Wah-hoo!

Man, did this thread cover some ground while I wasn't looking! I'm going to have to compose this off-line, to make sure I don't miss anything.

From top to bottom, then:

Doug, bear in mind that Yamaha does things a little differently... Instead of a "Main/SW/BOTH" setting, most other brands set each speaker individually.

At the risk of duplicating Larry's comments: If the subwoofer is set On, it gets the LFE, all of it, period. For most "non-Yamahas," at least for the Kenwoods Thinkly and I own, there is no option to send LFE to any other speakers if the subwoofer is On.

If the subwoofer is set Off, the LFE will be divided among ALL speakers set to Large, whether Mains or not.

If the sub is Off and no speakers are Large, the LFE is lost.

When the subwoofer is On, the only remaining question is how many channels will add their individual bass signals to the sub on top of the LFE it's already getting, via setting those channels to Small (or Normal, or THX, or whatever the "Not Large" setting is called :) The LFE will still go -- only! -- to the sub, regardless of whether the other channels are Large or not.

Depending on the amp, some center channels can be diffused to help fill any hole between L&R, but that's another topic.

And on the subject of separate L&R subwoofers, that's REALLY another topic! Check out [Link: sonicdesign.se] if you're interested in more data on subwoofer placement and the use of multiple subs. In effect, that's what I'm doing with my main woofers, but the only way to send the LFE signal to them is by setting the amp to No Subwoofer.

Re "my THX setup." First, I need to clarify that I don't actually have a "THX certified" setup, precisely because of my "non-certified" speakers (and DVD player, and wiring, and...) As you have read, the most common THX setup consists of satellite speakers on all channels, freq cutoff at 80Hz, and all channels' bass below that PLUS the LFE going to a single -- extremely high quality -- amplified subwoofer. This is both because of the quality THX demands of their certified subwoofers and amplifiers, and because (as I mentioned above) the cost of amplifying ALL channels to those standards and buying full-range speakers for all those channels is out of many people's ranges.

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Thinkly,

Q: "I can have the mains set to large and the sub can still receive an LFE signal?"

A: True. Actually, the sub -- only -- WILL receive the LFE signal if it is set On. The mains setting has no impact on this.

Q: "All other bass frequencies below the receiver cutoff will be handled by the mains regardless of which channel we are talking about?"

A: No. If the mains are Large, the others small, and the sub is On, each main will handle only its own bass. The other channels will send their bass to the sub.

Q: "How does the sub crossover effect this distribution?"

A: Any frequency, regardles of channel, above the crossover will be thrown away.

Q: "I will suppose that it does not effect the LFE at all?"

A: No, it affects the LFE also. The LFE contains no frequencies above 80Hz, so if your crossover is set to that freq or higher you will not lose any LFE signal. But if you set it lower than 80Hz, see the previous answer...

Q: "I will also suppose that if my sub is set at 60 hz that only frequencies (again not a brick wall)60 and below will go to the sub. What happens if the mains are set to normal in this case? Will the high passed frequencies from the sub be redirected back to the mains, or are they lost?"

A: They are lost, as are the frequencies from all the other "normal" channels (see below).

Q: "does a reciever's cut off frequency vary if the bass management is changed from large to small or vice-versa?"

A: No. Strictly speaking, the receiver's cut-off frequency never varies. However... If a channel is Small, the cut-off is implemented (always at the same frequency); if a channel is set to Large, the receiver does not impose any cut-off at all!

So the RANGE of frequencies sent to the speaker definitely varies, but the cut-off -- when implemented -- is always at the same point.

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"After more research here is my decision and my reasoning. 1.Mains>Large. 2.Sub>On. 3.Center and Surround>Normal. 4.Sub Crossover> 80hz." That looks pefect to my way of thinking, if your receiver also cuts off at 80Hz.

Thinkly, where did you find out that the receiver cuts off at 100Hz? Is that in the documentation somewhere? I couldn't find a manual for the VR-507 online.

As Larry stated, "blocked" frequencies will not be re-distributed. If you are stuck with a receiver low pass cut-off of 100Hz and a subwoofer high pass cut-off of 80Hz, you are losing any freqencies between 80Hz and 100Hz from every channel not set to Large.

And if this is in fact the case, I only know three ways to solve that. Fortunately the first one is free.

1) Set the Subwoofer OFF! This will force the receiver to divert the bass from all channels, and the LFE, to the Large mains. Since the mains don't drop the 80-100Hz range, and since they are now getting the bass from all channels instead of only their own, that will do it.

2) Replace the subwoofer with one that can crossover at or higher than the receiver cuts off.

3) Or, Replace the receiver with one that can crossover at or lower than the subwoofer cuts off.

Of course, you can also try to just live with the gap. Perhaps the amount of 80-100Hz information being sent to the small channels is not enough to matter if it gets lost...

-Bruce