The Klipsch KP-250 is often billed as a “super Heresy”. Similar design in that both are horn based 3 way speakers in a more or less 2 cu. ft. cabinet. The KP-250 is a ported box and the Heresy is a sealed box. Klipsch with their always generous spec's rate the KP-250 -3db @ 70hz. My measurements show -3db at 90hz. The woofer is, I am told, in fact an industrial strength Electrovoice woofer. This seems right. The mid horn (K-704) is the best part of this speaker and is also used in the current Heresy IV. The mid and hf drivers use titanium diaphragms.
The units below have been recapped. The mid driver was replaced with the K55m (Electrovoice) and the tweeter was replace with B&C DH-10 with a milled aluminum lens. That setup is far smoother with far less “shout” than the titanium drivers. The bass has been extended using a pair of SB Acoustics 10” subs crossed @ 100hz. A single sub would work just as well, I just had the dual subs already setup and the KP-250s fit nicely on top.
The completed setup sounds surprisingly good. Not as detailed as my prior Tannoy DMT15s, but far more forgiving. Almost any music I put on sounds good. I suspect I will be listening to these for a while.
The frequency scan upper left is the original 250 Mk 2. The frequency scan lower left is the 250 with the new tweeter and sub.
Note with the original the have a heavy midrange tuning with a heavy emphasis on the 100hz to 3500hz range. The post mod frequency scan shows a speaker much more balance and generally better suited to hifi use. I would again note that this speaker REQUIRES a sub. It's really not optional. With any sub crossed at 100hz it becomes a very good speaker..
Pre upgrade original tweeters
Original tweeter is on the left and the new tweeter is on the right. The new tweeter is seriously better in terms of build quality and sonics