A previous discussion included a statement about crossover components.

The commentator stated something to the effect that some very high end speakers really cheaped out on the capacitors and resistors in their crossovers, and hinted that replacing them with high quality components might improve the sound quality of the speakers. My question is "Have you ever replaced the caps and resistors in your speakers crossovers, and to your ears did that result in better sound quality?" Also, what brands of caps and resistors do you consider to be "the best", and why?


"Have you ever replaced the caps and resistors in your speakers crossovers, and to your ears did that result in better sound quality?"

Yes, and yes. Many times. On a good system it’s pretty audible. It helps reduce/eliminate one of many potential sources of masking the signal.

I haven’t tried the modern boutique caps, but always found Solen to be a good bang for the buck. My best caps are from Convergent and are unobtainium. GS Research likes the Clarity Caps. Wire wound non-inductive resistors, larger gauge air core inductors, and sometimes better wire are also desirable. Be mindful of any significant changes to DC resistance between inductors. Remove any circuit breakers and fuses too, but it goes without saying that you have to be mindful of the fact that they're no longer protected. Sometimes adding a bit of extra polyfil can be beneficial in the mids by reducing cabinet resonance too.

What speakers are in play here?

In the 90's, MIT capacitors were "the bomb". I haven't been keeping up and I wonder if these are still made? Anybody?

Whether speaker makers scale their crossover components with the rest of the system varies a great deal.

Magico and B&W are two brands that do, using higher end Mundorf in the higher end speakers.  Focal is a brand I've only seen use OEM versions of low-mid grade Solen caps at best.

Personally I don't like high end Mundorf caps as I think they are a bit oversaturated, too colorful and splashy.  I do prefer Clarity caps overall though I've found that the high end Clarity caps still benefit from bypassing with copper foil caps at the larger (> 4uF) sizes. 

I have heard really good things about upgrading Wharferdale Diamonds even with low end Mundorf MKPs (I like the MKP's the most in the Mundorf line).

I suggest anyone who really wants to get into this to build speaker kits instead of starting off with an expensive pair of speakers. It's also much more rewarding.


Spatial M4 Holograms. Just got my Precision Fidelity M7-A back together and am looking forward to a test drive. The Spatials are sensitive 93 db at 4 ohms so they should be a good match. Spatial offered a crossover upgrade when I bought them, but I had to pass on that.Now I might consider replacing some of the components. Since the M4 is no longer in production, I assume the crossover upgrade is no longer available also. It might be fun!

It couldn’t hurt to ask them if the upgrade is still available, or at least what they’d recommend. Otherwise, go your own way...it should still be an upgrade from cheap electrolytics, sand cast resistors, and iron core inductors. Should definitely be fun to do if you’ve got that gene! Good luck!

Don't recommend adding polyfil to open baffle speakers! 😁


Here is a photo of the crossover components on a $83K/pr speaker.


Here is a pair of crossovers I made for my speakers:


As you can see I use a lot of Mundorf caps (I read with interest Erik’s comments).  I also added a couple of Duelund bypass caps.   I also use Jantzen foil inductors and path resistors.

The sound is clearer, cleaner, and more accurate.


@carlsbad2  So, your first picture demonstrates the parts for a very (to me) expensive speakers, and the second picture is crossovers for a set of your speakers, not replacements for the high dollar speakers?

Correct. I don’t own an $80+ pair of speakers. My speakers are $8k and I spent $2k upgrading the crossovers.


Like several others in this forum, following Don Sachs's lead, I replaced the el cheapo caps in my Cornwall IV with V-cap ODAM, and the resistors with Path Audio. Big improvement in sound quality, but at a pretty big expense.

My Coincident Total Eclipse II speakers have one tweeter capacitor (Very simple 1st order crossover). There are no resistors. The stock capacitor is Solens. The sound quality in stock form is very, ,very good.

