[bprochford]

My newly built N3s have replaced a pair of the original Meadowlark Audio Kestrels.  I pulled the crossovers out of the Kestrels, and would like to upgrade the components therein with some nicer stuff (SoniCaps, Mills resistors, etc) from Danny, and use these speakers in a bedroom setup.

In the x-over circuit, there's a Bennic electrolytic 31 mfd capacitor wired in parallel with a 4.75 mfd cap (not sure the make), yielding a total capacitance of 35.75 mfd.  I'm a rookie at this, so bear with my possible ignorance, but can I simply find two SoniCaps that when their capacitance values are added, equal 35.75 mfd?  Is there a best practice for selecting values to get to this total?

Also, do I have to have exactly 35.75 mfd, or will I be ok at 36 mfd total?

Any input or guidance would be very much appreciated.

[Danny Richie]

If you have a schematic then post it and I'll make recommendations.

When making up an odd cap value always use two caps of the same value. If you use a 10uF and a 6uF to make a 16uF then the charge and discharge rates will be different and it will cause a slight phase shift in the audible range. It will have a slight smeared sound. It would be fine though to use a pair of 8uF caps to get that value.

If by-passing then use a very small value typically no larger than a .1uF. This puts any phase shift above 20kHz and out of range of hearing it.

In some positions in the circuit you might want to just use an Erse poly cap (good and inexpensive) then by-pass it with a .1uF Sonicap. That might be the best bang for the buck for a large value.

In the tweeter circuit or any shunt caps in the mid-range circuit might be best served with a Sonicap.

And when making values it is not so important to hit an exact value as much as it is important that the left and right channels match.

[Æ]

When making up an odd cap value always use two caps of the same value. If you use a 10uF and a 6uF to make a 16uF then the charge and discharge rates will be different and it will cause a slight phase shift in the audible range. It will have a slight smeared sound. It would be fine though to use a pair of 8uF caps to get that value.

I forwarded your above comments to a very knowledgable person at another website. Someone who is definitely your peer when it comes to loudspeaker building. I'll leave him nameless, at least for now.

His reply:

"Wow, no truth at all, at least not that matters. I don't know who said that, but it doesn't appear that they actually know what they're talking about.
 
George Short at Northcreek recommends exactly the opposite in what he calls "multicapping". His view is to use multiple caps of different values in parallel to arrive at larger values when needed so you can divide up ESR and other deleterious factors better."


Of course this is your "Circle" and you'll always get the last word.
I'm not quite sure who to believe.

[bprochford]

If you have a schematic then post it and I'll make recommendations.

Thanks, Danny.  I've added a schematic which I think I've got correct, as well as a photo of the crossover in its present and original setup.  The yellow cap at the bottom is the one labelled 475K, which I've taken to be 4.7 uF.  Is that correct?  The blue one it's soldered to is the 31 uF Bennic.  If I remember correctly, the Kestrels are a 1st order, transmission line design.

Your guidance is always appreciated.

[corndog71]

I see some Kimber 4PR speaker wire there.  Nice touch.

[bprochford]

I see some Kimber 4PR speaker wire there.  Nice touch.

Meadowlark wired up their speakers with Kimber cables.  I think on the higher-end models they may have even used the 4AG.  I loved these speakers, used them for almost 15 years.  My N3 towers are killing it right now, but the Kestrels will make for a nice second system.

[Danny Richie]

The 5 ohm resistor looks like it might be an older Mills resistor. If so it is good.

I'd replace the 5.6uF cap with a Sonicap. That is your only cap in line with the tweeter.

The LCR network is a notch filter and is all in shunt. So it is basically causes a short to ground. It passes no signal to the tweeter. So what you are looking for here is just no stored energy. And any phase shift from dissimilar values is of no concern in this position. I'd just replace the electrolytic cap with an inexpensive Erse poly and replace the sand cast resistor with an inexpensive Lynk resistor (60 cents) and call it good.

[bprochford]

Cool.  Thanks so much, Danny.

Can I use the same inductors? I mean, are there radically audible differences between types or brands?  Also, is there an easy way, without a power supply and a scope, to test the inductance value of a coil? The big one in this circuit isn't marked with a value and I'm curious as to it might be.

Best,
Brad

[Danny Richie]

Cool.  Thanks so much, Danny.

Can I use the same inductors? I mean, are there radically audible differences between types or brands?  Also, is there an easy way, without a power supply and a scope, to test the inductance value of a coil? The big one in this circuit isn't marked with a value and I'm curious as to it might be.

