OLD STYLE!
As many of you know, I am a fan of level controls, as most vintage speakers came with.
So, I immediately checked, and the KLH Model 5 comes with a 3 position Acoustic Balance Switch. It is preset for: ’normal’, ’live’; very live’ (no position for dull).
download manual here:
Pre-set positions control the changes equally, so balance between L & R is easily maintained, however pre-set limits the changes you can make for your individual space.
Both my Electro-Voice and Acoustic Research AR-2ax come with 2 level controls: L-Pads, Changes relative to the unchanged woofer: 1 for the mid and 1 for the tweeter. Each: Center is normal; up any amount for dull rooms/down any amount for live rooms.
Using L=Pads with no pre-positioning, you have to work hard to get the L & R to match. SPL meter with test tones helps, then your ears on very familiar content with excellent imaging.
Independent L and R, and freely adjustable can help with irregular spaces