Out of curiosity, I opened up my old speakers (B&W DM630 from about 1993) today to see what the crossover looked like. There are 3 coils and 3 caps that all say bennic bi-polar on them as well as things about MFD and WV. Are these something that can be easily upgraded? and is it worth doing? Any advice would be graciously accepted.
-d
-d
There are a number of modifications you can make to your crossovers d that subjectively you may find will bring an improvement to sound quality.
The bennic bi-polar capacitors are electrolytic types. Many high quality audiophile crossovers specify polypropylene types as an alternative. There are plenty of brands to choose from if you wish to replace the capacitors. The coils can also be replaced with air-core types, again often a preferred choice for high quality crossovers, this however is not so easy to do without knowing the values of the existing coils. An LCR meter is required to measure the values of the coils if you’re unable to establish this by other means.
The thing to note is that the crossovers will have been voiced with the existing components therefore replacing like for like component values may still result in a subtle shift in tonal presentation. I’d suggest you replace the series tweeter capacitor with a polypropylene type to begin with – SCR is as good a choice as any.
Other than this try removing the crossovers to external enclosures. This I find consistently improves the performance of loudspeakers particularly in terms of high frequency detail.
The bennic bi-polar capacitors are electrolytic types. Many high quality audiophile crossovers specify polypropylene types as an alternative. There are plenty of brands to choose from if you wish to replace the capacitors. The coils can also be replaced with air-core types, again often a preferred choice for high quality crossovers, this however is not so easy to do without knowing the values of the existing coils. An LCR meter is required to measure the values of the coils if you’re unable to establish this by other means.
The thing to note is that the crossovers will have been voiced with the existing components therefore replacing like for like component values may still result in a subtle shift in tonal presentation. I’d suggest you replace the series tweeter capacitor with a polypropylene type to begin with – SCR is as good a choice as any.
Other than this try removing the crossovers to external enclosures. This I find consistently improves the performance of loudspeakers particularly in terms of high frequency detail.
m0tion said:
They are definitly electrolytics.
Soulwax said:
It looks like the values are small enough that I could use solens all around and not spend more than about $30. Considering that the speakers weren't super cheap, I am a bit surprised B&W didn't do this in the first place ... on second thought, not I'm not.
It's funny, when buying new equipment, one wants to find ony top quality parts. Otoh, when moding it, it is better if there is garbage.
Soulwax said:
This is probably more than I am going to do in the short run.
By air core, does this just mean that the inside is hollow, i.e., that I can see through it? If so, they are air coils. If not, well then they're hollow.
Soulwax said:
Well, if voicing changes for the worse, I guess it will be time to tinker a bit more. Is it worth paralleling a small oil cap or something boitiquey with a solen, or just stick with the polyprop for the series tweeter?
Thanks for the help.
-d
hmmmm active surplus had loads of them in different values. I thought the dude was pulling my leg when he said they were amazing for crossovers. These things were the size of Liquor flasks and then they got progressively smaller.Yes.
I wouldn’t be concerned with using a small value bypass capacitor. However, if possible, damp the series tweeter cap by rolling it in a sorbothane strip or similar, securing with a tie wrap, and using copious amounts of epoxy to secure.
I’d also advise caution if soldering wires directly to tweeter connection tags as the transmission of heat can cause damage to the tweeter.
Upgrades
As one of the services we offer is speaker upgrades, I have been into and modded a lot of commercial speakers, including several B&W's.
Most of their speakers use just about the cheapest components out there and they have in the past sourced out their complete crossover assembly to Bennic.
There is much improvement ahead by upgrading the parts quality.
The biggest improvement is in the caps. If it uses the Bennic electrolytic caps then just about anything you put in there will be an improvement.
Even some cheap poly caps like Solen or Axon (made by SCR) will be a nice improvement. Further and even more significant improvements can be obtained with various high end caps.
On a budget good results can be obtained by by-passing a Solen or Axon with a high end cap in the .1uF range and still not spend much money.
