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External Crossovers ???


elviszappa

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I’ve been thinking… seems a lot of high end audio folks are
concerned with isolating various components in the audio chain from the obvious
one such as turntables and CD player right on through to the sub’s and
speakers. Here’s one quote on the subject from the Galen Carol Audio Website…(there
are many others along these lines)



“In the same way
vacuum tubes are sensitive to external vibration, so to I believe, solid state
and passive components are too. Capacitors (in particular), resistors,
transistors and the like are sensitive, at least to some degree, to the
influence of vibration. More and more we are seeing designers take these
concepts into consideration when designing a new product. Chassis damping,
improved structural rigidity/integrity and individual component damping are now
almost commonplace.”



I’m not sure I buy into this, but some of it is common sense,
such as for isolating turntables. So here’s my though. If there is an
effect to electronics, sonically, from vibration, would it not make sense to
have the crossover outside the speaker…not even attached? Just think of the vibration
inside the speaker cabinet. How did they miss that!!! Food for though and hopefully discussion. EZ

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My personal opinion is that it's B.S.!

If an air wound inductor in a crossover network is placed near the magnetic filed of a driver, an unshielded woofer maybe, a signal would be induced in the inductor as it vibrates, but it would be small and would be totally overwhelmed by signal applied to the network from the amp. I doubt a cap would be any more susceptible to this kind of induction that a simple wire. It's the sort of thing you just forget about and look to more serious things to improve your system. Like spacing your speaker cables off the floor with Styrofoam cups spaced every 12 inches! [bs]

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http://en.wikipedia.org/wiki/Microphonics

I think that most passive crossovers are better outside the speaker box than inside...ever wonder what the SPL is inside an acoustic suspension speaker (like the Heresy)?

The Khorn, La Scala, and Belle crossovers are effectively outside the box. Cornwall, Forte, Heresy, Chorus, and most of Reference line is inside...

Chris

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I believe the notion has no merit whatsoever.

It is true that tubes can become "microphonic." That probably results when the components inside are not firmly mounted, or maybe the physical connection to the socket gets loose. Some problems might arise from bad solder joints, too. It is a historic reality that when a piece of gear gets cranky, giving it a tap or harder will improve things.

I have not seen reports of modern healthy transistors or I.C.s exhibiting microphonics.

Turntables, yes. The pick-up is a little microphone. Like with microphones they feed amplifiers with gains of 100s, 1000, or 10,000s.

But we're really talking about the passive components in speaker crossovers. They are feeding speakers which are relatively insensitive -- at least they are not feeding an amplifer of any sort.

Consider that the classic crossovers in K-Horns and LS are somewhat outboard. They are not in the woofer box. (The modern K-Horns are an exception.)

Maybe there should be an experiment with one of these older units. You can get at the crossover and tap the components. I'm sure you'll hear nothing out the speaker.

The other argument is that effective values of the components shift in response to mechanical shock. I really doubt that a shift, if any, can be significant. Even if it was 10%, I doubt you could hear it.

The bottom line is that this is all conjecture. You can't make things better by solving a problem which doesn't exist.

Wm McD

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Styro foam cups.... try these

http://www.oregondv.com/CableElevators.htmforums

A quote from a web site....

A recent customer that had purchased a set our cable stands has sent us back this feedback, validating what our customers are finding.

"I just got the speaker cable stands via UPS and installed them in my system.
I must say that the noise floor dropped significantly. I have a pair of
Magnepan Tympani 4a's that require significant amounts of power. I have a
McCormack DNA-1 powering the woofer panels. There has been quite a bit of
white noise and a low level hum coming from the woofer panels. I have tried
just about everything to get rid of it. I am using an active crossover with
sensitivity adjustments. I have tried to tweak that repeatedly with
little success. Once I got my IC (7meters long) from the preamp to the
crossover up off the floor with your speaker stands just about all of the
noise and most of the hum disappeared....amazing. The sound is definitely
more holographic and placement of instruments more defined."

And another........

"I must say I am floored at the increase in clarity and leading edge transients with the stands in place. Like wow. I would not have believed it."

cableelevator2.jpg

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No matter how far out an idea can go, even in fun, somebody will take it seriously!

No matter how obvious it is that a product is just snake-oil, somebody will buy it and think it's wonderful!

When it's plausible, like the microphonic network myth, then the arguments start.

B.S. has a big advantage, it has no restraints placed on it by truth. It only needs to be composed to sound believable!

Human nature sure can get interesting!

Al K.

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Guest David H

B.S. has a big advantage, it has no restraints placed on it by truth. It only needs to be composed to sound believable!

It's true, I have a freind who has been spending big $$$$ on high end power cables. Just last week he spent a large amound of time trying to convince me his new $90 1 meter USB cable made an astonishing improvement. I tried to explain the vitrues of the 0"s and 1's but he is thoroughly convinced.

B.S., Snake Oil, and my new favorite Cryo treating, are huge money makers, and none of their merrits can be measured.

Ugg...Dave

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Just last week he spent a large amound of time trying to convince me his new $90 1 meter USB cable made an astonishing improvement.


But did you actually have a listen, just in case he was right? It would not have taken long to swap the old and new cables, and then you and he could decide whether or not there was an audible difference.
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Hmm. Here is what Wikipedia says. There is no explanation of the magnitude of microphonics in some film type caps. The author also mentions microphonics in wire.

I will be sarcastic and point out that this means the woofer voice coils are microphonic and must be removed. Ohhh the horrors.

Smile

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Guest David H

But did you actually have a listen, just in case he was right? It would not have taken long to swap the old and new cables, and then you and he could decide whether or not there was an audible difference.

I did not, USB is a digital connection. I have played the blind A/B test game with him in the past, and never have been able to discern and audible difference.

Dave

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I don't know if ther'are audible differencies but I used external crossovers on my cornascalas.

They're decoupled from the cabinet by silent blocks.

With music the vibrations are present on the cabinet but not in the crossovers.

I think that's good.

;-)

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Linkwitz did the math for closed box woofers - and it's pretty high...too high for me to ignore the effects of microphonics, IMHO, without considering the discrete devices used (especially film caps).

Chris

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I put titanium and silicone dampers on the power tubes in my guitar amp (4ea EL-84's) and it made a world of difference, all for the better, in the sound of the amplifier, effectively "re-voicing" it, to the extent that I then had to modify some of the electronics internal to my guitars to get the best sound (to my ears) from the combination. Going from my own experience with this Class A guitar amplifier, I would put dampers on tubes for sure...splinting the glass sidewalls has an immediately noticeable and material effect. See http://herbiesaudiolab.net/tube.htm for more info. Along this same line, I was having vibrational distortion on CD playback which I eliminated by using raquetballs under the feet of the CD player. Beyond the obvious, I think it is futile to consider these other machinations.

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