Gain Structure - Overload Indicator - Distortion ?

T

Tetyana

Member
I have a question I'm sure has been covered before, but I'm not able to find much help.

My issue is that when I create presets, often times the volume level is much lower than that of the factory presets, and the overload light blinks with audible distortion (the bad kind), despite the volume of the preset being low.

I've tried adjusting the gains of the various blocks, but to no avail. There's no meter that I know of to show the actual level through each block (unless I'm not seeing it, I use AxeEdit almost exclusively). I noticed the compressor block has a gain reduction meter on the green screen but I see no other meters.

At first I thought I was distorting one of the blocks, but turning down the volume at an early stage and using the volume control or the last block at the very end of the signal chain to boost the level back up causes the same overload on the CPU and distortion I get when I just leave the levels near default.

What am I doing wrong? I've had to go through all the presets and turn down the volume by about 10dB to give me the headroom I need to make my own presets loud enough, but I'm raising the noise floor by 10dB. Are there meters I'm not noticing? Is there a systematic approach to setting levels throughout the signal chain to minimize distortion.

One last question. My presets use over 90% of the processor power. Is it possible that when the processor is pushed hard that it has reduced dynamic range and is more prone to overload at loud volumes? The overload light SEEMS to be dependent on the level of the signal to some extent, I'm just wondering if I'm imagining it, and how to fix it.

Thank you to anyone who can help me solve this issue. I'm a relative noob but I read the manual a few times before I could buy my AXE II so I know how it works for the most part. I just don't know how to set the gain on each stage. Unity doesn't seem to work. I keep coming back to the theory that if the processor is on the verge of overload that increasing the output volume (making it "crunch" larger numbers?) can cause actual overload, a blinking indicator, and distortion. I don't know - I'm asking.

If I have to simplify my patches a little not a big deal, I just want to know what I'm doing wrong.
 
When you're nearing 90% there's a good chance that is the reason.
Turn off a couple of things to bring down the cpu load just to see if it gets rid of the issue.
There are meters in Axe itself, I believe on one of the I/O pages.
 
Tetyana said:
One last question. My presets use over 90% of the processor power. Is it possible that when the processor is pushed hard that it has reduced dynamic range and is more prone to overload at loud volumes?
Click to expand...

No.
 
If it's the OUT 1 CLIP light that's blinking, your gain is funny somewhere. You may have too many blocks working at once in a patch, and that will cause clipping and distortion, but as Cliff said, more output won't additionally tax the CPU. Maybe post a patch that this happens on and let us see what's up?

And- what Katsu said.
 
hi. my name is chris.

this is katsu

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OP: if you post a preset or two I can look at them and see why they might be clipping.
 
I ran into similar problems when I would make patches with almost every effect under the sun, and was running a lot of them in parallel.

I had all my bypasses set to 'thru' and found that I needed to reduce the level of the effects that were sidechained by 6db to even the level out for when they were engaged.

Is it possible you're doing it this way?

If so, try using feedback send and return to keep your blocks in series.

Again, I obviously have no idea what's exactly going on in your patch without seeing it, but thought I'd throw out a possible solution to your potential scenario. [emoji6]
 
Problem Solved - Another Question

FractalAudio said:
No.
Click to expand...

Further experimentation verifies this is true - thank you - it saved me some time. It was my error in programming. I created a PEQ I was using in most of my patches right after the cab that had a big boost in the lower midrange as well as about 4dB of gain in the level control. I did not have it set at or below unity gain. I think I was either overloading the EQ or the following stage.

I brought the PEQ level down from the 4dB boost to a 3dB level CUT to give myself 7dB extra headroom and make sure I wasn't overloading the EQ (digitally) or the next stage. I then brought the volumes back up at the last stage, and now I'm able to get the same volume level on my patches. Stupid mistake on my part. I'll further fine tune the gains to maximize the signal level. However, this unit is so quiet there's plenty of room for error on the low volume end. At least there is less hiss than a real amp.

It does seem that the EQ can be distorted easily if you have a hot input and you do a lot of boosting. I've never seen a digital EQ that had infinite headroom so that's not a criticism.

Thanks to everyone for the suggestions and offers of assistance, and sorry for the mistake.

I did notice one other thing. The subjective volumes of two different patches that have the same level can be a lot different. Some patches seem to clip at a much lower volume (but the same peak level) as others (clean vs. heavy distortion - limited vs. non-limited). For this reason I'm going through all of my patches individually and trimming the volumes 10dB at the output. This way I can always match the volumes of old patches and never run out of headroom.