Replacing the respectable Solens capacitor with the Duelund CAST copper foil capacitor was an undeniable sonic upgrade across the entire spectrum. It is one of the most rewarding and cost effective modifications I've experienced. An expensive capacitor that was more than worth every penny paid. High quality crossover capacitors definitely make a positive impact.


I’ve done this for both speaker crossovers and tube electronics. My favorite caps tend to be one of the following depending on what I am trying to accomplish:

  • Mundorf Silver Gold Oil
  • Audience Auricap XO
  • V-Cap
  • Obbligato Gold or Ultra Premium
  • Audio Note Kaisei
  • Audyn True Copper Max
  • Miflex

This webpage is a goldmine, basically providing references to the sonic characteristics of a multitude of capacitors:


I hav3 been upgrading Xovers for over 15 years ,having owned a audio store 

and having techs work for me ,I discovered with electronics ,as well as speakers 

on average only 25%  actually goes into the product the rest R&D overhead and markup .. sadly you see many using Solen capacitors or far worse ,and ceramic resistors ,cheap inductors and speaker terminals gold plated cheap brass which is 3 x less conductive then Gold Copper which = 3 x more resistance and noise

st least start there the WBT next gen are only $40 each , and if you have whst I call fake bywire setup 4 terminals many just are internally connected then you get the crappy straps ,always buy or make quality jumpers i,you can hear the difference 

go to Humble homemade hifi capacitor test for starters judt to see quality .

Duelund are the Bentley of the bunch. Path audio resistors, or Mundorfs Ultra resistors with a heat sink ,inductors I like Jantzen open coil Big for woofers and mids Waxedpaper Copper foil inductors very close to Duelund inductors. 
I spent over $1600 just in Xover parts this is a mid grade build but better then anything at $40k in a speaker.

@audioman58 your posting in a previous forum is what inspired me to start this thread. Thanks for sharing your insight. @blisshifi thank you for the reference  to The Humble Homemade page-WOW, what a treasure.I am going to contact Spatial and find out if they offer the crossover upgrade for my M4's, and if not see if they will get me a copy of their crossover layout-not holding my breath on that one, but the worst they can say is no.....and i've heard that before.

This thread is awesome.  I too know crossover caps can make a big difference.  I personally feel they have enough of an influence or sway power to ‘make or break’ a system.  I second @erik_squires observation with the mundorf capacitors and I too prefer the mundorf m-cap classic MKP or the mundorf m-cap evo oil.  I read good things about clarity cap. I’ve had good experiences with audyn plus mkp capacitors.

...and I appreciate and thank y'all for sharing comments, links ( @blisshifi 👍 ), and the knowledge gained by experience I've not had...

Kudos, Gentlemen.

This is interesting. I responded to a thread asking about when speakers become hi-fi verses mid-fi and was excoriated for stating that my Klipsch Heritage speakers were easily modded in the crossovers, making them more palatable for me as hi-fi. Crossovers can always be made better depending on your other equipment and musical tastes. Spend 40 years building your system and have a rudimentary knowledge of electronics and the world is your oyster.

Good Morning 

I am in the almost finial act of upgrading my crossovers , while I don't consider my Thiel CS2.7 speakers as " high " end they are of high quality build except for the quality of the crossover parts .  The " made for Thiel " 1uf bypass capacitors by Clarity were the only high end component used .   

My thoughts on upgrading were to use the best quality that I could fit onto the board ,  I also decided to try to keep the sound signature by using upgraded film capacitors by the same manufacturer as well as increasing the voltage rating as much as the size allowed .

I have a few questions for the experienced here ,  How does a larger gauge wire on the inductors improve the sound ?  Has anybody replace an electrolytic capacitor with a film and heard the improvement ?  Have any of you moved the crossovers out of the cabinet or are considering moving them out  ?


@peporter , Yes, the quality of caps in the crossover network can and often does yield differences.

Sometimes changing them out doesn’t sound any better--just different. Other times, it can be pretty darn significant of an improvement.

