Disklavier

Recently I have heard about supposed limitations of the MIDI 
interface vis-a-vis the Disklavier.  Perhaps someone can explain to 
me whether this is in fact true, and whether such limitations -if 
indeed they do exist - are audible.

The argument is that a MIDI interface outputs the signal 
sequentially - it serially outputs notes to be played, and so (it is 
said) chords from piano roll emulations are not played back in 
perfect synchronization but instead are slightly arpeggio'd, or 
broken. (Especially in comparison to, say, a pneumatic roll piano 
player which can activate virtually any number of simultaneous 
keystrokes  completely in parallel.) I have always understood the 
Disklavier to be able to record and play back up to 16 notes 
simultaneously.

Assuming the limitation described above is real,

1.  Is it material, i.e. can it possibly be audible, to a well-
trained ear?

2.  Is the problem interface-bandwidth-dependent? e.g. worse with a  
RS-232 serial interface and better with a USB interface?  (and what 
speed is the Disklavier's MIDI-in interface capable of?)

3.  Does the Disklavier buffer the MIDI playback signal so that the 
output to the solenoids is parallel when it needs to be?

4.  Does conversion of MIDI files to ESEQ format eliminate the 
problem?

5.  Relative to this problem, does it matter whether the MIDI output 
is from an I/O device within the Disklavier control unit, vs. a 
signal from an external PC?

6.  Is the problem greater with older model Disklaviers?

Personally I have not experienced this problem, and I listen to 
piano roll emulations frequently on a Mark II Disklavier.  Pianists 
often play broken chords anyway, so I'm not sure how one tells which 
chords are supposed to be all-at-once. ( There must be a term for 
this but sorry I don't know it. )

Any facts someone can bring to bear on this would be appreciated, 
and probably of general interest.

Mike McGregor
Double Oak, TX

Mike, I do not have the definitive answer to your question, but I have 
some thoughts.

It's pretty difficult to make measurements that would answer your 
question.  Here's why:  Suppose you wrote MIDI files with two, three, . 
. . up to 16 simultaneous notes, put them on a diskette, and played 
them.  With a DAT recorder, you could audio-record the result and 
examine the resulting audio waveforms using software like Sound Forge or 
Cool Edit.  When you looked at the summed waveforms of all the notes, 
however, you would see a scramble of the initial transients of all the 
notes piled upon one other.  You would not be able to distinguish any 
particular note lagging another unless the timing error were really 
gross.  Playing through and recording just 15 files would not be 
sufficient.  You would also need to vary the velocities of the notes in 
the range of, say, 20 through 100, and, in addition, you should vary the 
Disklavier volume control setting in steps from, say, 0 to say -9.  All 
of this would be a lot of work and wouldn't yield the answer to your 
question.

The approach to take is not to try to determine how many milliseconds 
the timing errors are, but to listen for a problem (and no fair watching 
the keys).  Can you detect any timing differences aurally?  As you've 
indicated, you haven't discerned a problem.  I can't say that I have 
either, at least not with PianoSoft diskettes.

Here's what I have to offer:  One of the experiments that I have done 
with the Disklavier was to determine the timing accuracy of my Mark II 
from recording to diskette through reproduction.  I played a series of 
random legato notes about one second apart at various random velocities. 
  While playing those notes, I recorded, simultaneously,

1) E-SEQ to a Disklavier diskette

and

2) to a DAT with microphones connected.

Using Sound Forge, I determined to within a millisecond the time 
differences between the starts of the notes that I played.  (With the 
notes separated by about a second, it was easy to read the time where 
each started.)  I then played the Disklavier diskette (Volume = 0), 
recorded the audio again with the DAT, and compared the note initiation 
time differences as reproduced with that as originally played.  Here's 
what I found:

1) At note velocities between 80 and 100, 90% of the timing errors were 
within plus or minus 5 milliseconds.

2) At note velocities between 20 and 40, 90% of the timing errors were 
within plus or minus 15 milliseconds.

Those results don't apply directly to your question, but suppose the 
timing errors within a chord did run 5 to 15 milliseconds.  Would it be 
possible to hear unwanted arpeggiation?  Here's my opinion based on a 
short experiment using Sound Forge:  As one approaches 10 milliseconds 
time difference between two notes that are supposed to be played 
simultaneously, the playing does begin to sound a little sloppy. 
(Anyone is free to disagree with me.)

Based on the foregoing, I would expect that if you are experiencing 
arpeggiation of chords, you may be able to improve things by raising the 
velocity of the notes in the chord or by operating the Disklavier at a 
higher volume setting.

