evolves round the problem of three ways.

As I have stated before many times, the lowest most practical crossover point to the woofer in a passive three way is 350 Hz. Otherwise you create a boat load of problems and make a speaker that is a nightmare to drive. At 350 Hz it is usually bad enough. In order to get the crossovers far enough apart, that puts the upper crossover about 4kHz.

That leaves you with few options for a really high end three way. The ATC mid now further developed by PMC is top of the pecking order. The B & W a second, and the third is the Dynaudio D76. Sadly NLA unless you have pull, and Dynaudio kindly let me purchase a pair from them about four years ago. That is a great midrange, but a 400 Hz crossover point which is what I use, is pushing that driver to the limits. You just get away with it, if you don't want to play offensively loud.

Really the answer to three ways is active speakers, for the woofer mid crossover point at least. ATC have been proponents of active three ways for years, and now they are joined by PMC who have formed a tight alliance with Bryston.

I see huge problems for B & W if they don't convert at least the top end of their 800 range to active speakers. They are already getting beaten up badly in the high end European monitor market, for this very reason.

 

[Alex2507]

I don't understand how it wouldn't be mentioned on basically every speaker review of the unit.

That's why we have you, my little golden eared guinea pig.

 

[Swerd]

His series 2 has the older mid range driver. That does have some break up modes.

His later Ns have the midrange driver that is a bend driver by design.

This whole issue evolves round the problem of three ways…

Which is worse? Having the woofer-to-mid crossover too close to the mid-to-tweeter crossover, or having the mid-to-tweeter crossover so high that the midrange break up modes are audible.

I've heard similar problems in B&W 2-ways using the Kevlar midwoofer, where the crossover was at 4000 Hz. In my opinion that is way to high for a 6½" driver no matter what its made of. If they choose a different tweeter capable of being crossed lower, say 2 to 2.5 kHz, this would not have been a problem.

 

[Swerd]

… I don't understand how it wouldn't be mentioned on basically every speaker review of the unit.

Yes you do .

Even (maybe I should say especially) paid reviewers at well known magazines are subject to hearing what their attitudes, beliefs, and expectations prepare them to hear. And no matter what they may hear, those attitudes, beliefs, and expectations can also affect what they write.

 

[JerryLove]

~sigh~

This is a very expensive way to find out a speaker is sub-par. The Series2 I chalked up to (among other things) mucking by the previous owner... but the 801N's are pristine, and hurt my ears when I turn up the volume.

I've been hoping it's something stupid (hence crossover question), given not only the high reputation in professional reviews, but in ameture reviews, the recording industry, and amongst many here on audioholics (usually said of the 802, but still).

I'm a little confused though what the inherent problem in cone sizes you are referencing is. My Paradigm S2's (with tweeter and midrange similar in size ot the 801N) paired with a sub (similar sized woofer) don't have nearly this severe an issue.

 

[JerryLove]

That's why we have you, my little golden eared guinea pig.

I believe I have a good ear to hear problems, but a lousy brain to describe them.

I'd love to drag an audioholics with more skill than I to my house for any number of reasons.

 

[Alex2507]

I believe I have a good ear to hear problems, but a lousy brain to describe them.

That's why we have Swerd and TLS Guy. I wonder if you have been spoiled by Chris' speakers. I also wonder if the issue you had with the crossover programming may be something only the golden eared would notice. It seems we have a little collection of guys who ain't so fond of certain B&W lines. Seems like you're in good company there ... except for ADTG ... he's just crazy.

I'd love to drag an audioholics with more skill than I to my house for any number of reasons.

Doug is rushing back to his car ... Twister mat is already in the trunk.

 

[JerryLove]

That's why we have Swerd and TLS Guy. I wonder if you have been spoiled by Chris' speakers.

My problem with Chris's speakers seem to be in the same area, but opposite direction, as the B&W.

I'm *pretty* sure that the problem is with the mid-bass for several reasons. I *know* it's not inherent to the drivers themselves (as it does not exist in the unmodified P362's), unless it's the tweeter, and that wouldn't fit.

(guessing) Either the encolsure for the mid-bass drivers is the problem (It's much smaller than in the stock 360), or there's a problem with the corssover/amplification.

I also wonder if the issue you had with the crossover programming may be something only the golden eared would notice. It seems we have a little collection of guys who ain't so fond of certain B&W lines. Seems like you're in good company there ... except for ADTG ... he's just crazy.

I think that people often focus one what they like about something and miss other parts of the same sound. I remember a pair of McIntosh 717's I purchased off craigslist. The owner didn't hear the buzzing that was really obvious to me until I found just the right song and put his ear near the tweeter.

After noticing it, he could hear it in everything we played on that speakers (he replaced the tweeter before I baught the speaker).

His ear wasn't the problem... he just didn't notice.

Doug is rushing back to his car ... Twister mat is already in the trunk.

Winter is coming: I need to get back on horseback

 

[TLS Guy]

~sigh~

This is a very expensive way to find out a speaker is sub-par. The Series2 I chalked up to (among other things) mucking by the previous owner... but the 801N's are pristine, and hurt my ears when I turn up the volume.

I've been hoping it's something stupid (hence crossover question), given not only the high reputation in professional reviews, but in ameture reviews, the recording industry, and amongst many here on audioholics (usually said of the 802, but still).

I'm a little confused though what the inherent problem in cone sizes you are referencing is. My Paradigm S2's (with tweeter and midrange similar in size ot the 801N) paired with a sub (similar sized woofer) don't have nearly this severe an issue.

If the 801 N is as bad as you describe, then there is something wrong. What are you driving them with. I suspect a speaker/amp interface issue here. But I would check the crossovers.

 

[Swerd]

~sigh~

This is a very expensive way to find out a speaker is sub-par. The Series2 I chalked up to (among other things) mucking by the previous owner...

Do you know what the previous owner did to them?

I've been hoping it's something stupid (hence crossover question), given not only the high reputation in professional reviews, but in ameture reviews, the recording industry, and amongst many here on audioholics (usually said of the 802, but still).

It may be fixable. I am aware of someone who owned an older pair of large B&W 3-ways (it looked similar to this]. He brought them to a DIY speaker building friend (Dennis Murphy) who has measuring equipment. I don't remember what the result was of their measurement, but one outcome may have been designing a new crossover for them. The other outcome may have been - do nothing to them. I can ask if there is an alternative crossover for the 801 series 2 model.

I'm a little confused though what the inherent problem in cone sizes you are referencing is. My Paradigm S2's (with tweeter and midrange similar in size ot the 801N) paired with a sub (similar sized woofer) don't have nearly this severe an issue.

It's not cone size per se. Every cone speaker has what are called "break up modes". At some higher frequency, the cone stops acting as a well-behaved piston and starts "breaking up". This results in an irritating edge to the sound. Speakers that at first seem to add detail over and above what is in the recording generally suffer from this kind of upper midrange break-up noise. Stiffer cones, such as metal or kevlar fiber, are known to have prominently loud break up noise. Softer cones, such as paper or polypropylene, often roll off enough so that their break up modes are much quieter.

The crossover designer must find out what frequencies are too high for a given midrange or midwoofer driver to smoothly reproduce, and cross over to the tweeter at a frequency low enough to filter out that noise. There are a variety of ways to deal with this, as your Paradigms seem to demonstrate.