Best coil for crossover

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hpolkerman

Member
2006-12-10 3:23 pm
Searching this forum I could not stop to wonder which coil I should use for the Zaph's SR71 parallel-bass coil.

The value is 3.3mh, the coil is used till 1750Hz. If I use and air-coil the resistance would be too high.

Wich core coil should I use, I have the options of a Tritec/Ferrobar coil, the HQ58 coils from InterTechnik, a Ferrobar coil, a torobar coil and a torobar coil.

What's the difference except the minor differences in the resistance?
 
I can't get the Madisound Sledgehammer 15 AWG...

I can order at Speaker&Co and Capsandcoils, there both located in the Netherlands. This would safe me some shipping-costs as well as the trouble of converting Euro to US-Dollars.

But the Slegdehammer 15AWG has a ferrite core, or an iron one? And why should I not use Tritec/ferrite coil or the HQ58 coils from Intertechnik?
 

hpolkerman

Member
2006-12-10 3:23 pm
The main problem is that I can't get the Sledgehammer, and I want to know which coils is a good replacement for the Sledgehammer.

Cores are made up of different materials of iron; ferrite, copper(corrobar) even wood and plastics.

Which is a good replacement, which core should I look for?
 

tinitus

Ex-Moderator R.I.P.
2005-11-24 1:47 am
I dont see why a toroid would be unsuitable, well DCR is a bit on the low side ... its about 30EUR


There is also an IT, i-PUNKT, 3.3mH, DCR 0.21, 23EUR, iron with grainoriented silicium

Super Q from Caps&Coils should be fine too
 

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tinitus

Ex-Moderator R.I.P.
2005-11-24 1:47 am
As far as I know they are airgapped or with laminated core or the core contains air to act like airgap - they have the advantage of not "talking" with other inductors, no or less strayfield
Aircore would be the best, but not possible here
 
hpolkerman said:
The main problem is that I can't get the Sledgehammer, and I want to know which coils is a good replacement for the Sledgehammer.

Cores are made up of different materials of iron; ferrite, copper(corrobar) even wood and plastics.

Which is a good replacement, which core should I look for?


I'm not trying to answer your question here as my self is having similar question...

I'm actually looking for the coil as well for speaker x-over and found 2 type of cores for the coils which are air core and magnet core. As far as I know the main advantage using air core coil is much less saturation distorsion and hysteresis loss compare the iron, ferrite or magnet. But on the other hand the trade off would be the bigger size (not a problem if we have enough space to accomodate) and higher resistance compare the other type of cores.

With all characteristics of each cores, if we use proper ferromagnetic core for the purpose (very little hysteresis loss/ saturation distorsion) rather than the air core, is the different sound signature between those 2 cores audioable?

Does anyone have an experience on this when comparing both types of cores?

I understand it would be 'hard' to compare as most likely they have different wire, size...etc but at least I just want to know the main different between ferromagnetic core and air core sonically..;)

Thanks,

Joshua
 
I'll try to answer as best I can from what I've heard and read so far...

If the air coil has to much resistance it'll sound worse, not only because of the higher damping of the woofer, the control over the woofer is less(is what I've read)...The sound improves if you take an cored coil if the resistance tends to get higher then 0,5Ohm for the coil in series with the woofer. Somehow it affects the sound in a negative way.

What I could chose is a very expensive and large coil, a tritec for example which would be around 150 Euro... Instead I used the Jantzen Wire coil with non ferrite, the so called P-core. They say it has much less saturation distorsion and hysteresis loss than a normal core, and costs about 25 euro's.

I've tested the core and they do sound great, offcource I haven't bought the tritec, so there is no comparison to make...

Sonically it would be hard to hear, on the one hand you'll have the high resistance, on the other some more saturation distortion and hysteresis loss. Most people chose the latter with high value mh coils. Onder about 1,5mh, I'd use an aircoil where possible.
 
