Single wave file for voice storage versus one per note.

[twanguitar]

Er, no, can't admit to being actually bowled over John, as you have already informed this or other forums of your qualifications. Personally I have never felt the need to brag about such things, so will keep my counsel with regard to mine.

Nevertheless I do agree with you that more equals less in these matters, and that it has nothing to do with the thread.

Another of my attributes is that I never feel compelled to have the last word. So having made my points, I'll now leave that to you or anyone else with the inclination.

TG

[HOW]

Hello TG,
Sorry, but I had no intent on "tooting my horn" when I mentioned my occupation. All considered, I am a nobody as is most of the world's population and if I were to brag about something, it would be regarding the attributes of Holy God of whom I am a slave.
Regards,
Stan

[HOW]

Hello All,
Using a wave editor and a typical reed stop sample from the low C1 (16' pitch) I kept scaling up approximately 1/2 octave each step. The voicing did not seem to change much until around F3. Then the upper harmonics were no louder in proportion to the fundamental and somewhat distorted. I am not sure that this is an error resulting from the wave editor processing. Next I took a C5 sample and did the reverse operation by scaling down. It seemed as if the low notes were missing the upper harmonics. This again could be the fault of the wave editor. OR, this verifies that the harmonic structure of the pipe rank does in fact change from low notes to high such that the higher harmonics are subdued. If this turns out to be the case and the wave editor is accurate, I would assume that the fluid dynamics of the vibrating air column if the cause - IE the smaller the diameter of the pipe, the more the restriction of flow resulting in the upper harmonics being damped and attenuated.
Next I will use a harmonic analyzer to compare a C1 with a C5 or 6 to be certain that the wave editor is not skewing the results.
A hand held string instrument such as a guitar or violin have a single formant since the same size sound resonator "box" is used for all string lengths which would indicate that when changing the fundamental pitch (effective string length change) the harmonics are forced to resonate in the same by the same box. In other words, even though proportional to the fundamental, the some harmonics are attenuated and others are increased so that they are conformed to that of the box. If an organ pipe had vibrating strings it would seem that the harmonics would be proportional all the way up to the top pipe since each resonating "box" or pipe is proportional to the fundamental frequency.
I'll report on the results of this test later - time is too short.
Best regards,
Stan

[Analogicus]

HOW,

I think TG was aiming his flame dart at me. It seems to have escaped his notice that I mentioned a conjunction of engineering and theology only because he rather ungraciously (in my opinion) scorned the suggestion that anyone one individual could be knowledgeable in both areas! As to bragging, let me put it on record that my assessment of myself would resemble your own self-assessment, very closely.

But to return to the subject of this thread after this unfortunate sidetrack, my original post about the way harmonic structure differs across the range of pipe organ ranks was based simply on the results of many recordings of pipe sounds, which were then subjected to analysis. I have found the Analyser function in Audacity to be very useful in this regard. I can assure you that there is a clear and consistent pattern in the way the harmonic structure alters across a pipe rank, and this applies to reed ranks as well.

Analogicus

[HOW]

Hello Analogicus,
Thank you for your comments and the information regarding the Audacity Analyser. I will test that. Would you agree that the most obvious and very desirable feature of the pipe organ is the indefinite pitch of each pipe, especially when two or more stops are played?
Best regards,
Stan

[Analogicus]

HOW,

Not sure what you mean by "indefinite pitch", but having pipes slightly out of tune with each other and sounding together adds a vibrancy which is very desirable if it is not overdone. As with all such matters, it can become very much a matter of individual taste. The standard soundfont protocols allow you to set the "fine tuning" of individual notes to achieve that result, but as the smallest "off-tune" available is usually one cent, this is not very useful for the notes at the top of the range, because it produces beat rates which are too fast to be pleasant. One workaround is to make samples for those high notes where you have detuned the pitch by less than one cent, and the Audacity Speed-Adjust function comes to the rescue for that. (I prefer that to the Pitch-Adjust function, as I seemed to get better results that way when I was learning to do these things. I find Audacity invaluable, and also Viena from the SynthFont website).

I should warn you that whether or not the beating together of two tones is a pleasant result, depends very much on the nature of those tones and their loudness relative to each other. I tend to avoid tuning differences for tones with the same basic pitch in case it sounds too much like a celeste effect. An exception would be reed stops, where low in the range I certainly detune them from flue stops of the same basic pitch. However I remember one instance where the 8' reed caused an unpleasant beating when used with the main 8' flue stop in the same department, but it only seemed to happen on one particular note, so on that one note I abandoned the reed detuning, making its pitch identical to the flue stop pitch.

Analogicus

[HOW]

Hello Analogicus,
I know indefinite pitch normally refers to the slight variation in pipe frequency depending on the air regulator but yes, I was using this as a "catchall" term so to speak and as you stated that is the great feature of the pipe organ. However, there is another feature that is seldom addressed that we call a traveling wave effect which is similar to the Doppler effect. If one uses an audio signal generator amplified and driving a speaker, the sound is very dead. However, if you walk towards the speaker, you will introduce the traveling wave effect and the sound becomes more alive. I believe the pipe of an organ produces this effect by the air flow causing the wave to travel in outward from the mouth (albeit the wave within the resonant pipe chamber is stationary for the most part.)
Anyway, I further experimented with the difference of using long recorded pipe samples of 1 per note compared to the MOS 1 Allen single period (32 words X 8 bits) which is the same waveform for each note but scanned or read at different rates. (The address points may be repeated for the lower notes which Allen called phase angle processing). The swell division was set up to play the same sounding Allen stops as the great division which was set up to play 30 second recordings or wave files. Other than variations in the recorded samples on certain pipes that might have been "out of spec" I was hard pressed to find any difference in the formant or harmonic structure from C1 to C6. I was using the Hlabs Traveling Wave Generator on the Allen voices to approximate a long recorded sample so far as the "indefinite pitch" is concerned. Keep in mind that I was only concerned with the particular voice identification parameters, not the variation in phase or what not. In other words, the tonal qualities that identify a particular voice were constant from the low notes to the high ones for both the simplistic single wave versus the actual recordings. From this I would conclude that the harmonic structure is constant (so far as the voice identification) throughout the division for both.
Best regards,
Stan