# Creating a cross-fade instrument in Kontakt 2 that does not phase



## Moonchilde (Feb 21, 2007)

http://www.garritan.com/stradivari.html

Alex brought this up over in another portion of the forum, but I thought I'd bring it up here too because I've always been curious about this. A Sonic Morph between velocity layers has to be done via scripting, correct? Has anyone thought about attempting this or have any idea how this is done? I notice it is mentioned to be a convoluted hybrid instrument, perhaps something is being done there, too?


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## Fernando Warez (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

He! He! I was just wondering about that! :wink:


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## kotori (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

_"Garritan Stradivari does a 'sonic morph' instead of a cross fade"_
No, it does a sonic morph in order to be able to do a cross fade. I think _morphing_ is primarily a marketing term. _Harmonic alignment_, although a somewhat less cool term, seem to me to be a better description of what is shown on that page - a very clever audio preprocessing technique to make crossfading without phase issues possible.


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## Ned Bouhalassa (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

Audio _preprocessing_? Do tell...

Oh, wait, I think I might guess it: the harmonic content of two samples of the same note are analysed and aligned using FFT analysis?


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## kotori (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



Ned Bouhalassa @ Wed Feb 21 said:


> Audio _preprocessing_? Do tell...


I don't know more than what can be read out of the images at the page linked to above and the fact that it can't use more realtime processing features than what's available in K2.


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## Ned Bouhalassa (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

If I'm right, than maybe that should be on the wishlist of new features for Redmatica's Keymap: harmonic alignment! :shock: 8)


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## Hans Adamson (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

I guess that would be:

"Sonic Morphing" = "Harmonic Alignment" = In Tune - and starting in phase... ~o)


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## kotori (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

I think it's patented though.


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## Hans Adamson (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



kotori @ Wed Feb 21 said:


> I think it's patented though.


Why do you think so? It would be very easy to check if it is.


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## Hans Adamson (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

It is not patented in the US. Also, Garrittan's website says "patent pending", which means it has possibly been applied for a patent, although there is no legal protection for anything "patent pending" - it's just an information notice. /\~O


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## José Herring (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

hmmmm,

What if you phased a aligned all samples, normalized each one, slightly overlapped the layers like traditional crossfading and simulated dynamics with a script that modulated DC offset and a highpass filter? Do you think that would work?

The problem being and I think I hear this in the Strad and the Gorf. Cello is that slightly overlapping the layers would cause cancellation thus creating a slightly thin tin like sound. Which both the instruments suffer from now and again. 

http://en.wikipedia.org/wiki/DC_offset

Jose


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## Hans Adamson (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



josejherring @ Wed Feb 21 said:


> hmmmm,
> 
> What if you phased a aligned all samples, normalized each one, slightly overlapped the layers like traditional crossfading and simulated dynamics with a script that modulated DC offset and a highpass filter to simulate dynamics? Do you think that would work?
> 
> ...


I think you just described "Sonic Morphing" - except normalizing would not be necessary, because you are cross-fading the volumes (amplitudes). The only addition that I can possibly think could be in the concept would be if there for some reason were a discrepancy in the harmonics while the fundamental is "aligned" (in tune). Then you would need to "align" (tune) the harmonics individually. I don't think that is the case though. But the "thin" sound you are describing could be an example of this...the real world doeas not behave like a mathematical formulae unfortunately, and physical characteristics of an instrument's strings etc will affect the harmonics.

DC Offset is when the zero crossing of a wave form occurs somewhere else than at zero...like the wave form was pushed up, or down a bit from the x-y grid. The zero crossing is not happening at the nominal gain. Easy to fix.


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## José Herring (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

I see what you mean.

Do you think that if the fundamental was perfectly in tune that the harmonics would also be in tune given that the same player was used and I assume the same strings in the same room?

The reason why I say normalize the sample is because the sample would have to be the same amplitude in order to phase align properly. At least numbers wise if the sample was normalized to the same db you could align them exactly. Though you are right in the diagram shown it doesn't look like the samples were all normalized to the same db level.

I don't think the processes can be patented. The name "sonic morphing" and any special script or software used can certainly be protected but if some clever scripter where to develop a whole new script from scratch I don't think that anybody could do anything about that. Also, what judge in the world is really going to know what the hell we're doing anyway. :lol:


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## Moonchilde (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

Jose, what you're describing would be very easy to do. Just stretch the sample zone velocity values to cover the beginning of the next, and use Kotori's cross fade script. 

Example: MP's highest velocity value is 67, MF's lowest is 64. Load up Nil's DXF equal power script, set layer 1's highest value to 67, and proceed to crossfade as usual. I do not know what type of effect this would give, it is possible that it would sound much worse if the wavs just aren't aligned and tuned properly.


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## Ned Bouhalassa (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



josejherring @ 21/2/2007 said:


> ... if some clever scripter where to develop a whole new script from scratch I don't think that anybody could do anything about that. Also, what judge in the world is really going to know what the hell we're doing anyway. :lol:



Huh... don't forget that Gary's a lawyer! >8o


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## Hans Adamson (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



josejherring @ Wed Feb 21 said:


> I see what you mean.
> 
> Do you think that if the fundamental was perfectly in tune that the harmonics would also be in tune given that the same player was used and I assume the same strings in the same room?


Well you would think so, but the actual exact frequency of harmonics is dependent on physical attributes of our imperfect world, so you would have to test and see if it would work with your recordings.



josejherring @ Wed Feb 21 said:


> The reason why I say normalize the sample is because the sample would have to be the same amplitude in order to phase align properly.


There is no need for the same amplitude to achieve phase alignment.



josejherring @ Wed Feb 21 said:


> I don't think the processes can be patented. The name "sonic morphing" and any special script or software used can certainly by protected but if some clever scripter where to develop a whole new script from scratch I don't think that anybody could do anything about that. Also, what judge in the world is really going to know what the hell we're doing anyway. :lol:


Even if a patent is granted, it is up to the court ultimately, to decide if the patent was a unique idea, or if it was something evident. Patents are challenged all the time. But in this case there is no patent.


