Why is everyone so against electrolytic caps in crossovers?

[Wigwam Jones]

I have often thought that a person could run their own tests easily enough.

Recap a simple crossover with a variety of capacitors on a rotary switch, so that each one could be switched in and out of the signal. Position A, you're listening to cheap electrolytic, position B, you're listening to an expensive film cap, position C, you're listening to a motor run cap, position D, you're listening to a cheap electrolyic bypassed by a boutique cap and so on.

Then invite the friends over and set up some measuring equipment or whatever and have some fun.

The questions would be a) can anyone hear the difference? b) can they tell which one is which? c) is there an improvement in the sound with a particular choice?

 

[bare]

Alnico mags in speakers should NEVER need a regauss The flux density life is theorised as stable for over 2,000years.
Unless someone hammers on the mags with a 5lb hammer.. repeatedly.
Sales babble by incompetents often suggest otherwise. Caveat Emptor kids.
Swapping out electros with films is part of the Bigger is Better attitude.
Little point in a non signal path, But given the low prices for decent films? Albeit more than a few Competent Speaker designs WERE voiced to the exact parts fitted.

Vandersteens as an immediate example. Many others as well.
Changing esr's will make a difference, not always for the better.. tho most dilettantes will 'assume' it is better
Cheap ass speakers were the ones fitted with whatever the budget allowed

 

[doucanoe]

Never?


RC

 

[Dukiedook]

I believe he CAPS LOCKED never. I forget, is that the same as yelling in one's face with spittle and face redness?
I have seen lots of theoretical stuff turn out to be nothing but theory when subjected to real life use.

 

[DON73]

All I would ever expect from replacing caps in a crossover is to return the speaker to it's original sound. They sold me with their sound and if they had lytics in the crossover I'll be happy with lytics. They'll all outlast me


I don't understand the concept of using a "bypass" cap or adding a resistor to a crossover. What is the purpose of a bypass cap or an added resistor? Sorry for the totally noob question.

 

[Wigwam Jones]

I don't understand the concept of using a "bypass" cap or adding a resistor to a crossover. What is the purpose of a bypass cap or an added resistor? Sorry for the totally noob question.

A resistor is generally added to 'pad down' the output slightly. Many speaker crossovers incorporate a resistor for that purpose. If a speaker has an L-Pad adjustment on it for the midrange or the tweeter or both, those are just variable resistors. So it should not affect the sound, just the volume. The idea is that some drivers are more efficient than others, and the sound they produce may be louder that the other drivers in the same cabinet; so padding the loud one down with a resistor seems appropriate.

As to bypass caps, I have never done this, but I hear about it. As I understand the theory, if you wish to save money on expensive high-capacitance capacitors in a crossover design, use a cheap capacitor and then place a very high-end small-value capacitor in parallel with it. This is supposed to give most of the advantages in sound quality of the boutique cap, while costing significantly less.

Does bypassing caps work? Well, lots of people say it does. I will just say I do not engage in it and leave it at that.

 

[sKiZo]

Main purpose of a bypass cap is to eliminate the ac component (ripple current) that can tag along with the signal and degrade purity ...

... or so they say ... you know ... them ... the ones that use em.

I figger it couldna hertz ... so why not? Poly caps are dirt cheap nowadays.

 

[doucanoe]

I believe he CAPS LOCKED never. I forget, is that the same as yelling in one's face with spittle and face redness?
I have seen lots of theoretical stuff turn out to be nothing but theory when subjected to real life use.

I think he/she must have been in the process of editing their post when I commented. The addition of the disclaimer " Unless someone hammers on the mags with a 5lb hammer.. repeatedly." makes the "never" claim a bit more reasonable statement.


RC

 

[jessearias]

Some quotes from Bob Crites

Here are some quotes from Bob Crites regarding caoacitors.

"You have new good quality capacitors installed in your crossovers. Capacitors have exactly two qualities that effect the sound of your music that goes through them. Those are capacitance (what we use them for) and ESR. ESR is the sum of all other qualities of a capacitor other than capacitance expressed as an Equivalent Series Resistance. ESR is a bad thing. Good caps have ESR so low it is barely measurable, on the order of a couple of hundredths of an ohm. ESR is made up of stuff like the resistance of the leads and their connections to the foil inside the capacitor or stray inductance or dielectric absorption."

