Invisible (but audible) octave?

[Francois2010]

View and listen please.
Measure 1, third note: the trombone sounds an octave too high. I think we hear the E + E an octave higher (invisible) Same at mes.2.

[pcartwright]

I hear it too, but it's a natural phenomenon. I think you're hearing the first overtone from the Eb supported by overtones from the C in the bass voice. Though the two notes are not strictly linked to the C's harmonic series, the subsequent shared overtones by the Eb and the C (those above the "phantom Eb") may create an "artificial fundamental" that the brain interprets as another, higher, Eb.

This article gives a little information regarding phantom pitches generated by related overtone series (http://en.wikipedia.org/wiki/Missing_fundamental).

I remember taking a class in college where two flute players illustrated this phenomena by playing familiar hymns with particular voicings which created "phantom" bass and middle voice tones. If you closed your eyes, you would swear that there were three parts being played; however, only two players were present.

[Francois2010]

Thank you!

Note this: it does not occur with string instruments. What do you say to that?

[Surfwhammy]

Thank you!

Note this: it does not occur with string instruments. What do you say to that?

Your hearing is quite excellent!

There are explanations for what you hear, so the key is to discover how to identify them, for sure . . .

For example, after listening to the audio produced by the Notion 3 sample score you provided, I immediately recognized one source of the problem, and it is is very easy to correct . . .

Switch to the Notion 3 Mixer for the piece, where you will notice that you have the Notion 3 Reverb on the Master output track set to its default values {Dry/Wet = 50, Room = 50, Damping = 0, Predelay = 25} . . .

If you remove or disable the Notion 3 Reverb or set all its parameters to zero, then the spurious note is not heard so loudly, which as explained below tends to suggest that it is a characteristic either (a) of the room or studio in which the instruments were played and sampled or (b) of the instrument itself, where the behaviors of the Notion 3 Reverb tend to have an amplifying affect on the spurious note . . .

[NOTE: I really like the Notion 3 Reverb, but I tend not to use it on the Master stereo track, and for the most part I do not use it at all, since I prefer to record the Notion 3 computer-generated audio in Digital Performer 7 in as dry a way as possible. I would be very happy if the Notion Music folks packaged Notion 3 Reverb as a standalone VST plug-in, and I certainly would purchase it as a standalone VST plug-in, since it is a very melodic reverberations that is both nice and easy to use . . . ]

Specifically, (a) stringed instruments and open air column instruments behave differently from (b) closed air column instruments, where the former produce all harmonics while the latter produce only odd harmonics, but brass instruments while being closed air column instruments are enhanced and modified to be able to produce a fuller range of harmonics, so it is not unexpected that string instruments will behave a bit differently from brass instruments and closed air column instruments like most clarinets, oboes, bassoons, and so forth . . .

Additionally, the ways that sampled sounds of instruments interact will depend on a virtual festival of things, but all of them are governed by the fundamental rules of physics, and from another perspective it is not the least bit unusual for the particular acoustic behaviors and characteristics of the rooms in which instruments are played and recorded to have additional affects with respect to sampled sound interactions, where I certainly can envision the scenario where a bit of room resonance which for a single instrument sample might be negligible could become quite noticeable when several instruments all played and recorded in the same room are combined in a score, since one of the biggest problems in the digital universe is the additive phenomenon of hiss, background noise, and so forth and so on, which includes the acoustic resonance behaviors and characteristics of the rooms and studios where the instruments were played and recorded . . .

Specifically, a room or studio can have what one might call "hot spots", where the room itself tends to amplify certain very specific pitches, and similarly a room or studio can have "cold spots", where the room itself tends to diminish certain very specific pitches, so as noted it is entirely possible that some of what you are hearing derives not so much from the particular instruments as from the acoustic behaviors and characteristics of the rooms and studios where the various instruments were played and recorded . . .

The acoustical architecture aspects ofmusic rooms, concert halls, recording studios, and listening rooms are not simple matters, at all . . .

One of the more fascinating architectural acoustic phenomena is the "whispering gallery", really . . .

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

Really!

