Piano World Home Page Forums Our Most Popular Forums Digital Pianos - Electronic Pianos - Synths & Keyboards How important is "polyphony" when buying a digital piano?

Hello everyone.

What exactly is polyphony, and to what degree should it be considered when buying a digital piano?

A friend told me that 128 is the bare minimum; he says I shouldn't really look at anything less or else I'll just be wasting my money.

Thoughts?

Polyphony is how many notes a keyboard can sound at once. If you play more notes simultaneously (i.e. with sustain pedal down) than a keyboard has polyphony, some notes will drop out. (There are actually more variables than this, but that's the basic idea.)

IMO, for most people, using a board for nothing but playing piano, it is not important at all. Also, even if you do care about it, the numbers don't necessarily tell you all you need to know.. the only real test is to play the piano yourself. As I've mentioned here before, I've used a MOX8 with 64-voice polyphony, and if I tried *really* hard, I could coax a dropout out of it (nothing I'd expect to ever be an issue in actual performance)... but the funny thing is, I played the same passage on a lower end Yamaha that had only 32-note polyphony (NP30, I think), and I could not manage to hear a dropout on the same passage that tripped up the MOX! (The NP30 probably just had a better piano-specific note stealing algorithm.)

There are many things that affect the quality of a piano's sound and action... and almost none of them can be determined from reading a spec sheet. I suggest ignoring all the buzzwords (polyphony, graded action, triple sensor, number of velocity layers, etc.) and just play them. Whatever sounds and feels best to you is the one to get, regardless of which "feature" it has or doesn't have. A Yamaha CP1 does not have graded action or triple sensor, yet, weight and cost aside, I don't think anyone would choose a Casio PX-130 (which does have those features) over a Yamaha CP1. So ignore the marketing points on the spec sheets, and trust your fingers and ears.

All that said, where polyphony does start to matter more is perhaps if you intend to start layering sounds, or especially, if you are going to be using it to playback multi-track multi-instrument arrangements, because then you can go through notes a lot more quickly than you would by simply playing a piano sound on it.

Simply put, press the sustain pedal, keep playing scale or full chords without releasing the pedal, and see when these previously played notes start to stop sounding. That is when you reach the maximum of the polyphony of your instrument.

Your personal playing style of how many simultaneous notes make a difference if 128 is enough.

As anotherscott mentions, different manufacturers measure polyphony differently, so you can't really compare polyphony across models or really even know without testing whether it is possible to overwhelm the polyphony in a given piano. When digital pianos were a new invention, low polyphony was sometimes a significant problem, but no current models I'm aware of have this problem. Basically the only time you can get notes to drop out in a modern digital (even a low end one) is when you are trying to do so, hard, by mashing all the keys at once with the sustain down. Even then you often can't do it.

Notice that there are only 88 keys on the piano. What's the chance you will want more than 64 (for example) of them to play at the same time? Even if you do full-piano glissandos you will only play the white keys most likely. And there are only 52 of those. You can think of examples that use more, but they are not common.

In short, with any piano made in the last decade or so I wouldn't worry about polyphony one way or the other for piano playing. If you plan to layer sounds, for example, you can use up the polyphony much faster. Most people don't, though.

Not relevant at all. I don't know of anyone who had problems with polyphony at 32, which was standard 10 years ago. Later came 64 and 128. It just doesn't matter.

It's just a marketing checklist item, as in: you wouldn't sell just ANY leather if your competition is selling "rich Corinthian leather". In the end it's just marketing babble, aka bullcrap.

+1

While we are in agreement that polyphony is pretty much a non-issue, your description does over-state the case a bit. If a piano sound is stereo, than each key uses up two notes of polyphony. It also may be possible, in some implementations, that re-striking the same note (with the pedal down) may use up an additional note of polyphony, so you may not have to play, for example, 32 different stereo-sampled keys to exhaust 64 notes of polyphony. There also may be factors like layer cross-fading and string resonance samples that can effectively reduce polyphony.

But the bottom line is, we all seem to be in agreement, for straight piano use, it generally is not an issue worth worrying about. For years, I gigged with a 32-note-polyphony Casio, and its main sound was stereo which reduced it to 16 note, and even then, in the context of a gig, I don't think I ever noticed a dropped note unless I added a layer of strings, which effectively lowered polyphony to 11... and even then, I only noticed it a handful of times! So with today's boards having a minimum of 64, I wouldn't give it a thought unless I knew I had a specific application likely to create an issue. Straight piano playing? Nah.

+1

and speaking of...
http://www.youtube.com/watch?v=E_HMIN0nGl0

I started with 32 voices on a Roland, but all sounds had layers of some kind and that reduces the polyphony to a level that midi timing and note steeling became indeed a problem. Next stage was a 24 polyphony machine, by that one also had stereo sample - cutting the count in half - cross fading over the velocity layers and multiple layers. Again note steeling was audible. Next Board was 48 voices. That one also had some issues, because as polyphony increased, the programmers where tempted to use more layers and other effects that ate up voices. Only from 64 voices and up I found piano only voices to be playable without any voice steeling effects. And that is piano only, meaning no additional sounds, sequences etc added to the basic sound.

