NDSP Quad Cortex

Orvillain said:
@2dor legend has it that you've got a solution to make sure you get the right amount of gain from a Neural capture, so that you don't lose gain in the capture when compared to the guitar going into the amp???
Click to expand...

That's my one big issue with QC, the gain staging is weird for captures. You always seem to lose gain. Best I did was to dial in the sound running the pedal or amp in the effects loop, then switch it over to capture and get it as is. That seemed pretty close. Anything else was off.

That issue seems like it would be straightforward for NDSP to solve, but here we are years later...
 
mbenigni said:
It was also really weird that they made the TINA announcement at the same time as the big PCOM (finally) announcement.

"We built a massive, insanely expensive robot that can turn physical knobs so that we're better prepared to convert our software plugins to run on a different processor." Hmm.
Click to expand...
IMG_0655.gif

The robot
 
Orvillain said:
That is pretty cool.

I've been envisioning a board with the QC and my Meris LVX and MercuryX, plus maybe some kind of midi controllable drive or boost pedal, all in 4-cable-method with my Dual Rectifier and a midi switchy box, wah pedal, volume, and an expression pedal.
Click to expand...
I struggled with the H9 in the loop and getting levels right. But you are smarter than me with this stuff 🤣
 
Orvillain said:
It takes about 3 minutes to capture an amp using QC. Assuming their internal tech takes the same amount of time, and let's assume that the amplifier has these knobs:
Gain
Bass
Middle
Treble
Depth
Resonance
Master

And assume you're capturing 10 positions of each knob. That would be 10,000,000 permutations. It would take approximately 57 years of continuous profiling to capture all 10 million permutations, assuming it takes 3 minutes per permutation.

If you assume 3 positions of each knob, it would take approximately 4.56 days of continuous profiling to capture all 2,187 permutations, assuming it takes 3 minutes per permutation.

So I'd think interpolation would almost certainly be necessary, even with robotic automation of knob positions in sync with a scripted recording+capturing system.
Click to expand...
Skimmed through their paper and it says they modeled the DC-30 with five knobs using below method:
“Each example in the dataset consists of a pair of one second long input-target audio segments, sampled at 48 kHz. The control positions are kept constant over each segment, and stored together with the audio, as described in section 2.1. Input audio sequences were drawn randomly from a collection of guitar and bass recordings. The dataset totals around 4.5 hours of paired audio, randomly split into 15000 training and 1000 validation examples.”

Their language with pairs is confusing, seems like around 6 or 7 positions per knob was used.
 
There's definitely funky stuff going on with levels with the QC. It is actually quite tricky to wrap my head around. There's quite a lot of things to account for.

1727264510773.png


XLR outputs are +9.5dBu.
TRS 3+4 outputs are +15.5dBu if you use balanced cables. +9.5dBu if you use unbalanced cables. This is the first source of oddity.
The Send 1+2 outputs are +9.5dBu.

I've connected my Meris MercuryX to the send 1+2 and return 1+2. I've got the Meris setup for true bypass operation currently. I get a level increase when I turn the effects loop block on inside of the Quad Cortex. Which isn't really desirable. I can't say I've had this problem with the Helix or Axe3. I can double check, but I'm pretty sure I can just put a pedal into the loops on those units and get unity gain.

So there seems to be a bit of a juggling act with levels, and tbh, I don't even know where to start with optimizing the signal-path in order to get the right level hitting the front of outboard effects, the right level at the returns of the QC, the right level going into the PA without being too low, and the right level coming out of outputs 3+4 to send to on-stage power amplifiers.

With the Axe3 for instance, I can take a feed from output 3... turn the output 3 level knob on the front all the way up, and I know it is the same level hitting the front of a guitar amp as what it would receive if I just plugged my guitar directly into the amp.

The same does not seem to be the case for the Quad Cortex. I cannot trust that send 1 is the same level as what the amp would see if I was plugged directly in. And debugging this stuff is a mare.

Again to repeat, in 4-cable-method the QC is noticeably noisier than the the Helix and Axe3.

You can get a good sound. You can whack a noise-gate after the effects loop block to cut down any extra noise that the QC adds. But you don't need to do that with the other two devices.

It is very odd that the documentation doesn't really point any of this out, and doesn't give you any tools to improve the signal to noise ratio and to ensure unity-gain throughout the system. The Axe3 truly does.

My expectation is that you connect the thing up to a valve amp in 4-cable-method, leave all of the built in trims at 0dB, and there should be no level drops or boosts, and there should be no significant additional noise added.
 
Orvillain said:
There's definitely funky stuff going on with levels with the QC. It is actually quite tricky to wrap my head around. There's quite a lot of things to account for.

View attachment 29307

XLR outputs are +9.5dBu.
TRS 3+4 outputs are +15.5dBu if you use balanced cables. +9.5dBu if you use unbalanced cables. This is the first source of oddity.
The Send 1+2 outputs are +9.5dBu.

I've connected my Meris MercuryX to the send 1+2 and return 1+2. I've got the Meris setup for true bypass operation currently. I get a level increase when I turn the effects loop block on inside of the Quad Cortex. Which isn't really desirable. I can't say I've had this problem with the Helix or Axe3. I can double check, but I'm pretty sure I can just put a pedal into the loops on those units and get unity gain.