These are some useful links to different sections of the HyperPhysics website that provide information on harmonics, overtones, and so forth, for sure . . .

http://hyperphysics.phy-astr.gsu.edu/hbase/sound/rescon.html#c1

http://hyperphysics.phy-astr.gsu.edu/hbase/music/otone.html

http://hyperphysics.phy-astr.gsu.edu/hbase/waves/opecol.html#c2

http://hyperphysics.phy-astr.gsu.edu/hbase/waves/clocol.html#c1

http://hyperphysics.phy-astr.gsu.edu/hbase/music/brassa.html#c1

For sure!

Helmholtz resonators are another fascinating aspect of sound, which is fabulous . . .

[NOTE: There are links to very detailed information regarding the acoustic physics of specific musical instruments at this website . . . ]

http://www.phys.unsw.edu.au/jw/Helmholtz.html

[NOTE: The resonant behaviors and characteristics of bottles and jars was known in ancient times, where auditoriums and theaters sometimes were lined with large wine bottles that were filled with varying amounts of sand to change the acoustics of these listening rooms based on the expected audience, type of play or performance, and so forth and so on. In this respect, I had a bit of FUN when I was designing and building the RAE Multimedia sound isolation studio, which among other things has a fully-floated floor that sits on rubber mats made from ground truck tires; triple walls, ceiling, and floors with generous air spaces and heavy fiberglass insulation, as well as multiple layers of different thickness sheetrock (a.k.a., gypsum board); and a few carefully tuned Helmholtz resonating panels and so forth and so on, which makes it extraordinarily quiet with respect to external noises and subsonic vibrations . . . ]

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

Fabulous!

P. S. One of the most simple and effective ways to remove the bass and midrange "boominess" of a listening room is to get a few rolls of fiberglass insulation, which you stack in the corners of the room. If you prefer, you can cover the rolls of fiberglass insulation with a cloth screen or whatever, which makes it look a bit more stylish, but regardless of how it looks, it works very nicely and does not require a lot of work . . .

[pcartwright]

Note this: it does not occur with string instruments. What do you say to that?

Surfwhammy gave a pretty good answer as far as getting rid of the offending "invisible" note (reverb can often amplify the effect). You may also want to try detuning one of the instruments by a few cents. There are several free pitch shifters around, but they can be a major drain on your CPU power.

To answer your question, there are, as I understand it, three major reasons why some instruments are more likely to produce phantom pitches.

First, the tuning between the two pitches must be fairly precise. Considering the string section is, of course, made up of several musicians, it is unlikely that every player in a section will play the same note at the exact same frequency; they will most certainly be off a few cents here and there (this holds for samples of string sections as well). Therefore, the overtone series for strings will be slightly off and more distorted compared to notes played by a single instrument (such as a trombone).

Second, the tuning between different families of instruments will be different as well. String players, of course, change pitch by adjusting the length of the vibrating string; brass players must change the length of the instrument with valves. The modern equal temperament tuning system doesn't strictly follow the overtone series for tuning; therefore, while a string player can make subtle adjustments in order to tune to our current standards, a brass player is usually forced to play notes that may be slightly out of tune with our current system. All of this to say that phantom notes are going to be most common when similar instruments are playing together.

Finally, instruments with stronger overtones are more likely to cause this phenomena then those with softer/weaker overtones. Typically, bright instruments (instruments with more "high" overtones) such as brass, some woodwinds, and many bell type percussion instruments will produce these effects (assuming of course, that the tuning mentioned above is correct). In fact, there are several pitched percussion instruments that have such strong overtones that, depending on the room conditions, etc, it is difficult to know what octave the instrument is really playing.

[Francois2010]

Thank you!

Note this: it does not occur with string instruments. What do you say to that?

Your hearing is quite excellent!

There are explanations for what you hear, so the key is to discover how to identify them, for sure . . .

For example, after listening to the audio produced by the Notion 3 sample score you provided, I immediately recognized one source of the problem, and it is is very easy to correct . . .

Switch to the Notion 3 Mixer for the piece, where you will notice that you have the Notion 3 Reverb on the Master output track set to its default values {Dry/Wet = 50, Room = 50, Damping = 0, Predelay = 25} . . .

