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Variax Vs. Axe Fx Pitch Shift?


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#21 johnnyayyy

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Posted 25 August 2013 - 06:12 PM

Uhhh... So, is anyone using their Variax in a live setting switching between various tunings in a hard rock/metal setting? Are you satisfied with the tracking, palm muting, and other playing nuances? How big is the difference between the Variax and a rack full of differently tuned guitars?

Thanks guys, ,

R

 

 

Not 100% on topic and if you start a new thread asking this question you will get more responses, but... Palm muting on the models is not quite 100% tho I would say it is greatly improved over the old Variax, maybe 90-95% correct now - some things you will definitely still need the magnetic pickups to pull off effectively but there they are and easy to switch to any time you need them.

 

I recommend finding a JTV at a dealer near you and trying it out before you buy to see if it works for you, or if this is not possible you could always buy a JTV and return it within the 45 day period most online dealers allow.

 

Tracking is good on  the 6 string models, not perfect and a little slow w some noticeable latency on the 12 string models in my experience/opinion.


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#22 ozbadman

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Posted 25 August 2013 - 07:04 PM

Yes but it still has to have a sample of the pitch it's going to shift so there has to be some digital delay.

 

No, that's my point, it doesn't need a sample of the "pitch". It just needs to sample the amplitude at twice the highest frequency it wants to reproduce, e.g. 44.1KHz, then play it back at 44.1KHz - 6%, dropping every 17th sample. The delay is effectively 0.

 

The overtones and warbling is caused by the dropping of the samples, so you need to do some nice stuff for that, but changing the frequency by itself doesn't inherently require "sampling the pitch". It can be done without any knowledge whatsoever of what notes are being played.


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#23 clay-man

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Posted 25 August 2013 - 10:05 PM

No, that's my point, it doesn't need a sample of the "pitch". It just needs to sample the amplitude at twice the highest frequency it wants to reproduce, e.g. 44.1KHz, then play it back at 44.1KHz - 6%, dropping every 17th sample. The delay is effectively 0.

 

The overtones and warbling is caused by the dropping of the samples, so you need to do some nice stuff for that, but changing the frequency by itself doesn't inherently require "sampling the pitch". It can be done without any knowledge whatsoever of what notes are being played.

 

I know it doesn't need the pitch, but it still needs data and time to process everything correctly.

 

First half is the pitch shifter on 38 ms latency, second half is on 3.5 ms latency

it can't even track chords on 3.5 ms.

 


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#24 ozbadman

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Posted 25 August 2013 - 10:21 PM

I'm just trying to separate the two concepts. Charlie said you need a sample of the "pitch" so I was clarifying that.

 

To re-iterate,

 

1) you can pitch shift without determining the frequencies being played as described above. In fact, it's very easy, but doesn't necessarily sound very good.

 

2) to compensate for the artifacts that are created if you do the most basic pitch-shifting, which has essentially 0 latency, you need to introduce computing to try to determine how to minimize those artifacts. Even then, you're probably not looking at the freqeuncies of the notes being played. More like the general shape of the nearby samples to try to work out how to adjust for the dropped samples with minimal artifacts. Now, that data does include the shaping caused by the frequencies being generated, but you're not inherently looking at the frequencies themselves.


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#25 clay-man

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Posted 25 August 2013 - 11:07 PM

I'm just trying to separate the two concepts. Charlie said you need a sample of the "pitch" so I was clarifying that.

 

To re-iterate,

 

1) you can pitch shift without determining the frequencies being played as described above. In fact, it's very easy, but doesn't necessarily sound very good.

 

2) to compensate for the artifacts that are created if you do the most basic pitch-shifting, which has essentially 0 latency, you need to introduce computing to try to determine how to minimize those artifacts. Even then, you're probably not looking at the freqeuncies of the notes being played. More like the general shape of the nearby samples to try to work out how to adjust for the dropped samples with minimal artifacts. Now, that data does include the shaping caused by the frequencies being generated, but you're not inherently looking at the frequencies themselves.

 

It definitely does need some detail in order to minimize artifacts indeed. It's why polyphonic pitch shifting can get a bit warbly but still not sound like complete trash, because the more notes you have in the input, the more complicated it is to work with the wave.

 

Not only does having a pitch shifter assigned to each string allow you to tune each string individually, but it helps the Variax pitch shift with better results.

 

Either way, the latency is used as a fallback to have time to tailor the signal into a good quality pitch shift.

The best VST pitch shifter I've seen is called Pitchwheel, and that needs 46 ms to do high quality pitch shifting. It sounds remarkable.

Reaper's ReaPITCH also is high quality and has high latency.

 

The less latency, the less natural and professional the pitch shifting will sound.

 

For the Variax, you need a good balance between latency and quality. Fast enough to not ruin your guitar playing, but good enough quality for it to pass as capo/detuning substitute.

I say the Variax does a nice job.


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For a minute there, I lost myself.