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## José Herring (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

Seems good. The only stop would be to correctly tune all the dynamic layers. I wonder if anybody would be willing to experiment with the Westgate freebee trumpet samples? Could be interesting especially with an automatic key switching script and SIPS. Just a thought. :wink: 

Jose


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## Hans Adamson (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



Ned Bouhalassa @ Wed Feb 21 said:


> josejherring @ 21/2/2007 said:
> 
> 
> > ... if some clever scripter where to develop a whole new script from scratch I don't think that anybody could do anything about that. Also, what judge in the world is really going to know what the hell we're doing anyway. :lol:
> ...


From the information I have, the extent of his lawyer expertise stems from being a former real estate lawyer. Very different from this area.


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## Moonchilde (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

Hans, how do you do phase alignment? I don't know anything when it comes to phasing, other than hearing it as a synth effect.


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## Hans Adamson (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



Moonchilde @ Wed Feb 21 said:


> Hans, how do you do phase alignment? I don't know anything when it comes to phasing, other than hearing it as a synth effect.


Phase alignment means that two wave forms have their maximums, minimums and zero crossings happen at the same time. They are perfectly in tune. To stay aligned they have to either 1. Have a frequency without any fluctuations. or 2. Have identical fluctuations. If they drift apart, there will be a thinning of the sound, or an in-and-out phasing effect.

Repeated use of Antares AutoTune can give frequencies without fluctuations. It also has a risk of giving audible artifacts. Maybe Melodyne is better. I haven't tried it. ~o)


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## Moonchilde (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

Both are expensive and wouldn't be of any use to EWQLSO anyway... most cross fades are ok, but there are many times when the cross fade is very noticeable because the samples will not be in tune with each other.


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## Hans Adamson (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

If there would be a discrepancy in alignment of harmonics while the fundamentals are aligned you can split the wavs up in separate files depending on frequency range. You could then possibly align each harmonic, or group of harmonics separately. Finally re-assemble the source material. No special scripting would be needed to make this work as it is done on sample level.


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## Moonchilde (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

Anyway to check that stuff in Audacity or Cubase?


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## Hans Adamson (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

Don't know about those programs. It would be possible in Samplitude, or Red Roaster (Samplitude Master). Probably in many other sound-editing software as well.


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## Nick Batzdorf (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

How can you patent tuning two recordings and aligning their phase?


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## Hans Adamson (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



Nick Batzdorf @ Wed Feb 21 said:


> How can you patent tuning two recordings and aligning their phase?


You can apply for a patent for anything. There is no limitation or qualification for what to include in a patent application as regards to the originality of the concept. The originality will be determined by the patent office, and ultimately by the courts.


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## tfishbein82 (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



Nick Batzdorf @ Wed Feb 21 said:


> How can you patent tuning two recordings and aligning their phase?


That's like saying 'how can you patent combining two chemicals and putting them in a capsule.'

The point of patents is to protect processes, so that people will spend the time and money to create those processes.

Garritan's team spent several years developing this technique, just as a drug manufacturer would spend years developing a new drug.


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## Moonchilde (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

Patent Pending, from what I've seen, is most often a marketing term to make the potential buyer think they're getting something special they can't get elsewhere. It could be true too, that there really is a patent pending, but people just feel more secure with something like that on their product.


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## Hans Adamson (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



tfishbein82 @ Wed Feb 21 said:


> Nick Batzdorf @ Wed Feb 21 said:
> 
> 
> > How can you patent tuning two recordings and aligning their phase?
> ...


However, the amount of time you spent developing is irrelevant in the decision by the Patent Office to whether or not a patent will be issued.


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## Giorgio Tommasini (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

Dear friends,

I read this thread with great curiosity. My invention seems to raise some interest after many years, and I’m very happy to find some good old friends here. Hans was actually one of the first who encouraged my research, after listening to some examples of harmonic alignment on a confidential basis, as of August 2001. Of his appreciation I’m still very grateful.

I feel that some clarification may be in order. Nils nicely summarized the whole matter: 

“I think morphing is primarily a marketing term. Harmonic alignment, although a somewhat less cool term, seem to me to be a better description of what is shown on that page - a very clever audio preprocessing technique to make crossfading without phase issues possible”. 

Some hypotheses:

Ned: “I think I might guess it: the harmonic content of two samples of the same note are analysed and aligned using FFT analysis? If I'm right, than maybe that should be on the wishlist of new features for Redmatica's Keymap: harmonic alignment!”

Hans: “Sonic Morphing" = "Harmonic Alignment" = In Tune - and starting in phase...”

Hans: “It is not patented in the US. Also, Garrittan's website says "patent pending", which means it has possibly been applied for a patent, although there is no legal protection for anything "patent pending" - it's just an information notice”

Jose: “What if you phased a aligned all samples, normalized each one, slightly overlapped the layers like traditional crossfading and simulated dynamics with a script that modulated DC offset and a highpass filter? Do you think that would work?”

Hans: “Then you would need to "align" (tune) the harmonics individually. I don't think that is the case though.”

Jose: “I don't think the processes can be patented”

Ned & Hans:” Huh... don't forget that Gary's a lawyer!” “From the information I have, the extent of his lawyer expertise stems from being a former real estate lawyer. Very different from this area.”

Hans:” Phase alignment means that two wave forms have their maximums, minimums and zero crossings happen at the same time.”




Well, I’m afraid all the above is plainly wrong 


However, Hans is undoubtedly right when saying: “You can apply for a patent for anything. There is no limitation or qualification for what to include in a patent application as regards to the originality of the concept. The originality will be determined by the patent office, and ultimately by the courts.”


The harmonic alignment process was developed by, and belongs to me. It was applied for a patent under the filename: "Time alignment of the phase of a set of musical sounds to be used with samplers". Extension to international patent application is warranted with priority rights for 12 months. So, it would be probably unwise to apply for a new patent, or to use its basic principles in a commercial application.