If you remove or disable the Notion 3 Reverb or set all its parameters to zero, then the spurious note is not heard so loudly, which as explained below tends to suggest that it is a characteristic either (a) of the room or studio in which the instruments were played and sampled or (b) of the instrument itself, where the behaviors of the Notion 3 Reverb tend to have an amplifying affect on the spurious note . . .

[NOTE: I really like the Notion 3 Reverb, but I tend not to use it on the Master stereo track, and for the most part I do not use it at all, since I prefer to record the Notion 3 computer-generated audio in Digital Performer 7 in as dry a way as possible. I would be very happy if the Notion Music folks packaged Notion 3 Reverb as a standalone VST plug-in, and I certainly would purchase it as a standalone VST plug-in, since it is a very melodic reverberations that is both nice and easy to use . . . ]

I do not hear music with N3 Reverb Off. It's really too dull for me.

Specifically, (a) stringed instruments and open air column instruments behave differently from (b) closed air column instruments, where the former produce all harmonics while the latter produce only odd harmonics, but brass instruments while being closed air column instruments are enhanced and modified to be able to produce a fuller range of harmonics, so it is not unexpected that string instruments will behave a bit differently from brass instruments and closed air column instruments like most clarinets, oboes, bassoons, and so forth . . .

Additionally, the ways that sampled sounds of instruments interact will depend on a virtual festival of things, but all of them are governed by the fundamental rules of physics, and from another perspective it is not the least bit unusual for the particular acoustic behaviors and characteristics of the rooms in which instruments are played and recorded to have additional affects with respect to sampled sound interactions, where I certainly can envision the scenario where a bit of room resonance which for a single instrument sample might be negligible could become quite noticeable when several instruments all played and recorded in the same room are combined in a score, since one of the biggest problems in the digital universe is the additive phenomenon of hiss, background noise, and so forth and so on, which includes the acoustic resonance behaviors and characteristics of the rooms and studios where the instruments were played and recorded . . .

Do you believe that N3 could make corrections to this instrument for the next update?

[...]
These are some useful links to different sections of the HyperPhysics website that provide information on harmonics, overtones, and so forth, for sure . . .

http://hyperphysics.phy-astr.gsu.edu/hbase/sound/rescon.html#c1

http://hyperphysics.phy-astr.gsu.edu/hbase/music/otone.html

http://hyperphysics.phy-astr.gsu.edu/hbase/waves/opecol.html#c2

http://hyperphysics.phy-astr.gsu.edu/hbase/waves/clocol.html#c1

http://hyperphysics.phy-astr.gsu.edu/hbase/music/brassa.html#c1

For sure!

Helmholtz resonators are another fascinating aspect of sound, which is fabulous . . .

[NOTE: There are links to very detailed information regarding the acoustic physics of specific musical instruments at this website . . . ]

http://www.phys.unsw.edu.au/jw/Helmholtz.html

Thank you for these links!

[...]

[Francois2010]

Note this: it does not occur with string instruments. What do you say to that?

Surfwhammy gave a pretty good answer as far as getting rid of the offending "invisible" note (reverb can often amplify the effect). You may also want to try detuning one of the instruments by a few cents. There are several free pitch shifters around, but they can be a major drain on your CPU power.

To answer your question, there are, as I understand it, three major reasons why some instruments are more likely to produce phantom pitches.

First, the tuning between the two pitches must be fairly precise. Considering the string section is, of course, made up of several musicians, it is unlikely that every player in a section will play the same note at the exact same frequency; they will most certainly be off a few cents here and there (this holds for samples of string sections as well). Therefore, the overtone series for strings will be slightly off and more distorted compared to notes played by a single instrument (such as a trombone).

You'll notice that I used for my example of solo strings.

[...]

Thank you for these interesting explanations!

[wcreed51]

Here’s another example: listen to the half note d# in the second measure. It’s clearly being doubled and sounds totally different then the d# in the first measure.

[pcartwright]

Here’s another example: listen to the half note d# in the second measure. It’s clearly being doubled and sounds totally different then the d# in the first measure.

This sounds like a different issue... The example from francois definitely sounds like a false fundamental where your example sounds like a bug.

[wcreed51]

To tell the truth, I didn't hear anything odd with francois's sample.