In the last few days I have been trying to sort out the issue of capacitor choice for use in passive crossovers. There seems to be an inordinate number of people (both seasoned designers and technically incompetent "audiophiles" alike) who express strong opinions and actual preferences for certain capacitors. For example, bizarre claims like "Xcap really opens up the speaker while Ycap sounds gritty" are not uncommon. Yet, I can find ZERO objective testing data. Not a single SPL trace.
Does anybody have some objective data on this issue. I've heard all the opinion, now I'd love to hear some facts.
Does anybody have some objective data on this issue. I've heard all the opinion, now I'd love to hear some facts.
There is some evidence that caps can have an audible effect:
AES E-Library: Audio Capacitors. Myth or Reality?
and this discussion on it makes it seem more dubious:
http://www.diyaudio.com/forums/multi-way/67687-need-impressions-capacitors-4.html
Then there is this:
ABX Double Blind Test Results: Capacitors
Don't set fire to your caps!
Dan
AES E-Library: Audio Capacitors. Myth or Reality?
and this discussion on it makes it seem more dubious:
http://www.diyaudio.com/forums/multi-way/67687-need-impressions-capacitors-4.html
Then there is this:
ABX Double Blind Test Results: Capacitors
Don't set fire to your caps!
Dan
No doubt a poorly-made capacitor will exhibit non-capacitive artifacts (that is, it will behave in a non-ideal way). I'm surprised we haven't seen anyone do some SPL and distortion sweeps using a selection of audiophile-grade polypropylene capacitors using a simple, say, high-pass filter. When corrected for differences in capacitance (there will be small variances in overall capacitance which could bias some tests), it seems very unlikely to me that differences are audible. But who can say without the data?
Many years ago when "AudioXpress" was just a monochrome "Audio Amateur" there were CRO results published. Cyril Bateman in "Electronics and Wireless World" UK did harmonic distortion measurements a few years ago. (Magazine now may be called by another name.....) The same mag published work on the effects of the mechanical changes in the dialectric and how that might change the results. That was more recent. "Audio" also published distortion results for ceramic caps, I think. That would be 30 yrs old now.
But what is more interesting is the dynamic effects that are harder (or impossible) to see in steady state results.
There is a decisive result in this country (Australia) of how a large polyester cap had a quite distinct "memory" of a previous charge appear after the operators had assumed it had been fully discharged. Can't quote chapter and verse off hand. But it is that sort of quality that makes some of us suspect that we are hearing a "smearing" or other change when comparing caps of different types.
I know some of the terminology is a bit vague but I am committed to serious hard science and that when we know what to look for and how to measure it appropriately then things will appear more rigorous.
But what is more interesting is the dynamic effects that are harder (or impossible) to see in steady state results.
There is a decisive result in this country (Australia) of how a large polyester cap had a quite distinct "memory" of a previous charge appear after the operators had assumed it had been fully discharged. Can't quote chapter and verse off hand. But it is that sort of quality that makes some of us suspect that we are hearing a "smearing" or other change when comparing caps of different types.
I know some of the terminology is a bit vague but I am committed to serious hard science and that when we know what to look for and how to measure it appropriately then things will appear more rigorous.
Check this out as well:
http://www.classicspeakerpages.net/IP.Board/index.php?act=attach&type=post&id=5415
Badman, have you read the AES article? If so, could you summarize it a bit?
Thanks,
Dan
http://www.classicspeakerpages.net/IP.Board/index.php?act=attach&type=post&id=5415
Badman, have you read the AES article? If so, could you summarize it a bit?
Thanks,
Dan
The classics:
http://waltjung.org/PDFs/A_RealTime_Signal_Test_For_Capacitor_Quality.pdf
http://waltjung.org/PDFs/Picking_Capacitors_1.pdf
http://waltjung.org/PDFs/Picking_Capacitors_2.pdf
I realize with surprise that I am very weary of such posts and discussions. I guess I'm coming to feel:
Try it yourself, with some moderately highly recommended types, and some with bad reviews, in the crossover prototype. Use good assembly practice, good solder joints, star ground, etc., installing all the "good" and then all the "bad" caps; or just build two prototypes. If you hear a difference, it exists, if not it doesn't. If you're not willing to try it yourself, then the (no doubt unworthy) suspicion of trolling is raised.
