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Difference between revisions of "Pitch block"
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* '''Virtual Capo'''
* '''Virtual Capo'''
* '''Dual Detune Delay'''
* '''Dual Detune Delay'''
==Chromatic : Dual / Quad==
==Chromatic : Dual / Quad==
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'''Quad Diatonic''' (4 voices). Previously: Quad Harmony
'''Quad Diatonic''' (4 voices). Previously: Quad Harmony
Revision as of 13:44, 31 May 2022
- 1 Available on which products
- 2 Channels or X/Y switching
- 3 Pitch types and effects
- 4 Position of the Pitch block on the grid
- 5 Pitch block in firmware Ares and later
- 6 Pitch shifting, CPU usage and latency
- 7 Factory presets
- 8 Learn mode
- 9 Note display
- 10 Parameters
- 11 Tips, tricks, info
Available on which products
- Axe-Fx III: 2 blocks
- FM9: 1 block
- FM3: 1 block
- Axe-Fx II: 2 blocks
- AX8: 1 block
- FX8: 1 block
Channels or X/Y switching
- Axe-Fx III and FM9 and FM3: 2 channels
- Axe-Fx II: X/Y
- AX8: X/Y
- FX8: X/Y
Pitch types and effects
Pitch types in the Axe-Fx III, FM9 and FM3:
- Dual Detune
- Quad Detune
- Dual Chromatic
- Quad Chromatic
- Dual Diatonic
- Quad Diatonic
- Classic Whammy
- Octave Divider
- Crystal Echoes
- Advanced Whammy
- Custom Shifter
- Quad Chromatic Delay
- Quad Diatonic Delay
- Virtual Capo
- Dual Detune Delay
Chromatic : Dual / Quad
Firmware Ares and later replaces the Fixed Harmony mode with:
Dual Chromatic (2 voices). Previously: Dual Shift
Quad Chromatic (4 voices). Previously: Quad Shift
Note that Quad Chromatic doesn’t have Feedback parameters.
Diatonic: Dual / Quad
Firmware Ares and later replaces the Intelligent Harmony mode with:
Dual Diatonic (2 voices). Previously: Dual Harmony
Quad Diatonic (4 voices). Previously: Quad Harmony
The processors offer several ways to create an Octaver effect (octave down):
- Pitch block: fixed shifted pitch, 1 octave down
- Pitch block: Octave Divider type
- Ring Modulator block in Tracking mode.
The results sound different. The Octave Divider sounds slightly like a synth, where a fixed harmony adds identical lower or higher harmony notes at fixed intervals. The Ring Modulator sounds vintage.
Pitch detuning is a great alternative to a chorus, without the "swirl" associated with 80's chorus tone. Use it in stereo for a very wide effect. Van Halen's sound on the Balance album is well-known example of stereo pitch detuning.
- Detune up and down the same amount, between +/-5 and +/-10
- Delay the voices for more width (i.e. 7 ms)
- Set mix at 25% or lower
- Put the block after the Amp block but before the stereo Cab block
- Pan the voices for a wide stereo effect
Try running a Chorus block before or after the Pitch block for a more intense effect.
Beware of Phase cancellation when running mono.
Firmware Ares and later has two Detune modes:
Dual Detune (2 voices)
Quad Detune (4 voices)
The Multitap Delay block in firmware Ares and later is also capable of multi-voice detuning.
Firmware 19.03 for the Axe-Fx III added a Dual Detune Delay type. This type is comprised of two detuners with delay up to 2.0 seconds. Each detuner can feed back to itself and/or the other detuner.
Use the Classic Whammy pitch type, and attach a pedal to the Control parameter.
Use Auto-Engage in the modifier menu to automatically engage the Pitch block.
You can engage a Whammy on the fly without using Auto-Engage ("Golden Whammy", M@'s idea, ). It's demonstrated as part of the factory preset "JS410" (firmware Cygnus 16.00 and later).
Tip: increase the Scale parameter in the modifier menu to create some "flat" space at the top, so the octave arrives earlier and stays put.
Decrease the max frequency of the pitch-shifted voice to 5 kHz, or even much lower, to make it less "digital" and less thin.
(about the original Whammy pedal) "I would venture to guess that the pedal sample rate is low, like maybe 11 kHz. This limits the frequency response to 5K. Higher sampling rates mean more processing power which means more expensive DSP. These things were designed to be inexpensive." 
Or use this trick (by forum member Moke):
"Try adding a Filter block right after the Pitch/Whammy block. Use the 'Lowpass' type. Attach the same controller that you are using for the Whammy control to the 'Frequency' parameter in the Filter block. Use it to cut the increasing high-end as the pitch is raised. Set it up with a Min frequency of 20,000 Hz, and a Max of 1000 Hz. All other settings default. Setup both blocks to Engage at the same time." 
