Humble apologies to all and thank you for bearing with me. My memory is flawed. I was thinking that I’d needed to turn QC’s input knob way down. That’s not correct. What I did was turn it up (you were right, 747) to get a “nominal” reading on the input meter. If I left it set to 0.0 the meter deflection would be way low (peaks below -20). But turning it up caused distortion at even the lowest gain settings on various amp models.
When I leave well enough alone and don’t change the QC’s input gain—ignoring what I worry are lame levels resulting inferior S/N ratio when looking at the input level meter—the distortion goes away. I can actually get a clean amp sound. Yay!
Again, sorry for all the trouble. But it does bring up what I think is a bit of an ergonomic (if not outright design) flaw in the QC: the placement of the red zone at the top of the input meter’s “deflection zone” is not calibrated in a useful way, but in a misleading/confusing way. I’d assumed (rationally, I think) that, as with other audio gear, the bottom of the red zone is where you want to aim for signal peaks. Above that is traditionally fair warning that you’re getting close to trouble. As in clipping of your signal.
But on the QC you can run into trouble well before you would know it by looking at the input meter. Who knows what the red zone even indicates? Hardware clipping of the input, maybe? Looks like some (perhaps all?) of the amp models (and captures?) are calibrated such that unity gain (as far as the amp models are concerned) going in is somewhere well below the start of the input’s red zone. And I guess (hope) that setting the knob to 0.0 is the way to achieve actual unity gain (thank you 747) with respect to whatever you stick on the grid, just as if plugging into real-world hardware.
This really ought to be made plain in the user manual. I sure haven’t been able to find it.
It begs the question: so what is the red zone on the input meter intended to help us with? And why isn’t it calibrated to match the QC’s virtual world of devices?
I sure hope that this same unity gain level is expected by all other virtual devices in the QC. It’s got to. Right?
Good to hear that seemed to solve the issue for you. And I fully agree that it should be mentioned in the manual how to set up the inputs and what levels you should roughly aim for. Because it clearly causes a lot of unnecessary confusion for many users.
The meters are not a design flaw but simply show how much signal is coming in. Which is perfectly fine once you know how to interpret them. But again, I agree with you, this should be mentioned in the manual.
So in short: forget everything you learned in the analog world and don’t worry about the S/N ratio in the digital world and you are good to go.
Yeah, but this goes beyond the analog/digital distinction. With the QC it appears that zero dBFS is something like 25 dB above the top of the useful analog dynamic range at the input. And dat ain’t right.
Sure, with 24 bits it’s not going to be a problem in terms of quality. But the ergonomics are just messed up.
The engineer in me really wants to know what those meters are actually showing us. What are they calibrated to? And why? In what way are they helpful?
Sure, it’s a way to check that you’re getting signal into the QC, but a blinking light can do that. Why the red zone? Why not calibrate it so it actually is useful to us, showing us the level that we should be aiming for? Instead we’re left kind of shooting in the dark.
Good points! There is probably a feature request on the Unity forum for more I/O level details as well! And IMO, there is never a need for apologies, asking questions is the benefit of this forum outside of support. Many threads are escalated to support/dev teams as needed so the dialog is always helpful.
Yeah, your above post is spot-on, IME. I use some passive pickups, not hot at all, and find that when I raise the input gain to where the loudest strums just tickle the red, clean amps distort too early and dirty amps get added unnatural fuzziness and don’t react right (definition and detail is lost). Leaving the input at zero solves the problem, BUT, the meter is extremely low, generally peaking somewhere between -20 and -12. It drove me crazy for a while too. But I’ve learned to live with it. But I’m with you; I have no idea what the units on the meter actually mean, because it seems like the red line does not correspond to what we expect. I wonder how many QC owners are raising the input gain so their guitar just touches red (reasonable approach), then get disappointed because it sounds like crap.
Not crazy. I think you just needed to identify the issue clearly and rule out some variables first. I kind of think about it like one of the above posters said: Zero is like just plugging your guitar into a physical amp. But why the QC starts sounding weird when this input level gets boosted, I don’t know. Theoretically, it shouldn’t be much different than putting a clean overdrive before the input on a physical amp, but it is.
Also, to your earlier thought about boosting gain with a block before the amp block: I’ve found this works/sounds the same way as increasing the input gain (i.e. crappy). Your mileage may vary. I don’t understand the engineering details here. But in my experience, the QC amps seem to “expect” the lower levels which most passive guitar pickups seem to supply with the input gain set to zero.
Another consideration is that when you turn up a non-master volume guitar amp, it will get really loud long before it distorts (assuming it as 15 watts or more). But when you turn up a non-master volume amp in a modeler, it could distort at much lower volumes depending on how loud your playback system is. So you might think the guitar amp is cleaner, but it’s really because the relative sound pressure level you’re comparing them with is not the same. That’s the motivation for the recommendation to do all patch adjustments at gig volume.
I had the same exact experience and determined that the factory IR’s or cab sims were the issue. I downloaded the York Audio IR’s (only $15 USD) and the Quad came to life!! I hope this helps. https://www.yorkaudio.co/product-page/mrsh-412-t75
I just got my QC a few days ago and was getting very muffled sound similar to what you described. What I was doing: Guitar input 1, Output 1 Mono. I switched this to Output 1/2 and it came to life. This may not solve your issue but others may find this helpful if they did the same as me.
If you are running a stereo line into a mono output and that changes your tone the problem is very likely phase related. By summing two signals (stereo) into a single signal (mono) constructive or destructive interference can be the result.
That’s what I was thinking. Comb filtering, otherwise known as “tone suck” in the guitar world, is not uncommon in such scenarios. Stereo stuff should be kept stereo, and if you have to go mono with it, it’s much safer to split one side off rather than combine the two. IME. YMMV.
