crossover inductor education please.

[ferninando]

Crossover inductors are either air core or iron core. Each have their own properties at the crossover frequencies.
What dictates the use of one over the other? Can you exchange an iron core for an air core? Or visaversa?:scratch2: Why would you want to?:scratch2:
thanks.

 

[whoaru99]

Size is a big factor. An air core inductor typically will be much larger than an equivalent iron core inductor, and in some cases that size and or the resulting DC resistance of the windings may make an air core impractical for a certain use.

 

[SET12]

Crossover inductors are either air core or iron core. Each have their own properties at the crossover frequencies.
What dictates the use of one over the other? Can you exchange an iron core for an air core? Or visaversa?:scratch2: Why would you want to?:scratch2:
thanks.

Education!

Well friend your hearing from a person that uses the largest manufactured Air Core Inductors in the world. 8AWG's

Why would you want to ?

Better read these FAQ's http://www.northcreekmusic.com/COILS.html

The sound is so compressed from Iron cores, I can hardly stand to listen seriously to anything that uses iron cores because the compression is so evident.

The compression gives wimpy limited bass and also extends to the sound stage size as well. Its usually over whelming to people when the hear the pair of stock Forte's that I have here for comparison.

Imagine listening to pair of stock Forte's that are 9 ft apart with lateral imaging that can only extend a foot or so to the left and right of the speaker pair. Total width maybe 11ft. Some would say thats fine! But I'll say thats tiny when I'm listening to a symphony or a full blown live rock concert.It just doesn't convey the life size of the event. I might add the stage is what is recorded and the stage size does vary a lot. Small jazz in a club can be just between my speakers if recorded as such.

The same pair of speakers modified as I have done exhibit a stage that is often 10 ft or more to the left and right of each speaker.

One has to have electronics though that are capable of doing this as well as not all electronics excel at this. Tubes often have the capability and it not to say that SS can't but it is often less often unless you have very good stuff. getting Digital to do this is hard as well but mine does, its funny to listen to digital that can't and there is a lot of expensive stuff out there that can't as well.

Depends what you want, but I can tell you it literally an event to listen to my system, not something I chose to listen as back ground, to much going on.

Its funny how people use 16AWG speaker wire for there speakers but have no idea about the 50-100ft of 20-22AWG wraped in their Inductors.

As to the Inductors DCR the large Air Cores are often comparable to smaller Iron Core DCR's

As to the sound difference even with lower DCR's even if there may be a slight and I say slight level difference for the driver IMO it doesn't mean a hill of beans compared to a room variation in frequency balance. One can tune the room somewhat.

Here is a side by side difference. IMO I got what I paid for and then some.

For more current photo's see this page on my thread.

http://www.audiokarma.org/forums/showthread.php?t=159340&page=12

The nice thing about a lot of Klipsch's but not all is the simple networks.

And you probably haven't looked at some of the worlds better caps!

Check this out http://www.humblehomemadehifi.com/Cap.html

Unfortunately yeah there are some bargain caps out there. Some decent basic caps but extraordinary are unfortunately somewhat costly. But even I am on a budget. A pair of my Mundorf Silver/Oils would pay for all the components in my stock network, maybe not including the Autotransformers but maybe close!

I have hardly scratched the surface on what can be spent. But I will say inductors are seriously underrated.

SET12

 

[ferninando]

Thanks for the edu., SET.
Sounds like aircore and big guage is the way to go then. Certainly something to consider.
Do tweeters get the same treatment?

 

[SET12]

Thanks for the edu., SET.
Sounds like aircore and big guage is the way to go then. Certainly something to consider.
Do tweeters get the same treatment?

Absolutely, it really helps with the body of the highs, I once tried a 14AWG Solen Litz and found it to be thin and wiry sounding. Although the Litz has better specs usually in a high frequency circuit, for me it was to much information besides sounding thin.

When I went back to the 8AWG solid wire it was heaven, lots of body plenty of detail and so on. The large gauge for tweeters is far cheaper than the typical Low frequency inductors that are often used. In my case 3mH vs .16mH for the tweeter.

And it doesn't stop here. I use 28lb output transformers and will be using near 1KW power transformers for each of my mono blocks which already are using a 2000uf supply/mono of course big supplies often don't sound good for tube gear but I use a different design approach to get them as fast and as transparent as the small supplies but with much greater authority.

Don't forget the Autotransformers I have listened to 3 models and I currently use a C-Core design which is nearly twice the size of the stock model.

SET12

 

[sled108]

Hey Set12, I'd like to build a 'Proper' set of X-Overs for my KG3's...They are the same as used in the KG3, 3.2 & 3.5, according to Bob Crites...But, he uses Iron Cores, I want to use Air Cores....Do you, or anyone else have a Schematic for these?