Drop-tuning and virtual capo
AX8, FX8, Axe-Fx II:
- Put a Pitch block in series at the start of the grid
- Set it to Fixed Harmony
- For a drop of two semitones set one voice to -2
- Set the other voice's Level to -80 to mute it
- Set Mix to 100%, Tracking to On, Pitch Track to Poly
You can also use the Advanced Whammy mode in the Pitch block. Sounds and works the same but a little easier to to configure.
If you can't stand the latency:
- lower Tracking, or
- try "Simeon's ADSR trick"
Axe-Fx III, FM9, FM3:
Use the Virtual Capo mode in the Pitch block (firmware Ares and later) for drop-tuning as well as virtual capo. Put the Pitch block in series at the start of the grid.
"This is a simple one-voice pitch shift that is intended for drop-tuning and virtual capo use and is easy to configure and use."
To maintain the state of the Virtual Capo (engaged or bypassed) throughout scenes changes, assign a Control Switch to the block's Bypass parameter.
To find examples of presets with droptuning, search the Factory presets page for "drop".
To simulate an automated "dive bomb" pitch effect:
- Create a preset with a Pitch block
- Set Pitch mode to Classic Whammy, Up|Dn 2 Oct., Tracking off, 100% mix
- Enter the Modifier menu of the Control parameter in the Pitch block. Set Source to one of the externals. Set Damping to 750, for starters
- Enter the Modifier menu of the Bypass parameter in the Pitch block. Set Source to the same external controller as above
On the foot controller:
- Program a switch to send the external controller's CC
- The switch can be latching or momentary, whatever works for you
To operate: select the preset. Press the switch (press and hold if it's a momentary switch) for the effect to kick in. Press again (or release) to stop, and bypass the Pitch block.
You can also use your expression pedal instead of a switch. Use the corresponding external controller.
Instead of a switch, you can also use Auto-Engage.
You can adjust the length of the dive through the Damping parameter, use another Whammy mode, make it even more dramatic by adding a Flanger, etc.
Bakerman's tip to dive deeper than two octaves: select "Whole Tone" for Harmony. In the modifier menu set Minimum to 1, and Maximum to the desired drop (try -19). Increase Glide to get rid of the steps.
Stepped Auto Tune effect
- Select a Diatonic (Harmony) mode
- Set Mix to 100%
- Use a single harmony (mute the other(s)) and set it to "1" (unisono)
- Set Pitch Quantize to "Stepped"
- Use a low Glide Time value
Smoothen the Crystal Echoes effect by fading in the effect: assign the Envelope Controller to the Input Gain parameter.
Simulate a 12-string guitar
To simulate a 12-string guitar:
- Put the Pitch block between the Amp and Cab blocks
- Select the Fixed Harmony or Dual Chromatic type, or Virtual Capo
- Shift one or both voices to +12
- Increase Detune a little to add realism
- Set Mix between 20% and 30%
This isn't a true simulation, because on a real 12-string the bottom four strings are doubled a full octave higher, while the two highest strings are doubled (same octave).
An alternative approach would be using the Crossover block (Axe-Fx and FM9 only) or Pitch Follower.
The "Custom" Pitch type uses the values on the Custom Scales page in the Global menu.
It's important to understand how Custom Scales work. You must (temporarily) transpose the part to the key of A, and program the custom scales based on that key. After having done that, enter the correct key for the part in the parameter field.
Position of the Pitch block on the grid
If you want to add harmonies to your main signal, put the Pitch block between the Amp and Cab block for best results. As demonstrated in the factory preset "Lonely Heart". Alternatively (Axe-Fx only), split the signal into two rows before the Amp block, and put Pitch and a 2nd Amp block in the other row.
If you want to shift the entire amp signal (100% wet), e.g. to simulate a down-tuned guitar or capo, put Pitch before the Amp block.
"When going direct, pitch shifting often sounds best when placed BEFORE the Cab block. The factory presets may have the block doing the shifting (pitch or multidelay) after the Cab block. Try moving the pitch before the Cab for smoother results."
(Bakerman) "The pitch block basically shifts the entire cab freq. response up/down if it's after cab. A slight detune might sound about the same either way but with a half step, whole step, etc. the difference becomes more apparent."
(M@) "I'll use the harmonizer in front of the amp too -- but it needs to be 100% wet, single voice, and a dedicated amp. The less you shift distortion, the more natural it sounds." 
Pitch block in firmware Ares and later
Firmware 12.08 for the Axe-Fx III:
"Improved Intelligent Pitch Shifter algorithm. This applies to all Pitch types except Dual and Quad Detune or when the Tracking Mode is set to OFF. The pitch detection algorithms have also been improved. The Tracking Mode parameter has been renamed “Pitch Tracking” and is selectable between OFF, FAST and SMOOTH."