Changing out the inductors to air cores will be a nice improvement too, but you really need to measure the DCR of the ones that are on there and try to match that value. You will need to go up in wire gauge on the inductors to do that.
Also, they typically use the Bennic sand caste resistors. Get ride of those and upgrade them to. Those are bottom of the barrel on the performance scale. Even a really inexpensive film resistor from Links sounds better.
Keeping the values that you swap out the same will not change the tonal balance of the speakers either.
Good luck, and if you need specific help in needing to know anything feel free to shoot me an e-mail and I'll tell you all that I can.
As one of the services we offer is speaker upgrades, I have been into and modded a lot of commercial speakers, including several B&W's.
Most of their speakers use just about the cheapest components out there and they have in the past sourced out their complete crossover assembly to Bennic.
There is much improvement ahead by upgrading the parts quality.
The biggest improvement is in the caps. If it uses the Bennic electrolytic caps then just about anything you put in there will be an improvement.
Even some cheap poly caps like Solen or Axon (made by SCR) will be a nice improvement. Further and even more significant improvements can be obtained with various high end caps.
On a budget good results can be obtained by by-passing a Solen or Axon with a high end cap in the .1uF range and still not spend much money.
Changing out the inductors to air cores will be a nice improvement too, but you really need to measure the DCR of the ones that are on there and try to match that value. You will need to go up in wire gauge on the inductors to do that.
Also, they typically use the Bennic sand caste resistors. Get ride of those and upgrade them to. Those are bottom of the barrel on the performance scale. Even a really inexpensive film resistor from Links sounds better.
Keeping the values that you swap out the same will not change the tonal balance of the speakers either.
Good luck, and if you need specific help in needing to know anything feel free to shoot me an e-mail and I'll tell you all that I can.
I noticed great improvement in my tweeter sound when i swapped my solen cap for a Hovland musicap, i would go so far as to say that it made all the difference between good sound and high end sound, only use air core inductors. Bennics are just as good as solens but between those two and the hovlands and some for the mundorfs thwere is no comparison.
I find that MOX resistors add a layer of high frequency hash and are best avoided. Preferable are non-inductive wirewound resistors, although sometimes difficult to source.
Substitution of like for like component value but of differing component type has the potential to cause subtle change in the frequency response of the crossover. This at least is my experience of modifying crossovers.
I've not noted any obvious subjective differences between various polypropylene capacitors of comparable quality; I think this is more wishful audiophile thinking. Certainly there are audible differences between bi-polar electrolytic and metallised polypropylene capacitors when used in loudspeaker crossovers.
Still, the larger gains are to be had by structurally de-coupling the crossover from the loudspeaker enclosure in some manner.
crossover components
I agree. My favorite is the Mills non-inductive wire wound resistor. Sourcing them really isn't a problem though. I stock all values from .5 ohms to 100 ohms. They can be order from our web site.
If the values are the same then the measured frequency response is the same, but that does not mean it will sound the same.
I'd have to agree that differences between comparable quality caps is minor. For instance Solen, Axon, or Bennic poly caps.
But not all poly caps are of equal quality or performance. Some are much better. If you haven't heard the difference that a higher quality cap like the Sonicap and many others can make then you are missing out.
I would have to say that was extremely minor compared to upgrading cap quality.
I agree. My favorite is the Mills non-inductive wire wound resistor. Sourcing them really isn't a problem though. I stock all values from .5 ohms to 100 ohms. They can be order from our web site.
If the values are the same then the measured frequency response is the same, but that does not mean it will sound the same.
I'd have to agree that differences between comparable quality caps is minor. For instance Solen, Axon, or Bennic poly caps.
But not all poly caps are of equal quality or performance. Some are much better. If you haven't heard the difference that a higher quality cap like the Sonicap and many others can make then you are missing out.
I would have to say that was extremely minor compared to upgrading cap quality.
