Bender - nasty artefacts, warbling

[JerryJK]

This is really nasty.  

I'm playing chords, 2 semitones down, 100% mix.

It behaves as though Firehawk (FX, v 1.20) is trying to "track" the notes played, like the intelligent bender does but that is completely unnecessary.  It should be trivial in such a powerful processor to simply pitch shift the whole signal.  I suspect there is a mistake in the program.  I think there is also some latency, which supports the idea that it is trying to track before making a sound.  I have switched off all other effects (except amp/cab) but it still happens.  It seems to get worse as the level dies away, again suggesting that it tries to track.

 

Line6 - please fix.

 

[ADBrown]

The bender effect really shines on monophonic stuff. As soon as you add more notes or try chords it can start misbehaving. 

[JerryJK]

Yes indeed, in mono it's fine but an 'unintelligent' shift should work with chords.

[FlyingSquirrel]

Even the original Wammy pedal had these same artifacts.

[phil_m]

Yes indeed, in mono it's fine but an 'unintelligent' shift should work with chords.

 

Well, it's not a polyphonic effect. None of the Line 6 pitch effects are at the current time. Some people have had some success with them for tuning down a 1/2 step, but that's kind of it. You get artifacts and tracking weirdness with larger intervals and chords.

[JerryJK]

It doesn't need to be 'polyphonic', it's a single audio stream, which needs a single mathematical process to alter the frequency of the whole signal.  It only needs to be a polyphonic process if you want to alter different concurrent notes by differing amounts.

Pitch shift (without changing tempo) works beautifully on the music collection on my iPad, android and PC devices.  It's the same requirement.

I strongly suspect they've used the Intelligent Bender as a basis for programming this effect, unnecessarily and in error.

Please, please ask the tech guys to consider this.

[phil_m]

It doesn't need to be 'polyphonic', it's a single audio stream, which needs a single mathematical process to alter the frequency of the whole signal.  It only needs to be a polyphonic process if you want to alter different concurrent notes by differing amounts.

Pitch shift (without changing tempo) works beautifully on the music collection on my iPad, android and PC devices.  It's the same requirement.

I strongly suspect they've used the Intelligent Bender as a basis for programming this effect, unnecessarily and in error.

Please, please ask the tech guys to consider this.

 

I don't think it's as simple as that... I'm not a DSP engineer, so I don't know all that details. But I imagine if it were completely simple, it would be done more often. None of the major multi-effects manufacturers do polyphonic pitch shifting in this price range as far as I know. I imagine part of it is that with the apps you mention, latency isn't a consideration. For real-time effects processing, it's critical.

[JerryJK]

Please please, it's not polyphonic.  It's just like on my iPad, android and pc except those are 2-channel stereo, Firehawk is 1-channel mono at many points in the signal path.

 

There are many pitch shift apps on the market for various devices, most of which work very well.
Check out Pitch Shift / Equalizer for iPad which changes key for the whole band and vocals of any track you play through it.
Also BandHelper in practice mode has a similar pitch shifter with optional slow-down mode for learning any track you play through it and works well on my quite feeble tablet.  BandHelper is available for both iPad and Android.

On PC, Audacity is the first that springs to mind.

 

There are many more on all 3 platforms.  Some are free, though those are generally less good quality.  They are not polyphonic and work on the whole audio stream.  None produce artefacts like those from Bender.

 

I do know a bit about this as I have a tech background and my company uses DSPs in radio equipment.

 

Please speak to the guys in the back room and feel free to quote me.

[silverhead]

Why not contact Line 6 directly via support ticket? Or post the suggestion on ideascale? Sounds like you can make your case better yourself than asking someone else to do it for you.

[phil_m]

Please please, it's not polyphonic.  It's just like on my iPad, android and pc except those are 2-channel stereo, Firehawk is 1-channel mono at many points in the signal path.

 

There are many pitch shift apps on the market for various devices, most of which work very well.

Check out Pitch Shift / Equalizer for iPad which changes key for the whole band and vocals of any track you play through it.

Also BandHelper in practice mode has a similar pitch shifter with optional slow-down mode for learning any track you play through it and works well on my quite feeble tablet.  BandHelper is available for both iPad and Android.

On PC, Audacity is the first that springs to mind.

 

There are many more on all 3 platforms.  Some are free, though those are generally less good quality.  They are not polyphonic and work on the whole audio stream.  None produce artefacts like those from Bender.

 

I do know a bit about this as I have a tech background and my company uses DSPs in radio equipment.

 

Please speak to the guys in the back room and feel free to quote me.

 

I'm not a Line 6 employee... Although I do know many of the guys in their "back room". :D

 

I don't think what's going on with the apps is equivalent to the real-time processing for these types of effects. The Helix doesn't do this sort of polyphonic (and I'm saying it's polyphonic simply because chords are polyphonic) shifting either. It was only in 2014 when the Digitech Whammy could do it. It's not simply a matter of shifting the original signal. It's having the final product sound and feel right. Like I said, I imagine that latency of some of these apps could be quite high. It's just that for audio playback it doesn't matter. You don't notice it because you aren't hearing the original signal. With real-time effects you are.

[JerryJK]

Variax manages to do it 6 times concurrently (that's probably what you'd call polyphonic as it's presumably done in one dsp).

 

Also, all that warbling is fairly critical.  I'd take a bit of latency instead of that.

[phil_m]

Variax manages to do it 6 times concurrently (that's probably what you'd call polyphonic as it's presumably done in one dsp).

 

Also, all that warbling is fairly critical.  I'd take a bit of latency instead of that.

 

Each string is processed individually on the Variax, but, yes, that's true polyphonic shifting there.

[JerryJK]

I think I've figured it out.  Variax can do it 6 times at once because it's not a real, complex signal with character that must be maintained.  That hex (polyphonic) signal is mostly about base frequency, amplitude and some overtones.  All the character is added later, so the maths to lower the frequency and the re-stitching of the waveforms to fit the timeframe is not as difficult as in the real audio world.

That said, I do have a Vox pedal which does it a little better than Firehawk, at least for the song I'm playing at it but with a little more latency.

You are quite right that we don't know - and it doesn't matter - how long it takes the ipad etc to get to work.  Though it does do it in real time, it could well take too many mS to get going.

I would still take some latency for a "Chord Bender" (you could call it polyphonic, though we know it isn't) if the guys could be persuaded.

Thanks for the voyage of discovery, though I'm still suspicious that the 'warbling' sounds like attempted tracking. Maybe it's failed attempts at re-stitching the wave.

[JamieCrain]

The warbling gets worse the smaller the interval between concurrent notes. Makes it unusable IMO.

 

I got around this problem by getting a EHX Pitch Fork off Amazon for a bit over $100. I run my mag pups through that and into the FH, and my piezo line through the FH FX return.

[JerryJK]

My old (from the 90's) Roland GP-100 'HR' ('Harmonist' - in mode 2) effect does it much better for chords, and latency wasn't a problem.  I'm not even sure that it's more than the FH's Bender's latency, though I was at a gig and in a hurry to get something usable.  It certainly sounded better.  I am considering a Variax, which will make the problem go away.  Shame though - it can be done better.  You would expect better with 15+ years of newer technology.

That said, FH is great in many ways.