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dre 13th February 2013 08:38 PM

when to use high grade caps
 
Hi

I'm about to build some high quality speakers and have to buy capacitors for the crossovers. The question that rises is which ones will give a good result. There are some realy expensive capacitors out there and I wonder if these are worth the money. I read some threads on this forum, and I see that the opinions vary. Some claim you might just as well buy the cheapest ones around and others are willing to spend hundreds of $$$ on a crossover. I have no clue what to choose.

I have the following questions.
- Under which conditions do high grade capacitors matter?
- I want to build a three way speaker. Which crossover parts (tweeter, mid , bass) benefit from better caps.
- If there is a resistor or a coil in series with the capacitor does it still matter?
- which ones have a good price quality ratio
- which commercial speaker brands use what type. (from what I've seen, they use entry level "audiophile" capacitors like mundorf MCap or just elco's)

SY 13th February 2013 08:49 PM

I'll come out in the middle. You want a high quality cap with low microphonics, ESR commensurate with the crossover requirements, and relatively low inductance. That means encapsulated, machine-wound caps, high tension windings, with polypropylene being the preferred dielectric. Metal foil would be preferable to metallized.

Avoid any cap labelled "audio" or "audiophile" or any cap boasting of exotic materials- that usually degrades performance, which makes some audiophiles happy because of the added distortion and microphonics.

Stick with well-engineered mass-produced brands. Wima, Vishay, Panasonic, that sort of thing.

opensource 13th February 2013 09:07 PM

Hello.

About which capacitor could have a better sounding than another: try this well known site http://www.humblehomemadehifi.com/Cap.html
You should put a better quality capacitor where the "signal" goes through. Typically (but depends on your filter) on the highs and some of the mids. Standard quality should ne OK for the others.
I put Obligato as "high quality" in my filter, MCap as standard quality. Also: bass are a little more punchy with high quality air coils (lower resistance is better). True for coils on the signal path (bass and maybe on the mids).

Philippe

marce 14th February 2013 01:48 PM

I second Sy here, well made commercial brands as listed are going to be better than exotic audiophile caps...plus you will save money:)

dre 14th February 2013 08:05 PM

Quote:

Originally Posted by opensource (Post 3368670)
Hello.

About which capacitor could have a better sounding than another: try this well known site Humble Homemade Hifi
You should put a better quality capacitor where the "signal" goes through. Typically (but depends on your filter) on the highs and some of the mids. Standard quality should ne OK for the others.
Philippe

The article you mention starts with the equivalent circuit diagram of a capcitor. There is a resistor and a coil in series. This is the reason why I wonder if there is anything to gain (if there is any to begin with) with an expensive capcitor if the series resistance/inductance is far lower than the parasitic components "inside the capcitor".

In my understanding of electronics all parts in the filter are part of the signal path. Whether these are in series of in parallel is not relevant. Or
do I not I not understand you correctly?

SY 14th February 2013 08:16 PM

Quote:

Originally Posted by dre (Post 3369979)
This is the reason why I wonder if there is anything to gain (if there is any to begin with) with an expensive capcitor if the series resistance/inductance is far lower than the parasitic components "inside the capcitor".

It won't be. If you get a good, name-brand non-audiophile foil/film cap, the inductance will be negligible for this application. The linked site is... imaginative, lots of story-telling to market their services.

edit: I notice they also sell "audiophile" capacitors as well as a variety of audio placebos. Add several large grains of salt to anything you read there.

opensource 14th February 2013 10:41 PM

Quote:

Originally Posted by dre (Post 3369979)
In my understanding of electronics all parts in the filter are part of the signal path. Whether these are in series of in parallel is not relevant. Or
do I not I not understand you correctly?

I was meaning components in series. Beware: I didn't told you that you'll have to buy some Duelund capacitors to build good speakers. Also: you'll not transform "standard" speakers into high quality one with just some good components. You only may expect to have a slight/moderate improvements (more "punchy" bass with low resistance air coils on bass, some better definition with the highs and no idea for the mids. I only built a pair of 2-way floorstanding speaker) so don't spend too much with components in your crossover.
10%/15% of the total amount of your speakers+cabinet would be reasonable.

Quote:

Originally Posted by SY
The linked site is... imaginative, lots of story-telling to market their services.

Ok. Your point of view. The "capacitor test page" is an old page. There wasn't shop on the web site some years ago and I agree it's not a good idea to mix "tests" and "shopping".
Guess what you may find in the crossover of some B&W speakers? Mundorf capacitors...
600 Series | Technologies - Bowers & Wilkins | B&W Speakers

SY 14th February 2013 10:56 PM

Yes, branding is important in that market segment. Data and evidence... not so much. Fortunately, those of us building for ourselves can just pick the best performing components and not worry about how they'll look in brochure photos or if they'll impress chimp reviewers. :D

JonSnell Electronic 14th February 2013 11:05 PM

Quote:

Originally Posted by SY (Post 3368637)
I'll come out in the middle. You want a high quality cap with low microphonics, ESR commensurate with the crossover requirements, and relatively low inductance. That means encapsulated, machine-wound caps, high tension windings, with polypropylene being the preferred dielectric. Metal foil would be preferable to metallized.

Avoid any cap labelled "audio" or "audiophile" or any cap boasting of exotic materials- that usually degrades performance, which makes some audiophiles happy because of the added distortion and microphonics.

Stick with well-engineered mass-produced brands. Wima, Vishay, Panasonic, that sort of thing.

I am sorry but "low microphonics" in a crossover, that has no gain?
Low microphonics should be used in any sort of amplifier that is subject to vibration. Not a loudspeaker crossover.

JonSnell Electronic 14th February 2013 11:08 PM

There is a post on this site with a guy selling a component that retails for 60p (0.55euro or 40cents US) for $40.
This should stop!


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