The same is true for the other process involved in the solo strings series, namely: "Determination of modal resonances and body impulse response of a musical instrument by analysis of sounds performed with pitch changes. Application to the synthesis of vibrato & portamento with samplers”.

I’m not a real estate lawyer though, so don’t take me too seriously. 

Sincerely,

Giorgio


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## Hans Adamson (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

Hello Giorgio,

Congratulations to finishing the project. 

You are saying we are all wrong in our assessments above. Are you willing to explain in what way?

To crossfade two samples with identical fundamental and harmonics that do not drift over time would not give any phasing. Do you believe that's correct?

Also, I was not able to find any record at the US Patent Office of the patent you describe, neither as an issued patent nor as a published application. Do you have a number?

Best,
Hans ~o)


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## Moonchilde (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

From the man himself! Now how about that...

Perhaps you might not be able to tell us, but does this all function via a nice custom script and sample processing? I'm just really curious of this compared to the traditional cross fading technique we've had for quite a while.

I'm surprised that people haven't really discussed this or taken interest in it since Stradivari has been on the market for some time now.

*Adding* I also want to note, it seem Stradivari doesn't use vibrato samples... and is done by a script or something, just something other than recorded vibrato. I think that is a great idea! I notice when dealing with the EW samples, the non-vibrato stuff is much more in tune than the vibrato stuff, and keeping it in tune is a lot easier... It is such a pain to try to tune vibrato samples in the sampler base level... if only they were auto-tuned before being programmed or at least editable...


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## Hans Adamson (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

I noticed that the Garrittan website uses the term "patent-pending" for this technology. Is that accurate? The US Patent Office's rules regarding "Patent Pending" are:

_"The marking of an article as patented when it is not in fact patented is against the law and subjects the offender to a penalty. Some persons mark articles sold with the terms “Patent Applied For” or “Patent Pending.” These phrases have no legal effect, but only give information that an application for patent has been filed in the USPTO. The protection afforded by a patent does not start until the actual grant of the patent. False use of these phrases or their equivalent is prohibited."_


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## Nick Batzdorf (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



> That's like saying 'how can you patent combining two chemicals and putting them in a capsule.'



Wait a minute. Hold on.

First of all that analogy isn't quite right, 

Well no - first of all I wasn't dissing what Giorgio is doing for one second, just saying in the abstract that it's positively bizarre to think that phase-aligning and tuning samples could be patented. People tune samples all the time, and sliding audio to align the phase is as old as the hills. I mean, as soon as Gary said that he was cross-fading samples, it was obvious to anyone who knows anything a all about audio that they were phase-aligned; what else could it mean?

As to your analogy, I have no doubt that Giorgio worked for a long time, and the demos I've heard of the Gofriller cello are really good. But unless there's more to the process than the obvious, it's a pretty safe bet that the work was in processing the samples, not in the basic concept of Borat: Phase-aligning and Tuning Samples for Purpose of Glorify Sound of Music Instrument Samplers.

In other words, it's the grunt work that took the time. Combining two perfectly standard operations in an audio editor isn't something that should be eligible for a patent, any more than creating "sample layers" by using EQ should be. That's what Audio Impressions is doing, and I don't see them patenting that, for example.


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## Nick Batzdorf (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

And then I see this from KI:



> It uses alot of proprietary algorithms Giorgio built. It took a LONG time for Giorgio to fine tune the approach



...which proves I have no idea what I'm talking about.  o=<


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## JonFairhurst (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

Didn't Pink Floyd demonstrate the phase align technique on "Sheep" from the album "Animals"?

As for getting patents on simply combining two things, it has been done, awarded and confirmed by courts of law. Many years ago a company patented connecting a computer to a video color corrector. Computers were known. Color correctors were known. The patent office and the courts believed the combination to be non-obvious. The company non only sued the other companies that made computer-controlled color correctors, they sued the broadcast and post houses that bought them. Someplace, in this great country of ours, there is a landfill filled with many, many nearly-unused color correctors...

The strategy of cornering the market with the patent had unintended consequences. The industry *hated* those guys. The company had to change its name after the patent ran out, and I'm pretty sure it still went out of business. Had they simply licensed the technology, everybody would have been better off.


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## Peter Alexander (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



Hans Adamson @ Wed Feb 21 said:


> Even if a patent is granted, it is up to the court ultimately, to decide if the patent was a unique idea, or if it was something evident. Patents are challenged all the time. But in this case there is no patent.



READ: Apple vs. Creative Patent Info. Worth reading.
http://blogs.law.harvard.edu/jim/2006/08/


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## Peter Alexander (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



Hans Adamson @ Wed Feb 21 said:


> Hello Giorgio,
> 
> Congratulations to finishing the project.
> 
> ...



Hans, FYI, patents are filed on a country-by-country basis.


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## Hans Adamson (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

Giorgio,

I am glad we have this dialogue now. Particularly if there are pending patent applications. I am relieved that you say these applications are not based on the basic concepts I outlined in this thread.

I got involved in this thread to defend the rights of musicians and developers to create crossfade solo instruments that do not phase, using techniques that I would consider self-evident - an important criteria if a patent would be challenged once it is issued.

I have no idea what is in your patent applications, neither have I ever tried an instrument where these techniques have been applied. My sole point of view for participating in this thread is to discuss ways to achieve crossfade solo instruments that do not phase.

Best,
Hans


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## Hans Adamson (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



Peter Alexander @ Wed Feb 21 said:


> Hans Adamson @ Wed Feb 21 said:
> 
> 
> > Hello Giorgio,
> ...


Yes, but they are also only enforceable in the country where they are issued. Giorgio can very well have applied for a European patent, and I have not claimed any knowledge whether or not he has. I only stated what I could easily check, and what is relevant from an American point of view: There is no official record regarding an issued, or applied for patent in the US. There could be the explanation, that he has also filed for "non-publication" of the application. However, whatever the reason, there is no official record that I have been able to find by searching the records. Maybe its my fault, but a patent number, or patent application number would sort that out.


