Tom
[SCENARIO 1]
I use my X-30 in the simplest fashion, as per scenario 1 of the manual :-
A single cable connecting the AV processor "LFE Out" to the X-30 "Sub In" . . . and a single cable connecting the X-30 "Sub Out" (no.1) to the LFE input of the sub.
[SCENARIOS 2-4]
The other options are only relevant when you are using separate components :-
(a) power amplifier (or receiver, acting as a power amp), and
(b) processor (or pre-amplifier of some sort).
rather than an all-in-one receiver
. . . or . . .
if your processor / receiver does not have a dedicated LFE out channel, but does have an extra low level "preamp" output Left + Right channel.
In the scenario where you are using a separate amp and processor (without the X-30) you would have :-
(A) a pair of interconnect cables linking the "Line Level Outputs" of the preamp / processor to the "Line level inputs" of the amp. (it's these "Line level inputs" that the X-30 manual somewhat confusingly refers to as MAIN-IN)
(B) a pair of speaker cables linking the "High Level Outputs" of the amp to the speakers
To use the X-30 in such a scenario, you basically have to insert the X-30 between the processor and the amp. This is what is described in scenarios 2 and 3 of the X-30 manual :-
[SCENARIO 2]
In Scenario 2, you basically connect the X-30 in parallel with the amp (using a pair of Y-connectors) :-
(1) a pair of Y-connectors splitting the "Line Level Outputs" of the preamp / processor in two directions . . . (2) and (4) below :-
(2) a pair of interconnect cables linking the "Line Level Outputs" of the preamp / processor (via one leg of the Y-connectors) to the "Line level inputs" of the amp.
(3) a pair of speaker cables linking the "High Level Outputs" of the amp to the speakers
(4) a pair of interconnect cables linking the "Line Level Outputs" of the preamp / processor (via the second leg of the Y-connectors) to the left & right channel "low level inputs" of the X-30
(5) a single cable connecting the X-30 "Sub Out" (no.1) to the LFE input of the sub.
Note :- in the above scenario, the full range of frequencies is sent to the speakers, which may not be desirable (they may produce distortion in attempting to play the full range signal)
[SCENARIO 3]
In Scenario 3, you connect the X-30 in series between the preamp (or processor) and the amp :-
(1) a pair of interconnect cables linking the "Line Level Outputs" of the preamp / processor to the left & right channel "low level inputs" of the X-30
(2) a single cable connecting the X-30 "Sub Out" (no.1) to the LFE input of the sub.
(3) a pair of interconnect cables linking one of the three "High Pass Outputs" of the X-30 (which engage one of high pass frequency filters) to the "Line level inputs" of the amp.
(4) a pair of speaker cables linking the "High Level Outputs" of the amp to the speakers
Notes :-
- in the above scenario, the X-30 only forwards low level signals to the sub :- it blocks the lower frequencies from being sent to the speakers, based on which of the X-30's three "High Pass Output" pairs you selected :- with cutoff frequencies of 50Hz, 80Hz or 120Hz.
- the X-30 "High Pass Output" options are still low LEVEL signal outputs :- they are not high level signals (like the speaker output of the amp)
[SCENARIO 4]
The scenario they don't really explain (but imply in both scenarios 2 and 3) is if your receiver is an all-in-one unit which :-
- connects directly to the speakers
- does not have a dedicated LFE output channel
- but does have an extra "Preamp" out pair
In this case you basically complete scenario 3, but ignore the X-30's High Pass output connectors :-
(1) a pair of interconnect cables linking the "Line Level Preamp Outputs" of the receiver to the left & right channel "low level inputs" of the X-30
(2) a single cable connecting the X-30 "Sub Out" (no.1) to the LFE input of the sub.
Note :- again, in the above scenario, the full range of frequencies is sent to the speakers, which may not be desirable (they may produce distortion in attempting to play the full range signal)
HTH