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#26 Charlie_Watt

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Posted 26 August 2013 - 05:37 AM

Yes - the pitch shift is achieved by resampling but resampling requires digital filtering too.  I was not implying that there would be lots of latency in pitch shifting but there is some - and I doubt that anyone can really detect it.  More likely what folks notice is some artifacts if the filtering isn't done properly.  Today's processors are plenty fast to be able to do complex digital filtering without adding noticeable latency.


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#27 johnnyayyy

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Posted 27 August 2013 - 05:07 PM

I was not implying that there would be lots of latency in pitch shifting but there is some - and I doubt that anyone can really detect it.  More likely what folks notice is some artifacts if the filtering isn't done properly.

 

Really...? Have you played the 12 string acoustics in HD 2.0 alt tuned down 3 or 4 half steps? I would be surprised if anyone tried this and did not feel the notes coming out of their headphones waaaaaaayyyyyy after they are played. It feels like I am playing in slow motion, if playing without a timing reference I keep feeling myself slowing down waiting for the sound in my headphones to catch up to what my fingers are doing.... unless that is what you mean when you say " filtering artifacts" -  I always thought that time delay I am experiencing (around 17ms between the time I strike a note and it is played back by my JTV as shown in the ProTools screen caps above) ) was what everyone means when they say "latency". Am I misunderstanding what you are saying?


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#28 johnnyayyy

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Posted 27 August 2013 - 05:27 PM

Yes - the pitch shift is achieved by resampling but resampling requires digital filtering too.  I was not implying that there would be lots of latency in pitch shifting but there is some - and I doubt that anyone can really detect it.  More likely what folks notice is some artifacts if the filtering isn't done properly.  Today's processors are plenty fast to be able to do complex digital filtering without adding noticeable latency.

 

Also, I am not 100% sure that what is going on in the 12 string emulation is a simple pitch shift - glitches in the 2.0 software show the processing is behaving differently than a regular pitch shifter.

 

If you have not already, try this:

 

Physically tune your D string one step down to C. Select the Chime 2 Rickenbacker 12 string and play the string open a few times until you hear what sounds like a car crashing. Hear that hugely out of tune clash? The string is sounding a C but the JTV is generating a C the same as the string tuning with the simulated octave string sounding a C#.

 

Now slowly turn the D string tuner sharper and you will hear the lower not rise while the higher octave note stays the same UNTIL both notes are in tune, similar to what a "smart" harmonizer does when you play a note that is not in the scale you have set the harmonizer to follow.

 

Try it! Then please explain what is going on. According to Line 6 it is impossible for the JTV to generate an alt tuned note more than one octave above the note it is tracking, but this experiment says otherwise. According to Line 6 support the JTV is calibrated to operate with the guitar tuned to standard tuning only, and tuning the string to anything other than standard tuning is not supported.

 

Another L6 support person tells me that harmonics are confusing the alt tuning and the problem is possibly due to the guitar's setup (buzzing fret rattle or bad intonation), I thought this might be the case and had already checked the intonation and raised the action so sky-high at the nut that the string could not possible be hitting any of the frets when played open but this does nothing to reduce the amount of random pitch generation.

 

Explanation?

 

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#29 Charlie_Watt

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Posted 27 August 2013 - 05:53 PM

I played around just now with the 12 string models and standard tuning and I do not notice any latency when playing.  Maybe it's me.  One thing I did notice is a big improvement in the 12 strings when I added some damping above the nut.  Much cleaner sounding to me.  One thing to consider - a real 12 string has a little latency on the string pairs when strumming them.  Of course this would depend on the direction of the strumming.  Overall, I am very pleased with the 12 string sounds - much better than on my old 500 model.


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#30 johnnyayyy

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Posted 27 August 2013 - 06:25 PM

I played around just now with the 12 string models and standard tuning and I do not notice any latency when playing.


Me too, did not notice any latency in the 12 strings with standard tuning and measured only around 5ms. When switching to alt tunings I noticed a big latency and measured around 17ms, or an additional 12ms when compared to standard tuning.

Measurements were made picking single notes with a standard plectrum, no strumming involved.

And while the friction from the extra six strings on a real 12 string might slow down picking or strumming if strength and angle of attack were the same as on a 6 string, the notes would certainly not take longer to get to my ear just because there were 12 strings - this is what I am hearing on the 12s with alt tuning, the alt tuning is causing a longer delaybetween the time a note is struck and it reaching my ears.
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#31 ozbadman

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Posted 27 August 2013 - 09:09 PM

 the alt tuning is causing a longer delaybetween the time a note is struck and it reaching my ears.

 

So, move your ears. :)


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#32 johnnyayyy

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Posted 27 August 2013 - 09:57 PM

So, move your ears. :)

 

Hmmm, the signal path at the moment is JTV, Headphone amp, headphones, ears... so the ears should go before the headphones or before the preamp...?

 

JTV 1/4" out DI to ears? :lol: 


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#33 ozbadman

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Posted 27 August 2013 - 10:57 PM

JTV 1/4" out DI to ears? :lol:

 

      


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