LFE vs High-level subwoofer connection, for FIDELITY

@bartsw 

"I'd push back and ask why would you want to listen to bass in mono? Mono is so obsolete."

You can push all you like. We can disagree on audio setups, but there is no reason to be disrespectful. I mentioned subs, not mono.

I have borrowed this from @richardbrand who correctly states:

2. High-level (or loudspeaker level) is inferior to line-level because it includes the distortions of the power amplifier and the back voltages generated by dynamic speakers.  Inside the subwoofer, it is reduced to line level anyway.

You misread and misunderstood my post. Well done. Carry on.

@gournard 

You can push all you like. We can disagree on audio setups, but there is no reason to be disrespectful. I mentioned subs, not mono.

Trust me, I wasn't being disrespectful. Being disrespectful reads 100x worse. If you can't question something that doesn't make sense to you, then there's something wrong here.

High-level (or loudspeaker level) is inferior to line-level because it includes the distortions of the power amplifier and the back voltages generated by dynamic speakers.

But that implies using a speaker (tweeter, mid-range and woofer) is inferior, especially when using a Hypex, Purifi, ICE class D amp that measures better than most 'no-name' amps found in subs. Yet, we choose not to listen to music with just subwoofers instead of speakers.

It also implies paying up to $$$ more for 1000 feet of RCA cables that are subject to EMI/RFI and running them all over the room is superior to running a 3 feet lamp cord to a speaker, which isn't subject to EMI/RFI within the audible range. There isn't a one is better than the other here. I've compared stereo line level from my streamer to my subs vs high level and there's no real difference other than cleanliness, convenience and cost.

I'm using both LFE and high level with class D gear, with and without tubes in the chain, and see a lot of nonsense opinions based on hearsay, not self-experienced use, like the flat measurement fans. Room correction is blind to overlapping frequencies. It simply sees peaks and dips and corrects it regardless of high level or line level, just like it does on tweeters and mid-ranges. Also, tube amplifiers objectively measure worse than class D. But is is not fact because tube fans believe it is subjectively superior to class D. Some people like the bloom in bass, especially for certain music.

@bartsw 

Yet, we choose not to listen to music with just subwoofers instead of speakers.  ...  It also implies paying up to $$$ more for 1000 feet of RCA cables that are subject to EMI/RFI and running them all over the room is superior to running a 3 feet lamp cord to a speaker, which isn't subject to EMI/RFI within the audible range. There isn't a one is better than the other here

Hard to know where to start on this twaddle!  If a subwoofer could be made to handle the entire audible frequency range, that would be excellent.  But that would turn if from a subwoofer into a full-range driver. Physics stands in the way, at least for conventional dynamic drivers fabricated from cones and electromagnets.

Quad has made full-range drivers for over 40 years, but they are electrostatic panel speakers using featherweight membranes.  They also use sophisticated delay lines to emulate the ideal of a point source of sound.

Other manufacturers like KEF and Fyne address the point source of sound ideal, using dynamic drivers with the tweeters concentrically placed inside their woofers.

With my preferred wiring suggestion, the OP would only need 1000 feet of RCA cable if his electronics were 250 feet from his subs.  Unlikely.  At a separation of 6 feet, he would need a more reasonable 24 feet, one fortieth of what you suggest. 

As far as EMI is concerned, I would prefer to run balanced interconnect cables but KEF has made no provision for balanced connections.  Presumably they don't see sufficient benefit.  Note that EMI covers the entire electromagnetic spectrum, of which RFI is just a small part.

The OP's SoulNote amplifier is deliberately designed without negative feedback.  This means it measures poorly in conventional frequency-based distortion tests.  It is done to get the highest possible fidelity to the transient waveform in the time domain, which is where music actually resides.

The OP can easily try both wiring options to see which is better for the FIDELITY in his thread title.

Can I just add that SoulNote does list three cables, two of which are balanced interconnect cables with XLR connectors. The third is a clock cable.

In keeping with their time-domain-first philosophy, these balanced ICs do not have any shielding, and the two conductors are each made from a single strand of solid copper, all in a foamed Teflon dielectric.

I used to run high level input from my BHK300 (hybrid monoblocks) fed from all tube 2 box preamp, to a pair of Velodyne DD10+ on 22" Sistrum stands, coming in from 40Hz on down. 

Then i decided to run from the preamps extra XLR outs and found it to be more articulate.  

I’m auditioning a new solid state preamp now and haven’t yet tried the high level connection, but the XLR from the preamp is giving me the most articulate, fastest deepest bass I have ever experienced, and they match up well with the extremely fast electrostatic bass I’m getting from my new Prodigio WR1’s.  

I also suggest people try getting their subs off the floor.  I’ve found better articulation with them off the floor.

The Velodyne actually allows you two combine both inputs, the high level and the line level, as there are trim pots for each.