I had recently taken the grill off my bookshelf polks. I started up SoundForge and created a new sound file, then went on to insert a simple sin wave at 2Hz. Yes two hertz.
To my surprise, this actually played. From the specs of my polks, these speakers have a frequency response from 50Hz-26,000Hz yet they played a 2Hz tone. First of all, does anyone know why? Heck, even my amp's input line is rated from 20Hz on up, so how come a 2Hz tone plays? (I didn't actually hear two hertz, obviously that's below what human ear can pick-up, but seeing the woofers respond to the frequency was what bugs me, and creates further problems as you'll see below).
And yes, it was rather cool seeing the woofer cone on my speakers move in and out, slowly and gently like a breathing lung, going out twice per second. Well it was cool for a short while, until I overloaded my amp as I increased the volume at which point it shut down. (I'm hoping repeated amp overloads don't damage any of its circuitry. Shortly afterwards, the only sound my amp put out were the high frequencies, and mid-to-low level sounds came off sounding highly distorted. This went away after about 10 minutes)
My dilemma is that I've got my bookshelf polks, and a 12" powered subwoofer hooked up to a Denon amplifier This unit has a pre-amp out for the subwoofer (which has a built-in amp of its own). However, when watching movies, or other types of sound with Low Frequency Effects, my bookshelf speakers are trying to reproduce the low frequencies as well, alongside the subwoofer, which is often causing amp overloads and sound distortion. This isn't a 5.1 receiver, just a stereo receiver rated at 80w/channel @ 8 ohms (totally sufficient since my bookshelf polks are rated at 100w max @ 8 ohms). I have it hooked up via a stereo RCA connection to my DVD player.
I tried bringing down the bass on the equalizer, but doing so also impacts the bass level going to my subwoofer.
Is there any simple way to restrict the sound that my bookshelf polks play to be ABOVE, say 200Hz? And nothing below? (my sub is sensitive from 20Hz to 200Hz).
Before getting the sub, I normally assumed that my bookshelf polks (being that their spec sheet lists their frequency response from 50Hz-26,000Hz) would NOT play any sounds below the 50Hz range, but obviously I was wrong. These 5inch woofers on them it seems are trying to play and and every frequency (as I've previously tried with the 2Hz tone)
Maybe I'm just missing something here, or don't fully understand how all of this works? If anyone could offer any helpful info I would greatly appreciate it!
Ideally, I'd like my bookshelf polks to only play sounds above 100 or 200Hz, and let the sub handle all ranges below that.