Se connecter
Se connecter

ou
Créer un compte

ou
Agrandir
Le Pub
le Pub fun

Qu'est-ce qui vous amuse automatiquement ?

  • 58 858 réponses
  • 598 participants
  • 1 981 139 vues
  • 478 followers
Sujet de la discussion Qu'est-ce qui vous amuse automatiquement ?
Putain!!! y démarre grave ton topic :mdr:
Afficher le sujet de la discussion
41541
J'aime bien l'explication de Marc Doty, mais ça prend plus de 5 minutes :

Citation :
I just posted this on my Facebook page:

PARAPHONIC vs. POLYPHONIC

It's one of my pet peeves, actually. There seems to be some extensive confusion about what these terms mean, and what they mean in relation to each other.

Even the Wiki page states something ridiculous about "true polyphony."

So, I'm here to set the record straight (in regard to synthesizers).

Monophonic/Monophony: This synthesizer, triggered from a keyboard, can only play one note at a time. Now, depending on the amount of oscillators, more than one note may be heard... but all of these notes will move in tandem when different single notes are played on the keyboard.

Duophonic/Duophony: This synthesizer, triggered from a keyboard, can only play two notes at a time. This term came into being in regard to synthesizers at the point where synthesizer oscillators were modified to be either "low note priority (the lowest voltage is played, all others are ignored)," or "high note priority (the highest voltage is played, all others are ignored)." Synthesizers like the ARP Odyssey, the Moog Sonic Six, and some versions of the ARP 2600 are duophonic. You can play two notes at a time, one for each voltage. Of course, you also need at least two oscillators.

Polyphonic/Polyphony: This synthesizer, triggered from a keyboard, can play two or more notes at a time. Yes, I know... that overlaps with the term "duophonic," but these things can't be helped. "Polyphonic" is a very general term.
In regard to analog synths, there are two types of polyphony.

There is top-octave divide-down polyphony, where the top octave of keys has its notes provided by 12 fixed-pitch oscillators and those frequencies are divided in half to aquire each subsequent descending octave. That means the synthesizer has 12 oscillators, and 12 dividers per octave after that. Every SINGLE note can be played at the same time on this synthesizer. This is, by definition, "true" polyphony. It started in 1939 with the Hammond Novachord, and has been used extensively in a variety of synthesizers up until the 1980s.

There is "limited, but individually-articulated" polyphony. This is polyphony where a microprocessor scans which notes are played when, and applies that information to the available oscillators. This type of polyphony came about with advances in microprocessor technology that made microprocessors less expensive and more available in the 1970s. It allows you to have more control over the articulation of each note, but severely limits the amount of notes that can be played at once. The Sequential Circuits Prophet 5 and the Yamaha CS-80 are examples of this method. The limitation comes in because each note needs a variable oscillator... or even two. And those are expensive.

Of course, with digital technology, polyphony increased from 2 notes to 4 notes to 8 notes to 16 notes, and etc. More powerful computers means more powerful voice allocation and less expensive digital oscillators.

[Note: there is actually a type of polyphony that was created by Harald Bode back in the 1930s which allows electric note allocation, but apart from the Warbo Formant Organ, I don't think it has been implemented anywhere else... I'm really curious about it]

Okay, and that's it. That's the end. Those are the types of polyphony.

"But wait!" You say... "What about PARAPHONY! Isn't that a form of fake or not true or not-quite-real polyphony?"
No, it most certainly IS NOT. It really has NOTHING TO DO WITH polyphony. In fact, every monophonic is ALSO paraphonic.

I know you're running to your favorite online dictionary right now... but I'm going to plow ahead.

"Paraphonic" is a term that has to do with articulation... not a term that has to do with how many notes a synth can generate. A "paraphonic" synthesizer is one where all of the notes generated... from 1 to 1,000,000... go through a single filter and VCA combination. That's it. That is what "paraphonic" means. It's just more noticeable when you're trying to articulate polyphonic passages.

A synthesizer like the ARP Omni is paraphonic. It has a divide-down polyphony scheme, but all of those notes, and every triggering of those notes, is forced through a single filter and VCA. What does this mean? It means you can't have each new note played featuring new filter articulation without having that same articulation occur on the notes you're holding. Or, it means that new notes get articulation, but old notes get nothing. Is that awesome? Well, not really. In fact, people kind of hate it, sometimes. They want each note to trigger a filter and VCA. Which is, I must point out, just like a piano. People really like how each note played has its own volume and filter articulation.

Just like, say, a Prophet 5 or a Memorymoog. But the problem with those is that you run out of notes quite quickly. In the Prophet 5, you only have 5 notes to play before you run out of polyphony. What kind of polyphony is that? SEVERELY limited polyphony. But... people tend to favor it because they like the articulation more than they like the note-count.

Of course, you could always go the route of the Korg PS-3100. It is divide-down, but instead of going the paraphonic route, it has A FILTER AND VCA FOR EVERY SINGLE ONE OF ITS NOTES. Yeah, that gets expensive fast... which is why most manufacturers didn't take that route.

And that is what it comes down to. "Polyphony" is how many notes a synth can play at once. "Paraphony" is the instance where those notes are directed through a single filter/amp combination. Synths can be polyphonic AND paraphonic. Synths can even be monophonic and paraphonic. But the only "real" polyphony is when every note can be played at once... whether you seek individual articulation or not. Instead of saying things like "real polyphony," we should describe full polyphony with full articulation with a term like "ideal polyphony."



Okay, all of that being said... if you really examine this graphic, it's probably most likely that this is a duophonic synth, and not a polyphonic synth. Look at the "duo mode."
41542
En moins longtemps : sur un polyphonique, chaque note a ses propres articulations et son propre filtre.
Sur un paraphonique, tu peux jouer plusieurs notes en même temps, mais elles partagent toutes la même articulation et le même filtre.
41543
Comme quoi ceux qui disent que l'anglais est une langue plus synthétique racontent des conneries... :volatil: :fleche:

Do not take life too seriously. You will never get out of it alive.

41544
Je prefere l'explication de Doty, elle est plus systematique. :oops2:
41545
+1. Mais c'éttait pour résumer pour les organistes qui ne sont pas concernés par les détails vu que chaque note a son tuyau. :bravo:

[ Dernière édition du message le 01/08/2014 à 16:22:18 ]

41546
L'orgue (ptain j'allais dire l'organe icon_facepalm.gif) est en effet un instrument a polyphonie reelle.
41547
polyphonie ET polytimbralité réelles, Môssieur :oops2: Dans les jeux de mixtures, on a même parfois plusieurs tuyaux (de 2 à 13) pour une seule note, chacun donnant des harmoniques différentes de la note piquée (= la note appuyée sur le clavier).

Citation :
c'était pour résumer pour les organistes qui ne sont pas concernés par les détails vu que chaque note a son tuyau

Certes, mais je ne possède ni filtre ni VCA, du coup. :|
41548
Ben si.

Le VCA, c'est en gros la colonne d'air qui entre dans le tuyau plus la bouche ou l'anche. Le filtre, c'est le tuyau.
41549
Oui mais tu as une réverbe extrêmement convaincante, c'est pas rien ça ! :bravo:
41550
La réverbe est bonne certes, mais elle n'est pas réglable :|