ZiggyZipgun

That's just a couple of the ways that I use it, and I'm not trying to do those things simultaneously or split it twice. But thanks for your original suggestion!

Chorus? No problem. 70s Chorus? Merged. Reto Reel? No problem. Doubler? Merged. Very inconsistent, but probably due to DSP handling. Each model uses a different amount, but I have no issues running an extra preamp, an amp, and a dual cabinet, along with and drives, modulations, and delays in each of my patches. Separate amps and cabinets does limit the selection.

The Helix Floor and LT have aux inputs, but the impedance matching is not applied to that aux input. The Stomp and XL are the only units that apply it to both inputs, and I do use it a lot - often set ~136 hz. I run a second Stomp in the FX loop just for reverbs, since I use the dynamic split to shift between two parallel stereo reverbs. The Stomp produces enough latency that you will notice it if you use it for anything other than delays and reverbs, so I keep that second unit 100% wet and blend it on the first unit. Well, it's not - it's not even consistent behavior from one effect to another. I can run a different phaser/flanger/chorus on each path and keep the pickups separate, no problem; switch one to a rotary cabinet and they're suddenly blended together (before the split). You were certainly right when you suggested using the stereo effects, but it doesn't work for every model, and that's not the behavior I would expect after using 5 generations of Line 6 modelers over the past 20 years. They're less common now, but there were bi-amping bass combos that had a crossover built in, and that's easy to emulate with one input. And a number of famous custom rigs sent different pickups to different amps, and that's easy to do with the Y-split. Now I know these can be combined, even if it is definitely an edge case scenario. It does have a unique benefit of being able to really combine two different pickup sounds into one, rather than layering, and it works equally well on my fretless P-bass with a mudbucker in the neck, my Jaguar tuned from A to A in all 5ths, and my Tele-ish Godin Session Custom tuned down to C# standard. I've been using the Y-split for a few years, and it's pretty sweet to be able to save my pickup selection in each patch, flip the phase of a pickup with a footswitch, or switch from the neck to the bridge with an expression pedal.

Certainly any mono block placed after the Mixer will combine both signals. But when splitting two inputs with the crossover, you have to set the Mixer panning to hard left and right to keep the inputs separated, and placing any mono block (and some stereo ones) in Path A or B (before the Mixer) will automatically combine both inputs before the crossover. Yeah, not an issue with one input. And not a issue with the Y-split, sending two inputs to separate amps. But using one pickup for highs and one for lows gets tricky!

I just tried it, and the stereo blocks do keep the high and low paths separate - but these blocks are placed in one path or the other, where you could not have a stereo signal when using the crossover. When two inputs are used, it will send one to the high and one to the low, and that's what I'm trying to maintain. The stereo distortion, modulation, and delays blocks in each path will help, but they will eat up more DSP, and since there are no stereo amp or preamp models, we're not able to create a proper bi-amping patch the way many bass rigs are built.

Has anyone else noticed that certain effects or amps will combine the inputs and apply the crossover at the end of the individual signal paths? My guitar is wired in stereo so I can route the neck and bridge pickups to different channels, and there lots of great tones to be found by combining the top end of one pickup with the low end of the other (I'm currently splitting at 875hz). This works well until I turn on any blocks in the individual paths, and then it's clear that both inputs are combined before being split into high and low channels. Some legacy effects don't cause this issue, but it seems that all non-legacy effects do. Is this a known issue?