LFE vs High-level subwoofer connection, for FIDELITY

Well, reminder that no AI can actually hear a damn thing.  Whatever your AI is using it’s subject to whatever garbage it found here or on Reddit.  Also every AI I know of is trained to be conversational and invent text that sound like they were typed by a person, without necessarily having a bit of evidence for their statement.  Just like a person but with less responsibility. 

I personally think that a major benefit of a subwoofer is to limit the stress on the main amplifier and loudspeaker.  For this reason, line level with a high pass filter is best, and I think this is how you get glorious subwoofer behavior.   One thing that you cannot do with speaker level outs is to use a separate EQ.  With stereo systems I like to put a miniDSP in line with my subwoofer only.  This is where the big corrections are often needed and keeps it out of the way of the main signal path. 

I’ve never heard full range speakers run with an additional subwoofer that sounded worthwhile, but if that’s your jam, then running from the speaker outs seems to be how you keep your amp flavor, for good or bad.   Consider a speaker with very low impedance in the mid-bass, a common thing.  Many amps will gently sag there, causing an output depression.  If you use the speaker level inputs, you'll replicate that sag. 

@jbuddha882 Yes, High Level is what you would want to use and not LFE if you are using it in a STEREO system setup. Never use LFE for anything other than SURRONDSOUND. LFE is for bass management in an AV receivers surround sound frequency functions to decoding the signal from the AV receiver and will send it to the sub. Line Level is a straight and direct signal that is and will always be the best connection to the sub in a stereo plus subwoofer system. You will have to adjust the bass frequencies from the subwoofer’s frequency controls on the back of the subwoofer or from an APP if the subwoofer has the access and functions to that format. Remember this is for stereo listening only when adding a subwoofer. Other than that, LFE input is strictly for home theater AV systems. But if you intend to use an AV receiver for your musical listening you can definitely and for sure use the LFE input on your subwoofer when listening to surround sound music. 

GOOD DAY AND PEACE TO ALL

@jbuddha882 

im looking at an anthem SA35 to get Dirac live in a system

I can’t speak for Anthem but an AVR is probably the worst thing you can do to add noise to ’fidelity’...for music. So if you go straight from your source (ie streamer) to amplifier, high level is the most obvious option. I can run two or more long RCA from my steamer, plus splitters to my subs around the room, or I can simply use a short lamp cord to high level it from the speakers to subs without having to run multiple cables all over the room to the AVR or integrated amp.

No I am not using the Onkyo for music, I just tested it against my reference 2 way system. My system is, AfterDark NetONE SFP network switch, externally clocked. Fiber fed, so galvanically isolated from the wall. The NetONE -> Holo Audio Red -> Gustard S26 -> Khozmo Acoustics flagship balanced Vishay Zfoil r2r volume control preamp -> Soul Note A-2 amplifier. Conditioned by Furman, externally clocked by a TEAC CG-10m-X clock. 

Side note. The largest sound improvements were: upscaling Roon to DSD 512 with a Mac mini m4, and adding a clocked SFP network switch with good S/FTP Ethernet cables