Originally Posted by MagnumX
OMG..... This is getting farking old... I do have other things to do in life, believe it or not.
I *ALREADY SAID* :
*If you cross at 80Hz with the LPF on the LFE, you will have a crossover curve of what I assume is the standard 1st order 12dB/octave crossover on the LFE channel! That MEANS that it will start rolling off the LFE channel at 80Hz. 160Hz is one octave above 80Hz. At 12dB/octave, that means with a SETTING OF 80Hz, it will be down 6dB at 120Hz in the subwoofer. That is not "throwing out" information! It's slowly dropping it in level. I also said if you run your sub hot like 75%-85% of ALL home theater users do (average is +6dB on bass), that means you are FLAT at 120Hz with a setting of 80Hz. FLAT! You haven't lost a damn thing! It actually creates a SMOOTHER transition to the upper bass and rest of the range than crossing at 120Hz. Bass starts becoming boomy at around 100Hz.
*Better yet, reducing 120Hz levels to the sub minimizes the possibility of localization, which starts at some point above 80Hz for most people. \
*Moreover, the 120Hz range for the LFE channel was NOT created to put 120Hz bass content in that channel! It was purely for HEADROOM! Film mixers are NOT supposed to be going significantly over 80Hz in that channel in actual usage. If you tell the system you have no subwoofer, it will move ALL the LFE channel material into the mains that are set to large (if none are set to large, it sends it anyway to the front L/R channels which it assume will be the largest in use). That has been true since the mid to late 1990s on most processors. Nothing is lost without a sub as long as you have full range speakers. It is not thrown out. It is either reduced in level or moved to the mains depending on the setting. If your setting is low enough or your speakers can't handle the frequencies (including crappy subwoofers), then you may not actually hear it, but that is not the same as "throwing it out" as you seem to imply. Reduction in level is not removing. All normal crossovers reduce, not brick wall.
I've SAID *ALL* of that before. I will not repeat myself again. Good luck proving even ONE of those things aren't true.
The point of this post is not to enter into this crossover frequency discussion, but to gather information on the typical, standardized, used by some companies, whatever, slopes / filters orders, that involve the transition from L, R, C, etc. speakers to the subwoofer a the home theater system and also the filter used for the LFE channel. What do Denon/Marantz or Yamaha actually use for example, not opinions concerning what they "should" use.
First some housecleaning: 12 dB per octave filters are 2nd order, not first order
A bit of searching hasn't found a definitive answer, which is surprising, but it "appears" most crossover filters in AVR's/AVP's have the following orders/slopes.
High pass filters - 2nd order, that is 12 dB per octave
Low pass filters - this would be to the subwoofer(s) - 4th order, that is 24 dB per octave - This applies both between the subwoofer and regular speakers and the LFE channel.
Here is one well written, although not necessarily authoritative source on the subject.
Are the filters listed above the ones used in practice? Authoritative references would be preferred.