Good capacitors

Well, how many people do you know that set their tone controls or graphic equalizer perfectly flat?

John

On Tue, 07 Mar 2006 19:44:10 -0800 in sci.electronics.design, John Larkin wrote,

The controls aren't supposed to be perfectly flat -- if they were you wouldn't need it. I have one with a built-in noise generator and spectrum display, comes with a microphone, so you can set the result of the whole system flat (including your room furnishings.)

Flat where?

John

"Ah, but doesn't that change the sound of the amp?

-- John Fields Professional Circuit Designer "

It sure does.. isn't it WONDERFUL ??? :)

Whatever improves the overall reproduction accuracy of the unit. If it

- Matt

"Well, maybe not, but $10,000 power chords have done a lot for rock and roll musicians."

Like who? Unless I am missing a joke or pun?

"And this "signal injector" is what, specifically? "

I don't disclose information about my test suite. But I will tell you it was written by Moi. It runs with a computer driven 4 channel scope scope interface and a secondary communication device for output as well. It is capable of outright bashing an amp to the outer regions of the universe while giving me distortion @/vs slew, THD, TIM, etc.. it's funky stuff... And admittedly way more then I need. But it gave me a chance to test the limits of my coding abilities. We all know spelling isn't my strong point ;)

"Not true.

Loudspeakers and room acoustics have a lot to do with it, as do the ears and brain (or lack of) of the listener. "

A very true statement, but we are not on the same page and that is my fault. When I made the "sound" satement I made it *after* admitting my only ears were a scope and injector. I was not referring to an actualy listening situation where so many other varibles obviously come into play.

"Oh, so true, but then they go and spoil it all by putting those nasty old tone controls and equalizers on them... "

Now we come to a bridge. I am afraid I must generalize this becase I cannot sit here all nite and type. Actually I believe tone control has it's place. But it's not built into an amplifier. And there are a lot of reasons why I think this is just plain retarded in general.

When an amplifiers sole duty is to amplify without coloration why the hell would you put a bunch of goodies on it in *order* to colorize it? Even if you set it all flat those components don't dissapear from the signal path and the damage is already done. Secondly it should be up to the user to select thier sound coloration device of choice. You sould not be forced to accept you amplifier manufacturers 'ideal' methods of doing so.

If I had my way I would march into every amplifier manufacturers building, march straight up to the head engineers office, and scream in his face "Just make the f****ng signal bigger and don't f*ck it up!!" But we don't live in a perfect world.

"What requirements are you talking about?"

The simple answer is "consult your equiptment service manual"

"What do you mean by "true to it's" (its?) "values"? "

I mean they make a reliable cap with good QC and I have not seen an example off the shelf outside specs yet. Do they exist? They have to as no process is infailable. But I have good experience with using these caps as far as "being what they claim to be out of the box"

"Don't just try, when replacing filter caps, _always_ replace with a cap rated for a voltage _at least_ as high as the voltage rating of the cap being replaced."

Withing voltage specs *means* at least the originol voltage. I'm sorry if anyone construed that differently.

- Matt

Everything in the room colors the sound. That's why the people who take it way too seriously have anechoic listening rooms with acoustically transparent furniture. (They're absolutely correct, in their theory at least; the people being referred to as 'phools in this thread are a few steps beyond that.)

So if you want to have actual real objects in your room, and arrange your stereo around your decor instead of the other way around, your room will favor some frequencies over others. You use the eq to pre- or de-emphasize bands so that what reaches your ears is colored as little as possible by the environment.

Not that many home listeners actually do this; most people I've encountered with graphic eq's just tune them so that they "sound good," with "good" being pretty much anything imaginable. Sound reinforcement regularly employs graphic eq, though.

This sounds really interesting, but I can't figure out what they were trying to prove. It doesn't sound like they could have concluded anything about interconnects. Maybe they could have made a statement about the psychology of audiophiles, but from your description the test group had no idea what to listen for (i.e., anyone who'd spend the money on such a product should know what difference it would make on the sound.) It also doesn't sound particularly "blind." Would you by chance be able to cite it?

I personally believe that it's a lot easier to earn $5000 for a hideously expensive speaker interconnect than it is to develop the listening skills that would make one enjoyable to use.

If you sit in a concert hall, or a jazz club, or most anywhere, moving to the next row or the next chair will greatly change the acoustics. And small changes in microphone placement will radically change a recording. And no two ears have anything like equal, much less flat, frequency response. And some studio jock has already mixed and bent the tracks to *his* satisfaction. So it's silly to sweat a dB or three, or to sweep your "listening room" with microphones and spectrum analyzers. Just listen to what you like, twist the controls the way you like, and dump the snobbery and esoterica. And especially don't clutter sci.electronics.design with meta-religious nonsense like audio.