 

[ferninando]

SET12, I don't understand the changing of inductor values with wire size. doesn't that change crossover freqs? Pls. explain. Can't I just get larger guage aircore coils of same mH values for the coils now in the xovers?

 

[battradio]

Hey Set12, I'd like to build a 'Proper' set of X-Overs for my KG3's...They are the same as used in the KG3, 3.2 & 3.5, according to Bob Crites...But, he uses Iron Cores, I want to use Air Cores....Do you, or anyone else have a Schematic for these?

The quickest way would be for you to open up one of your speakers and draw it out .

 

[sled108]

I Have...And, this was what I saw...And, as you See...It's a Tad Different...I'd rather have a Schematic to Build a New Set from, before I Un-Seal one of these to Hopefully figure out the Correct Values...Which might not be that Hard...Except for the Coil...Whose value is probably under It...Like as L2's...

 

[ferninando]

thanks for the hijack.

 

[SET12]

The quickest way would be for you to open up one of your speakers and draw it out .

Battradio is correct although people can mislead themselves when reverse engineering I know I have.

I Have...And, this was what I saw...And, as you See...It's a Tad Different...I'd rather have a Schematic to Build a New Set from, before I Un-Seal one of these to Hopefully figure out the Correct Values...Which might not be that Hard...Except for the Coil...Whose value is probably under It...Like as L2's...

You could e-mail or call Klipsch service to see if they would send you the schematic. They have in the past for a number of people including myself also you should be aware sometimes they'll make changes during production runs

Hey Set12, I'd like to build a 'Proper' set of X-Overs for my KG3's...They are the same as used in the KG3, 3.2 & 3.5, according to Bob Crites...But, he uses Iron Cores, I want to use Air Cores....Do you, or anyone else have a Schematic for these?

Nope, If you already have Bob's then it should be pretty easy to follow connections.

I have to tell you, I lived with 2-ways for many years and it took a long time for me to realize that when a two-way uses a woofer any bigger than a 7in. things in the mids are compromised like great definition and especially dynamic punch. Drivers may get to the midrange but definition and dynamics are another story IMO.

In the end its about having fun and what your needs are that counts though. If you do get a hold of that schematic please do send me a copy and I'll try and give you some insight on what your looking to improve.

SET12

 

[SET12]

SET12, I don't understand the changing of inductor values with wire size. doesn't that change crossover freqs? Pls. explain. Can't I just get larger guage aircore coils of same mH values for the coils now in the xovers?

ferninando,

I'm not an expert at Inductors but George at North Creek is. I did go to school for Electronics so I do have some knowledge as to how parts work.

To answer your last question first.

Yes you can and thats exactly what I did.

Some would argue well your changing the DCR of the original coil and thats correct. And your changing the voicing and yes thats correct.

The DCR or DC resistance is added in series with the inductors AC resistance Inductance value in ohm's for a final value. It will have an influence but its nil IMO. For instance my 3mH Air Core North Creek inductor has a DC resistance of lest than .1 ohm and the stock Iron Cores maybe .5 ohms.

Assuming the that both inductors are 3mH the resistance is 13.188 ohm's at 700hz my crossover frequency. With the DCR's added the difference is 3% between them. Hardly a big deal when other network parts can have a variation of 10% individually.

So basically the DC resistance is smaller with larger coils and large for smaller coils. Iron cores can be quite small but they have their own issues.

George at North Creek believes its the DCR that perhaps makes most of the difference. For me there's just something about core size like the 28lb Single-Ended output transformers I use which have an amazing sense of foundation with music.

To be clear here, I'm an audiophile in pursuit of the best sound I can for the limited funds I have. I am not after functionality but extreme performance is what I seek.

Unfortunately High End Audio can cost in the 10's of thousands. And I'm spoiled cause I have friends that have spent this that I can not afford. So I pursue DIYing to an extreme and the North Creek stuff met my needs in spades at 1/4 of the cost I could of spent, there are others of course but North Creek has been the best bargain for me and everything he has said I certainly have heard.

But this is the biggest thing that I have heard from Iron Core Inductors is

"distortion sounds like compression - and also measures as wave-form compression."

And I agree with what he says below

From North Creek's site

What about ferrite core inductors, which have very low DCR?

The problem with ferrite core inductors - all of them - is hysteresis distortion. Hysteresis is related to the energy loss incurred by the core material during the magnetization polarity shift that occurs in every cycle of the signal flowing though the inductor wire - for a 500 Hz signal, this is 500 times the core polarity has to be reoriented, per second! Hysteresis distortion sounds like compression - and also measures as wave-form compression. Furthermore, when the current though the inductor is large enough, the core will saturate and the value of the inductor dynamically shifts to a much lower value. This is also clearly audible.

