Please bring me back to earth on capacitor selection for speaker crossovers

[Pfenning]

I have a pair of Pi 4 speakers that I am planning some upgrades too. I will be replacing the Eminence Omega Pro 15" with JBL 2226 15", and adding the upgraded horn from Pi. Currently I'm keeping the Eminence compression driver. I'll be making one swap at a time, and listening in between to see what the differences are with each change. While I'm on the upgrade (hopefully upgrade) path, I am considering some cross over updates. Current crossover components are the regular old Radio shack white block resistors, Solen capacitors, and 18ga coils. I have been looking at upgrading resistors to Mills, and possibly going to 15ga Jantzen coils. Capacitors are where the choices are endless, and the expense could be great. The each crossover has 2- 20uF, a 10uF and  a 6.8uF capacitor. Those big caps are expensive. Upgrading to Auricaps would cost me close to $300 per speaker, and there are a lot of others commanding even bigger prices. I'm looking for the best bang for my buck, whatever my budget ends up being. Here's my general list of choices, I'm open to any ideas or suggestions you might have.

Option 1- leave the Solens in place, and bypass with a small high quality capacitor. I see this referred to a lot here on the forums, and other places. What does it do?

Option 2- Grab some Russian Paper in Oil caps off eBay, and give them a shot. I might experiment with bypassing these too. Will the PIO soften the sound too much? It wouldn't cost me much money to try them.

Option 3- Save my money till I can afford the Auricap or Mundorf upgrade.

Option 4- Some clever idea presented by a fellow Bottlehead.

My system is Turntable into Seduction into Foreplay into Paramours with upgraded iron. Bring me back to earth, what should i do?

Pfenning 

   

 

[ALL212]

Solens aren't terrible but...

I love Sonicap Gen 1's. Your bill for all caps would be under $200. 

 

[2wo]

Try some of the PIO, especially on the hi pass. a less costly experiment...John

 

 

[Tom-s]

The russian PIO's are worth the shot. In my crack they function great as output caps.

 

[Pfenning]

If I'm going to try bypassing the capacitors with something like a Russian teflon, what value would I use?

Pfenning

 

[drewh1]

FYI, my speaker designer really likes Sonicap - pretty affordable and very neutral.  Available on SonicCraft.com.  might be a good alternative to the very expensive caps but still perform very well.  I haven't used them yet but really trust the guy that built my speakers.

 

[mcandmar]

I used Solen caps when i rebuilt my speakers and have been very happy with them.  .....until i read this thread :

Keep us updated whichever path you chose as i am curious to hear your findings.

 

[Pfenning]

So I'm going to start with bypassing the existing Solen's with some Russian teflon caps. If you have experience with bypassing, please let me know if you thunk the values I plan to use are large enough to hear a difference.

20uF cap = .47uF bypass cap
10uF cap = .22uF bypass cap
6.8uF cap = .1uF bypass cap

I did some reading last night, and it sounds like the recommended bypass cap size is between 1% and 10%. Is it a case of the closer I get to 10% the more the sound is affected?

I'm working on a plan now, to test these crossover changes. Step 1 is to order some Russian teflon bypass caps, and get them on my break in set up. I plan to do the driver swap this weekend, and move the crossover to outside the speaker for easy changes.

Pfenning

 

[corndog71]

For tweeter caps I also recommend Sonicap Gen1.  GR Research sells them too and will provide matched pairs for no extra charge.  I would stick to 0.1uF for all bypasses.  Russian PIO should work well but Sonicap Gen2 is my preferred choice.  I recommend Erse coils vs Jantzen and if possible stick to air core.  Erse caps are ok but a bit warmer in the treble compared to Sonicap. 

It took me a long time to consider upgrading speaker crossovers.  They're the first thing that gets compromised in most commercial designs which is a shame considering how much they affect the sound quality. 

