Hello,
The RB-75 and the Heresy are both great speakers The RB-75 is a little more forgiving, The RB-75 is very dynamic and uses a 1.75" titanium compression 90x60 degree Tractrix tweeter and a ceramitallic woofer in a two way bass reflex configuration. The woofer is crossed over at a higher frequency and does double duty as a mid range/mid bass and low frequency transducer. Many horn purists scoff at this configuration, but Klipsch has done a very good job with the crossover and the driver components to make it all work.
The RB-75 has a lower effective FS and is a more compact contemporary looking speaker. The RB-75 would be easier to build a HT around using the RC-7 center and RS-7 or RB-75's as the surrounds. This configuration will give you seamless transitions and pans that are perfectly voice matched.
The Heresy is old school it uses a dedicated horn tweeter and horn midrange with a 12" pulp paper woofer. This speaker just received an update
the new Heresy III uses a titanium based tweeter and midrange this replaces the older phenolic type. The old Heresy was less forgiving and often sounded hooty, spitty, simbalant and forward/bright depending on the front end and the source material.
I have been told that the new Heresy is much smoother. The Heresy is placement sensitive and less tolerant in non-acoustically treated rooms. If you are building a home theater system around the Heresy You should be looking at using 5 Heresy's or 3 Heresy's up front and the KPT-100 for surround duty.
Both the RB-75 and the Heresy will require a subwoofer with the ability to keep up with the speakers. The effective cross over point for the RB-75 is
about 55Hz and about 65-70 for the Heresy. Disregard what the lititure states, as the advertised numbers are not realistic.
I am curious about the new Heresy III and will be ordering 5 of them I have the RF-7 based system that I will be comparing them to. I really like the Heritage speakers. Many people love horn speakers and many hate them. You
really should take the time to demo the RB-75 Most likely you will not find a dealer demoing the Heresy so you will need to make a leap of faith with this speaker. I don’t think that the Heresy III is shipping yet I will have more info
next week.
I really like horn speakers I love the revealing, aggressive and dynamic sound that they produce. For home theater applications they are a tough act to follow but you must decide if they will fulfill you musical needs.
Hope this helps
Ray
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Your Inland Empire THX Certified Dealer/Installer
www.rlahometheater.com