Hi,

Roland here (Caps&Coils), just looked up the design on Zaph's page:

If you are rounding up your own components, be aware that the low DCR of the steel laminate core isn't an absolute requirement. Just try to keep the impedance under about 0.7 Ohms and the difference in the effect on the woofer will be minimal.

So, air "core" is an option.

Kind regards
Roland
 
hpolkerman said:
I'll try to answer as best I can from what I've heard and read so far...

If the air coil has to much resistance it'll sound worse, not only because of the higher damping of the woofer, the control over the woofer is less(is what I've read)...The sound improves if you take an cored coil if the resistance tends to get higher then 0,5Ohm for the coil in series with the woofer. Somehow it affects the sound in a negative way.

What I could chose is a very expensive and large coil, a tritec for example which would be around 150 Euro... Instead I used the Jantzen Wire coil with non ferrite, the so called P-core. They say it has much less saturation distorsion and hysteresis loss than a normal core, and costs about 25 euro's.

I've tested the core and they do sound great, offcource I haven't bought the tritec, so there is no comparison to make...

Sonically it would be hard to hear, on the one hand you'll have the high resistance, on the other some more saturation distortion and hysteresis loss. Most people chose the latter with high value mh coils. Onder about 1,5mh, I'd use an aircoil where possible.

Hi,

That’s exactly what I’m looking for - the trade off between having high resistance vs saturation distortion/hysteresis loss…. Thanks for the explanation;)

I’m building 2nd order xover for full range and woofer speaker. The value I need are 3.5 mH and 9 mH. Near field listening, so I won't put too much power to the speakers.
I found Erse 16G Super Q Inductors at PartsExpress website. They looks interesting but Jantzen P-core is another coil for me to consider…

Any thought between those 2 ?

Thanks!

Joshua
 
I have read reports by some highly regarded speaker builders that unless you are pushing your speakers to near concert like volumes, saturation is fairly inaudible in the steel laminate cored inductors.....I currently am using the Sledgehammer 15 gauge steel laminate coil 8mH, (which actually measures out to 7.75mH) in my system and I play it pretty loud.....I am getting clean bass..........But here's the deal with these coils: They are made by a guy who used to work at Madisound in Wisconsin, USA, as was told to me by one of their employees........So they are a basic construction with nothing fancy to them....It seems to me that if you follow Zaphs' guidelines, that probably most any reputable steel laminate coil that you can get ahold of should suffice.........My research has indicated to stay away from ferrite cored inductors......PURCHASING NOTE: If you have a way to measure your coils, I would recommend that you buy the next value HIGHER than what you need......Like I said earlier, my 8mH coil actually measured between 7.65 and 7.75. This being said, if I had done that, I may have purchased an 8.5mH coil that measures 8.25, and then I could have unwound it to measure 8mH........Respectfully.....Omni
 
joshuajoshua said:


Hi,

That’s exactly what I’m looking for - the trade off between having high resistance vs saturation distortion/hysteresis loss…. Thanks for the explanation;)

I’m building 2nd order xover for full range and woofer speaker. The value I need are 3.5 mH and 9 mH. Near field listening, so I won't put too much power to the speakers.
I found Erse 16G Super Q Inductors at PartsExpress website. They looks interesting but Jantzen P-core is another coil for me to consider…

Any thought between those 2 ?

Thanks!

Joshua


I would use the Erse Super Q, lower Rdc with good data, and they seem to work very well from what I've read... But this is more a question for roland bios, since he's from Capsandcoils and sells both the Erse Super Q and the Jantzen P-cores...
 