So 128 seems to be save, but for multiple layered stereo sounds more may be needed. Of course , by then you're not purely playing AP or EP anymore but acting in another league (workstation / sequencing / arranger). It would be nice if the manufacturers could tell us of all these nice new resonance effects etc eat into your polyphony count. If not 128 should be more than fine.

My personal experience with polyphony:
As a classical pianist playing relatively advance repertoire, I noticed frequent dropouts on my first keyboard (Yamaha DGX-620 with 32 note polyphony) and occasional dropouts on other 64 note board I've tried...never have I had major problems with 128 note polyphony boards except in extremely uncommon situations (Large chords with 2 hands, followed by arpeggios and lets say a very long trill or trill like ornament on a group of notes all without change of pedal).

256 note polyphony? Can't imagine maxing that out with solo piano alone; seems to me like the safest number without being terribly overboard (but then again, depending on personal usage, people may disagree wholeheartedly)

Kawai's PHI system triggers voices, from keys you are holding down, that are relative octaves and fifths away from keys that are subsequently pressed. Holding down a 4 note chord and then playing 2 more notes will use 6 stereo voices(12 notes) and potentially trigger 4 to 6 sympathetic voices. A 6 note chord could possibly use up a whopping 24 voices of polyphony. Kawai's polyphony is claimed to be 256.

That's an interesting case where high polyphony means something... not because of anything magic about lots of polyphony itself, but because their particular sound engine makes higher demands of polyphony than most.

And that points out, again, the futility of just comparing numbers. A 64-note-of-polyphony board could theoretically go further without note stealing than a 128, if the tone implementation on the 64 is inherently less demanding.

I used to practice on a PX-575 Casio that had 32 voices. I was surprised that with playing the material I was practicing at the time(the same stuff I still seem to be practicing), 4 to 6 voice jazz chords with solo lines, I never really noticed a polyphony issue.

Polyphony is important with workstations and such but not as much on digital pianos, 192-256 can be important on workstations and synths due to layered arpeggiation, this could not be achieved under 128 and whole arpeggiations would be cut out and layers, take for instance a 7 note chord thats arpegiated up and down with a synth program that uses 6 layers, you now are using 42notes and then arpeggiate that, and now add in a new sound while that plays, you can start to see how quickly 128 can disappear.

Unless you are planning to practice pieces that requires huge sustained chords (like Rachmaninoff's "It" Prelude), don't worry about polyphony, especially the numbers.

I personally am more interested on how the already playing notes are taken away when one asks for more notes than the instrument can offer. The "note stealing" algorithm can differ depending on brand and model, etc.

Two very easy tests to verify this is, first, with sustain pedal on : play a loud bass note, then do very soft runs in the mid/high registers. If the "note stealing" algorithm is well done, this bass note should continue to decay as normal, even if you play twice as many notes than the polyphony can give.

The second easy test is to strike a loud 8 note chord with both hands with sustain pedal on in the mid register, then play much softer runs above and below that loud chord, including in the bass. In this case, a good algorithm will be able to keep most of the loud chord decaying as normal, without giving advantage to the soft ones nor the soft bass note struck afterwards.

So if ever you are concerned with polyphony (which again is not very important after all), those two very simple tests will tell you more in a few seconds than all the specs and numbers you can read.

Lots of responses, but I think the OP can have a simple rule of thumb.

If it is for solo piano or simple duets, 2 track recording, 64 note is plenty for 98% of the piano playing population.

If you are layering tracks, 2 or more including complex tones, rhythms or samples, then 128 note is a safer number.

The need can become complicated for certain older models, synths and workstation applications, but I think that is good enough for current DP's.

I think there are two aspects: a) whether or not you'll notice dropouts, and b) whether or not you'd notice a general improvement in the tone if you had more polyphony. As most have said, I wouldn't be concerned about a) these days. Regarding b), I'm not sure. It's definitely conceivable that with more polyphony, the sympathetic resonance might improve, producing a more pleasing, fuller sound when using the sustain pedal.

Greg.

I feel compelled to write this again. I owned a GranTouch for 12 years with 32 (though I remember reading 30 in the literature) note polyphony.

I never encountered any dropped notes that I was ever aware of.

I remember a time when the 32 note polyphony on the DX1 was considered such a incredible and amazing thing. People could never see it as being ever used up. Never dropped a note on that I can recall. Never dropped one on a DX7 either which had "only" 16 polyphony which was also considered pretty amazing in 1983. Today it only matters when things like multilayer stereo samples can use up 4 notes of poly in a single key press.