My favorites are:


Clarity Caps (I think the top of the line ones can sound eerily big and have great sense of space)

Auricap XO


I’m no engineer, but...I highly recommend staying within the tolerances designed into the circuit. So, if you see a pretty run of the mill 5uF 200v Bennic cap in your network, you’d want to replace it with the exact same capacitance value and voltage rating. Don’t change the values unless you know what you’re doing or have incredible patience for experimentation. (Note: you can increase voltage rating but try to avoid decreasing it). 

Finally, sometimes the OEM will use some pretty decent if not great caps that are rebadged for the manufacturer. Manley comes to mind. I know they use some nice REL Caps that are not a cheap product, wrapped in a Manley labeled wrapper. Other times, manufacturers might use something more basic while wrapped in their own wrapper. It may be helpful to see if you can find out what brand(s) they used. I replaced the caps in my Cornwall IVs because they looked to be some fair but not great Dayton caps--so the upgrade was definitely worth it. Other times, maybe not so much.

Yes, the quality of caps in the crossover network can and often does yield differences.

i very much agree with this comment

i recently undertook a fun project of upgrading the wiring, connectors and crossover components of my magnepan 1.7i’s ... i bought a second pair to keep as stock as a control

the difference is monumental, and the capacitor choice in the crossover is of major importance, especially feeding the upper frequency drivers

@audioman58, and anyone else experienced... How would you approach upgrading an isolated woofer crossover with cap values of 125uF and 250uF? Just stick to adding bypass caps to the OEM caps, or no? Those big uF values are basically non-existent for the select caps aforementioned in this thread.

Clarity capacitors sells big values perfect for bass if 8 knew the value I could help

and you can reach me direct at 

Audioman58        At

 G       Mail



Solen caps are a standard stock cap very fuzzy vs the many top quality caps Solen rated a 7 ,vs top 15 Duelund  that why I left 

Humble homemade hifi capacitor test   It’s the standard to go by at least 90+ accuracy with drivers there can be exceptions to the rules   Personally I wouldnot  use a Electrolytic capacitor even in a woofer , maybe exception the Clarity ones and use a 1uf as a bypass or bigger like a clarity CSA cap

Hifi collective in the U.K I buy many things ,and FedEx int For small parcels $28 U.S  they have great int rates and list everything and how many of each item .

the go to place arrives in 3-4 days .

HELLO Peporter!  Capacitors come in $0.50, $5, and $50 versions, like wine and cars. Is that surpriing? I hope not. I've bee upgrading passive speaker crossovers for years.  My "Best for the Buck" rating is Mundorf MKP (250 volt rating). Delund is best but very pricy. I've tried them. They sound about 5 -10% better than Mundorf but Mundorfs sound a good 50% better than what is probably in your speaker's stock crossovers. Foil or ribbon (flat strips) coils sound better than round wire inductors, but not dramattically. Yes, you can spend huge $$ on passive crossover parts - but why? (I have seen passive crossovers a big a large picnic coolers!)  An electronic two way crossover will set you back $100 or so (the price of a pair of small Delund caps) and shock you with better sound. Yes, you will have to remove the passive crossovers and add a new set of terminals (use good ones - no magnetic parts) and add an amplifier (don't you have a couple sitting around?) but the results are spectacular for the $$ spent. 

You realize that modern solid state amps have very high "damping factors," right? That means they can control the motion of the loudspeaker and minimizer errors in a speaker's  motion that distort the music they are playing. A passive crossover limits the amount of control the amp can exert because they are inserted in the path between the amp and the speaker's moving (sound producing) parts. Electronic crosovers go between the preamp and power amps and allow direct connection between the amp and speaker's drivers. You think cables make a difference? (They certainly do!) But removing all those parts between the amp and actual drivers that produce the sound is an enormous improvement!  50 watts is plenty for an amp driving tweeters. Try it, you'll like it! Happy Listening.