"Good caps all sound the same. Let's define that term. A good cap has the value of capacitance we need and has very low ESR (I defined ESR earlier). A bad cap has either the wrong value of capacitance and/or higher ESR. If we compare a good cap to a bad cap, we would probably hear a difference. If we compare two bad caps, they would also probably sound different. If we stay with good quality polypropylene caps, we likely meet the two qualities we need....right value of capacitance and very low ESR"

"In testing caps, I look at ESR as a sign of quality in manufacturing. When testing some of the cheaper polypropylene caps, I see low ESR, but ESR that varies between caps more than I like to see. I would rather see all the caps measure about the same and very low in ESR. For instance one popular brand of inexpensive polypropylene caps I have tested varied from about .02 ohms ESR to around .06 ohms ESR in a batch of ten caps. Now .06 ohms ESR is still a good cap and I consider that to be very low ESR. But, since there is a variation between the caps, that makes me question the quality of the manufacturing process for those caps. And since ESR increases with age as a natural part of the aging process, I consider that starting out with very consistent values of ESR when new, is likely to result in the caps staying good (with low enough ESR) longer". .

 

[stanko]

I've attached a link to a series of articles in Audio Magazine in February and March of 1980.

http://www.reliablecapacitors.com/pickcap.htm

 

[allsmith]

So if one was to change out there aging electrolytics with polys that are in series with the midrange and tweeter,what value resister would i use to add back the lost esr,if i think there sound is too bright ? Or should i say what values should i start out with so i could play around and experiment? Also where would i install these resistors? Would they be in series with the driver(just installed into the positive wire going to the driver), or across the drivers leads?

 

[Gang-Twanger]

Seems to me, film caps had humongous voltage ratings back in the day, which tended to make electrolytics a closer electrical match to the crossovers. The lower ratings available today and more in demand are a fairly recent development - maybe the last 10 years or so ...

Electrolytics are a LOT closer tolerance now as well. Caps can also have a specific "sound" ... which explains maybe the ridiculous prices on vintage "bumblebees" for old school guitar amps and pedals.

Given all that, best bet is probably to just stick with as close a match as possible to what was in the original design and spec.

Don't think I joined in on this thread yet, so...

What I've experienced with capacitors in electric guitars is that they DO have a certain "sound" (I have two mounted on the tone-pot of my guitar, an "orange drop" type and a paper-in-oil, with a push/pull switch to choose between them, and there is a HUGE difference in that particular scenario... The oil cap is more-open and musical-sounding while the orange drop has a bit tighter feel but less personality than the oil cap... On a tone-pot, cap-type differences are VERY-noticeable).

I'm playing it safe and buying paper-in-oil caps for my W90's as soon as I can (They were already recapped, but not with oil caps, and I want to restore the crossovers to their original state... I wish he had kept the originals). I'll get to it as soon as I can afford it (Only 4 caps, but paper-in-oils are quite the expensive little bastards).

On a different note, I just swapped in a new music-server last night. No more god-awful fan noise in my right ear. BIG difference (The old computer was getting tired and overheated, and the fan would kick up to high-speed when things started getting hot, creating quite a noise-floor... All gone now).

 

[bowtie427ss]

I think he/she must have been in the process of editing their post when I commented. The addition of the disclaimer " Unless someone hammers on the mags with a 5lb hammer.. repeatedly." makes the "never" claim a bit more reasonable statement.


RC

No, it doesn't. Never is a loooooooooooooooong time.

Alnico mags in speakers should NEVER need a regauss The flux density life is theorised as stable for over 2,000years.
Unless someone hammers on the mags with a 5lb hammer.. repeatedly.

Without citation or reference, this is hogwash and might as well be about moon rocks. He might as well have said "alnico always sounds better".

More on topic, i read an article(maybe a few) several months back that suggested that voltage ratings of crossover caps can have a sonic impact.

http://www.reliablecapacitors.com/pickcap.htm

http://www.classicspeakerpages.net/...e&module=attach&section=attach&attach_id=5415

 

[leesonic]

Because they believe more money = better performance. The only way to really tell the difference is to do a blind listening test where you have no idea of which caps you are listening to. If this means building a crossover with both caps, and having wires come out of the reflex port to a switch that you can change from film to electrolytic, then do it. It's the only way you'll tell any difference.

Me? If the film caps are only a few bucks, then I use them, but anything over $10 a cap is getting too pricey for my liking. Especially larger values in woofer circuits where the cap is just sinking high frequencies to ground. Or, in a speaker like my upgraded JBL L100s, there are so many crossover caps that it would have been cost prohibitive to use films. Maybe one day I'll change to films in the tweeter and possibly midrange sections, but it's not high on my list of priorities.

Lee.

 

[musichal]

I'm not everybody, just one guy, and I'm only against using them in MY speakers.