Pitch detection in the FM3 and FM9 has also been improved in current firmware.
(FM3) "The pitch block was updated in 5.xx. The pitch detector still isn't up to Axe-Fx III standards but it still works well. There simply isn't enough horsepower to run the Axe-Fx III pitch detector without sacrificing the number of simultaneous effects. 
Pitch shifting, CPU usage and latency
The Pitch block in the AX8 and FX8 is very sensitive to CPU usage, even far before the limit is reached. When using the Whammy mode for example, try to keep CPU usage below 60%. Some Pitch types in the AX8 and FX8 provide an Economy mode, which offers comparable audio performance but uses less CPU.
"Once the CPU usage crosses a certain threshold (which could happen if you are streaming audio) the pitch detection will slow down as the global pitch detector necessarily has a lower priority than the primary audio processing. If you change the Pitch Source to Local then the local pitch detector runs at the same priority as the audio." 
"Pitch detection has a lower priority than audio processing. If CPU usage is very high the pitch detectors won't run often". 
"The better the pitch shifting, the more the latency. It's a perceptual process. There is no mathematically perfect way to do it. Also, when you pitch shift, the sound coming from the speakers doesn't reinforce the strings (since it's at a different frequency) so you don't get sustain and feedback harmonics." 
"A low E has a period of about 12 ms. This means you have to buffer at least 12 ms to shift anything from low E and up. To also work with bass then low E is 24 ms."
"Pitch shifting necessarily adds latency. Pitch shifting is a perceptual process. It requires a reasonable amount of history to work. This adds latency. Typically 20ms and up. Some people are more tolerant to latency than others. I've compared the latency of our algorithm to other products and ours is equal or better but there is latency in any pitch shifter. All pitch shifters have tradeoffs. The lower the latency the more prone they are to tremolo artifacts, double transients and other issues. Solving those issues increases the latency and the computational burden. The only pitch shifting algorithm that has negligible latency is the "Rollers" algorithm but that requires insane amounts of CPU and the samples I've heard aren't impressive. It also has its share of issues (smearing, chirping)." 
"Pitch detection is a difficult problem. Polyphonic pitch detection is orders of magnitude more difficult. Real-time pitch detection is much more difficult than non-real-time. Polyphonic real-time pitch detection is nearly impossible." 
"To do polyphonic pitch shifting well you need around 50 ms of history. So nominally the delay will be half that, 25 ms." 
"You can do really good pitch shifting if you don't care about real time. The FFT phase vocoder is capable of excellent results but the latency is far too great for real time use. Once you get into real time constraints things become MUCH more difficult. So we have to do it in the time domain which is much less forgiving." 
"All real time pitch shifters display some degree of tremolo on certain chords. Ours is better than most. The worse your guitar's intonation the more tremolo." 
"The way real time pitch shifting works is the input is split up into "granules" which are little snippets of audio. Those granules are played back either faster or slower to shift the pitch up or down respectively. An analog analogy is a tape recorder with rotating heads. As these heads rotate they eventually leave the tape and the other head enters. As this happens the heads crossfade. If the audio isn't perfectly correlated during the crossfade the amplitude will vary. This causes the tremolo. The pitch detector's job is to find the pitch so that the audio is correlated during the crossfade. If your intonation is off the correlation will be weak during the crossfade causing more tremolo. Pitch shifting isn't perfect, especially in real time. It's a perceptual process. It's not like solving equations or modeling amplifiers. It's about fooling the human auditory system. So any pitch shifter is going to have some level of artifacts. In my comparisons with other products I feel these latest algorithms are among the best. I compared my Eventide Eclipse, Kemper and Digitech Whammy DT. The Eclipse is the weakest of the bunch. It tracks very slow which causes artifacts when you change the note you are playing. It does, however, track complex chords well. For example, if you are playing a harmony the harmony will change from, say, a major 3rd to a minor 3rd depending upon the note you are playing. The slow tracking causes the shifter to sound the wrong interval for a bit until the tracking catches up. So you get a pitch "blip" when you change notes. It has a pleasant characteristic sound which has an almost bell-like quality that makes it useful for certain special effects. The Kemper has pretty good shifting and tracks much faster than the Eclipse. It exhibits the most tremolo of all the devices tested (I know why this happens but I'm not about to spill the beans :) ) It struggles, however, with chords. If you play a D/F# (the classic pitch shifter stress test chord) it goes all wonky because it can't figure out the pitch. This is because it's pitch detector window is too short. It has a "smooth chords" mode which doubles the window length but then the latency becomes much greater and the tracking much slower. It also has a formant shifting feature but in my tests it's all but useless. It only works with single notes, adds a lot of latency and doesn't really sound convincing. The Whammy DT is an interesting device. It exhibits almost no tremolo effect regardless of the chord played. The Eclipse, Kemper and Axe-Fx all have similar sounding shifting. IOW they seem to be based around similar algorithms implemented to varying degrees of success. The Whammy has a fundamentally different sound. This is both good and bad. The lack of tremolo is good. However when playing even simple chords (i.e. an open E or A) there is an underlying grittiness and "inharmonicity" and the guitar sounds out of tune. It also exhibits a strange behavior during the pick attack. The Whammy glitches during the pick attack kind of "cuts out". For the Axe-Fx I'm using a wavelet approach to the pitch detector which results in a multi-resolution pitch detection. This means the pitch detection window is short when you want it short or long when you want it long. This results in extremely fast tracking. There's almost no audible "blip" when the harmony changes. It also tracks complex chords pretty well but it does sometimes struggle with locking onto the pitch and will alternate between the "best guess" when there isn't a clear answer. To be fair the other products do this too. So all the devices exhibit their idiosyncrasies and artifacts. The question becomes which artifacts are the least offensive. If I were to choose I would choose either the Whammy or the Axe-Fx. However the Whammy only supports chromatic shifting. It has a "Harmony" mode but it isn't diatonic harmony where you can set the key and scale/mode." 
