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1:1 - Let`s talk A/B testing actual Amps to their Axe-Fx II Counterparts

Morphosis

Fractal Fanatic
...or you could listen to a "Pacosipulami" in another forum some months ago, which told you how things work :mrgreen:mrgreen:mrgreen

lol .... grey theory can`t and didn`t convert me, i have to experience this for myself... it seems .... YOU should know that ;) :frog:
 

BigD1977

Power User
Big +1. And there is lots of research on the placebo effect confirming the above. Which is why for most academically recognized scientific research involving humans a double blind study is required and the papers are subsequently peer reviewed and blind tests involving experts in anything that qualitative, whether it be wine tasting, audiophile products, guitar gear, etc, invariably makes the experts look like idiots.

It's also why forum opinions, youtube video comments, clip postings, etc, are for the most part meaningless.

Sometimes I'll try to close my eyes when listening to A/B comparisons, etc, but even then if the person performing can see the gear, it will affect their performance, etc, so it's hardly any kind of substitute.
Aye, it can even be applied here, when people A/B amps and don't tell which is which in public comparisons. I think the same needs to be done with the 'in the room' effect.

Anyone reading this, please note 'I can hear the difference' doesn't apply UNLESS you have done a blind test with a third party controlling all the variables.
 

mortega76

Fractal Fanatic
Yes. That's why I put that SPKR page in there and why I've posted so many things about it. The one drawback of ALL digital amp simulators is that they simply can NOT know the impedance of the speaker. It is physically impossible. Fortunately the impedance is very predictable and with a little work one can adjust the speaker impedance parameters accordingly.
Can someone point me to just what that 'little work' is? I seem to recall something about palm muting and moving one of the values around until it 'rings' or something to that effect. Thanks again!
 

zenaxe

Fractal Fanatic
Can someone point me to just what that 'little work' is? I seem to recall something about palm muting and moving one of the values around until it 'rings' or something to that effect. Thanks again!
See the Cliff's notes section. Cliff just posted info on this yesterday! :)
 

stm113

Experienced
The only real world A/B comparison I can make in real time is with my Peavey 5150. Infact when inplay live out 1 goes to FOH and out 2 goes the the fx return or my 5150 head. I find that the A2 tone wise is pretty spot on. I can tell some difference but I can't discern if its my eyes or ears to say that if I had a way to do a blind test I am not confident that I would know which is which. This is impressive to me for many reasons one of which being that (and I have been told this by more than one engineer that works on these kinds of things) there is something about the 5150 that makes it damn near impossible to accurately model. The comparison was done by running into my head as I normally do, then unplugging from the fx ret and plugging into the high input on the amp.

The other guitarist in my cover band plays through a modded JCM 900 50 watter w/6L6's and I use his tone as a comparison for my dirty tone on Love Song by Tesla and its spooky how close our tones sound side by side on that preset. Different power amps, different cabs, different guitars and players. I think that in itself it a great testament to the sonic and editing power of the A2. FWIW since fw10 the feel on that preset is better on my rig than his.
 

UnsungHeroGuitars

Fractal Fanatic
I can tell some difference but I can't discern if its my eyes or ears to say that if I had a way to do a blind test I am not confident that I would know which is which.
One thing that is for sure, once your sound is in the full mix, the audience won't have a clue either
 

PacoCasanovas

Fractal Fanatic
lol .... grey theory can`t and didn`t convert me, i have to experience this for myself...
The reason for telling you how it works, "was" that you have to try it out for yourself (otherwise you would never know it) - now finally you did! Remember, increasing the LF or HF resonance doesn't mean you turn up an EQ, you turn up the speaker load for your virtual tube amp, which results in its behavior. If the load increases 10 times for example because of the speaker resonance thump on a tube amp, the amp "thinks" he can increase it's maximum amplification level by 10 times, so instead of a 100V voltage swing, he produces 1000V which is impossible due of limitation by the power supply - it will clip for sure, which resulting in dynamic feel for what you will hear, especially on clean tones which feel "thicker"! Cliff also explained that on his "About LF Resonance"-thread in the "Cliff's Notes" ;)

Grey theory is always grey for those who just read it..... ;)
 
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fisioaura

Inspired
Ehh... Sorry guys!! Can you explain (to stupids) what LF and HF resonance is?? And how affects the tone?? Is it that "in the room" sensation??

