Eleven Rack vs Axe FX II

Discussion in 'Digital & Modeling Gear' started by gtrdaddy, Sep 3, 2011.

  1. Scott Peterson

    Scott Peterson Administrator Staff Member

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    ***In relation to Amp Sounds/Tones and specifically to the 11R***

    You cannot vary up the input impedance (aka use the True-Z) with the 11R unless you put an effect in there first... and even then, you are varying up the input impedance of the first effect - NOT the amp.

    That's why I am a bit flabbergasted with guys promoting the True-Z on the 11R as the key to the dynamic and realistic tones they are hearing from the 11R Amp Tones. The amp input impedance in the amp block is not adjustable in the 11R. Only the effect blocks are and even then ONLY the first block is. It is set automatically by the 11R based on what effect you put in the first block.

    If you used a Radial Dragster to vary up the input impedance.... any change - and there is a change - could be done perceptually through EQ and the results are very close. This is the same thing as changing the pot values on your guitar's volume pot. 250K vs. 500K for instance. The load on the pickups, presented to the pickups, is different and adds up to a different sort of tone - darker or brighter. This stuff isn't new, it wasn't introduced by Digidesign or Fractal - it's simple electronics. It's always been there with every effect pedal from back in the '60's. This isn't new. Every guitar does the same thing if it has pickups and a volume/tone pot. Let's be honest - 11R marketed it first and did it right. True. But they didn't invent this stuff; they just acknowledged reality from decades of what the analog world is and how it works.

    So my point is/was that all the talk of the 11R True-Z as some magic bullet for killer amp tones from the 11R are simply misguided and incorrect.

    Again, if you think I am full of s*** and disagree, then roll with it and don't mind me.
     
    Last edited: Sep 7, 2011
  2. jrockbridge

    jrockbridge Member

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  3. Scott Peterson

    Scott Peterson Administrator Staff Member

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    I'm trying. Really trying.

    At some point the eureka moment happens and I can stop... repeating... repeating...

    ;)

    :D
     
  4. mtmartin71

    mtmartin71 Silver Supporting Member

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    I am mostly going direct, but either way, I'm digging the feel and response of your new box. Thanks for making it!
     
  5. JackBruce

    JackBruce Active Member

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    No reason to be falbergasted! Most if not all guitar players use at least one effect in their chain. If it's relevant to the first effect then it's relevant to most guitar players.

    I'm not saying it's a magic bullet, but the fact that Fractal adopted it also, makes me think that it has some contributions, and in the end of the day every little thing counts, true bypass, better cables, no load tone pot, heavier strings, true Z, etc..

     
  6. blewis

    blewis Member

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    Hello. This is my first post. I've lurked here for months. I own an 11R and a HD500.

    From the 11R manual:

    "When set to Auto, the input impedance is determined by the first active effect or amp in the signal chain. You can also choose a specific load value to best match your pickups."


    From the 11R manual:

    "True-Z alters the frequency response of your guitar signal by loading your pickups in the same manner as plugging into a real amp or effect. This feature can also be manually controlled and saved as part of a Rig setting."


    The default behavior is as you have described, but there is a manual adjustment. I may have read your post out of context, but the use of the ".Period" absolute did not jive with how I understand the feature to work.


    From the Avid 11R blog (this is just informative, not contradicting what you are saying):

    http://community.avid.com/blogs/avid/archive/2010/04/06/the-truth-about-true-z.aspx

    "Tube amps are an especially interesting case, because their input impedance decreases considerably at high frequencies. This occurs because tubes inherently act like capacitors. True-Z can also add capacitance (that's what the "+ Cap" means in the True-Z control) to closely match the impedance of an actual tube amp."

    I believe the input impedance is set to "1MOhm + Cap" on the 11R when True-Z is set to Auto and the amp is the first block active in the chain. This provides, as you've stated, the most common input impedance of most amps... but the 11R also adds the capacitor to emulate an aspect of tube amps they have determined to be important.
     
  7. mouzer

    mouzer Member

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    Scott; I think you're wrong about that first part. I'm pretty sure you can manually set the impedance on the input, independent of the signal chain in the 'rig'. I just played with it and there is definitely an audible difference between 1M+cap and 22k, even with the Amp/Cab as the first block in the chain, with everything else disabled. It may not be representative of reality since the vast majority amps are 1M, but it can be done inside the 11r. Setting it to Auto will keep it at 1M unless the signal chain dictates otherwise.

    That said, it's not the magic bullet that some people are making it out to be. Its definitely a handy way of affecting the high end response coming into the unit, and that's all I use it for.
     