Unfortunately not so easy to source this side of the pond Danny. The main electronic component supplier in the UK and Europe is RS Components who only stock non-inductive film resistors.
My point here is that any substitution of crossover capacitors will be of some consequence irrespective of nominal rated values because no two capacitors, certainly those of different construction, are the absolute same in terms of electrical characteristics.
Sonicap and Auricap are the two brands I see most often quoted as a class above the rest. I'm not sure I could justify the extra expenditure over a good quality metallised polypropylene; maybe they are better in some respect.
I'd have to disagree here Danny. At least based on my experience. Have a look here for an interesting patent for loudspeaker crossover isolation.
http://www.patentstorm.us/patents/6173064.html
Thanks for all of this feedback.
Both Percy and Welborne stock Mills, and in fact Welborne is replacing them with Riedon claiming that they are more transparent.
As for caps, I think that I'll use something like Solens, but bypass the tweeter series cap with a small oil filled. All of my components have better than Solen caps in them (all Kimber now, all Jensen before too long) so the speakers proably should too where it is feasable.
I think that taking the crossovers out sounds like a good idea, but it will have to wait for a while. One thing at a time.
Last, does anyone have thoughts about replacing the dampening? It is just sheets of foam. Percy sells fancy stick on stuff for a small fortune. Anything else I should look at?
-d
Both Percy and Welborne stock Mills, and in fact Welborne is replacing them with Riedon claiming that they are more transparent.
As for caps, I think that I'll use something like Solens, but bypass the tweeter series cap with a small oil filled. All of my components have better than Solen caps in them (all Kimber now, all Jensen before too long) so the speakers proably should too where it is feasable.
I think that taking the crossovers out sounds like a good idea, but it will have to wait for a while. One thing at a time.
Last, does anyone have thoughts about replacing the dampening? It is just sheets of foam. Percy sells fancy stick on stuff for a small fortune. Anything else I should look at?
-d
Sure they are. We ship overseas to various countries three or four times a week on average.
I shipped a small padded envelope to Poland a few times recently (Bybee filters inside) for about $2.50 US. Insurance is more.
For some reason we ship a lot of product to Australia, Malaysia, Singapore, and Indonesia.
This is true.
They are considerably better. The Sonicap has the edge over the Auricap and is less expensive to boot.
Oh I am not dismissing this at all. I use a similar mounting method as well. I am saying that the cap upgrade is still more significant. Maybe you should give them a try some time.
I know, Blackhole 5 is kind of high. I stock it too, but there is nothing on the market right now that is better.
I have had something new designed that I recently tested and approved that will be very effective and less expensive. It's made by the same company that makes the BH-5. It uses a damper (the layer that adheres to the enclosure wall) that is nearly twice the thickness of the damper in BH-5. But then it simply has a 1" layer of textured open cell foam.
It performs damping and absorption functions as well as BH-5 and then some, but does not perform the isolation function.
I have found that in some sealed box designs the barrier layer in BH-5 (and other cheaper copies) can mass load the driver some. So this new product I am having made does not have that layer.
It will also be about $38. a sheet. We sell BH-5 for $48. but due to cost increases from the manufacturer it is going up to $50. a sheet. Most already charge $52. a sheet or more.
You can DIY something that will get you close (not as good, but more than half way there) if you spend the time to make it and it will be less money if your time is worth nothing.
I can tell you how if you like.
Danny said:
I didn't see the BH-5 on your site. Did I miss it?
The stuff at Percy is called Deflex. It is $12/panel, and I figured out I would need 40 panels to do the insides of my speakers. I have the sense that this is not a good use of my money.
I would be very interested in learning how to make my own, though I am still going to start with the cap upgrade and do one step at a time to see the effect of each. I also have started about 6 projects lately, am in way over my head, and am moving in a month, so even the caps won't happen for a while.
-d
It is under components.
http://www.gr-research.com/components/blackhole_5.htm
This is not in the same ballpark as BH-5. They are vary different.
