RM6700's internal filter???

section19

I recently purchased the RM6700 package and have heard conflicting information regarding whether they all have a built in crossover filter @ 150 Hz. If that is true I can see why Polk so strongly recommends that you hook up the mains through the sub. However, the manual states that the they're rated down to 95 Hz. So why have a filter that cuts in at 150 Hz?

The highest crossover setting on my 1803 is 120 HZ but my sub does go up to 150Hz. I currently have things set up the "Club" way not the "Polk" way (yes, I've been lurking a bit) so that disables the subs crossover. Am I in danger of having a significant frequency gap between sats and sub by not following Polk's suggestions?

Thanks in advance for anyone who takes the time to respond.

TonyPTX

Hey Section,
Welcome to the club. From my past experience (RM6700 w/PSW404 sub) I would say that you are lacking some of the bass between 120-150Hz. The 6700's do have an internal x-over @ 150Hz as stated to me by Polk CS. The speakers are rated down to 95Hz do to the simple fact of how x-over's work. 150 is not a hard nosed number where anything below that is just cut off. Most x-over's have a roll-off (6dB/octave - 1st order, 12dB/octave - second order, 18dB/octave - 3rd order, etc...) depending on the order of the crossover. I can't remember what the roll-off on the 6700's are, but the speakers will play below the 150 Hz mark, thus they are designed down to 95Hz to protect the speaker and let the x-over do the major work.

In your case, as with most sat/sub combo's I would seriously suggest you connect it the Polk Way as stated in the manual. Speaker level from AVR to subwoofer, then speaker level from subwoofer to Front L/R channels. I would set the subwoofer to OFF/NO, set the front speakers to LARGE, and crank the subwoofer x-over knob all the way up to 150Hz.

Hope this helps.

Tony

FYI, an octave is the distance or gap in frequencies that is half of the original frequency, i.e. an octave below 100 Hz would be 50 Hz, an octave below 50Hz would be 25Hz....

section19

Tony,

Thanks much for the info and the welcome. In my heart I figured Polk new what they were talking about regarding their own speakers, but, basically, my brain didn't want to have to roll up my $40 sub cable I bought with the Entra and stick it in the drawer.

I now have a project for this evening.

Thanks again. this is a cool site. :cool:

TonyPTX

I feel your pain about putting the $30 sub cable into the misc. wire drawer. In the end, I just wasn't happy with the 6700's and ended up going with some RTi70's instead.

Glad I could help.