So there seems to be a bit of a juggling act with levels, and tbh, I don't even know where to start with optimizing the signal-path in order to get the right level hitting the front of outboard effects, the right level at the returns of the QC, the right level going into the PA without being too low, and the right level coming out of outputs 3+4 to send to on-stage power amplifiers.

With the Axe3 for instance, I can take a feed from output 3... turn the output 3 level knob on the front all the way up, and I know it is the same level hitting the front of a guitar amp as what it would receive if I just plugged my guitar directly into the amp.

The same does not seem to be the case for the Quad Cortex. I cannot trust that send 1 is the same level as what the amp would see if I was plugged directly in. And debugging this stuff is a mare.

Again to repeat, in 4-cable-method the QC is noticeably noisier than the the Helix and Axe3.

You can get a good sound. You can whack a noise-gate after the effects loop block to cut down any extra noise that the QC adds. But you don't need to do that with the other two devices.

It is very odd that the documentation doesn't really point any of this out, and doesn't give you any tools to improve the signal to noise ratio and to ensure unity-gain throughout the system. The Axe3 truly does.

My expectation is that you connect the thing up to a valve amp in 4-cable-method, leave all of the built in trims at 0dB, and there should be no level drops or boosts, and there should be no significant additional noise added.
Click to expand...
Drop suport a mail. I`m sure they can help with your problem. I don`t remember, but there was something said about the Ffx loop in the QC, to get it to be unity gain. Sorry I cant help you with any more then that
 
unity.neuraldsp.com

Quad Cortex. Should I buy it?

Many thanks for the welcome @PickinPete ! Yeah, really enjoying the intuitive and fast UI. Yesterday first rehearsal with QC!! not my main band but a Pink Floyd tribute. It blew me away the ease of creating presets. As I said I’m a “one preset for all” guy and in a few minutes I could get one...
unity.neuraldsp.com unity.neuraldsp.com
 
Orvillain said:
There's definitely funky stuff going on with levels with the QC. It is actually quite tricky to wrap my head around. There's quite a lot of things to account for.

View attachment 29307

XLR outputs are +9.5dBu.
TRS 3+4 outputs are +15.5dBu if you use balanced cables. +9.5dBu if you use unbalanced cables. This is the first source of oddity.
The Send 1+2 outputs are +9.5dBu.

I've connected my Meris MercuryX to the send 1+2 and return 1+2. I've got the Meris setup for true bypass operation currently. I get a level increase when I turn the effects loop block on inside of the Quad Cortex. Which isn't really desirable. I can't say I've had this problem with the Helix or Axe3. I can double check, but I'm pretty sure I can just put a pedal into the loops on those units and get unity gain.

So there seems to be a bit of a juggling act with levels, and tbh, I don't even know where to start with optimizing the signal-path in order to get the right level hitting the front of outboard effects, the right level at the returns of the QC, the right level going into the PA without being too low, and the right level coming out of outputs 3+4 to send to on-stage power amplifiers.

With the Axe3 for instance, I can take a feed from output 3... turn the output 3 level knob on the front all the way up, and I know it is the same level hitting the front of a guitar amp as what it would receive if I just plugged my guitar directly into the amp.

The same does not seem to be the case for the Quad Cortex. I cannot trust that send 1 is the same level as what the amp would see if I was plugged directly in. And debugging this stuff is a mare.

Again to repeat, in 4-cable-method the QC is noticeably noisier than the the Helix and Axe3.

You can get a good sound. You can whack a noise-gate after the effects loop block to cut down any extra noise that the QC adds. But you don't need to do that with the other two devices.

It is very odd that the documentation doesn't really point any of this out, and doesn't give you any tools to improve the signal to noise ratio and to ensure unity-gain throughout the system. The Axe3 truly does.

My expectation is that you connect the thing up to a valve amp in 4-cable-method, leave all of the built in trims at 0dB, and there should be no level drops or boosts, and there should be no significant additional noise added.
Click to expand...
This is the biggest weakness with the QC in my opinion. I never got it to sound great with my Dual Rec and it always added noise and wasn’t transparent.

I did a bit of experimenting sticking it in front of a clean amp and it was a struggle to keep it transparent there as well. I did mess with levels and EQ but it never truly sounded right to me.

Tried a drive pedal in the loop and managed to get the levels sorted but still didn’t sound right. It added tons of noise as well.

I’ve never truly worked out which output you’re meant to use going into the amp either, there’s quite a lot of differing option out there.

I do like the device but it’s really only useful as a standalone unit IMO, there’s much better choices if you want to run an amp as well.
 
timbuck3 said:
unity.neuraldsp.com

Quad Cortex. Should I buy it?

Many thanks for the welcome @PickinPete ! Yeah, really enjoying the intuitive and fast UI. Yesterday first rehearsal with QC!! not my main band but a Pink Floyd tribute. It blew me away the ease of creating presets. As I said I’m a “one preset for all” guy and in a few minutes I could get one...
unity.neuraldsp.com unity.neuraldsp.com
Click to expand...

So What No GIF


I don’t care if this dude were using every piece of Fractal gear, no one playing in a Floyd “tribute” band is nailing Gilmour’s tones in “a few minutes”.
 
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