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## Moonchilde (Feb 21, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



Hans Adamson @ February 21st 2007 said:


> My sole point of view for participating in this thread is to discuss ways to achieve crossfade solo instruments that do not phase.



The whole reason I created this thread  I think this is important for future sampled instruments, and well I was just curious about how it was done. It seems like a really cool idea, and I like these types of things. Gary's explanation starts to make more sense after reading people's posts about harmonic phase alignment and Hans' idea of zero crossings matching up with the next sample...


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## Giorgio Tommasini (Feb 22, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

Moonchilde: “Perhaps you might not be able to tell us, but does this all function via a nice custom script and sample processing?”.

I’m afraid this will remain a little secret between Hans and me :roll: 



Hans Adamson “I noticed that the Garrittan website uses the term "patent-pending" for this technology. Is that accurate?”

I believe it is. Patent applications are not confined to the US, are they? (o) 



Sincerely,

Giorgio


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## Dynamitec (Feb 22, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

Hi everybody!

This is a very interesting discussion here. And i really understand Hans point to discuss this issue. 

In my opinion the idea of crossfade two phase aligned samples can't be a patent because as Hans already said: this is what everyone of us try to do as good as possible. Why do we cut samples as exactly as possible? Why do we try to have samples that are in tune?

And: i searched a little bit on google and there are SO MANY technical papers and different work from universities about phase alignment and "real" morphing of samples. Including some mathlab applications (i didn't know that you can do audio calculations with a mathematical application, but it seems to be used a lot for this). 

But after all: if Giorgio developed a program that could do phase alignment with a special technique, this could possible be a patented application. But i don't think that there will be a patent for the simple fact that two samples are phase aligned before corssfaded. This would mean you aren't allowed to crossfade samples which are - for any reason - perfectly in tune :?: :!:


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## Ned Bouhalassa (Feb 22, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

Hmmm... good thing that no one has a patent pending on sending a sampled sound™ through a multi-mode filter™. Or triggering a sample by pressing on a MIDI™ keyboard. :roll:


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## Dynamitec (Feb 22, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

I just want to say here, that we should keep this discussion fair!

I don't like the idea that someone owns a patent for common or often used concepts.

But i also want to say, that i think that Giorgio has done a lot of research and if he
found an alogrithm or a way to do this task - which isn't surley easy - we should keep in mind, that it was a lot of work. And it would be unfair to get in a direction, he could think, we talk bad about his work. I wouldn't like this situation for myself.
We should respect his work and maybe just talk about solutions for us to do similar things!

I just don't want to misunderstood. I respect his work and his research. I think a patent for the WAY he did it could be fair. But i don't think that a patent for this CONCEPT would be right!


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## Moonchilde (Feb 22, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



Dynamitec @ February 22nd 2007 said:


> I just don't want to misunderstood. I respect his work and his research. I think a patent for the WAY he did it could be fair. But i don't think that a patent for this CONCEPT would be right!



I think it is very fair to patent the way he does it if it is original and he spent years developing. The Strad is also one of the first I've seen ever mention such a focus on harmonic alignment and all that as a feature to the instrument... and I think that deserves respect anyway you look at it, whether or not it is done by conventional or unconventional means.


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## tfishbein82 (Feb 22, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



Nick Batzdorf @ Wed Feb 21 said:


> > That's like saying 'how can you patent combining two chemicals and putting them in a capsule.'
> 
> 
> In other words, it's the grunt work that took the time.



This is exactly why I believe the analogy is correct. Drugs are formulated by mixing various chemicals. It's what chemicals and how they're mixed that is critical. Once the correct formula is found, mass production is incredibly simple. Similarly, which techniques and how Giorgio utilized them are critical to the result. Once he found the right process, implementing it became (relatively) simple.

In any event, without Giorgio divulging his secrets, it seems it would take the brightest minds here about 4 years to catch up - as it took the man himself that long. So I think we're at the mercy of Giorgio and his traveling circus until then.


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## Hans Adamson (Feb 22, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



Giorgio Tommasini @ Thu Feb 22 said:


> Moonchilde: “Perhaps you might not be able to tell us, but does this all function via a nice custom script and sample processing?”.
> 
> I’m afraid this will remain a little secret between Hans and me :roll:


I am afraid I don't know what you are referring to here. I guess it will have to be your own secret until the patent is issued. 

Recapturing what we discussed earlier: I believe two samples can be cross-faded without phasing if the fundamental and the harmonics are separately treated individually to ensure that no particular tonal frequency causes phasing. The only part of the equation we have not discussed so far is the effect of cross-fading on the noise components. This can be tested by stripping two samples of all tonal material and cross-fading them to see the effect in isolation. It may need some optimizing to fool the ear that it is hearing the real thing.

All of this reasoning are just evident logical deductions drawn from commonly known facts. I have not given any though to all of this until reading about it here yesterday. So, as far as the time to establish the basic concepts and create a plan for achieving this, it took no more than the time to read the thread. From what I understand of Giorgio's response in this thread this is not what he is seeking patent for though. /\~O


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## Dynamitec (Feb 22, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



> This is exactly why I believe the analogy is correct. Drugs are formulated by mixing various chemicals. It's what chemicals and how they're mixed that is critical.



This is right, but i don't think it's the same thing here!

Think about this:

If samples would be flour, crossfade would be water and phase alignment would be salt and one thought it would be the best to put all in an oven - the result would be bread.

Now, if you don't know know how to do this by yourself, go to the baker and buy your bread. But if you know how to do it yourself - shouldn't you be allowed to? Or may no one else bake bread now since a baker learned it a long time before you learned it?


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## Dynamitec (Feb 22, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



> Recapturing what we discussed earlier: I believe two samples can be cross-faded without phasing if the fundamental and the harmonics are separately treated individually to ensure that no particular tonal frequency causes phasing. The only part of the equation we have not discussed so far is the effect of cross-fading on the noise components. This can be tested by stripping two samples of all tonal material and cross-fading them to see the effect in isolation. It may need some optimizing to fool the ear that it is hearing the real thing.