The Pitch block is showcased in many factory presets. Search the Factory presets page for "pitch" or "crystals".
The Pitch block has a Learn function. Turn it on, play a note and hold it, and the device will set the key according to the note you played.
In firmware Ares and later, the Pitch block doesn't have be engaged to be able to use Learn.
Firmware Ares and later features a Downtune control in the Tuner menu, which allows for simplified tuning when tuning down one to four semitones. The Tuner display will display the “natural” name of the note, i.e. if tuning down one semitone an Eb will read E. This also applies to notes in the Pitch block.
The parameters are also explained in the Owner's Manual.
Tracking Mode: Poly or Mono
NOTE: parameter is not available anymore in firmware Ares 12.08 and later.
The Pitch Track setting impacts latency and the quality of tracking, depending on the input signal.
Poly — works best for shifting chords
Mono — works best for shifting single notes
"If you set the Tracking to Mono there will be less latency. For small shifts (up/down a few semitones) there is no discernible difference between mono and poly. Even for large shifts mono works well now whereas before it didn't track chords well." 
"To do polyphonic pitch shifting well you need around 50 ms of history. So nominally the delay will be half that, 25 ms. If you set the detector to Mono the latency will be less but it won't track chords, especially complex ones, as well due to lack of correlation in the history buffer." 
"Poly will track complex chords better as it increases the autocorrelation length. The granules can be larger though which can increase effective latency." 
Replaces the Tracking Mode parameter in firmware Ares 12.08 and later.
Values: OFF, FAST and SMOOTH.
Pitch blocks in the Axe-Fx 3, FM9 and FM3 have their own pitch detectors, separate from the internal Pitch controller.
Pitch detection has been further improved in the Axe-Fx III, FM9 and FM3, and the number of voices has been increased to 4.
"Make sure you set Pitch Tracking to smooth. Fast is intended for single notes." 
"Lowering the Tracking will reduce the latency but can lead to artifacts. 5.0 is a good compromise between latency and smoothness." 
Pitch source: Global or Local
This parameter determines which signal the Pitch block uses for tracking.
Axe-Fx II, AX8, FX8:
- Global (default) — the signal at the input of the grid (pitch controller) is used to track the pitch. This will usually suffice, unless there are specific demands or when the CPU load is high (see below)
- Local — the signal at the input of the Pitch block on the grid is used to track the pitch. Use this when you need accurate and fast pitch detection in high-CPU usage presets
Axe-Fx III, FM9, FM3:
The Pitch block uses its own pitch detector, separate from the Internal Controllers. Choose between "Block" (equivalent of "Local", see above) and "Input x".
This is placed before the Voice Level parameter. So when Feedback is turned up and Level is turned down, you'll still hear repeats.
Low Cut, High Cut
These parameters are present in every Pitch type. However, they are not operational in the Octave Divider.
"In an Eventide the high cut is always set very low, around 2K. 
"Don't set both voices the same or you can get phasing. There's no point in setting both voices the same." 
This parameter has been added in firmware Ares and later.
Just — ratios are defined by the harmonic overtone series
Equal (default) — sweeter harmony, especially when followed by distortion
For a demonstration of the difference between the two settings, try factory preset "Lazy Man's Arpeggio" and switch the parameter between the two settings.
Tips, tricks, info
The FM3 factory preset "Sustain Maniac" demonstrates how to achieve long sustained feedback.
This preset goes further, and simulates feedback based on the note played.
The Owner's Manual explains the different harmony scales.