  8. Scott Peterson

    Scott Peterson Administrator Staff Member

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    Ok - I am wrong that you cannot do it with the setting at Auto. And I admit that I have not studied the 11R nor was clear on that function being manually available. The guy that owned the 11R and showed me was misinformed and that is what he was telling me when I checked it out; so I am admitting I am ignorant of what it could do until corrected here (as is the 11R owner I won't now name... but I'll tell him!).

    Thanks for letting me know.

    But....


    ...that makes the case made by JackBruce even more confusing to me. In my first post I asked him to try to vary it up and report his findings.

    If you can manually change that setting, then can you or he or anyone then tell me I am wrong about my opinion that lowering that setting just darkens your tone? Please? (Hint: I am not wrong. Which in the end and past all the details of the tech or the settings was the point in the first place and cost me how much time trying to explain in posts? Arrg.) :D

    It's not the magic bullet. Amps - quality amps - are 1 mega ohm + a cap across their input.

    Quality analog input sections, properly designed and executed, along with quality A/D converters with proper signal to noise levels are why the Gen1/Gen2 Fractal, 11R and Line 6 HD series sound better than other older modelers IMHO. YMMV.

    That's why the Gen1 Fractal boxes still sound great and react to pickup changes - though not in the same fashion as the Axe-FX II (due to setting the level of analog input *into* the A/D converters - and to date the ONLY box offering this as a savable setting).

    Let's just not toss around "True Z" as some mystical cure all 'magic bullet' that Digi created out of ether. Not that you did, but it was implied by some and I see it on other threads too.

    It's nothing that new, nothing that revolutionary... if you've ever played a real amp with real pedals. They just gave it a cool name. The Axe-FX II just calls it what it is - variable impedance. That isn't as sexy, but it is what it is.

    Beyond the details of the technology... can any of the 11R guys please take a few minutes and either back me up or refute my opinion that it just darkens your tone as you lower the setting? Please?
     
  9. Stef_herbuel

    Stef_herbuel Member

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    just a question : i remember reading that if the signal is buffered (HF system for example) the trueZ doesn't have action anymore, is it true ?
    if it's the case is this true Z have so much "impact" to the sound ? because if you loose it with a single hf system, that's a big pb.
    but i don't know if it's true , if someone can answer , thanks ! :bow
     
  10. Scott Peterson

    Scott Peterson Administrator Staff Member

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    Use a low impedance pickup (like EMG) or a buffer on your signal and see. You don't need an 11R or any other rack unit to test.
     
  11. Stef_herbuel

    Stef_herbuel Member

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    i tested with my fuzz haze (fuzz face clone ) , it did'nt like it at all !. BTW i just wanted to show that if it's the trueZ who makes the "difference" and brings the "magic" in 11R , and that a EMG pickup or wireless system kills that, that's a big pb !
     
  12. JackBruce

    JackBruce Active Member

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    According to the avid blog,you are correct it does darken the sound as you lower the settings but that doesn't mean as you hinted in your earlier post that it can simply be approximaged by EQ. In the early nineties speaker simulations on some of the multi effects were approximated by EQ curves. So sure I can say that cab simulation can be approximated by EQ curves and you can say that True Z can be approximated by EQ curves but that would be like putting a smoke screen were the reader might think, I don't need impulse responses because they can be approximated by EQ or I don't really need true Z because it can be approximated by EQ...

    From the Avid blog:
    "here’s how you can easily hear the difference of True-Z for yourself.
    First, create a preset with the wah first in the signal chain. You'll see that this will automatically set the True-Z impedance to "90k + Cap". Now if you go to the input block you can override the automatic impedance and set it to 1 Meg ohm, which is approximately the impedance of a typical DI. You can save these as two separate presets, so you can quickly switch between them while you play. Notice how the wah sounds “harsher” with the 1 Meg impedance. You can also do the same test with the fuzz or the amp as the first effect."



     
  13. ejecta

    ejecta Supporting Member

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  14. blewis

    blewis Member

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    Yes, changing (reducing) the input impedance does darken the tone. I've heard other users also say the sound gets "more squishy" as the tone gets darker. I can't confirm that. I think I have heard it, but it could've been placebo after reading about what to expect.

    I can't (won't) attribute the 11R magic to the True-Z. I'm sorry to quote the Avid inventor so much, but his writing is very clear:

    Another way of saying this is "each of your guitars sound more like they sound when plugged into a real amp". Someone else also mentioned that when you reduce your volume, your pickup and your pot will be interacting with the 1MOhm + Cap circuit to create a unique RC circuit that's specific to your guitar.

    But yes, when you change the input Z away from 1MOhm + Cap to something lower, the immediate effect is the tone is darker. The exact shape of that newly created filter is guitar specific - albeit subtle.

    Personally, I don't fiddle with it much and just leave it on Auto. I hear the difference most on the Wah effect. When I use the Wah on my HD500, I hear ice picks when the toe is down. I attribute the lack of ice picks on the 11R Wah with the True-Z circuit as the Avid guy describes it.
     