Sounds good, but how to treat the fundamentals and harmonics seperatly?


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## Hans Adamson (Feb 22, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

I can do that with my 10 year old editing software, I believe. I'm not going to patent the technique :wink: , but I will keep it to myself for now. o/~


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## Dynamitec (Feb 22, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

You could just tell us then which 10 year old software you are using


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## Hans Adamson (Feb 22, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

More thoughts:

The ideal instrument to start with would be an instrument such as a violin, or another small instrument, because they have substantinally fewer harmonics than an instrument that reaches into the lower octaves. Bass instruments have clusters of harmonics and it will take longer to finish, and get reliable results.


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## Hans Adamson (Feb 22, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



Dynamitec @ Thu Feb 22 said:


> You could just tell us then which 10 year old software you are using


For you I will Ben, because you are so generous with your knowledge. I use Red Roaster by formerly SEK'D.


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## Thonex (Feb 22, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

I have often thought about doing a "phase aligned" patch. I never did though... but if I was going to, it would probably go something like this:

Hire a player and sample him/her.
Tell him/her to not play any pitch vibrato 
Go into Melodyne and tune everything exactly so that the frequency would be uniform throughout the sample (for phase alignment).
Do zero crossing edits only... including the sample start.


Then the script would be responsible for all the vibrato and pitch humanization. But this approach sounds so cold... it sucks out all the human performance out of the sampling session.

I dunno.... a wild guess.. maybe the Strad employs a similar approach.

Cheers,

T


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## Moonchilde (Feb 22, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



Hans Adamson @ February 22nd 2007 said:


> I have not given any though to all of this until reading about it here yesterday. So, as far as the time to establish the basic concepts and create a plan for achieving this, it took no more than the time to read the thread. From what I understand of Giorgio's response in this thread this is not what he is seeking patent for though. /\~O



So, now that you're thinking about it, are you thinking about putting this to the test?


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## Hans Adamson (Feb 22, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



Moonchilde @ Thu Feb 22 said:


> Hans Adamson @ February 22nd 2007 said:
> 
> 
> > I have not given any though to all of this until reading about it here yesterday. So, as far as the time to establish the basic concepts and create a plan for achieving this, it took no more than the time to read the thread. From what I understand of Giorgio's response in this thread this is not what he is seeking patent for though. /\~O
> ...


I do feel an urge to document and publish the results as soon as possible considering these pending patent applications. Even though Giorgio is assuring that he will not try and shut the door on us. I have a few samples to work with to make preliminary tests. Hopefully, I will have time for this over the weekend.


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## Fernando Warez (Feb 22, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



Thonex @ Thu Feb 22 said:


> I have often thought about doing a "phase aligned" patch. I never did though... but if I was going to, it would probably go something like this:
> 
> Hire a player and sample him/her.
> Tell him/her to not play any pitch vibrato



X-Samples solo violins have no vibrato.


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## Moonchilde (Feb 22, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



Hans Adamson @ February 22nd 2007 said:


> I do feel an urge to document and publish the results as soon as possible considering these pending patent applications. Even though Giorgio is assuring that he will not try and shut the door on us. I have a few samples to work with to make preliminary tests. Hopefully, I will have time for this over the weekend.



Well, as long as it isn't the same it should hold up against a patent that doesn't do anything we've discussed anyway. However, according to one of Peter's links, people are allowed to build ideas off patents once the idea has been patented. It just can't be the same. How true this is, I don't know, since I have no experience in patents and I'm not a lawyer.


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## Moonchilde (Feb 22, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

Either way we look at it, this is a Kontakt instrument so it has to be doable for just about anything we can load into it


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## Robert Kooijman (Feb 23, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

From all things brought up in this thread, it still isn't clear to me if 'harmonic alignment' is done using an 'off the shelves' K2 player and a clever script. I don't see how true harmonic alignment can be done that way.

However, there appears a strong similarity with the "Phase Locked Loop" concept that is used in almost everything these days. I actually designed various such PLL's over the years for use in AF and RF devices...

A PLL maintains a strict phase relationship between two signals (regardless of their level and shape i.e. harmonic content). It can be done relatively simple in either in soft or hardware: http://en.wikipedia.org/wiki/PLL

I can imagine one way of doing harmonic / phase alignment in Kontakt using a specially written plug-in (K2 already uses this concept for filters etc.).
For instance, by taking one sample group as a 'master' reference, other groups could be phase aligned / locked using a 'PLL' style plug-in. Phase locking here effectively means continuous adjustment of the other groups' pitch. If not done this way, perhaps something to consider by NI 

Using multiple outs and an external PLL circuit, this could perhaps also be done.
For instance, one could assign unique MIDI pitch-controllers to different sample groups, routed to individual outs. A PLL circuit, fed from a 'master' sample group output, could then lock the various groups pitch to maintain the strict phase relationship required for smooth 'morphing' of various articulations


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## tfishbein82 (Feb 23, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



Hans Adamson @ Wed Feb 21 said:


> I got involved in this thread to defend the rights of musicians and developers to create crossfade solo instruments that do not phase, using techniques that I would consider self-evident - an important criteria if a patent would be challenged once it is issued.


First, let me say that I do not disagree with you.

But playing devil's advocate...

I think that anyone who did try to patent the process you describe would have a decent defense against any self-evident argument you waged. Quite simply, if it's so evident how come nobody - in all these years that they have been available - has utilized these techniques in this manner.


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## hv (Feb 23, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

If the current K2 engine is what's being used, the technique is probably very simple. For instance, if you had a lib with 1 velocity layer, you might use some filters to make softer velocities sound more mellow that louder ones. And if you add a velocity layer, you could simplify and just crossfade the samples to get those in-between velocities. But if you used the same filtering techniques as the 1-layer model, on each layer before the crossfade, you might get a smoother blend for those in-between velocities. And since its more than simple crossfading, why not call it morphing?