In summary, there are timing errors introduced by:

1) the pianist (as Mike pointed out)

2) the Disklavier recording process

3) the Disklavier reproduction process

In the design of the Disklavier, there are surely many engineering 
compromises.  For example, the keyboard and hammer motions are serially 
sampled; even at very high speed, timing errors, however small, must 
occur.  The important issue is: Overall, does the Disklavier, despite 
its engineering compromises, perform to your satisfaction?  Any 
detractor can rant about the engineering compromises inherent to the 
Disklavier and to the MIDI protocol, but do those compromises 
significantly--even noticeably--impair performance as you hear it?  And, 
could you afford a better alternative if there were one?

 >(and what
 > speed is the Disklavier's MIDI-in interface capable of?)

+++ All MIDI interfaces transmit and receive at 31,250 baud.  That's in 
the MIDI specification.

 > 3.  Does the Disklavier buffer the MIDI playback signal so that the
 > output to the solenoids is parallel when it needs to be?

+++ The Disklavier does buffer playback for about 0.5 seconds.  I don't 
know how closely in time two or more solenoids can be driven.  What does 
it matter to the listener if a timing error is present but is too small 
to be aurally detected?

 > 4.  Does conversion of MIDI files to ESEQ format eliminate the
 > problem?

+++ I've never been able to detect any difference in performance (as 
recorded on DAT and observed with Sound Forge) between a MIDI file and 
its corresponding E-SEQ file.

Be aware, however, that in playing the same E-SEQ file (or MIDI, for 
that matter) twice in a row (on my Mark II anyway), you will find 
differences in note timing betwen the two successive playings.  The 
errors are on the order of 5 milliseconds for note velocities of 40 to 
100, and up to 15 milliseconds at note velocities of about 20.  I can 
measure those errors using Sound Forge, but I could never hope to detect 
them by ear.

 > 5.  Relative to this problem, does it matter whether the MIDI output
 > is from an I/O device within the Disklavier control unit, vs. a
 > signal from an external PC?

+++ It depends.  An old PC I once had (running Windows 3.1) would 
lug-down, with Cakewalk used as a sequencer, if I started using Windows 
Explorer (or whatever it was then).  Now, with the commonly used 
machines and OS's, and with reasonable care, I wouldn't expect a problem.
-- 
Robert Welcyng
Anchorage, Alaska

Mike,

Some thoughts from my side: Even if you forget Midi, and just look at 
the basic recording/reproduction capabilities of the disklavier, there 
are limitations due to the mechanical and electrical design. If you are 
a critical listener and especially with classical music, you wiill know 
that on order to play an accent in a chord, you basically play arpeggio, 
in order to place the accent on the note where you want it to be. Now 
your fingers/ears are faster then the "resolution" of the Disklavier. 
This results in the reproduction of an arpegio that might be 5 ms into 
15 ms, as this is the fastest "resolution" of the Disklavier. ( do not 
take these figures as absolutes, they are just to illustrate the point).

Can you hear the difference?  Some people can,  my pianoteacher could, 
sometimes it just "hears" different. In pieces like Songs Without Word 
from Mendelssohn, where the accents  are extremely important, you might 
be hearing this easier then in Rags from Joplin.

I did some subjective tests taking a purchased recording that I play on 
my old MX100B to a new PRO model, and I found it noticable better, but 
then, it could also be that the Pro model was newer and better 
regulated. I have not been able to confirm from Yamaha, that the minimum 
"resolution" as I call it in laymans terms, has increased between the 
older and the Pro models.

Greetings from Curacao,  

Winfried.

Robert Welcyng wrote:

