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Old 7th May 2012, 03:32 PM   #1
DrDyna is offline DrDyna  United States
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Default The Holmberg Patch.

So in my routine this morning looking for youtube responses, I came across something written along with a video which was originally a pair of speakers for sale.

Disclaimer: This was not written by me.

Ladies and gentlemen, for your consideration, "The Holmberg Patch".



Quote:
These speakers are no longer for sale. They are part of the history of audio development and belong in a museum.

Part one. The reason these speakers sound so good is that I'm using a filter patch which I developed myself. Let it be known to the world as the Holmberg Patch. It's a self-correcting filter, correcting for the rise in impedance of any driver, without using a Zobel network.

Part two. When one is designing a second order filter one uses the assumption of a nominal impedance of the driver, most often 4 ohm or 8 ohm. When that impedance is inserted in varying formulas for second order filters, the resulting output of the driver, any driver, is off by a lot, because the driver is not a purely resistive reactance, which every second order crossover formula assumes it is.

Part three. By using the Holmberg Patch, now available to the world, without the option of ever being a patent, the way to get the impedance correction factor into any second order crossover formula is to calculate the crossover twice.

Part four. The Holmberg Patch: The first calculation concernes the first component of a second order filter, here the inductor when applied to a woofer. Use the nominal impedance for the woofer when calculating the inductor.

Part five. The Holmberg Patch: The second calculation concernes the second component of a second order filter, here the capacitor when applied to a woofer. Use the acctual impedance of the woofer at the desired crossover frequency.
The crossover is now complete and will work as theoretically intended.

Part six. The Holmberg Patch: When the low end slope of a second order filter is the use the Holmberg Patch, first calculate the capacitor using the nominal impedance, then calculate the inductor by using the actual impedance at the desired crossover point.

It's possible, likely, that the Holmberg Patch can be applied to any order of crossover by using the nominal impedance of the driver with the breaking componet, the first in the line of components, and for all the rest use the actual impedance at the desired crossover point.
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Old 7th May 2012, 06:01 PM   #2
DrDyna is offline DrDyna  United States
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Not even a "It belongs in a museum!" reference?

lmao.
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Old 7th May 2012, 10:58 PM   #3
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simply a 'rule of thumb' method for incorporating the effect of a zobel by oversizing one component in a 2nd order xover....
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Impedance varies with frequency, use impedance plots of your drivers and make crossover calculations using the actual impedance of the driver at the crossover frequency
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Old 10th May 2012, 12:41 PM   #4
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is there a link to the Holmberg thing with some diagrams or the like?
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Old 10th May 2012, 12:48 PM   #5
DrDyna is offline DrDyna  United States
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Quote:
Originally Posted by bear View Post
is there a link to the Holmberg thing with some diagrams or the like?
The Holmberg Patch The Holmberg Correction - YouTube

home-cooked 2-way speakers $500 shipped
lmao.
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Old 10th May 2012, 07:01 PM   #6
sreten is offline sreten  United Kingdom
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Hmmm....

More clueless x/o meanderings by our resident clueless x/o "expert".
It is of course completely wrong, as is nearly all of what he claims.

rgds, sreten.
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