Go to a local hardware store and buy industrial floor tile. This is typically 1/8" to 3/16" thick. It comes in 12" squares and is very cheap. It is a vinyl composite.
You can cut it up into small pieces and glue it to the walls of your enclosure using contact cement.
This wall add mass and dampen the enclosure walls cutting back on resonance problems.
Then add a layer of open cell foam. You can get open cell foam are most stores that sell fabric.
Glue it to the floor tiles.
You may still need to add some loose poly fill or fiberglass insolation for further standing wave control and box tuning.
Please keep us in mind for your cap upgrade as well.
Danny said:
Ah, there it is. It is expensive, but the pieces are large enough that I would only need about 5 to cover the entire inside which is way cheaper than the deflex solution. This brings up a second question ... is it necessary to cover the entire inside, or could I get away with something less? I actually like these speakers, and even without upgrading the caps I think it will cost well over $1500 to get commercial speakers I like better (partly because they sound pretty good, and partly because I am used to the B&W signature sound). So, if there are real improvements to be made, it is probably worth sinking a few hundred dollars into them.
Danny said:
Indeed I will.
-d
If you use BH-5 then you really don't have to cover all of the interior walls for it to be effective.
You can cover about 70 to 80% of the interior walls and still get most of the benefit.
Cut pieces out and place them in the middle of each panel or center leaving an inch or an inch and a half of space around it. In other words, not all the way to the front or back wall or brace, etc.
Placing the BH-5 in the middle of each panel will be very effective in resonance control. At the edges or right where a brace meets a wall is where there is the least amount or resonance any way.
Then stuff the remaining corners with poly fill or fiberglass.
Danny
You mention something about bypassing the existing caps with a good quality sonicap or else. Will this have almost as good results as replacing the existing cap altogether?
The problem in my case is that my crossovers have 75uf 30 10 and 16uf caps each all SCR and replacing those with good quality caps will cost no less than $500. What do you suggest?
You mention something about bypassing the existing caps with a good quality sonicap or else. Will this have almost as good results as replacing the existing cap altogether?
The problem in my case is that my crossovers have 75uf 30 10 and 16uf caps each all SCR and replacing those with good quality caps will cost no less than $500. What do you suggest?
Caps
By-passing your existing caps can often make quite a difference and can be a very inexpensive tweak.
Values in the .1uF range seam to work very well and have little effect on the overall cap values.
Prices can vary as can cap quality and performance.
I tried a lot of different types of by-pass caps. I liked the Infinicap Seti but they can be fairly high at around $11. a piece.
I liked the Generation 2 Sonicap a little better and they are only $2.15 a piece. These are designed to charge and discharge really fast. I liked the Sonicaps well enough to stock the entire line.
Dayton makes a film and foil .1uF cap that is in the $1.00 range that is not as dramatic but still effective. They can be bought from PE.
The best I have ever heard and by a good margin are the Sonicap Platinum. They are a Teflon composite based film and foil cap. They are great for electronics or any high end application where the absolute best is desired. .1uF's are $19.20 each.
By-passing your existing caps can often make quite a difference and can be a very inexpensive tweak.
Values in the .1uF range seam to work very well and have little effect on the overall cap values.
Prices can vary as can cap quality and performance.
I tried a lot of different types of by-pass caps. I liked the Infinicap Seti but they can be fairly high at around $11. a piece.
I liked the Generation 2 Sonicap a little better and they are only $2.15 a piece. These are designed to charge and discharge really fast. I liked the Sonicaps well enough to stock the entire line.
Dayton makes a film and foil .1uF cap that is in the $1.00 range that is not as dramatic but still effective. They can be bought from PE.
The best I have ever heard and by a good margin are the Sonicap Platinum. They are a Teflon composite based film and foil cap. They are great for electronics or any high end application where the absolute best is desired. .1uF's are $19.20 each.