>Mike, I do not have the definitive answer to your question, but I have 
>some thoughts.
>
>It's pretty difficult to make measurements that would answer your 
>question.  Here's why:  Suppose you wrote MIDI files with two, three, . 
>. . up to 16 simultaneous notes, put them on a diskette, and played 
>them.  With a DAT recorder, you could audio-record the result and 
>examine the resulting audio waveforms using software like Sound Forge or 
>Cool Edit.  When you looked at the summed waveforms of all the notes, 
>however, you would see a scramble of the initial transients of all the 
>notes piled upon one other.  You would not be able to distinguish any 
>particular note lagging another unless the timing error were really 
>gross.  Playing through and recording just 15 files would not be 
>sufficient.  You would also need to vary the velocities of the notes in 
>the range of, say, 20 through 100, and, in addition, you should vary the 
>Disklavier volume control setting in steps from, say, 0 to say -9.  All 
>of this would be a lot of work and wouldn't yield the answer to your 
>question.
>
>The approach to take is not to try to determine how many milliseconds 
>the timing errors are, but to listen for a problem (and no fair watching 
>the keys).  Can you detect any timing differences aurally?  As you've 
>indicated, you haven't discerned a problem.  I can't say that I have 
>either, at least not with PianoSoft diskettes.
>
>Here's what I have to offer:  One of the experiments that I have done 
>with the Disklavier was to determine the timing accuracy of my Mark II 
>from recording to diskette through reproduction.  I played a series of 
>random legato notes about one second apart at various random velocities. 
>  While playing those notes, I recorded, simultaneously,
>
>1) E-SEQ to a Disklavier diskette
>
>and
>
>2) to a DAT with microphones connected.
>
>Using Sound Forge, I determined to within a millisecond the time 
>differences between the starts of the notes that I played.  (With the 
>notes separated by about a second, it was easy to read the time where 
>each started.)  I then played the Disklavier diskette (Volume = 0), 
>recorded the audio again with the DAT, and compared the note initiation 
>time differences as reproduced with that as originally played.  Here's 
>what I found:
>
>1) At note velocities between 80 and 100, 90% of the timing errors were 
>within plus or minus 5 milliseconds.
>
>2) At note velocities between 20 and 40, 90% of the timing errors were 
>within plus or minus 15 milliseconds.
>
>Those results don't apply directly to your question, but suppose the 
>timing errors within a chord did run 5 to 15 milliseconds.  Would it be 
>possible to hear unwanted arpeggiation?  Here's my opinion based on a 
>short experiment using Sound Forge:  As one approaches 10 milliseconds 
>time difference between two notes that are supposed to be played 
>simultaneously, the playing does begin to sound a little sloppy. 
>(Anyone is free to disagree with me.)
>
>Based on the foregoing, I would expect that if you are experiencing 
>arpeggiation of chords, you may be able to improve things by raising the 
>velocity of the notes in the chord or by operating the Disklavier at a 
>higher volume setting.
>
>In summary, there are timing errors introduced by:
>
>1) the pianist (as Mike pointed out)
>
>2) the Disklavier recording process
>
>3) the Disklavier reproduction process
>
>In the design of the Disklavier, there are surely many engineering 
>compromises.  For example, the keyboard and hammer motions are serially 
>sampled; even at very high speed, timing errors, however small, must 
>occur.  The important issue is: Overall, does the Disklavier, despite 
>its engineering compromises, perform to your satisfaction?  Any 
>detractor can rant about the engineering compromises inherent to the 
>Disklavier and to the MIDI protocol, but do those compromises 
>significantly--even noticeably--impair performance as you hear it?  And, 
>could you afford a better alternative if there were one?
>
> >(and what
> > speed is the Disklavier's MIDI-in interface capable of?)
>
>+++ All MIDI interfaces transmit and receive at 31,250 baud.  That's in 
>the MIDI specification.
>
> > 3.  Does the Disklavier buffer the MIDI playback signal so that the
> > output to the solenoids is parallel when it needs to be?
>
>+++ The Disklavier does buffer playback for about 0.5 seconds.  I don't 
>know how closely in time two or more solenoids can be driven.  What does 
>it matter to the listener if a timing error is present but is too small 
>to be aurally detected?
>
> > 4.  Does conversion of MIDI files to ESEQ format eliminate the
> > problem?
>
>+++ I've never been able to detect any difference in performance (as 
>recorded on DAT and observed with Sound Forge) between a MIDI file and 
>its corresponding E-SEQ file.
>
>Be aware, however, that in playing the same E-SEQ file (or MIDI, for 
>that matter) twice in a row (on my Mark II anyway), you will find 
>differences in note timing betwen the two successive playings.  The 
>errors are on the order of 5 milliseconds for note velocities of 40 to 
>100, and up to 15 milliseconds at note velocities of about 20.  I can 
>measure those errors using Sound Forge, but I could never hope to detect 
>them by ear.
>
> > 5.  Relative to this problem, does it matter whether the MIDI output
> > is from an I/O device within the Disklavier control unit, vs. a
> > signal from an external PC?
>
>+++ It depends.  An old PC I once had (running Windows 3.1) would 
>lug-down, with Cakewalk used as a sequencer, if I started using Windows 
>Explorer (or whatever it was then).  Now, with the commonly used 
>machines and OS's, and with reasonable care, I wouldn't expect a problem.
>

Winfried and all,

You are quite correct that there are measurable errors in the recording 
and reproduction of the Disklavier Mark II.  At least that is what I 
have found on mine.  The regulation of my Mark II has been maintained to 
the satisfaction of my RPT and the keyboard and pedal calibrations have 
been  periodically performed.  The measurable discrepancies between what 
is played and what is reproduced are not limited to timing, but also 
include loudness.

Also, the same file played twice or more consecutively, reproduces 
slightly differently each time, both in loudness and timing.

