Month: September 2014

Why does it say "Excess CPU Usage!"? Why is there a crackling noise too?

Like most computers, the Axe-Fx has a limited amount of CPU or processing power. CPU is used when blocks are added to presets. Different blocks use different amounts of CPU, and within the same block different “Types” or settings can also use different amounts. There are actually two TigerSHARC processors in the Axe-Fx II: one is dedicated to the Amp blocks, and the other handles all other blocks. A completely blank preset uses about 9% CPU – this accounts for the Display and a few other background processes. Adding a single Amp block raises the CPU only to about 12%. Compare this to a Reverb block which can raise the CPU to about 20%. The Axe-Fx II functions normally till about 90-92%. At that point, the CPU is being overloaded, having to process too many things at once. It’s usually best to try to not go above 90%. The Axe-Fx is programmed to prioritize audio at that point, so the display may seem to lag, preset changes may become slow, and there may also be crackle’s and pops in the audio signal. A warning will flash on the screen displaying “Excess CPU Usage! Reduce Load!” This means that somehow you must reduce the CPU usage in your preset. There are many ways to do this, but one of the easiest is to change Cab blocks from Stereo or Ultra...

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When do I have to "Update Amps Defaults" "Update Amps All Prsts" or "Reset the Amp Block"?

UPDATE 4-6-15: Firmware 18.06 has removed the “Update Amps All Prsts” (Update Amps in All Presets) function mentioned below. New Axe-Fx II firmware usually bring new features and improvements. It can also change the way Amps are modeled, therefore changing what the controls in the Amp block actually do. For example, in firmware A, the Amp block Bass knob set to 6 may sound “very bassy.” But firmware B might change how that knob works and what it controls, and therefore a value of 7.5 in firmware B may equate to what was a value of 6 in firmware A. The default settings for Advanced Parameters for different Amp types/models may also be changed with new firmware versions. In a hypothetical example, the default Negative Feedback setting for Amp type 59 Bassguy may be 4.50 in firmware A, but new research and improvements in modeling techniques might suggest that the default setting should instead be 5.20, therefore firmware B would set that default when an Amp is selected for the first time. Before moving on, it is important to note that generally speaking, if it sounds good to you, it doesn’t matter what the numbers, values, or settings are. Following the previous example, the old Negative Feedback setting was 4.50, but the new default is 5.20. If it sounds and feels good with the 4.50 setting, there is nothing “wrong,”...

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Where can I find details about the _____ feature in the Axe-Fx?

In addition to the User Manual and Release Notes (RTFRN), the Axe-Fx II Wiki is the best place for details, tips and tricks and features of the Axe-Fx II.  Much of the information is compiled from the Fractal Audio forum, with many contributions from Cliff Chase himself, creator of the Axe-Fx. Forum user Yek created and maintains the Wiki, with help from M@ and SC09. A very helpful section is Yek’s How To’s available here: Another helpful page is this post on the Fractal Audio...

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How do I send my Axe signal to a PA system and to a Guitar Amp and Cab at the same time?

Many people like to have their Axe-Fx tone and effects play through their favorite guitar amp and cab on stage for the “amp in the room” sound as opposed to the “studio recorded” sound that the full-range Axe-Fx signal can produce through a full-range monitor speaker. Additionally, instead of mic’ing their cab as they would with a traditional amp/cab setup, they want to send the full-range Axe-Fx signal to the front-of-house (FOH) mixer for the audience to hear. This can be done by having 2 sets of outputs: one with a cabinet simulation (Cab block) and another without a cabinet simulation (going to the on-stage amp and cab). To do this, you’ll have to place the FX Loop block in all of your presets and use Output 2 to send the non-cab-sim’d signal to your amp and cab. Output 1 will be used for the full-range signal with the cab sim. The Basics First create your full-range setup. This should have a Cab block in the layout. Most presets are created with the Cab block immediately following the Amp block. This is logical, as there is usually nothing in between a physical amp and cab. However, in the Axe-Fx, the Cab block doesn’t need to be placed directly after the Amp block. You can have Shunts (the blank connected spaces) or other blocks like Delay or Reverb placed in...

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How do I send my Axe signal to FOH and on-stage full-range monitors?

The Axe-Fx II has a bunch of outputs that we can use to send to various places, like the PA system, a personal monitor, or any other speaker setup.  There are different ways to do this, and this article focuses on Full-Range systems like PA speakers, Studio monitors or full PA systems (as opposed to a guitar amp head and guitar cab). Out 1 XLR & 1/4″ The simplest way to get the Full Range Axe-Fx signal to the Front-of-House (FOH) mixer and to on-stage full-range monitors is to use both XLR and 1/4″ outputs from Output 1.  Most sound engineers are expecting a 1/4″ jack to go to a DI box, so you can give FOH the 1/4″ outputs and you can use the XLR outputs direct to your powered speakers or power amp.  However you can also give FOH the XLR and use the 1/4″ outputs for your powered speakers if you’d like. With this method, the Output 1 volume knob on the front panel controls both the FOH feed and the on-stage monitors. So using this knob to turn your monitors up when the band “suddenly gets louder after the first song” will send more signal to FOH and possibly clip the FOH mixer, making you sound bad. Of course, you can control your stage volume from controls on your powered speaker or power amp, but sometimes these...

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