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KEF's New Tech is Real

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aarons915

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If they get it working down to 200Hz, i'll be very pleased.

A bit off topic but I'm curious since you've had success modifying KEF crossovers. Are there components in the crossover of the R3/R300 that purposely create the dips in the 1-3/4k range? They seem so perfect that it seems like KEF actually engineers the dips into the R series for whatever reason. I wonder if it would be easy to bypass a component and basically remove the dip without the need for PEQ.
 

Zvu

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Short answer is NO, there is no such a component. Here is the topology for R series crossovers
skretnica.png


For midrange it is 12dB/o high pass filter and 6dB/o low pass filter electrically (acoustically it is a different matter).

If you pay close attention to schematic, woofer has 6dB/o electricall filter (LC for cone breakup controll, and RCL for 100Hz hump) and since crossover frequency between midrange and woofer is at 450Hz, woofer participates in sound quite a bit - even at 1000-1500Hz. Problem is that woofer starts to beam off axis at that frequencies so resulting power response suffers. Also, if you look at Kef Reference 1 measurement done by Anselm Goertz, same thing is observable there. Shallow slopes and as a result a slight depression in horizontal directivity between 1000-2000Hz.

3-KEF-Reference-1-Frequenzgang.jpg

8-KEF-Reference-1-horizontale-Isobaren.jpg


Cure for that would be DSP controlled active version (since doing it pasive needs a showel full of components with very large values). I did try that but still found the sound lacking some transparency in lower mids. Sold the R300's and never looked back. I would like to get my hands on a pair of dual-concentrics from R series though. They are a marvel of engineering in my oppinion, sound great and are built like a tank.
 
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