The only practical application for ferrite-core inductors in high end audio is as low DCR "trap" coils in tweeter resonance trap circuits, where the circuit is functioning in a very narrow frequency window and the current flow is extremely small.


To answer your first question.

Its really all about shape form and length of wire that is needed for a specific mH value. Inductance is inductance no matter what the gauge of the wire is.

As to the sound of specific Inductors. It in how they are made and the quality of the materials which the North Creek site goes into.

As to changing the crossover frequencies as I pointed out above the only component that can is the DCR value and as I pointed out a few percent is no big deal in my book. Especially with ultra simple networks.

Here is a nice Inductor calculator which I used to compare my own 3mH 8AWG Inductors to.

http://www.diyaudioandvideo.com/Calculator/Inductor/

Coil diameter is the inner coil diameter the length is the thickness.

I measure my coils 1.5in inner coil and 1.5in tall 8AWG wire 3mH plugged in the #'s

What I came up with is pretty close to what I have. But one can see variation when changing size cores or wire gauge and so on.

SET12

 

[ferninando]

Its XsubL and XsubC that determine freq as I recal from my Navy and comm collg days.
And in this case crossover freq. all the rest determines inductance value in mH as I recall. wire ga, length, #turns etc.
So as I see it if you get a coil of the SAME inductance value with whatever # wire
you'll be ok in the xover freq area.
Dont misunderstand, Im not disputing what you've said. Im just addressing the basics of inductance vs freq in a crossover using a different larger # wire than stock. As long as the mH are = the xovr freq is the same and the speaker mfg is happy.

 

[SET12]

Thats correct :thmbsp:

 

[ferninando]

SET12, I appreciate your quest for audio perfection. Its fun. I couldn't hear perfection if paid to. My old ears arn't good as they used to be, but I do OK and if there's a tweek here and there can improve what I do hear Im for it. Just not sure I'll hear changes tweeking xover coils. Didn't hear any change with new poly caps, but the coils do sound like a worthy effort and I do understand why.
Thanks for enlightening me.

 

[SET12]

SET12, I appreciate your quest for audio perfection. Its fun. I couldn't hear perfection if paid to. My old ears arn't good as they used to be, but I do OK and if there's a tweek here and there can improve what I do hear I'm for it. Just not sure I'll hear changes tweeking xover coils. Didn't hear any change with new poly caps, but the coils do sound like a worthy effort and I do understand why.
Thanks for enlightening me.

Your Welcome

But that's just the half of it.

The low DCR Air Coils were night and day and contribute more over all IMO then the caps. The compression is pretty easy to hear along with the collapse of the sound stage. Not all coils are equal by any means. But as I have said the rest of the system has to be good to realize those benefits. I was fortunate enough that my associated components were top shelf performers and I don't necessarily mean just expensive ones.

I'm 56 and still have very good hearing for my age. What I found amazing is 3 out of 5 people in their mid 70's or so could use a hearing aid. I hope not to be one of them but if so then be so be it.

Hearing caps and coils can easily be system dependent, and system setup.

My system is a minimalist one with a mere 10 watts/channel no line stage with basically a two stage power amp and I can hear virtually most of its parts.

Don't know what brand of poly caps you refer to but most of the inexpensive ones in the $5 range or so don't make much of an impression on me as they seem to sound similar to one another. And what I do hear isn't great. Nothing like the AmpOhm's, Mundorf's or Duelunds.

One area I revisited just recently was the power supply DC resistance which on my own 15yrs ago discovered that high DCR resulted in a decrease in an amplifiers ability to display micro dynamics or individual instrument or vocal impact.

Had someone tell me that it was the 10-15 volt increase in B+ taking a 100 ohm resistor out that resulted in the perceived performance improvement of the amplifier.

Low and behold it was not. And with a 100 ohm's of resistance in the supply path it made the amplifier pretty boring as my musician friend would say.

I plan to write about my re-visitation of this phenomena soon.

But when all of the stuff is working together it makes for a very entertaining musical presentation.

Cheers

SET12

 

[Dave C]

I'm following along SET. I'd like to pay you a visit one of these months. We have much to catch up on.

 

[doucanoe]

The DCR of the 3 mH version of the Erse Super Q iron core ( as shown in sled108's pic) is actually .178

You also mention current saturation. Is this a concern of yours with your 10 watt amp?


RC

 

[SET12]

The DCR of the 3 mH version of the Erse Super Q iron core ( as shown in sled108's pic) is actually .178

You also mention current saturation. Is this a concern of yours with your 10 watt amp?