You were talking 100-250 uf That is huge , what kind of speakers are these ?

most speakers are under 10 uf for the Bass woofer. You can vary the tolerances up to around 3% of the total before it starts effecting the Xover point a decent 1% of the total in a decent poly cap will smooth it out abit , and a good quality 

awg 12 Jantzen inductor open core would do it justice , I don’t use junky 

cheap sledge hammer type a magnet 🧲 with wire wrapped around it .

Jantzen are my favorite and great quality value ratio if you want a quality inductor 

speaker you are keeping . I rebuilt a nice Dynaudio speaker last year ,that I will be selling in the fall it now is called the model 30:$8k  and the Xover use Mundorf Evo caps decent ,but Mundorfs Supreme are their much better line. In parts maybe $400 I spent $1600 just in parts ,a solid 15-20% improvement in fidelity ,

pits the 🧠 or ❤️ of the speaker everythung hood or bad goes through there 

thsts why I always use top solder Cardas or Mundorf, and WBT connectors 

stock connectors on 90% are bright gold over brass , WBT Evo next gen $40 each 

at VH Audio I spent $250: on the WBT classic  no short. Cuts ,Everything counts .!!

Yes x 2.

Like every other component, C & R have interaction with everything else.

You can install "THE BEST" of everything and have an unlistenable system.

A slightly veiled cap maybe just the ticket with a screeching tweeter

Just last week I asked for information about crossovers from B&w, they would not share any details with me except for the crossover point.

So no one has any idea what's in speakers these days.

It's all cheap crap and it's horrifyi…

I would've paid extra to get better quality crossover stuff this is absolutely horrifying

@emergingsoul yeah man me too.  But what sucks is, if you get the opportunity to, more than likely they too are making even more of a profit off of you.  I wish they could increase the quality of crossover components by for example $300 and charge me like $330 more. Not like $600, whereas before it would be $30 in crossover components and they charged me $60….

5x is standard mfg markup. $300 wholesale is $1500+ retail.

Sky's the limit for 'high end'

A local dealer builds custom speakers (mostly horn-based, using vintage drivers).  I’ve heard these systems being tuned in, which includes changing internal wiring and crossover components.  The sound can be quite significantly changed by choice of different caps.  This particular builder hates Mundorfs of all sorts in both speaker and electronics builds (he doesn’t like Duelunds either).  Most of his builds are done with vintage caps (some very old and hard to find, like Western Electric paper in oil caps) and modern caps from Audio Note.

@ieales: You have the markup formula correct, but the nomenclature incorrect. Wholesale is the price the retailer pays the manufacturer (or distributor) for a component, which in hi-fi is typically 60 points (percent) of the retail list price. So a piece which retails for $1500 typically costs the retailer $900. The $300 figure you cite is correct (for a component which retails for $1500), but that is not referred to as the wholesale price, but rather the cost to manufacture a piece of hi-fi gear (there may be a more technically specific term for that price, but if so I’m unaware of it).

The difference in price between the cost to manufacture ($300 in this example) and the wholesale price ($900) is the amount the manufacturer (or distributor) makes ($600), the difference between wholesale ($900) and retail ($1500) prices what the retailer/dealer makes (also $600, assuming the component sells for full list price).

However, in some product categories (cables and hi-fi "tweeks") the cost to manufacture may be far less than 1/5th the wholesale price. That’s one reason those items come under such harsh criticism from the "skeptics". The creators of such products defend their pricing in terms of the man hours that were invested in developing their products.

I’ve found changing out caps can make a nice speaker sound much more enjoyable. I started out with Sonicaps there cheap and if no improvement it wouldn’t break the bank, there was a fair improvement.

After a few months I pulled them out and replaced them with clarity cap CMR’s. This was a big improvement. I then bypassed them with Miflex and Duelund with another nice improvement. The Clarity CMR’s are big so I just built the crossover outboard. I also changed from Mills to path resistors another nice improvement. I also tried the Jantzen Aluminum z’s they were nice, I even mixed and matched them with the CMR’s. I also tried the Vcap odom’s in other components and would like to try them in some speakers.