Best,
Brad

It is an air core inductor so it should be fine. Going to an Erse XQ or foil inductor will be a slight to almost un-noticeable deference (it really depends on your system). So I don't know that it would be worth the added expense.

You might consider lining them with No Rez though. That always makes a nice improvement.

[Rclark]

 Ae's comment appears to have been unnoticed, I'm curious what Danny thinks.

[Danny Richie]

I forwarded your above comments to a very knowledgable person at another website. Someone who is definitely your peer when it comes to loudspeaker building. I'll leave him nameless, at least for now.

His reply:

"Wow, no truth at all, at least not that matters. I don't know who said that, but it doesn't appear that they actually know what they're talking about.
 
George Short at Northcreek recommends exactly the opposite in what he calls "multicapping". His view is to use multiple caps of different values in parallel to arrive at larger values when needed so you can divide up ESR and other deleterious factors better."


Of course this is your "Circle" and you'll always get the last word.
I'm not quite sure who to believe.

I stand by what I stated. Sounds like someone lacks some experience, and/or they have never listened with their ears.

[Æ]

Ae's comment appears to have been unnoticed, I'm curious what Danny thinks.

I haven't taken sides for or against his particular methodology just yet. I'm hoping to gather more credible information before I make up my mind. Seriously, if there is real technical merit to his statement, I'll incorporate into my own future designs, builds.

[S Clark]

I haven't taken sides for or against his particular methodology just yet. I'm hoping to gather more credible information before I make up my mind. Seriously, if there is real technical merit to his statement, I'll incorporate into future designs, builds.

It makes sense to me to use the experience of the person that designs with a particular component.  If I was using NorthCreek stuff, I'd go by their guidelines, if using GR-Research stuff, I'll take Danny's advice.  In this circle, I'll defer to Danny.

[Æ]

It makes sense to me to use the experience of the person that designs with a particular component.  If I was using NorthCreek stuff, I'd go by their guidelines, if using GR-Research stuff, I'll take Danny's advice.  In this circle, I'll defer to Danny.

In this circle everyone has to defer to Danny, obviously.

If you want to get real technical, the OP was asking how to modify a pair of Meadowlark Audio Kestrel loudspeakers, not GR Research loudspeakers.

[S Clark]

No, but if you are using Sonicaps, follow Danny's advice.  If you want Northcreek, go to their forum.
Or perhaps contact the cap manufacturer.  If I am correct, Jeff at Sonicap was in business with Danny at one point.  He should have a good handle on how his products behave.

[Æ]

No, but if you are using Sonicaps, follow Danny's advice.  If you want Northcreek, go to their forum.
Or perhaps contact the cap manufacturer.  If I am correct, Jeff at Sonicap was in business with Danny at one point.  He should have a good handle on how his products behave.

Jeff only sells them, he doesn't manufacture them!

[*Scotty*]

Æ ,unlike the OP you sound like you are in a ideal position to do an experiment and determine for yourself which you prefer. I also don't understand why you have bothered to post on this thread in this circle.
You could have just as effectively confused the OP by PMing him the opposing viewpoint concerning bypass caps and also learned the same information by just lurking here. Your actions don't coincide with your stated motivation.
Scotty

[S Clark]

AE,
Actually, from what I have read, Jeff IS the designer of Sonicap and probably has it made to specs, much like Danny is the designer of the  M-130 mid woofer and has it made to spec for him. 

You've made your point that one other industry pro disagrees with Danny's approach.  Shall we move on?

Scott

[Rclark]

and AE I dont think Danny is some Tyrant who needs deference. He's just a straight shooter.

[Danny Richie]

Okay just for you guys I just took a few measurements tonight.

I just selected some caps with matching values. One pair of 27uF values measuring 53.91uF. The second pair was a 39uF and a 15uF measuring 54.95uF. That's pretty close.

Below are the measured responses.



One set of measurements show the impedance curve of each cap bundle. Those lines are Blue and Gray curves. It is hard to make out the Blue line because the Gray line lays right on top of it. They are virtually identical.

The next group of measurements show the phase response. There are three sets of measurements on each bundle just for the sake of showing consistency. These measurements show the difference in phase shift that is present between them. One cap bundle shows measured responses with lines Red, Orange, and Yellow. The other cap bundle shows measured responses with colors light Blue, Purple, and Green.

The phase shift using caps of differing values can clearly be seen. On a good system a side by side comparison also allows them to easily be heard.

Any other questions?