Also, it seems intuitively obvious to me that if you want to mix or morph 2 samples of the same note on the same instrument and the only intended difference is that one is sampled at a louder velocity level... that the closer to identical they are, the better you'll be doing. And if they're out of phase, that you can expect to hear strange things during the cross fade. Most sample lib vendors know this all too well and spend a ton of time trimming and tweaking the attacks of each and every sample. An automated tool, perhaps employing PLL techniques, might not only be more accurate and consistent, but would also a great time saver. But I'm not sure there's any need to put it in the sample playback engine. I'd think its more the kind of thing you'd want to do off-line as part of the library authoring process.

Wonder if I can patent putting catsup on a bagel with cream-cheese... if no one's ever done that before? I could serve it hot and franchise pizza noshes.

Howard


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## Hans Adamson (Feb 23, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



tfishbein82 @ Fri Feb 23 said:


> Hans Adamson @ Wed Feb 21 said:
> 
> 
> > I got involved in this thread to defend the rights of musicians and developers to create crossfade solo instruments that do not phase, using techniques that I would consider self-evident - an important criteria if a patent would be challenged once it is issued.
> ...


In this case that is a weak argument since streaming sampler technology only has been available since 1999 (a requirement for the technique I described) and any cross-fade instrument for Giga/Kontakt has been around since when? That discussion should be moot anyway, since Giorgio has stated that this is not what his patent applications are about.


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## Moonchilde (Feb 23, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

Well, Giorgio said it isn't as simple as that and took years to develop. He also doesn't have his patent yet, so I don't think it wise of him to discuss exactly how he does it... considering if he gave away his idea someone else could patent it and possibly get the patent before he does, therefore, he loses his work in a way. I don't blame him for not talking about it. I'm sure he'll be much more open to discussion once he gets his patent.

It is still interesting to discuss new ideas to get a less noticeable cross fade between sample velocities, whether or not Giorgio adds any input to the subject.


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## hv (Feb 23, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



tfishbein82 @ Fri Feb 23 said:


> ...I think that anyone who did try to patent the process you describe would have a decent defense against any self-evident argument you waged. Quite simply, if it's so evident how come nobody - in all these years that they have been available - has utilized these techniques in this manner.


The problem with that analysis is that it writes the non-obviousness test out of the law. US patent law contains separate independent sections requiring non-obviousness in one and novelty in the other. The idea being to only grant a temporary monopoly to someone who invented something new. Dealing with a problem that a person possessing the ordinary skills in the art would not know how to solve. Otherwise, instead of rewarding inventors, you'd be rewarding 1st time gamblers.

But sadly I think you're right. Because most judges these days in the US use the exact analysis you mention to skip over the non-obviousness test. In Europe however, some countries like Germany seem to take the similar "inventive step" analysis more seriously. Which will inevitably create an interesting problem... it's only a matter of time before over-liberal US patents start being overturned in European courts.

Howard


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## Hans Adamson (Feb 23, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

Here's another thought to add to the technique discussed above:

Since the hard drive can only read at one location at a time, there may be necessary to write in a short delay for one of the notes. This could be done with scripting.


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## Moonchilde (Feb 23, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

What about using mega samples? Kind of like the Mega texture id Software developed...

You make one massive sample with sustain notes in it... then make each zone read a different part. That would be wierd! Would probably require ram loading instead of DFD, not sure how well a dfd version of that would work.


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## JohnnyMarks (Feb 23, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

The Stradivarius samples are delivered with the phase alignment applied, K2 isn't involved with this.

Review describing Garritan technology:
http://www.cakewalknet.com/index.php?option=com_content&task=view&id=173&Itemid=2

As Dynamitec mentions there has been academic work around this. Here, for example, are papers by Jordi Bonada et al describing "maximally flat phase alignment," with (at least some of) the mathematics of their approach: 

http://www.iua.upf.es/mtg/publications/DAFX04-jbonada.pdf
http://www.iua.upf.edu/mtg/publications/9d0455-AES121-jbonada-mblaauw-aloscos.pdf

Perhaps there is enough here (I would doubt it) for one of our resident programming experts to implement using Matlab, CSound, CLAM whatever. Have at it! This is way beyond me.


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## Hans Adamson (Feb 23, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*

Albeit the title of this thread, I think it may be most productive to focus the discussion on ways to "create cross-fade instruments that do not phase". 

The Garritan violin may, or may not, be an example of this, we don't really know. This instrument is supposedly doing some kind of "morphing", a technology allegedly different and possible soon to be under patent protection. So I suggest we leave it out of the discussion. :wink: 

If a simple cross-fade instrument that doesn't phase is within reach with the common knowledge we share on this board, that would be enough of a feat.


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## janila (Feb 25, 2007)

Hans Adamson @ Sun Feb 25 said:


> I separated the noise components from the fundamental and the first 25 harmonics in separate wav's, so all in all there are 27 wav's of each note. There are three dynamics, piano, mezzoforte, and forte, totally 81 files to work with.


How did you do that? :?: 




> Next step would be to individually treat the tonal files, so that the frequencies do not fluctuate. I have an old version of Antares AutoTune (3.0?), that only works in Windows98. I will try that. If someone else has Melodyne, I wouldn't mind getting some assistance... o-[][]-o


Anteres has a fully functional demo of AutoTune 5. It works for two weeks or something.


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## Hans Adamson (Feb 25, 2007)

janila @ Sun Feb 25 said:


> Hans Adamson @ Sun Feb 25 said:
> 
> 
> > I separated the noise components from the fundamental and the first 25 harmonics in separate wav's, so all in all there are 27 wav's of each note. There are three dynamics, piano, mezzoforte, and forte, totally 81 files to work with.
> ...


Hello Janila,

Thanks for the tip. I will download it today. For each content-specific .wav I had to filter out the unwanted material. So for each of the files I started with a copy of the full .wav and then filtered out the irrelevant frequencies.