How's that?

John

I like that phraseology, "...meta-religious nonsense like audio." ;-)

...Jim Thompson

Hey! That's an very special receptacle! ;-)

I think the joke was, the cable from the mains outlet to the equipment is called the "power cord". That's "cord", as in umbilical cord. The OP misspelled it, "chord", which is a set of musical notes played simultaneously. Ergo, a "power chord" would be something produced by very loud rock musicians, who are apparently doing quite well, if some weinerhead will pay them $10,000.00 to play it. ;-)

It was actually pretty good for not having read my post at all. You nearly guessed what I was trying to say.

Room acoustics actually do not change very much with small variations in position as long as you don't get too close to walls. Three or four people sitting on a sofa in the center of a home theater will all experience pretty much the same image. So it makes sense to adjust the controls to favor the locations where you're likely to be actively listening. If you are in another room, it's not going to do you any good, and if a hundred people come over to watch the game, some of them are just going to have to deal with less-than-optimal conditions (and the fact that a hundred other people are drowning out sound that's already being drowned out by a crowd.)

A recording engineer actually does much more than tweak the sound to his or her liking. Yes, I realize that pop music is crap to begin with, and it's further crapified by the public's voracious apetite for bass and vocoders, but you can't even begin to understand what goes into mastering a recording. Most often it's a process involving two or three people who have to understand what their choices will leave the next to work with. I'll keep it short and tell you that there's a lot more knobs in ProTools than there are on your car stereo. Don't confuse what happens in the studio with what happens in the stereo aisle at Wal-Mart.

If by "jock" you are more appropriately referring to a radio DJ, then yes, you're absolutely right; although it's not entirely his fault. Radio broadcast is compressed nearly (or sometimes completely) to destruction, and EQ'ed to get that prized "two midgets in the back seat wrasslin'" effect.

But you and I and audiophiles have entirely different listening motives. While we might want a "good sounding stereo," audiophiles (all the ones I've met anyway) generally listen to concert recordings, and want the experience in their listening room to reflect the original performance as precisely as possible. So maybe we don't need an EQ as much as they do, fine.

You might resent the fact that some people are more demanding in their listening than you are, who knows. But don't assume that I'm one of those people. I listen to mp3's on my computer's built-in speakers most of the time!

Although millions of frat boys around the world can thoroughly enjoy a bottle of Cuervo Gold, you should not assume that it tastes exactly like Reserva.

But even the angle that a violin is tilted at any instant will radically change what a microphone gets. Musical instruments and voices are not isotropic radiators and are not anything like reproducible from performance to performance. Speakers are good if they're flat to 10 dB and are full of funny bumps and dips. Ears change from person to person and day to day. The actual noise floor, by the time music is played in a real room, is up there. So to claim that signal-path capacitors matter is plain silly.

I'd put money on the statement that nobody on the planet can, by listening to music in a blind test, distinguish the cheapest Jameco mylar coupling cap from the rarest Black Beauty or the most expensive hand-wound silver-foil PTFE cap of the same value. Of course, lots of people think they can hear the difference, but they're in the same boat as ESP sensitives and tea leaf readers and wine critics when confronted with a proper blind test. Gallo Hearty Burgundy wins over Chateau Latour when the label's removed.

Some things matter; signal-path caps don't. I don't resent the people who can hear the difference, I just know they're paying big bucks for delusion.

John

Actually if does if they are defective. Well, broken parts usually do matter. But there really is no difference between any honest functional part, regardless of price. These audiophools are actually in a $pending contest, not any kind of verifiable audio difference.

Now that is almost properly derisive enough.

I have seen ceramic caps up to 1 uF. Somebody is using them.

You can get up to about 100uF. You really-really don't want to develop any audio voltage across it. They work in DC-DC convert applications etc so there is a strong demand for them.

These super-high-K caramics are very nonlinear on voltage so, as you say, don't use them where there will be a lot of AC signal voltage across them. But as a coupling cap, where most of the voltage across them is DC with a small superimposed AC component, they're fine. What would be nasty is to use them in something like a filter with large voltage swings, where all sorts of interesting things would happen. They make especially bad integrators.

Some ceramic caps are nonlinear enough to use them as shock lines or parametric amplifiers.

John