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KP-301 KP-3.0B Crossover


Dave A

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What I was wanting to know was why the extra small barrier strip? I figure for biamping but since I am not doing this I was wondering what on this crossover is not needed and thinking of removing the unused components. This is a really crowded crossover. My thought is there must be a best way to configure this crossover for passive only use that may well improve the sound. If there is nothing to be gained then I would leave it alone but the similar Chorus crossover is sure not this complex.

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21 hours ago, Dave A said:

Wonder why they made the LF separate from the HF?

 

there is another diagram on page 4 of the pinned crossover thread, when entering this technical forum section (the 2nd post on that page) and if I was to wonder, the polarity on the tweeter uses the mid range opposite connection (positive from negative connotation) thus, referring to the unknown's... such as why, but only answered by raising your hand to answer with (a wire got us here)….

 

entering the middle.jpg

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1 minute ago, windashine said:

and if I was to wonder, the polarity on the tweeter uses the mid range opposite connection (positive from negative connotation) thus, referring to the unknown's... such as why, but only answered by raising your hand to answer with (a wire got us here)….

If you're wondering why some tweeters and squawkers are wired out of phase it's because some crossover components cause a phase shift and it's corrected by changing the polarity of the wiring at the drivers.

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Just now, windashine said:

 

so I'd reckon that the inventor didn't want the LF in the equation.... only to work best by itself

The mid and high sections of the crossover are made to be acoustically in phase with the woofer.

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14 minutes ago, windashine said:

acoustically phased > by physical observation or mechanical detection > voltage directive's from multimeter's > component gate's > flood control > 1919 vs 2019

I have no idea what that means.

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9 minutes ago, CECAA850 said:

I have no idea what that means.

 

me either lol... just thinking in term's for the last 100 year's.  I saw a picture in the news this morning, with some T-38 jet's breaking the sound barrier, and all I thought about were Dave's bi-amp connectors on the back of his 301's...

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16 hours ago, Deang said:

It’s a stupid feature that customers want, so the company caves and adds it - because if they don’t, then it’s something the competition has that they don’t. It’s marketing, not engineering.  

So is it's intent to allow cutting of jumpers between barrier strips and to bi-amp these?

17 hours ago, CECAA850 said:

If you're wondering why some tweeters and squawkers are wired out of phase it's because some crossover components cause a phase shift and it's corrected by changing the polarity of the wiring at the drivers

How do you measure for or detect phase shift?

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Phase shift in the crossover is a known-enough quantity.  For each order it will be +45 degrees for high-pass and -45 for low-pass.  The "order" will be the number of elements excluding impedance-control or response-shaping.

 

In gallery_299_34_63980.jpg

from reference (0 degrees) it would be -90 for the woofer; +90 for the mid from the bottom, no reversal from there from the top (no low-pass elements); +135 for the tweeter.  

 

If the woofer and mid drivers had their voice coils in vertical alignment they would be "completely" out of phase with each other at their crossover point and it's fairly typical one of the two would be wired backwards.

 

(My youngest brother was given a pair of consumer-level JBL 2-way bookshelf speakers and gave them to me knowing I'd been a fan of JBL (at the time I was running nothing).  I had them on a high shelf in the garage and noticed (Medwin-wise-ly) that interstation FM noise changed character as I lowered and raised my head to below and above the box.  They have 2nd-order filters on each driver wired in phase from the factory (I looked it up).  I reversed the wires on the tweeter and the "sound check" smoothed almost completely out, staying a (fairly) steady sshh instead of an exaggerated sshhwwsshh when passing vertically through the two drivers axes.)

 

Chris A has shown many (and variously produced) examples of both the direct measurement of phase angle and time responses using a mike and software.

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