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nzlowie

Litz crossover inductors

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I'm really happy with the current configuration of my horns so it's time to finalise the xovers. Just threw the current xover together with parts I had laying around.

 

My question is for the HF and mid section inductors would i get any benefit from using litz wire coils? Having read about skin effects and the like with HF the litz coils look like they'd be 1st choice. Thoughts please.

Plan on using the Janzen Alumenz caps but not sure of coils....

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22 minutes ago, nzlowie said:

I'm really happy with the current configuration of my horns so it's time to finalise the xovers. Just threw the current xover together with parts I had laying around.

 

My question is for the HF and mid section inductors would i get any benefit from using litz wire coils? Having read about skin effects and the like with HF the litz coils look like they'd be 1st choice. Thoughts please.

Plan on using the Janzen Alumenz caps but not sure of coils....

I have tried LItz wire inductors (Solen) on a client's instructions. Neither of us could hear the difference. Logically, Litz wire inductors make little sense. LItz wire is, indeed, designed to deal with the skin effect. However, it is important to recognise several important facts:

 

* The skin effect is roughly 0.5mm at 20kHz. Therefore, a 1mm conductor demonstrates almost zero skin effect at any audio frequency. What the skin effect states is that the skin depth is where current density is approximately 37% of the surface conductivity. So, it's not like no conduction occurs at deeper levels, it's just progressively less conductive. 

* An inductor is designed to resist the flow of an AC current. A Litz conductor is designed to ease the flow of an AC current. Therefore, it could be argued that a parallel inductor with Litz wire MIGHT have some value, but a series inductor with Litz wire doesn't make sense. 

 

FWIW: I still have the Litz wire inductors somewhere around the place. I think they're 6mH or something close to that. Yep, they're for sale.

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I haven't used them, but I have been informed by someone who has that the Jantzen Foil/Wax are the preferred ones.

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Skin effect is an exponential function; it is not a binary phenomenon. The deeper you go (for a given frequency), the more attenuation you get, and the depth described is when there is hardly any further conduction at that frequency deeper in the wire. Solen shows the resistance relative to DC for various frequencies and wire calibres. Purely on a resistive level, you need to get quite thin wires (about 24 gauge) within the audible range to have no effect on resistance, but whether that's relevant or not is up for debate. That's why Solen also list the +10% resistance range as well since that's likely to be insignificant (maybe.) However, on simple principles, there's nothing wrong with using litz wires instead of solid core ones unless it increases the capacitance substantially. Coincidentally I use solen's inductors. Just on principle alone then, I tend to use solen's litz inductors for the mid and high frequency components of my crossover (series for midrange, but only parallel for tweeter) since I use overall 10 gauge inductors. At 10 gauge, +10% resistance works out to 2.5kHz but when resistance is equal it works out to a very low 700Hz. Switching to litz variants that changes to 30kHz and 8kHz. I know their resistance will be the same, and any capacitance it might add will be insignificant compared to the massive capacitors in the crossover already. Do I hear the difference? I haven't done the comparison with the inductors themselves... but I have done so with equivalent internal speaker wiring and it was audibly better (no blind testing.)

Edited by Ittaku

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Here's the cheat sheet from Solen showing when AC resistance is effectively equal to DC resistance at various gauges/thickness.

 

unm1gat.png

 

I also forgot to mention that while actual resistance in a wire is negligible when it's large diameter, the irony of inductors is they end up being very long wires (at least when they're air core inductors) and the resistance is no longer negligible. I calculated my 5.6mH inductors are effectively about 600 metres of wire - even at 10 gauge (2.6mm) diameter, they have 0.3ohms of resistance, so a negligible percent extra resistance of a negligible resistance may be irrelevant, but once resistance becomes significant, then any change to that resistance becomes more significant (how significant? who knows.)

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ALK has some interesting views on this subject.

 

If you go to http://alkeng.com & go to "Klipsch Upgrades"on the left menu, then "Questions & Answers" at the bottom of that page you will see his reasoning. 

 

Above my head as to whether it makes any sense, but he does make very nice sounding crossovers. 

Edited by sootshe

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35 minutes ago, sootshe said:

ALK has some interesting views on this subject.

 

If you go to http://alkeng.com & go to "Klipsch Upgrades"on the left menu, then "Questions & Answers" at the bottom of that page you will see his reasoning. 

 

Above my head as to whether it makes any sense, but he does make very nice sounding crossovers. 

Very interesting, thanks for the link. It pretty much aligns with my practice exactly, which is nice.