Another upgrade GR sells is a cabinet liner called No Rez.  For big cabinets like the Pi4 I would strongly recommend this to help damp cabinet resonances.  This is a much more effective upgrade than any bypass cap.  It may seem a little pricey but I've used it in many different speakers and always get a bump in clarity and drop in boomy cabinet colorations.

My final recommendation for extracting the most from your speakers is Isoacoustic stands.  They may not look like much but they too offer an immediate improvement in clarity and are very reasonably priced.

 

[Pfenning]

Corndog, thanks for the reply. I plan to give the Sonicaps Gen I and Gen II a try. That No Rez stuff looks interesting too. Can you explain the dampening feature on the Isoacoustic stands? The videos they have demonstrating them show a dramtic difference between the stand and just setting them on the table. It was very surprising to me.

Pfenning

 

[corndog71]

Corndog, thanks for the reply. I plan to give the Sonicaps Gen I and Gen II a try. That No Rez stuff looks interesting too. Can you explain the dampening feature on the Isoacoustic stands? The videos they have demonstrating them show a dramtic difference between the stand and just setting them on the table. It was very surprising to me.

Pfenning

From my understanding, there are several aspects that work in conjunction.  There is an upper and lower tier with a somewhat hard rubber isolation cup in each corner.  The cups are shaped to allow for forward/backward motion so they are directional.  Each set comes with a short and long set of metal tube legs that slide securely into each cup bridging the upper and lower tiers.  So when you place them under your speaker they kinda stick (suction cup effect) to the bottom of the speaker and also to whatever surface is under them.  There are even plugs included to allow for tilting the speaker upwards or downwards.  So they counter the forward and backward motion of the cabinet thus reducing distortion of the output of the speaker.  I tried the larger ISO-L8R200 under my tower speakers which caused the jaws of both my friend and I to drop!  It was not subtle!  Clearer mids and deeper, tighter bass.  My towers are supposed to have a lower end of around 60Hz but with the stands they seemed to go lower.  I use Isoacoustics on several pairs of speakers of varying sizes.

In another example I brought over the 130's to another friend's place where he records his own music and has small powered monitors.  He had them sitting on empty coffee cans(!)  We swapped the cans with the isoacoustic stands and again noted a remarkable improvement in clarity.

 

[Jamier]

If you haven't already done so, you should read Tony Gee' s capacitor
evaluation page (Humble homemade HiFi). His observations are
mostly about the use of the use of film caps in passive xovers
and while the comments are  mostly subjective I have found them to be
pretty much on the money. He has an incredibly long list of caps that
he has reviewed. It really is a reference.

 

[Pfenning]

Thanks for the reply Jamier. Yes I have read it. That article is what got me going on messing with bypassing caps. I can't imagine the time it took to compile all that information. I tip my hat to Tony for his extreme effort.

Pfenning

 

[Jamier]

In my experiences with bypass caps I got much better results when the
bypass cap had a much higher VDC rating than the cap being bypassed.
Northcreek Audio used to have their bypass citeria posted in an article
on their site. I haven't looked there in a while, so I don't if it is up
anymore , but I did use a lot of their ideas and they worked quite well.

 

[jrebman]

Hi Pfenning,

First let me say that I've always been a real admirer of your system in both it's minimalism, and how little it has changed over the years and probably sounds wonderful.

I'm going to be a bit of a heretic here -- first of all, I do not like the Sonicaps in any form, and would much prefer the white Sonicaps. The upgrade to the Mills resistors is a very good one, but getting back to caps, the Mundorf MKPs are very decent and not terribly expensive.

Also, when it comes to inductors, if you need any .1mH ones, I have a couple of brand new Alpha core 14 gauge , air core ones I can give you. I am also not a big fan of bypassing and it has never worked very well for me, no matter whose formula I have used, but it certainly won't hurt to try.

