The sonic benefits of an external crossover. A discussion.

Feb 11, 2012
1,286
1
0
Hangzhou, China
#23
My preference is the opposite , and have wires to drivers as short as possible , the added inductance between xover and driver will smear the mid/top end ..
If you're worried about adding inductance, you get more inductance per metre distance with the thicker cable you use between the amp and the XO, than with the thinner cable you can use between XO and tweeter.
 
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garylkoh

WBF Technical Expert (Speakers & Audio Equipment)
Sep 6, 2010
5,431
23
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Seattle, WA
www.genesisloudspeakers.com
#24
If you're worried about adding inductance, you get more inductance per metre distance with the thicker cable you use between the amp and the XO, than with the thinner cable you can use between XO and tweeter.
Exactly right. And if you twist the pair of thin wires together going to the tweeter, you'll get inductance even further down. The capacitance in that twisted wire will be at least one if not two magnitudes less than the error in capacitance due to the tolerance in the series capacitor for the high-pass filter to the tweeter.
 

treitz3

Super Moderator
#25
anonymous member of the WBF said:
Often external xover doesn't have anything to do with isolation of any kind but a larger internal cavity in the speaker cabinet for better bass response. Problem with the external xover is the additional lengths of wire and extra connectors needed.
My experience has not been for better bass response (sometimes it worsens though not usually). Length of wire and possibly connections are something I have definitely experienced a downgrade of the sonic signature. The end result after upgrading the components and going external yields a sonic signature that trumps (by far) any additional wire or connection inferiority.

Do you agree or disagree with this anonymous posters statement or not? Please do not pontificate. Serious answers only, preferably with first hand knowledge. ;)

Tom
 

the sound of Tao

Well-Known Member
Jul 18, 2014
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#26
Hoping for some advice on my next step in crossover upgrades.

0A63C4AE-8FF1-4677-98E1-010AD590CC49.jpeg

I’ve been modding the components in my Pureaudioproject Trio horns.

The Leonidas crossover was designed to enable rolling the caps and resistors. My aim is to use the Leonidas just to establish the best mix of components then transfer these to a point to point wired dedicated crossover.

step 1 - have replaced the 33 uF capacitor to the widebander horn with a Mundorf Supreme Evo Oil cap ... exceptional outcome.

step 2 - have also upgraded the parallel resistor to the horn with a pathaudio resistor.. the copper pathaudio has taken the horn to an even better place still.

step 3 - just now have taken the crossover off the speaker chassis... the xover is now external... oh my!!! Absolutely Epic/Perfecto!!!

Leonidas just trialled sitting up on rubber feet (stock feet from the Shunyata cyclops) on top of a 60mm thick bamboo sheet with metal points underneath holding it off the carpet... Clear step up in clarity, soundstage depth and overall definition, bass is cleaner and reaching deeper, mids were always amazing, now even more nuanced but also agile and immediate/natural, highs are now perfect. Most surprising the big, big shift in dynamics and lifelike immediacy. Very surprising difference. This is a different and better speaker now by quite some margin.

Big improvement especially with now going external and vibration free... that was virtually zero dollars and just minutes in the making and I am a super happy external crossover camper now.

I’ll just be trying out the Duelund cast silver bypass caps in parallel next with the Mundorf Evo Supreme Oil cap.

Then I just need to finalise a trial on an inductor upgrade for the woofers before moving on to turning the whole crossover into point to point silver wired external xover (possibly built out of panzerholz), copper encased and sitting up on proper isolation feet with silver wbt terminals.

Dave C mentioned the other day about the Mundorf zero ohm inductors. These were on my shortlist.

The stock inductor is a Mundorf 6.8 mH BSI40 feron coil with just 0.27 ohm impedance.

Sound since upgrading the hook up cable to pure silver foils and upgrading caps and resistors and now going external with the crossover is actually sooo much better (read epically so) than what I had with the start with the stock Pap horn setup. I am in truth quite a bit gobsmacked at how much bigger and better scaled the sound is now. Last night it was just completely captivating and I’ve very much loved the horns especially lately with some of the upgrades... but last night after going isolated and external with the crossover it all switched up a gear and it was just utterly musically convincing and mesmerising. A complete wow of a session of all music, jazz, classical (big and small) and rnb... even a bit of deep bass electronic dance.

Am thinking that moving the vibration sensitive crossover to a safer place (especially with regards to the inductors) has really yielded a deep change.

So now if possible gentle reader thoughts with regards to my changing now to a top of the line 6.8 mH feron zero ohm copper foil hybrid inductor that has 0.17 ohm impedance and is designed specifically for woofers in high sensitivity speakers run via SET.

Will 0.1 less ohms impedance value in the inductor make any real issue for using this higher grade inductor as a replacement. Am assuming/hoping the hybrid copper foil coil will add to even better sonic performance and timbre without sacrificing the bass performance and efficiency from this kind of core inductor.