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## rJames (Feb 25, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



Hans Adamson @ Fri Feb 23 said:


> Here's another thought to add to the technique discussed above:
> 
> Since the hard drive can only read at one location at a time, there may be necessary to write in a short delay for one of the notes. This could be done with scripting.



I don't know anything about programming or about creating x-fade patches but I do know that this is not an issue.

When Kontakt streams, it takes the data of of the hard drive and puts it into a buffer to play out in relation to the note start, the preloaded size and the note length.

It loads up this buffer and waits till it needs the wav and sends it out. 

Then does it again. There may be some issue with timing but it would be in CPU cycles and not in hard drive cycles.

This buffer is why Kontakt has a footprint (while totally empty) set by parameters in the options dialogue for "number of streaming voices"


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## Hans Adamson (Feb 25, 2007)

synergy543 @ Sun Feb 25 said:


> Hans, I don't understand how you can treat an acoustic instrument like a steady state wave. Even, if you use pitch correction and align all the beginnings of the harmonics. There will still be slight minor variations that could easily cause a tone to go out of phase over time. Your pitch alignment would need to be 100% precise across the length of the entire sample. Its like the difference between a sync tone on an digital recorder vs. an analog recorder. No matter how great an engineer calibrates the best analog tape deck, there will still be some drift over time. And the same I think goes for any acoustic instrument.
> 
> And some of these pitch flucuations are an inherent and integral part of the instrument's sound. For example, when you pluck the string of a guitar, there is a very slight pitch bend when the string is first hit as its stretched. By removing these, you also remove part of the character of the articulation.
> 
> *I'm just thinking there must be a simpler and better way - such as crossfading and "adding" only the harmonics of the louder samples (which would minimize phase cancellations - as the fundamental is the same and the softer notes have lower level harmonics). * Hey, this is a pretty good idea! - Patent Pending! - But OK for VI-Pro.


Greg,

I have thought about all the points you raise, and the only way to deal with them is to do it when the problem reveals itself.

No matter how much you treat two samples, there will always be a level of accuracy at where they will drift as they are not "phase-locked". The solution to this would be to loop within the time frame that is "drift-proof"

There are many unanswered questions and possible problems that need to be addressed, and maybe the focus of the solution needs to change as well. However, one thing is for sure: Problems with phasing stems from two freqeuencies being out of phase with each other, or, going in and out of phase with each other. A first step to try and solve the equation would be to create two samples with different characteristics in all aspects, except frequency and phase for all tonal elements. 

Sure it will loose the expressive element of pitch fluctuation, but just as in PCM based sampling, maybe this can be re-introduced after the cross-fade stage.


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## Hans Adamson (Feb 25, 2007)

*Re: Garritan Stradivari does a "sonic morph" instead of a cross fade*



rJames @ Sun Feb 25 said:


> Hans Adamson @ Fri Feb 23 said:
> 
> 
> > Here's another thought to add to the technique discussed above:
> ...


Thanks Ron,

One down... a few more to go...


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## synergy543 (Feb 25, 2007)

So why not extract harmonics of the louder notes and add these as you crossfade?

Have you tried this? I'll bet it will work as there will be far less correlation (so less to cancel out) than with two complete samples. It might not be a perfect solution but it could be worth a try and maybe as effective as SvK's very useful and opposite approach of filtering out but in a different way - such as for adding a bit more rosin to a bow.

Well, just thinking out loud here....off to get some more coffee...


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## rJames (Feb 25, 2007)

While we're on the subject...slightly off-topic;

this phasing between cross-fading samples is the reason that I don't use x-fade patches much.

My ears cannot hear it, but I don't have great ears. Isn't this an example of what the best midi artists tell us to avoid?

Yes, I would love to add timbre change as I change volume, but I don't want phasing, which seems to be finally recognized as inherent in every x-fade patch.

It must not be the most important issue for mockup guru's like TJ, Aaron, Colin, Nathan Furst and Craig or they wouldn't be relying on x-fade patches.

which is worse; phasing or no timbre change for expression?


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## Hans Adamson (Feb 25, 2007)

synergy543 @ Sun Feb 25 said:


> So why not extract harmonics of the louder notes and add these as you crossfade?
> 
> Have you tried this? I'll bet it will work as there will be far less correlation (so less to cancel out) than with two complete samples. It might not be a perfect solution but it could be worth a try and maybe as effective as SvK's very useful and opposite approach of filtering out but in a different way - such as for adding a bit more rosin to a bow.
> 
> Well, just thinking out loud here....off to get some more coffee...


It is an idea I will definitely try along the way. There is one problem though, but It could be solved as well: The relative loudness of fundamental and harmonics change between dynamics, so you would have to compensate the fundamental level to match.


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## synergy543 (Feb 25, 2007)

Excellent question Ron! o-[][]-o 

I think the answer depends upon the amount of phase cancellation. So possibly a smaller amount may be acceptable in exchange for greater expression. However, I too would like to hear the opinions of the mockup experts you mention.


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## synergy543 (Feb 25, 2007)

Hans Adamson @ Sun Feb 25 said:


> There is one problem though, but It could be solved as well: The relative loudness of fundamental and harmonics change between dynamics, so you would have to compensate the fundamental level to match.


Yes, I was thinking about that too but didn't write it. Maybe maybe raising the fundamental with velocity? Although, you'd also be raising the harmonics along with it. So, Ideally, you'd both filter out the harmonics from the first as your raising its volume! A bit tricky maybe. It would require two different programs in Kontakt I think unless you can process different groups with different effects?


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## rJames (Feb 25, 2007)

Greg, I think I'm going to answer my own question.

Its (probably/possibly) only extremely important in SOLO instruments.

Solo instruments' varying articulations are probably closer to each other (in terms of exact match); the harmonics generated by the instrument are so similar because of construction. 

A cross-fade of an entire section (seems to me) would add so many variables to the table that it would be more like just cross-fading two different sets of samples. The exactness necessary for phasing probably just isn't there for sections.