http://waltjung.org/PDFs/A_RealTime_Signal_Test_For_Capacitor_Quality.pdf
http://waltjung.org/PDFs/Picking_Capacitors_1.pdf
http://waltjung.org/PDFs/Picking_Capacitors_2.pdf
I realize with surprise that I am very weary of such posts and discussions. I guess I'm coming to feel:
Try it yourself, with some moderately highly recommended types, and some with bad reviews, in the crossover prototype. Use good assembly practice, good solder joints, star ground, etc., installing all the "good" and then all the "bad" caps; or just build two prototypes. If you hear a difference, it exists, if not it doesn't. If you're not willing to try it yourself, then the (no doubt unworthy) suspicion of trolling is raised.
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There was a rather good article with great measurements of caps posted on here a little while ago. Will see if I can find it.
Also check out the polypro vs ceramic files in the demo downloads of Audio DiffMaker. Both are compared to a piece of wire.
Audio DiffMaker
Also check out the polypro vs ceramic files in the demo downloads of Audio DiffMaker. Both are compared to a piece of wire.
Audio DiffMaker
You can listen to some capacitor difference test results here:
Audio DiffMaker example files
You'll need Audio DiffMaker to play them back:
http://libinst.com/Audio_DiffMaker_Install.exe
The situation that shows an audible difference was pretty extreme, though: the worst dielectric ceramic type used as a highpass with corner in the audio range. Using a good quality polypropylene film on the other hand didn't show much difference.
DiffMaker is not going to be a good tool for this alone.
It ether relies on measurement taken at two different times, or by two different measurer (channels).
But that's just my opinion.
There was an excellent post about using a mirrored test signal run back to back, then you reversed it and run it again. Than you flipped one of the mirrors and compared that (comparison could be done with DiffMaker if wanted)
It ether relies on measurement taken at two different times, or by two different measurer (channels).
But that's just my opinion.
There was an excellent post about using a mirrored test signal run back to back, then you reversed it and run it again. Than you flipped one of the mirrors and compared that (comparison could be done with DiffMaker if wanted)
Spectral Waveform Analysis was also used in an attempt to measure differences in $1 NPE's and $30 boutique film types with the same uF level.
Capacitor myths revisited - The Classic Speaker Pages Discussion Forums
Download the paper in the second post.
If you have ears, you will hear a difference. I do not see why if everything is the same on measurements it should sound the same. Sometimes it is very big, but...yes there is one "but" - If you try to compare capacitors with rubbish speakers for 50-100$ - you should not hear any difference. Sometimes you may find a cheap component made for a different application ( not "audio grade" 
) which sounds better than many "audiophile" caps, resistors and etc.
This will be my only post in this thread so please do not try to argue - it is my personal opinion and listening experience.
Cheers,
Mario
) which sounds better than many "audiophile" caps, resistors and etc.This will be my only post in this thread so please do not try to argue - it is my personal opinion and listening experience.
Cheers,
Mario
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Caps do make a difference to me. I performed a simple blind test at home with my dad, and got 47/50 attempts correct at differenciating between a 4.7uF solen vs 4.7uF Mundorf Silver in Oil cap. Whether you hear a difference is up to the person's personal listening skills and experience.
Is this skill a good thing to have? Not at all. Now I have to dump my cheap caps and spend more damned $$ !!
Is this skill a good thing to have? Not at all. Now I have to dump my cheap caps and spend more damned $$ !!
If you believe that cd is as good as our ears then Diffmaker proves capacitor swaps aren't generally an audible change. If however you believe you hear better than cd, then Diffmaker is just a pointless piece of **** cd quality junk software that deserves to be in the bin along with $5 Oscilloscopes.
The truth is probably somewhere in between these two extremes.
The truth is probably somewhere in between these two extremes.
Strange. I am not able to see a second post or the paper, only the first post.
Did you scroll down to post #2? the downloadable file is there. It's a .pdf.
I'd attach the same downloadable file here but it's too large for the diyaudio system to accept.
So, have you read the DiffMaker docs or tried the program? If not, a point of interest: you can use DM all the way up to 24bit, 192kHz, way above CD quality. It can be as accurate or better than what is being used to record the music you listen to (unless you are one to believe that vinyl or R-R is better than any digital). Quite insulting (not to mention, rather ignorant) post you made there.
Got it. Thanks. For some reason the subsequent posts would not display until I clicked on the add
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