Seem to read something like this every second post! The answer above is correct, but unreasonably brief!
I guess we all get sick of answering this same question.
Also, the way you play the Helix back needs to be known.
So you have people going FRFR or straight into a desk/monitors. Then you have people using a power amp into a guitar speaker box, and you also have people using a guitar amp and speakers. They all need to be handled differently.
I'm going to try to do this simply - what comes out of the Helix will need to be adjusted for these options.
So generally, you are trying to get the experience of a guitar amp while using a modeller into something like FRFR.
FRFR is full range flat response - a guitar amp and speaker is not.
The normal thing to do is set a low cut at around 100Hz and a high cut at 5 or 5.5kHz. This clamps the range to a typical guitar speaker, and then all of a sudden things sound like you expect.
You can do that globally (global EQ) or per preset so you can maybe leave some clean sounds a bit more HiFi. I just do it globally, and I've never found that the slightest limitation.
Some will argue with that.
Obviously, you would use much different numbers if you were going into a guitar speaker and power amp - you would also probably avoid using speaker simulation all together.
So the correct answer is it depends on your circumstances - but expect to need to use the high and low cut either per patch or globally.
Think about this as a studio in a box, not an effects pedal or a guitar amp.
Also you need to be aware of the Fletcher Munsen effect. your tone will vary with volume - it happens to everything - got nothing to do with he Helix - but becomes way more obvious because people build sounds at very low levels and then go to a gig and wonder why it sounds wrong. Try all your patches you intend to use live at realistic volume to tweak - bass in particular.
Oh, and you will therefore need to rebuild all your presets with that low/high cut - but it is totally worth it - even the most pristine clean sounds better built with a cut something like that.
And they suddenly feel good to play - all the touchy feely thing is suddenly there.
And be very careful with downloaded presets - look to see if they have this built into the speaker or IR - you don't want to do it twice.
IRs are another place where anything might be the case - so when you get that a huge cut in the lows and highs is not only OK but needed, feel free to use your ears! Who knows how that IR was made. you might be getting some cut in the IR. you might be hearing a mic an inch from the cone and that always is harsh without some taming.
So it's not just plug and play - the 100Hx and 5.5KHz thing is a 90% fix though!
Hoặc