 

[AintBeenDead]

One thing to remember is that the original designers had to design a whole system, and they usually had a price point to hit as well. If using electrolytics with the ESR available saved a resistor, then that's what they did. Low loss electrolytics were available but also did cost more. For most vintage speakers, the cost of using film caps, and resistors if they needed damping or attenuation added extra cost when cost was an issue.

Also, if the speakers were designed with electrolytics (especially for high cap values where volumetric and capacity efficiency vs. cost was needed), and they sounded "good" to great, then fine, the design was finalized. At that time, film caps in speakers weren't used much, but then crossover design wasn't all that sophisticated either, at least till the Jung-Marsh articles on picking caps really opened the doors. If the designer felt there was an advantage to using film caps, he had to balance that out to the bean counters about the added cost potentially eating into profit, or moving the speaker into another price tier against other competition.

Also, another factor is that practically no speaker makers felt their speakers would be used much more than 5-10 years before being discarded for the next latest greatest. They didn't have much reliability data for electrolytics anywhere (electronics or speakers) and I don't think that was going to be an issue for them. If you wanted them to "fix" your speaker's crossover, they probably would suggest to get new, rather than refurbish.

It is interesting to note that only a few manufacturers used film caps - JBL for most of their higher end crossovers, but a lot of regular vintage speakers used mylars, Dahlquist and the DQ-10's for sure, higher end Infinity, and the BBC LS3/5a which used film caps exclusively, due to their closer tolerances and consistency. In their design phase, they could have used anything, and the research team chose film caps, 6 or more of them.

Note that posts above cite cost also as a primary reason. Voicing issues aside, that is an echo of the original design choice. But if you could get better "sound" even with a bit more expense, what would you choose??

Really liked this post, and this comment. I had a question about a turntable once, where economics was a big part of the answer. It seems most people will look at a design, and wonder why something wasn't done better, or just assume it's right because that's 'how it is'. But I think we regularly forget cost, and that even 40 to 50 years ago with much better build quality per dollar, costs still had to be cut in all kinds of places.

"Also, another factor is that practically no speaker makers felt their speakers would be used much more than 5-10 years before being discarded for the next latest greatest"

This too is a lot of it. I recently recapped my AR-2ax (with Daytons), and clearly those things were not made to be opened/serviced. Or, as a similar example; I have a Philips turntable that has bad rotation hum. I looked through the brief manual several times only to find nothing to help this issue. Wasn't until the third read through that I noticed the very last line said something like 'This unit has self-lubricating bearings, and requires no repair/service'. Well, once I got to the bearing, it clearly needed 'serviced' as there was one dabble of half dried up lube on the whole bearing.

 

[Wigwam Jones]

Compare X to Y in the same crossover and decide for yourself.

 

[robgmn]

I have often thought that a person could run their own tests easily enough.

Recap a simple crossover with a variety of capacitors on a rotary switch, so that each one could be switched in and out of the signal. Position A, you're listening to cheap electrolytic, position B, you're listening to an expensive film cap, position C, you're listening to a motor run cap, position D, you're listening to a cheap electrolyic bypassed by a boutique cap and so on.

Then invite the friends over and set up some measuring equipment or whatever and have some fun.

The questions would be a) can anyone hear the difference? b) can they tell which one is which? c) is there an improvement in the sound with a particular choice?

After reading half of this thread, I was going to question whether anyone had done any scientific testing of one cap versus another (identical values).

Your voice of reason beat me to it!

 

[sonci]

How do you compare caps? Now thats should be pretty difficult, you have to solder some test the speakers, then open up resolder some others test again after some hours,
I find acceptable to hear difference when replacing 30 years caps, but with new ones, its like finding the right ammount of damping material,
putting expensive caps on a 40 years design speakers is like driving cheap bookshelves with a 10k amplifier...

 

[Frank Sol]

Here are some quotes from Bob Crites regarding capacitors.

"Good caps all sound the same. Let's define that term. A good cap has the value of capacitance we need and has very low ESR (I defined ESR earlier). A bad cap has either the wrong value of capacitance and/or higher ESR. If we compare a good cap to a bad cap, we would probably hear a difference. If we compare two bad caps, they would also probably sound different. If we stay with good quality polypropylene caps, we likely meet the two qualities we need....right value of capacitance and very low ESR"

Keep in mind Bob Crites & son use Sonicaps in their XOs

Not 'cheap' using the scale of many respondents in this thread

That is why I said...

Speaker people I respect say caps , at a certain level , are indistinguishable. Say a $20 sonicap vs $200 'whatever'