  15. Scott Peterson

    Scott Peterson Administrator Staff Member

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    Which is all true - here's the kicker - just roll off the volume on your guitar. Same difference assuming you know whether you have a cap across the pot or not and the value of it. It's all the same thing.

    I'll repeat - none of this is new, none of this should be so 'out there' and surprising to electric guitarists. If you use an electric guitar with a volume pot... you already have experienced much of the same phenomena. That's why some guitars put a cap across the volume pot, to stop the highs being bled off to ground as you lower the volume.

    It was a long time 'hot rod' thing to brighten your guitar by putting a 1Mohm pot in there - Torres Engineering used to sell it as a kit in the 90's and good luthiers worth their salt have been doing it with Les Paul's and Dimarzio's since the early 80's when I started playing guitar.

    It's a bit jarring that so many find this is all some sort of voodoo. It's not. :hide2
     
  16. JackBruce

    JackBruce Active Member

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    Well I never liked the cap across the volume pot because I like the way rolling down the volume rolls of some highs, but then again on my tone cotrolls I use "no load" tone pots so I have the choice of getting the full Non-Eqed sound of the pickup when I need to...

    Sure non of this stuff is outhere and guitar players experienced it before but not in a modeler except for Eleven and later the AXEII. It illustrates that Eleven had True Z a feature that was lacking in The AXE FX first generation that was rectifed in the AXE II, so Fractal just recently caught on to this and to them it was important to include. So in a thread about ELeven VS AXE II it's relevant to show that Eleven was ahead of the game in this regard and makes one think that the possibility of them being ahead of Fractal in other things a reality or Vice versa, in other words the two units are comparable with strengths and weeknesses in each...


     
  17. blewis

    blewis Member

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    That's good.
     
  18. blewis

    blewis Member

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    The only thing "new" about it, is that the 11R made the impedance dynamically adjustable in a way to mimic the real world signal chain. They also offered it to be statically stored as part of the preset.

    They also coined the term True-Z (and registered the trademark on that apparently). It's a marketing technique to label and sell it as new. That's the marketing team's job. I think they've done an effective job doing that based on the confusion you're sensing from guitarists.

    In the early days of the 11R, several people argued that this was nothing new and that the Radial Dragster already tackled the variable impedance trick. True - but, to my knowledge the Dragster did not dynamically change its values based on signal change arrangement or based on stored preset.

    From where I stand, True-Z may not be new, or voodoo, but the implementation of it is novel in the way Avid captured the feature. I would be surprised if they didn't try to patent the method for dynamically adjusting the input impedance based on a virtual signal chain.

    It may have not been patentable based on prior art found in Fender's Cyber Deluxe - an amp that swapped real resistors and capacitors around a single pre-amp tube in an attempt to mimic different amp configurations and offered those topologies as storeable presets.

    I'm not aware of any similar implementations prior to these, but I'd be interested in hearing about them.
     
  19. Gasp100

    Gasp100 Supporting Member

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    I agree with this above, but we can't read Cliff's mind. I assume he thought it was cool, figured he could do it and threw it into the AxeFX II. To be totally honest I did not use the feature much on the 11R and did only test it out on the AxeFX II. In both cases it did make a very, very slight difference -- not enough for me to get nuts over.
     
  20. cliffc8488

    cliffc8488 Member

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    Let me clear all this up:

    Some old stomp boxes, i.e. Univibe, fuzzes, etc. have a low input impedance. This low input impedance will load down a guitar's pickups and change the frequency response of the pickups. You cannot simulate the effect of pickup loading after signal acquisition since the pickup parameters are an unknown quantity.

    So if you want to exactly model one of these old stomp boxes you need to replicate the impedance loading. The 11R and the Axe-Fx II do this by switching in resistors and capacitors on the inputs that change the input impedance to match the device being modeled.

    I do not believe that input impedance affects feel in any way. This is simply impossible. I remember people saying they could feel the input "pushing back". Silly. It will, however, definitely affect the sound as the frequency response of the guitar will be altered. The resonant frequency of the pickups will shift downwards and the Q will be altered as well.

    Now... it is debatable whether this alteration in frequency is actually desirable. If you want to exactly duplicate the sound of a vintage effect then, yes, it is desirable. However, most, if not all, modern effects feature buffered inputs to prevent pickup loading. This is done because typically we don't want to load the pickups. When the pickup designer is designing a pickup he is assuming the pickup will not be loaded. He chooses the winding, magnets, etc. such that the pickups have a desired frequency response into a very high impedance (i.e. 1 Mohm or greater) load.

    Variable input impedance is a nice feature if you want accuracy but it's not that big of a deal and certainly doesn't make one device better than another. Personally I prefer the sound with it turned off.
     

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