omni said:
I have read reports by some highly regarded speaker builders that unless you are pushing your speakers to near concert like volumes, saturation is fairly inaudible in the steel laminate cored inductors.....I currently am using the Sledgehammer 15 gauge steel laminate coil 8mH, (which actually measures out to 7.75mH) in my system and I play it pretty loud.....I am getting clean bass..........But here's the deal with these coils: They are made by a guy who used to work at Madisound in Wisconsin, USA, as was told to me by one of their employees........So they are a basic construction with nothing fancy to them....It seems to me that if you follow Zaphs' guidelines, that probably most any reputable steel laminate coil that you can get ahold of should suffice.........My research has indicated to stay away from ferrite cored inductors......PURCHASING NOTE: If you have a way to measure your coils, I would recommend that you buy the next value HIGHER than what you need......Like I said earlier, my 8mH coil actually measured between 7.65 and 7.75. This being said, if I had done that, I may have purchased an 8.5mH coil that measures 8.25, and then I could have unwound it to measure 8mH........Respectfully.....Omni

Hi Omni,

I just looked at madisound and have a look to the coils you're talking about, now I have several choices here..;)..

Thanks for sharing the info and tips!!

Joshua
 
how to calculate L/C xover

I don't mean to hijack this thread but can't help to ask the people here about calculating the L/C xover.
I use the xover calculator that is available in the web for 2nd order xover, should I put the speaker impedance (ex. 4ohm, 6ohm, 8ohm) or Re - DC resistance instead, as the input?

The calculator says to put the impedance but some people prefer to use the DC resistance as the input...

Thanks in advance!

Joshua
 
It sounds like you are using a crossover calculator based on "textbook formulas"........This will only provide you marginal results.....It assumes that your drivers are purely resistive loads....In other words it assumes your speakers maintain a constant impedance as they are being driven... Usually, with these type of calculations, the nominal impedance of the driver is used...So if you are using a textbook formula, you would use the rated or nominal value for the driver, ie say, you have a woofer and a midrange, and a tweeter, all with rated impedances of 8 ohms... you would then insert 8 ohms into the formulas or calculator...........You do have other options available to you........1: you could call Madisound and have them design a crossover for you at a reasonable fee, providing you are using drivers that they carry........2 You may have heard of the program called SpeakerWorkshop, which is a free downloadable program which is reported to produce fine results, although it has a VERY STEEP learning curve and requires a lot of time, dedication and persistance to learn and use.......It was Sreten who turned me on to this website called rjbaudio.com ..........This website is a wonderful source for DIY speakerbuilding and has several programs to aid in crossover design for the person (like me) who has no equipment other than a couple of LCR meters, and a lot of TENACITY and dedication to take the time to design a crossover with reasonable precision.........The article that I will suggest you start with is called : Using FRD Consortium Tools to Design a Speaker...........At first it seems like a very daunting task, but with the help of friends on this site like Sreten, Tinitus, and Grant, I have designed an excellent crossover (which is now in the tweaking phase) with the FRD Consortium tools, and Jeff Bagbys' Passive Crossover Designer 5.1..... I think he has a newer version available for free download...........These tools do indeed take a lot of time to work with, but for me, it has been worth it.............But if you don't have the time to invest, either have Madisound design one, or, to reiterate my original answer to your question, use the rated or nominal impedance of your drivers to insert into the formulas........One other thing.......There are also a lot of proven designs available for you to use that are easily accessed on websites like Zaph Audio, rjbaudio.com and others as well..........Who knows, you may even find crossover designs on those sites that use your drivers.........But..... there is nothing like the thrill of designing a crossover with the help from friends here............Respectfully..........Omni
 
omni said:
It sounds like you are using a crossover calculator based on "textbook formulas"........

It was Sreten who turned me on to this website called rjbaudio.com ..........This website is a wonderful source for DIY speakerbuilding and has several programs to aid in crossover design for the person (like me) who has no equipment other than a couple of LCR meters, and a lot of TENACITY and dedication to take the time to design a crossover with reasonable precision.........The article that I will suggest you start with is called : Using FRD Consortium Tools to Design a Speaker...


Hi Omni,

Yes, you're right I use a simple calculator based on the textbook formula...that's all I know on how to design the crossover so far.

Thanks for the encouragement entering DIY speaker design. The website indeed looks interesting!

Regards.....Joshua
 
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