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Good reading, cheers.

Another question for the guru's....... is there any guidelines on xover placement? At the moment I have mine directly at the amp output, (same location, not at speaker) my reasoning is that for each driver the cable is only carry's that limited bandwidth. Not only does it reduce the power handling requirement but reduces the frequency it's carrying. Also reduces vibration risk.

But, everyone has a theory - so good, bad or otherwise?

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1 hour ago, nzlowie said:

Good reading, cheers.

Another question for the guru's....... is there any guidelines on xover placement? At the moment I have mine directly at the amp output, (same location, not at speaker) my reasoning is that for each driver the cable is only carry's that limited bandwidth. Not only does it reduce the power handling requirement but reduces the frequency it's carrying. Also reduces vibration risk.

But, everyone has a theory - so good, bad or otherwise?

I have mine here....at the back of the speaker....just easier to get to things, rather than having the crossover at the amp end, especially if you have lots of adjustments on the crossover that you might want to change. 

 

I just put a set of binding posts on the crossover board that go to the input of the crossover, then I can use my normal speaker cables & plug straight into the crossover input. 

IMG_20180330_161653.jpg

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2 hours ago, nzlowie said:

Good reading, cheers.

Another question for the guru's....... is there any guidelines on xover placement? At the moment I have mine directly at the amp output, (same location, not at speaker) my reasoning is that for each driver the cable is only carry's that limited bandwidth. Not only does it reduce the power handling requirement but reduces the frequency it's carrying. Also reduces vibration risk.

 

Limiting the frequencies carried by each driver's cable makes sense to me - because that's the theory used by devotees of bi-/tri-wiring.  And - if you believe in using solid-core wiring (as I do) - you can optimise the guage used for each driver:

  • thickest for bass drivers - say, several 18g insulated strands,
  • medium for mids - say, several 21g insulated strands,
  • thinnest for tweeters - say, several 24g insulated strands.

 

Andy

 

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2 hours ago, nzlowie said:

Good reading, cheers.

Another question for the guru's....... is there any guidelines on xover placement? At the moment I have mine directly at the amp output, (same location, not at speaker) my reasoning is that for each driver the cable is only carry's that limited bandwidth. Not only does it reduce the power handling requirement but reduces the frequency it's carrying. Also reduces vibration risk.

But, everyone has a theory - so good, bad or otherwise?

 

I have my units on top of the speakers for ease of db adjustment on the autoformer 

and connecting the three speaker sections 

Interconnect wire between speaker and crossover used is Kimber 8 TC 

 

The section where ALK indicates about not liking flat wire inductors - he was speaking about the “non” wax type 

 

 

 

 

5A45E6E0-CB2B-4811-97E9-EF451D8EB10B.jpeg

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On 16/08/2018 at 12:45 PM, nzlowie said:

My question is for the HF and mid section inductors would i get any benefit from using litz wire coils? Having read about skin effects and the like with HF the litz coils look like they'd be 1st choice. Thoughts please.

Plan on using the Janzen Alumenz caps but not sure of coils....

Maybe.... but there is something else important to consider.

 

 

The biggest cause of difference in what you hear with your crossover now, vs "final" one you build.... will be where the frequency responses of the drivers are not kept identical.

 

 

If for examples ...... you build you new crossover, and it has 1dB more in some frequency range, and 1dB less in another.... and tweeter high pass is a little steeper, and bass it a bit hotter (due to more baffle step correction), etc, etc ..... there THIS is what you will hear.

 

Unless you confirm via accurate before/after measurements that the response of the speaker is designed the same .... then this will dominate the difference in sound.

 

Too many people "build a new crossover" (or change one), and up with a different response.... and (ignore the different frequency response and) attribute the audible difference to the quality of the parts.

 

 

Note... I'm not trying to say that parts quality is completely irrelevant all of the time....  Just don't get caught by the 'wow factor' unless you are sure it is only the "parts quality" that you're auditioning.

 

 

 

 

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2 hours ago, Full Range said:

The section where ALK indicates about not liking flat wire inductors - he was speaking about the “non” wax type 

Is there data on the difference between wax and non-wax?

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48 minutes ago, Ittaku said:

Is there data on the difference between wax and non-wax?

 

Only have info on the Jantzen 

 

http://www.jantzen-audio.com/wp-content/uploads/2013/04/Information-on-copper-wire-and-copper-foil.pdf

 

For other data you need to search around 

Edited by Full Range

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