RC

Thank you for asking doucanoe. BTW I like and agree with your philosophical comment in the bottom of your screen. Its so true!

There's more to this then just DCR and current saturation.

There is a good discussion of Inductors here with ALK http://forums.klipsch.com/forums/t/38976.aspx?PageIndex=1

But lets start of with the Erse.

I love this comment from DeanG over on the Klipsch Forum from this page to be exact http://forums.klipsch.com/forums/t/38976.aspx?PageIndex=4

"I didn't expect to ever come back to this thread again, but have had a surprising experience. I finished my ALKs a few days ago, and as part of the build I went with some 10AWG Solen air cores which I mounted on separate boards because of their size. The DCR of the 10AWG air cores is .16, the same as the Erse Super Q steel laminates I've been using from Parts Express. FWIW, there's a pretty big difference in the bass. After an hour or so of listening I put some Super Q's into the circuit to see what it would sound like, and though still very good, sounded lean in comparison, and not nearly as full bodied and tight as the air cores. I've had the beasts laying around for a long time, and I'm glad I finally found use for them. I didn't expect to hear a difference, wasn't even listening for it, but it was pretty obvious."



The above statement really says a lot IMO. And I agree totally. And the Solens are not likely nearly as good due to resonance issues as the Solens are not vacuum varnished impregnated and suffer from micro fractures from high tension winding. And if he thought the Erse was so obvious just imagine what is heard in contrast to my stock Forte Inductors next to the 8AWG 3mH Air Cores that I use. Its not good! Maybe the Erse's are better but not likely much better than the stock inductors of my Forte's granted the DCR of the Erse is better but their are other issues like what North Creek mentions.

From North Creek's site

What about ferrite core inductors, which have very low DCR?

"The problem with ferrite core inductors - all of them - is hysteresis distortion. Hysteresis is related to the energy loss incurred by the core material during the magnetization polarity shift that occurs in every cycle of the signal flowing though the inductor wire - for a 500 Hz signal, this is 500 times the core polarity has to be reoriented, per second! Hysteresis distortion sounds like compression - and also measures as wave-form compression. Furthermore, when the current though the inductor is large enough, the core will saturate and the value of the inductor dynamically shifts to a much lower value. This is also clearly audible.

The only practical application for ferrite-core inductors in high end audio is as low DCR "trap" coils in tweeter resonance trap circuits, where the circuit is functioning in a very narrow frequency window and the current flow is extremely small.
"

My 10 watt amplifiers might be called extreme SET amplifiers as well as my CDP source direct that I use. Both mono-blocks and CDP have imense fast supplies.

I mention this only because I feel the system pieces go hand in hand together.

If I insert the stock Fortes with my amps and CDP you hear just a tremendous difference in sound. I hate to say this but its like going from a $10,000 speaker to a $1,000 speaker literally. But for $2500 I have into parts one ought to hear something and I and others sure do. So much so in fact some people I have demoed the stock pair in contrast to the modified didn't even make through one cut, it was so dramatic for them.

The the first thing one notices is the immense size of the sound stage in contrast to stock Fortes. It is so large that one would think a set of Khorns were in the room. And the bass? well its so much fuller especially over a wider bandwidth subs are really totally unnecessary as the Forte reaches the low 30's easily and of course extends up to 700hz. And thats the key! the bass is so full with its extended authority up to the crossover point that it makes subs laughable to me. I'd rather have the $500 low frequency inductors then the subs because whats a sub good from? 20hz to 120hz. You ought to hear the drums and the mid bass with such control it makes me laugh when damping factor is talked about. Good bass to me is not about damping factors necessarily at all, its the really the poor inductors that are often used.

My guess is that the hysteresis distortion along with some wave form compression really shrinks the sound stage IMO so much so that my modified Forte's have a stage width nearly 3 times the size. Lateral image definition extends up to 10ft or more to the left and right of the speakers with some music. It absolutely awes many people including myself. Granted that's not all there is to music, But the Inductors contribute to warmth as well. Even the 8AWG tweeter inductor is something else to be heard. I tried a 14AWG Solen Litz and it was thin and wiry. Maybe it had just to much info with the Ti Tweeters I use. Yes granted the Litz is electrically superior. But frankly it sounds awful IMO while the 8AWG North Creek excels at body and naturalness. I have had people comment on the continuity of the sound from top to bottom. The resolution is astonishing and very natural.

Your close enough to me to hear them for yourself, I have had a guy drive 500mi twice to hear them as he said no regrets.

I owe Redboy some Allen Amplifiers you could take back with you if he still wants them.

SET12

 

[SET12]

I'm following along SET. I'd like to pay you a visit one of these months. We have much to catch up on.

Hey Dave! You bet!