Thoughts especially from diy and speaker design savvy members would be greatly appreciated.
 
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Robh3606

Active Member
Aug 25, 2010
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Destiny
#27
* Ease of swapping individual components within said speaker/customizing/tailoring to suit one's preferences.
* With loss of vibrations, the values of the individual components retain a better consistency of proper operating performance.
* The ability to isolate said components just as one would with the rest of the gear.

What say you?

Tom
Well to point 1 you have no idea what you are actually doing. In many cases what you are hearing are F/R changes which is fine but you have no idea what kind of impedance changes are occurring. Are they giving you a range of safe swaps or just leaving it up to you? If they are leaving it completely up to the user it's a bad idea.

That's why you use solder screws frankly suck as an electrical connection.

Can't hurt but in reality the most of this is in the noise floor.

Rob
 
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Sablon Audio

Industry Expert, VIP Donor
May 22, 2015
590
149
43
#28
Tao, another tweak which is both effective and free is to bypass the binding posts and use them to clamp the wires together rather than act in series. The photos in this link should give readers some ideas - www.audiocircle.com/index.php?topic=107044.0

Whilst not XO specific, non magnetic brass screws and grounding for the driver baskets are also worth implementing.
 

the sound of Tao

Well-Known Member
Jul 18, 2014
1,267
709
113
#29
Thanks Mark, advice greatly appreciated.

I’m really enjoying the diy side of modding the Pap horn. The horn and woofers themselves are great drivers so supporting them with better hook up cables and xover parts is really getting much more out of them.
 
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treitz3

Super Moderator
#30
Well to point 1 you have no idea what you are actually doing. In many cases what you are hearing are F/R changes which is fine but you have no idea what kind of impedance changes are occurring. Are they giving you a range of safe swaps or just leaving it up to you? If they are leaving it completely up to the user it's a bad idea.

That's why you use solder screws frankly suck as an electrical connection.

Can't hurt but in reality the most of this is in the noise floor.

Rob
First off, I have been extremely busy so I am just now seeing this.

Second off? Wow. You have no idea just how far off you are. I will not get into it because it is truly not worth it to me but if you were trying to hit Antarctica with a bomb? You struck London.

I said nothing (unless time has escaped me in this thread) about screwed in posts. I would never do that in my rig, regardless of any debate.

Noise floor has not one thing to do with what I hear. That was not the point of what I did and with that said, I will be polite and leave this where it lies.

Tom
 
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treitz3

Super Moderator
#31
In your defense, I did make this post 6 years ago.

Since then, I have spoken with, consulted with and had COUNTLESS hours of conversation/education with industry insiders, industry professionals, manufacturers, designers, engineers as well as those that do this for a living.

My crossover unit took 3 and a half years to design and build from scratch. Beginning with the 4'x8' piece of Aircraft aluminum to build the enclosures. Here is a photo of my current rig at the last audio event she will ever be showcased at...

What you see and perhaps think is the subwoofers? Take a second look. Those are the crossovers in an enclosed unit. The subs are actually behind the speakers.

Please do not ever tell me I don't know what I am doing ever again and keep in mind on this board....you NEVER know who is on the other side of the keyboard.

Have a great evening.

The rig.PNG
 
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Robh3606

Active Member
Aug 25, 2010
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#32
Hello treitz3

That was not my intention my post was really related to the sound of Tao post #26 immediately before mine. I used your list to make observations about what I was seeing. No offense meant.

Rob :)
 
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the sound of Tao

Well-Known Member
Jul 18, 2014
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709
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#33
Well to point 1 you have no idea what you are actually doing. In many cases what you are hearing are F/R changes which is fine but you have no idea what kind of impedance changes are occurring. Are they giving you a range of safe swaps or just leaving it up to you? If they are leaving it completely up to the user it's a bad idea.

That's why you use solder screws frankly suck as an electrical connection.

Can't hurt but in reality the most of this is in the noise floor.

Rob
Apologies Rob,

Saw this earlier but also thought you were talking to Tom.

The idea with the provided easy mod crossover is to give new diy enthusiastics an approachable opportunity to trial the potential of rolling in different caps and resistors (using the same values but different brands or models). I got a price on a duelund cast silver tin caps but at 33 uF they would weigh like a truck and cost over half the price of the speakers again :)... loving the upgrades so far, just the inductor coil to consider now.

Yes, very much agree with the issue of the screw connectors but it was always my aim just to use the stock crossover simply as a testbed and then swap to a point to point dedicated crossover using the best parts implementation. The better caps and resistors as well as taking the crossover off the speaker frame have all yielded great results. The speakers are sounding so good I could easily leave it all as is and be happy with the upgrades of hookup cable and crossover mods as they are now but carrying the crossover through to a proper board and point to point silver all in a better copper-lined heavy laminated bamboo housing and all sitting up on isolation footers is still the plan.