It might not really be that important in a solo instrument; maybe its just a marketing ploy. Have we heard great sounding solo instruments from any developer? 

Probably so.


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## Alex W (Feb 25, 2007)

rJames @ Mon Feb 26 said:


> Greg, I think I'm going to answer my own question.
> 
> Its (probably/possibly) only extremely important in SOLO instruments.
> 
> ...



You're right, it only really affects solo instruments noticably.

[IMO] I think Westgate's solo flute sounds great, but I also think there would be less phasing issues with a flute, as long as all the notes were auto tuned. I think it's because it has a much more mellow tone, and the waveform itself seems a lot simpler than say a trumpet - closer to a simple wave form than any other instrument (a sine tone in this case). [/IMO]


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## Moonchilde (Feb 25, 2007)

What about adding in the harmonics via convolution?


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## Hans Adamson (Feb 25, 2007)

Moonchilde @ Sun Feb 25 said:


> What about adding in the harmonics via convolution?


I don't know if convolution can add content that isn't there in the first place. I know little about convolution, but my impression of what I have heard, would not want me to go that way. Maybe someone with more knowledge could elaborate.

There was a discussion about dynamic convolution in the samples discussion. This would be like cross-fading of convolutions. I would not know how to do that though.


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## Nickie Fønshauge (Feb 26, 2007)

Hans Adamson @ 26th February 2007 said:


> Moonchilde @ Sun Feb 25 said:
> 
> 
> > What about adding in the harmonics via convolution?
> ...


Apparently it can. The raw Stradivari 1 sustain samples sound a bit like a razor or food processor: an odd buzzing sound, you wouldn't normally connect with a violin. But after it has been through the proprietary convolution IR, it is a whole different story. So I think Moonchild has nailed it.


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## Hans Adamson (Feb 26, 2007)

Exactly what convolution can, or can't do, would be interesting to know... If anything can be made come out at the other end of the convolution process, then you could possibly convolve a tuba with a piccolo flute. Play the tuba, and out comes a piccolo flute...?!


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## Moonchilde (Feb 26, 2007)

Well, supposedly you can make a convolution of an acoustic guitar, mic an electric's strings, and run that through the convolution to get an acoustic sound. So there is probably all sorts of things you can do. I think PMI sampled the bodies of pianos and uses that to give characteristic sound to "raw" piano string samples. Not surprising that Stradivari would do the same.

I think the way to do it would be to phase the velocity samples proper, convolve the harmonics and mix in a blender.

However, I'm not really an audio guy and don't know jack about engineering audio and what is wrong/right. Nor do I have the equipment to test such things.


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## Hans Adamson (Feb 26, 2007)

Another way of doing it with convolution would be:

1. Treat noise separately as a simple cross-fade.
2. Use velocity-specific harmonics impulses that would ensure phase-coherent velocity layers.
3. Cross-fade also the fundamental+harmonics after convolution.

This technique would allow different relations between fundamental and individual harmonics depending on velocity, but would need phase aligned fundamentals for the different velocity layers.


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## kotori (Feb 26, 2007)

Hans Adamson @ Mon Feb 26 said:


> Exactly what convolution can, or can't do, would be interesting to know... If anything can be made come out at the other end of the convolution process, then you could possibly convolve a tuba with a piccolo flute. Play the tuba, and out comes a piccolo flute...?!


If I'm not mistaken (someone please correct me if I am) convolution in K2 is based on LTI systems, so they need to be linear (summing two inputs and running it through the filter should be equal to running each input value through the filter and summing the results) and time invariant (delaying the input should give a corresponding delay in output). If the real filter is not LTI the resulting filter will always be an approximation. I think it's quite unlikely that a satisfactory tuba to piccolo flute transformation could be achieved given these limitations.


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## Hans Adamson (Feb 26, 2007)

kotori @ Mon Feb 26 said:


> Hans Adamson @ Mon Feb 26 said:
> 
> 
> > Exactly what convolution can, or can't do, would be interesting to know... If anything can be made come out at the other end of the convolution process, then you could possibly convolve a tuba with a piccolo flute. Play the tuba, and out comes a piccolo flute...?!
> ...


I am not following you here, but I guess you are saying that it would be hard because there is no time dimension in convolution?


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## kotori (Feb 26, 2007)

Hans Adamson @ Mon Feb 26 said:


> I am not following you here, but I guess you are saying that it would be hard because there is no time dimension in convolution?


Yes, it's both the fact that the IR is constant over time and that the response is linear whereas it most probably is necessary to use non-linearities to achieve such a profound change.


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## Moonchilde (Feb 26, 2007)

The real problem with using a convolution to cover all the harmonics is the CPU processing required... I'm sure this won't be such a big hit in the future but imagine having to load a convolution for each instrument you load, that all adds up really quick.


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## Hans Adamson (Feb 26, 2007)

synergy543 @ Mon Feb 26 said:


> You guys might want to have a look at Ernest Cholakis thread about TI technology on NI. I can't decipher enough to explain but it seems very related to this discussion.
> 
> http://www.northernsounds.com/forum/showthread.php?t=52026 (http://www.northernsounds.com/forum/sho ... hp?t=52026)


I read the thread, and he is talking about regular reverb impulses and timbre impulses, as glorified EQ. I think the mentioning of 20 impulses in a few seconds was misunderstood by the reader making the question comparing it to dynamic convolution.


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## ddas (Mar 16, 2007)

Been reading this thread with interest. Hans, your icon looks a little like Maria Sharapova trying to disguise herself. Didn't know Maria was so into convolution and harmonic analysis of the Garritan Stradivari.

Really interesting discussion, and to it, I'd like to add a question: as a practical matter, how does one get an impulse response of, say, a violin? I realize the body of a violin is an empty cavity, but are people literally holding their violins up to a large speaker while a sine wave is played and then placing a microphone inside the violin?

Just curious to see how far convolution can really go.


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