How should I set the crossover on my receiver for just 2 main speakers

[RoadRunner6]

Without asking any more questions, I'll try to make the possible setup alternatives clear. That said, it really helps if when you ask a question you list all of your equipment. Not knowing which specific Onkyo receiver you have doesn't help. I'm also not clear if you have ordered only two Energy C-100 or 5 of them?

First of all the Energy ESW-8 sub is mainly designed for surround 5.1 systems. However, it can work OK with a 2.1 stereo setup if that is your intention. You need to read the owner's manual and determine the answer to one very important question. Will the Onkyo receiver play in stereo with the sub active? Mnay of the newer receivers do but some of them play only the two main left and right speakers without the sub in the stereo mode.

If you in fact will have a 5.1 system and play both movies and music in 5.1 surround sound then the setup is rather simple. Hook up the sub (one of the inputs, either left or right) to the sub pro-out jack on the reciever with a single audio RCA cable. Set the volume on the sub to about 10-12 o'clock as needed and then leave it there. Turn the crossover dial on the sub to the highest setting, all the way clockwise to the right (150Hz). Set the phase toggle switch to the one that gives the most bass at your listening position after all is set up. On the receiver set the crossover to 80Hz, 90Hz or 100Hz, your choice, however, I would try 90Hz as a start. Absolutley no lower than 80Hz. Designate all other speakers, either the two or all five, as "small" in the speaker setup section. You might have to set this manually. Do not under any circumstances set them to "large" even if the auto setup mode might mistakenly choose large. Set the sub as "yes." Be sure to carfully set the 2 or 5 speakers and the sub's volume level in the setup procedure using the sound test tones that cycle thru eaqch speaker. It is a great help if you use a Radio Shack sound level meter, about $40-$50. This meter is far more accurate that the human ear and will get the sound level of all speakers within 0.5 decibles of each other. This is very important for the best and smotthest surround sound. Be sure to get the analog model only, Do not get the digital model! You will now adjust the sub volume if needed in the receiver and not the sub. Also if you later get the center and surround speakers it is best to get all three from the exact same series, Energy C model speakers.

If you are going 2.1 stereo for now then their are two alternatives. If the receiver will play the sub in the stereo mode then simply setup as above.

If it does not play the sub in the stereo mode then do this. Hook up the left and right speaker as normal from the receiver speaker A outs. Then hook up the receiver to the sub using speaker wires on the speaker outs from the receiver B speaker outs. Turn on both speaker A and B, the receiver should be running both A and B in parallel and not series, check the manual. Now set the crossover (90Hz) and volume (as needed) on the sub. Set the speakers as small in the receiver and the receiver crossover as 90Hz, and sub at yes. This last method is not the best but the only choice you have in this situation because the Energy sub does not have speaker outs (this is now very common on subs).

In either case make sure you position the sub at the front of the room, between the left and right speakers or on either side. Preferably not snug in the corner for the cleanest and tightest bass and several inches away from the front wall.

I know this is very detailed but hope it will help you to achieve the maximum performance from these fine little Energy speakers.

RR6