Also, if you can build boxes for those crossovers and leave them outside the speakers, I think you'll be pleasantly surprised at what happens especially if you solder the connecting wires directly from the last component for each driver,  directly that driver. That has the potential to be a huge upgrade, and everytime I've done it for a friend, they've been shocked at the improvement.

This is why I like single, wideband drivers with no crossovers, or only a simple crossover in a sub, though I've had plenty of multi-way speakers with crossovers, in the past, so I'm not dissing themin the least.

Good luck. -- that JBL woofer should alone bring a very nice change, but you are on the right path to upgrade the crossovers at the same time.

HTH,

Jim

 

[Pfenning]

Jim, thanks for the reply. I already have the Sonicaps, so I will give them a try. I did replace the Eminence Omega 15" with the JBL 2226, and the difference is amazing. The Omega sounded pretty good, and they fit my budget when I built them, but the 2226 is a big step up in sound quality and extends much lower. I haven't even turn on my subs since installing them.

Update on the crossovers upgrade path. When I opened up my cabinets to replace the Omegas with the 2226's, I realized I had a very early version of the Pi crossover, and it wasn't going to work very well to do the upgrades in steps, as I had planned. I wanted to upgrade the caps, resistors, and inductors, in stages to see the difference (or lack of) with each component. The existing cross overs just didn't have enough real estate. I ordered the latest cross over boards from Pi, and plan to build up the new cross overs complete with all new components. I had already decided to move the crossovers to outside the speakers for easy access. I have some Russian Teflon caps for experimenting with bypassing, and also some gen 2 Sonicaps. I will build the crossovers without the bypass to begin with.

I'm all on board with soldering the leads from my speakers directly to the crossover. How would you recommend I get the wires out of the cabinet? Just drill holes in the cabinet and dab some silicon around the wire to seal it up?

I typically move at a snails pace on projects, because I have about 5 going at a time.  ;D  Currently I'm enjoying the JBL's and trying to finish up a pair of work tables for my garage, made from reclaimed oak (this turned into a massive project for me, with my first attempt at mortise and tenon joinery). As soon as those are done, I'll start working on the cross over upgrades.

I will say that getting onto the upgrade path has renewed my enthusiasm in sitting down and listening to music.

Pfenning

 

[Paul Birkeland]

I wanted to upgrade the caps, resistors, and inductors, in stages to see the difference (or lack of) with each component.

FYI - sometimes the DCR of a crossover inductor contributes to proper operation of the crossover circuit.  I would recommend checking with the manufacturer to see if any of the values are critical.

 

[jrebman]

Hi Pfenning,

Sounds like you're on the right path, so I won't derail you any further .

As far as getting the wires from the crossovers to the speakers, you can do it as you propose, but a much neater and cleaner solution would be to use something like Neutrik  SpeakCons, and just pick one with the number of pins you need. These are of course, a connection in the path, but I think that getting the crossovers out of the vibration inside the cabinet is going to be the larger improvement. You should see what Audio Note charges for the same speakers with the crossover external to the speaker. Not that it makes any sense in terms of pricing, but it does provide a sonic advantage -- how much depends on too many things for me to even guess at -- just have to do it and listen for yourself.

I keep trying to get a buddy of mine who has homemade kit AN speakers to try this, but so far he hasn't done it.

I'd love to see that workbench, but that would be impossible -- I'd have to feel it . A mortising jig for a drill press can be really useful -- you really don't need a dedicated mortiser.

-- Jim

 

[Pfenning]

Jim, again, thanks for the help. This time I used my router to get all the mortise slots cut, and then touched them up with a chisel as needed. It wasn't too bad of work, actually kind of fun. I like the hand work aspect of it. The killer was it was 32 times  . I sure hope they last me a lifetime.

Pfenning

 

[Pfenning]

FYI - sometimes the DCR of a crossover inductor contributes to proper operation of the crossover circuit.  I would recommend checking with the manufacturer to see if any of the values are critical.

Good call PB. I'll check with Wayne.

Pfenning