My other speakers sound very good so I’ve just left them alone but still would like to put better parts in but just haven’t and probably never will. Playing with caps and internal wiring is fun and very rewarding but where does it stop.


Surprisingly, replacing Mylars with Polypropylene or Teflon [$$$] can have more effect on the sonic signature than electrolytics.

AND if your crossovers are matched or selected per drivers, be sure to match the replacement parts to the same values.

I have an update on the upgraded crossover for my Spatial M4 Holograms. I called customer support and Clayton Shaw, the owner of the company answered the phone. I have spoken to him before, and both times I was  completely delighted. I asked him if the crossover upgrade was still available, and the answer was no, accompanied by a conversation about the whys. Turns out with the upgraded components they had to abandon the space in the built in crossover, and fabricate an external box to house the larger components So, that turned out to be an unworkable option.I told him I was going to upgrade the existing crossover parts, he immediately offered me copies of the schematics! He was genuinely excited about the prospect of upgrading the components, and thought it would be great fun.My kind of guy for sure. We also talked brands, and he pretty well agreed with The Humble Homemade Capacitor Test and the great choices presented there. It was a great conversation, and I really enjoyed it. My mind now goes to building an external plate for mounting the components.....perhaps a bit of walnut on some Herbie's Audio Lab Large Soft Fat Dots....



here is another capacitor comparison , not nearly as many but still ...

he is using a tube preamp with only the capacitor in the signal path .


... and ZERO description of rigor to ascertain identical listening conditions.

  • source[s]
  • line
  • ambient
  • tolerance match
  • ...




For  20 years now I have been upgrading Xovers for myself friends  and family.

I have literally over 10,000 hours in experimentation knowing capacitors ,brands 

and discounting many so called engineers saying a resistor is a resistor  for example they too have accuracy and a sonic signature ,I use between Path Audio,and Mundorf ultra with a heat sink like in the Magico A5 


I have upgraded my Magneplanar MG20 speakers with new caps from Janzen (silver/polypropylene) and Audyne (Copper foil). The inductors were replaced with Dueland 14 Ga flat copper air core design. This was done in steps with the caps first followed by Silver foil bypass caps from Dueland, then the inductors.  The crossover wiring was with 14Ga. solid silver wire. Each of these steps were a solid improvement with the best area being in the imaging solidity and 3D quality of the soundfield. All the standard improvements in frequency (highs, mids, and lows) were there also. Then I replaced the cheap steel speaker terminals with WBT silver with another step improvement in the sonic character of the music reproduced by my system. Good fuses made a difference, but silver wire replacing the fuses was even better. I eventually took out the silver wire for SR Orange fuses because I shudder at the expense of shipping 7 foot tall speakers back for repair after I burn the midrange element out, damaged the bass panels, etc.

What I have found out once your system is revealing enough, everything matters to the reproduction of the music. Sometimes the change isn't what you were thinking about when you made it, but the change was audible. In my opinion, it is better to get speakers you really like, amps that match up with these speakers, power treatment for the system, and good cables first. What I did was speakers first, then preamp, amps, power treatment, cables, then crossover mods.

I have also added Dueland silver foil bypass caps on the amps and preamps, better fuses to all elements of my system.

I am a dedicated tinkerer, and really enjoy this kind of "tinkering" with my audiophile hobby. (even though most of my friends think, but don't say, you're nuts!) These guys spend their hard earned $'s on travel, which is also a good hobby also. I can't get them to come over to hear my system, which is disappointing, and not understood!

so called engineers saying a resistor is a resistor

at DC they are... some with many parameters that vary with ambient conditions

What many enthusiasts don't understand is a change for better in one instance may not be in another.

And even worse, many equate change with improvement when it clearly is not... 🙄

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