By comparison I’d be far less likely to explore the crossover upgrade path in my Harbeth 40.2s simply because the setup has not been configured to make this easily or even reasonably viable.
 
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the sound of Tao

Well-Known Member
Jul 18, 2014
1,267
709
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#34
Hoping for some thoughts on this if possible. This is one of the potential inductors for the pair of OB woofers in the Pap horn that I’m considering for an upgrade in the planned external crossover. The info below suggests it would be ideal for high efficiency applications so the pap horns powered with SET seems a good potential fit.

It is the same 6.8 mH as the mundorf stock coil that it would replace but the copper foil hybrid version below has an impedance that is .1 ohm lower ie total .17 ohm rather than the .27 ohm for the stock inductor. Would this slightly different impedance be critical...


Info from the mundorf site...

Specifications:
Core material: FERON
Grain-oriented silicon iron 0.35 mm
OFC-Copper 99.997% pure
Our Zero Ohm Coil (ZOC)made from copper foil impressively combines the outstanding natural music performance of extremely low ohm Feron ZOC cores with the finely detailed musical texture and multifaceted richness of OFC copper foil.

These coils were specially developed for low frequency applications which do not focus on maximum capacity, but rather exceptional performance quality, micro-dynamics and outstanding technical properties such as matching perfectly with highly-efficient loudspeakers specially designed for low-power, single-ended tube-amplifiers.
 
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Robh3606

Active Member
Aug 25, 2010
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#35
It is the same 6.8 mH as the mundorf stock coil that it would replace but the copper foil hybrid version below has an impedance that is .1 ohm lower ie total .17 ohm rather than the .27 ohm for the stock inductor. Would this slightly different impedance be critical...
If you post a schematic I can run it in LEAP so you can see what the difference would be. I would have to use a standard load for the driver.

Rob :)
 

Folsom

VIP/Donor
Oct 26, 2015
3,622
296
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Eastern WA
#36
Hoping for some thoughts on this if possible. This is one of the potential inductors for the pair of OB woofers in the Pap horn that I’m considering for an upgrade in the planned external crossover. The info below suggests it would be ideal for high efficiency applications so the pap horns powered with SET seems a good potential fit.

It is the same 6.8 mH as the mundorf stock coil that it would replace but the copper foil hybrid version below has an impedance that is .1 ohm lower ie total .17 ohm rather than the .27 ohm for the stock inductor. Would this slightly different impedance be critical...


Info from the mundorf site...

Specifications:
Core material: FERON
Grain-oriented silicon iron 0.35 mm
OFC-Copper 99.997% pure
Our Zero Ohm Coil (ZOC)made from copper foil impressively combines the outstanding natural music performance of extremely low ohm Feron ZOC cores with the finely detailed musical texture and multifaceted richness of OFC copper foil.

These coils were specially developed for low frequency applications which do not focus on maximum capacity, but rather exceptional performance quality, micro-dynamics and outstanding technical properties such as matching perfectly with highly-efficient loudspeakers specially designed for low-power, single-ended tube-amplifiers.
Don’t change inductors unless you can match the resistance. The existing one probably has .5-2ohm of resistance (DCR). That resistance is part of the frequency response, parts of the crossover. Changing it will sound different because it’ll screw up the crossover a lot. So if you get a zero ohm inductor you’ll need to series it with a resistor equivalent to the existing inductors DCR. There are several more properties that may be very important, related to the DCR amount.
 

the sound of Tao

Well-Known Member
Jul 18, 2014
1,267
709
113
#37
Don’t change inductors unless you can match the resistance. The existing one probably has .5-2ohm of resistance (DCR). That resistance is part of the frequency response, parts of the crossover. Changing it will sound different because it’ll screw up the crossover a lot. So if you get a zero ohm inductor you’ll need to series it with a resistor equivalent to the existing inductors DCR. There are several more properties that may be very important, related to the DCR amount.
Many thanks Folsom,
That was my concern... I was unsure if a difference of .1 of an ohm was going to be significant. Plan B - I had thought of adding in a pathaudio resistor to then bring the DCR back up to .27ohm total to match the value of the stock inductor but definitely need to do a bit more research first... either way I would love to get my head around how it all works better. Much appreciated.
 

the sound of Tao

Well-Known Member
Jul 18, 2014
1,267
709
113
#38
If you post a schematic I can run it in LEAP so you can see what the difference would be. I would have to use a standard load for the driver.

Rob :)
Thanks Rob,
I’m thinking I’m at a crossroads and I need to make a choice shortly. If I go forwards with the driver config as is I’ll take the easy path and aim to match the existing values exactly so as to not upset the current mix with the sound which after the cap and resistors upgrade and with now going external with crossover is currently at the pretty awesome mark.

The other (more challenging but possibly also a bit exciting) choice is to choose now to go 2.5 way and add some matching woofers for the sub 80hz (maybe isobaric loaded)... in which case I’ll clearly need to completely change the approach with the crossover and it would be great to do some calcs then.
 

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