Does anyone else do this or is there a different way to accomplish the same thing that I'm not aware of?

Thanks.

T
 
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You aren't overloading the next stage or block. Most blocks do not affect the next. It was purely too much internal signal. Did you watch the video I linked? It explains the concepts.

If you do a lot of boosting anywhere, it will clip. It's not the EQ itself.

I would highly suggest using the Output Level in the Amp block to adjust preset volume. The dB readout doesn't seem to be accurate so 0dB on amp level is NOT unity gain. Other blocks' Level seem to be accurate.

Any other volume/level control I feel is for adjustment for specific situations, so you want to leave those available for later. Amp block Output Level is the best way in general.
 
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Chris@KatsuKuriMedia said:
You aren't overloading the next stage or block. Most blocks do not affect the next. It was purely too much internal signal. Did you watch the video I linked? It explains the concepts.

If you do a lot of boosting anywhere, it will clip. It's not the EQ itself.

I would highly suggest using the Output Level in the Amp block to adjust preset volume. The dB readout doesn't seem to be accurate so 0dB on amp level is NOT unity gain. Other blocks' Level seem to be accurate.

Any other volume/level control I feel is for adjustment for specific situations, so you want to leave those available for later. Amp block Output Level is the best way in general.
Click to expand...

I watched the video after I solved the problem - I think you did a very good job of explaining it in simple terms and you confirmed for me that some headroom needs to be programmed in so that future patches can compete in volume (not just peak amplitude) with old ones. Interesting concept to control patch volume with amp level.

How many people out there use the amp level parameter to control their patch volumes? Basically as long as you don't in any way boost the signal beyond the level at the unclipped input you're not going to clip the AXE is what I gather, but there are some ways to easily accidentally do that so you have to be careful. I also noticed that it's difficult to know where unity gain is on the non-linear blocks like amps since they both amplify heavily and compress at the same time. Thanks again for the video - another time saver.
 
Tetyana said:
I also noticed that it's difficult to know where unity gain is on the non-linear blocks like amps since they both amplify heavily and compress at the same time.
Click to expand...

that's one of the main reasons to use the amp block - its output volume number/value really doesn't mean anything. so you may as well use that and your ear to set the level. almost every other block, 0dB means 0dB, 1dB means +1dB, etc. so keep those at 0 until you need to use them.

i think majority of axe users use the Amp block Output Level to set the preset level.
 
I've got a nice template set up for just about any sound I need, excluding pitch shifting with multiple drives or amps. I use a separate computer audio interface to record direct and processed guitar but I use the AXE input to condition and preamplify the dry signal before recording it. I find I rarely need to reamp unless I set the gain wrong on the amp block. I use the return as a stereo input for an external source to play along with - don't need it for effects. I record raw amp and cab and apply EQ and effects in the DAW, although many tones require very little EQ. For practice while not recording the built in effects sound stellar. I'm just used to VSTs for recording and have a lot of nice presets developed for those. Otherwise I would use the AXE for reverb, delay, chorus, etc.

After about 3 months with the AXE II MKII and going back and forth between it and tube amps, I am convinced that the AXE II V16 can fool a seasoned player if used to drive a guitar combo amp speaker using a clean power amp. IOW, it sounds and feels like a real tube amp, or rather like real tube ampS. It can also sound essentially identical to some preamps. After owning a Standard and selling it after not being satisfied with the recorded tone, this is very encouraging. To me the day of digital guitar distortion rivaling tube distortion began only recently with the most recent versions of the AXE II firmware. I also played a friend's AXE II about a year ago, but it didn't sound like the AXE II FW16. There have been major improvements in both the pick attack (even without the control) as well as the sustain harmonics on some models. I clearly hear it.

What I am trying to say is that the incremental improvements have resulted in something that is much more realistic and is now to the point of being convincing to my hands and ears which it was not just a year ago. Please never stop trying to improve. As soon as you think you've done everything you can think of something else will come to mind. "Dynamic Presence" is great idea! Not a real amp, but another tool to use to increase the complexity, response, and musicality of the decay of a note or chord.

While I'm keeping my tube amps this is probably what I'll play 95% of the time. I'm glad I sold my Standard but I'm really glad I bought my AXE II MK II.

The next best digital distortion I've heard are the latest Roland COSM models, but they don't sound like this!

T
 
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