Reverb block

Reverb: in the owner's manual

• Axe-Fx II: 5.2 Cabinet [CAB]
• Axe-Fx II: 5.27 Reverb [REV]
• Axe-Fx II: 16.14 Setting Up Spillover

Reverb: Types

• Cliff: "There are seven base algorithms." source
  • SPRING
  • ROOM
  • HALL
  • CHAMBER
  • PLATE
  • STUDIO
  • TUNNEL

Reverb: position

• Cliff: "If there isn't distortion or modulation in the delay/reverb then the order is irrelevant since they are then Linear Time Invariant (or shift invariant in digital parlance). If there is a small amount of distortion or modulation then the order is probably still irrelevant. If there is a lot of distortion or modulation then the order may make a difference. However, typically the biggest difference, as noted above, is series vs. parallel since h1(t)*h2(t) is not the same as h1(t)+h2(t). If LTI h1*h2 = h2*h1. It may seem counter-intuitive that the order doesn't matter but try it and you'll be surprised." source
• Cliff: "Placing reverb after the Cab is the recommended routing. The reverb is stereo. The Cab block may be mono so you would lose the stereo field. Both blocks are linear so there is no advantage to placing reverb before the Cab." source

Reverb: tutorials

• Scott Peterson's tutorial

Reverb: spillover when switching presets

• Spillover of reverb and delay

Reverb: ducking

• Axe-Fx II firmware 16.02: "Added ducking to Reverb block. The ducking works analogously to the ducking in the Delay block."

Reverb: global adjustment

• The Rev Mix parameter in the Axe-Fx II: Global menu lets you boost or cut the Reverb Mix level across all presets at once. Note that this may not work well with reverb blocks in parallel rows which have Mix at 100%.

Reverb: maintaining unity gain

• When using Mix to control the volume level of the Reverb, the volume level of the dry signal is affected also. In other words, when increasing Reverb with Mix, the dry signal's level decreases. To deal with this: turn up Mix to 50% and set Level to +6dB and use Input Gain to set the desired amount of Reverb. Or put the Reverb in a parallel row, see Effects: series or parallel routing.

Reverb: simulating room ambience

• The CAB block has dedicated controls for adding room ambience to the sound.

Reverb: improvements in firmware 16.03, including Hold

• There are now two “Quality” options in the Reverb block: Normal and High. Normal quality CPU usage is similar to previous firmwares whilst still providing improved sound quality. High quality uses significantly more CPU but provides world-class reverberation algorithms.
• There are several new parameters associated with the new algorithms:
  • Early Diffusion: This sets the amount of diffusion in the early reflections. Higher values result in fuzzier and less distinct echoes. Lower values result in sharp, distinct reflections.
  • Early Diff Time: This scales the delay time of the early reflections diffusers. Adjust this control to suit the size and character of the simulated environment.
  • Early Decay: This parameter controls the decay rate of the early reflections. Higher values yield faster decay.
• The Tail Delay parameter has been removed as it is not compatible with the new algorithms. The reverb tail is now automatically set to the appropriate delay. In High Quality reverb mode an additional parameter is available: Late Input Mix. This parameter controls the mix between the (possibly diffused) input and the early reflections data input to the late reverb algorithm. Thus this parameter mixes the output of the diffuser and the early reflections prior to inputting that data to the late reverb generator. With the Late Input Mix at 0% the High Quality mode is identical to the Normal Quality mode. Values greater than 0% mix early reflections data into the late reverb using a proprietary decorrelation technique which eliminates any metallic qualities associated with the typical diffuser techniques used in other products.
• Several new types have been added.
• Increased maximum Reverb Time to 100 seconds and added a Hold function. When Hold is activated the wet input to the block is muted and the Time is set to infinity. This can be used to achieve pad sounds and drone notes/chords.
  • Cliff: "It requires a lot of calculations to change the Reverb time which is what hold does (it increases it to a couple hours or something). If CPU use is high the calculations won't finish during one block which results in a click." source
• Reverb hold tutorial by Cooper Carter for G66

Reverb: more information and tips

• Cliff: "David Griesinger probably knows more about reverb than everyone else combined. He's the father of the Lexicon reverbs. According to him, and I have no reason to doubt him, real reverb (i.e. reverb from a real space) is actually inferior to synthetic reverb. This is due to human perception. Real reverb (and by extension convolution reverb) actually reduces intelligibility and clarity due to the particular nature of the decay, the decay being exponential. Synthetic reverb allows one to craft the decay curve thereby rendering improved clarity. If the decay curve is flat for a period and then exponential it doesn't clutter the desired program material. The new reverb algorithms in the Axe-Fx are based on his theories." Source
• FX8 and Axe-Fx II Effects threads: Reverbs (REV)
• Wikipedia