If I´m running direct to FRFR, with amp and cab modelling, is it neccesary to find by ear the Lf and HF of every P.A. in every gig?
Sorry for my poor english!! And thaks for you patience:ambivalence:
 

DeVille

Member
Great Thread! I learned a lot.

Cliff,

Why isn’t the speaker’s impedance curve a part of the speaker sim block? If we could tune the impedance curve and save it as part of the speaker, couldn’t we maintain the speaker’s personality and effects as we swap speaker sims around in our Axe-FX rig?

Sorry if that's a stupid question. Just curious.
 

Morphosis

Fractal Fanatic
Why isn’t the speaker’s impedance curve a part of the speaker sim block?
1) Because this curve responds to whats located in the PowerAmp Section. This curve simulate whats happen in the PowerAmp!
2) Because than this would be get lost when using the Axe without a Speaker SIM
 

guitardoc

Experienced
In this case you would need an 'empty' cab block (or EXC block as in EXternal Cab) where you can enter the specific data of you individual guitar cab - which would make perfect sense. Or would it?
 

barhrecords

Axe-Master
In this case you would need an 'empty' cab block (or EXC block as in EXternal Cab) where you can enter the specific data of you individual guitar cab - which would make perfect sense. Or would it?
Seems like blocks are designed to pass audio to each other.

In the case of the SPKR page parameters, these settings affect the internal calculations of the AMP block. So it's not like passing audio from the AMP block to a another block.
 

guitardoc

Experienced
Ok, but wouldn't it be possible to internally copy the SPKR data from the cab block into the SPKR page of the amp block?
 

DeVille

Member
Well....

In this case you would need an 'empty' cab block (or EXC block as in EXternal Cab) where you can enter the specific data of you individual guitar cab - which would make perfect sense. Or would it?
It would seem to me that removing the Cab block, could be mean you do not want the effect of speaker loading and frequency response influences on your Axe-FX output,...perhaps because you are going into a speaker a guitar speaker cabinet. But, I see your point if a guitar speaker's load influences a real guitar amp's output in ways that it would not effect a FRFR PA power amp. In that case, the speaker's effect on the amp may need to be included in the signal chain, somewhere.

+
I still think it would be cool, if the speaker's impedance curve (as it influences a virtual power amp sim) could be tied to the speaker block / IR, so the sim of a Celection Blue inserted into a virtual rig, does what it would do in a real amp. Then when auditioning virtual speakers / cabs / IRs the swap would be strickly a change in the speaker cab, without need for tweaking the amp sim's speaker tab. Like doing away with the whole speaker acquisition and installation process isn't easy enough :0)
 

guitardoc

Experienced
No, because
Yes - but what happens in the Power Amp section depends on the speaker. If the speaker data from the cab block could be copied internally in the amp block when changing the cab block the behaviour would be dependant on the cab and still affect the power amp.
Likewise with an external cab - enter the data of the external cab in an 'EXternal Cab block [EXC], they could be copied into the amp block and the behaviour of the amp would depend on the external cab.

If this is possible of course - since we did not write the code only Cliff might be able to answer if this is feasible or not.
 

DeVille

Member
Maybe? What if all cab blocks initially held a generic (average) speaker impedance curve as a starting point (template). And the user could tweak and save the curve, of an IR, in the cab block (assuming the IR is just one component of the Cab block). Then, the impedance curve could be read by the Amp Block (speaker tab), or its function could reside in the Cab block. And a unique cab block(s) (call it external) could be the place to store the impedance curve of your real-speaker when you decide to go Axe>PwrAmp>Guitar Speaker.

Could you then both 1) allow the Amp block to interact appropriately with a guitar speaker (as if it were attached to the Amp block, in a real amp), and 2) selectively nullify the coloration inherent to that particular guitar speaker?

Just pondering out loud.
 

Casper

Inspired
FWIW, Cliff posted this which sounds like it address the issue.
Exploring this next boundary is where the money is for Cliff, since he has come so far already.

There has always been a desirability factor and increase in feel going from rack preamp-poweramp-cab setup, then to head-cab, and then to combo amp... with the combo amp often having the best musical qualities.
 
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