The magnitude of the errors (that I have found on mine) is generally 
dependent on the note velocity.  For example, with the Volume control 
set to "0", notes that were recorded at a velocity of about 100 are 
reproduced with a sound power from 1 to 4 dB softer than what was 
played; notes that were recorded at a velocity of about 25 are 
reproduced at a sound power of from 1 to 5 dB louder than what was 
played; notes that were recorded at a velocity of about 60 are 
reproduced at a sound power of from 0.5 to 2 dB louder than what was 
played.

With the Volume control set to "0", the sound output limits for note 
velocity values from 93 to 127--that is, there will be no difference in 
the loudness of a particular note whether its velocity is 93, 110, or 
127.  In order to hear those gradations in dynamics, you would need to 
set the Volume control to "-4".

Once again, the magnitude of error may or may not be noticeable, 
depending upon what is being played and who is listening.  Maximizing 
the profit of a product evidently doesn't require satisfying the most 
astute consumer.

Unfortunately, judging accuracy by ear is a very subjective process. If 
you are going to try that, and if you wish to approach the truth, I 
suggest a "blind" test wherein the evaluators do not know whether they 
are listening to an original performance or to a reproduction and can 
only sort them out later through coded names.

A comment on playing the old PianoSoft disks on the Pro:  The 
information that a Pro recording includes--that is the fine continuous 
time record of the key and pedal positions--is absent in an old 
PianoSoft disk.  Without the benefit of that information, the Pro's 
potential for accurate reproduction cannot be exploited.  To truly 
evaluate the Pro, you must listen to a Pro with a Pro recording.  A 
PianoSoft file cannot do it justice.

Yamaha surely knows its market which is probably why they have focused 
on the XG and now the CD features.  However, why, after developing the 
Pro and bringing it to market several years ago, Yamaha has not 
commissioned solo re-recordings targeted at Pro owners simply confounds me.

--Bob Welcyng



winfried wrote:

> Mike,
> 
> Some thoughts from my side: Even if you forget Midi, and just look at 
> the basic recording/reproduction capabilities of the disklavier, there 
> are limitations due to the mechanical and electrical design. If you are 
> a critical listener and especially with classical music, you wiill know 
> that on order to play an accent in a chord, you basically play arpeggio, 
> in order to place the accent on the note where you want it to be. Now 
> your fingers/ears are faster then the "resolution" of the Disklavier. 
> This results in the reproduction of an arpegio that might be 5 ms into 
> 15 ms, as this is the fastest "resolution" of the Disklavier. ( do not 
> take these figures as absolutes, they are just to illustrate the point).
> 
> Can you hear the difference?  Some people can,  my pianoteacher could, 
> sometimes it just "hears" different. In pieces like Songs Without Word 
> from Mendelssohn, where the accents  are extremely important, you might 
> be hearing this easier then in Rags from Joplin.
> 
> I did some subjective tests taking a purchased recording that I play on 
> my old MX100B to a new PRO model, and I found it noticable better, but 
> then, it could also be that the Pro model was newer and better 
> regulated. I have not been able to confirm from Yamaha, that the minimum 
> "resolution" as I call it in laymans terms, has increased between the 
> older and the Pro models.
> 
> Greetings from Curacao,  
> 
> Winfried.
> 
> Robert Welcyng wrote:
> 
> 
>>Mike, I do not have the definitive answer to your question, but I have 
>>some thoughts.
>>
>>It's pretty difficult to make measurements that would answer your 
>>question.  Here's why:  Suppose you wrote MIDI files with two, three, . 
>>. . up to 16 simultaneous notes, put them on a diskette, and played 
>>them.  With a DAT recorder, you could audio-record the result and 
>>examine the resulting audio waveforms using software like Sound Forge or 
>>Cool Edit.  When you looked at the summed waveforms of all the notes, 
>>however, you would see a scramble of the initial transients of all the 
>>notes piled upon one other.  You would not be able to distinguish any 
>>particular note lagging another unless the timing error were really 
>>gross.  Playing through and recording just 15 files would not be 
>>sufficient.  You would also need to vary the velocities of the notes in 
>>the range of, say, 20 through 100, and, in addition, you should vary the 
>>Disklavier volume control setting in steps from, say, 0 to say -9.  All 
>>of this would be a lot of work and wouldn't yield the answer to your 
>>question.
>>
>>The approach to take is not to try to determine how many milliseconds 
>>the timing errors are, but to listen for a problem (and no fair watching 
>>the keys).  Can you detect any timing differences aurally?  As you've 
>>indicated, you haven't discerned a problem.  I can't say that I have 
>>either, at least not with PianoSoft diskettes.
>>
>>Here's what I have to offer:  One of the experiments that I have done 
>>with the Disklavier was to determine the timing accuracy of my Mark II 
>>
>>from recording to diskette through reproduction.  I played a series of 
> 
>>random legato notes about one second apart at various random velocities. 
>> While playing those notes, I recorded, simultaneously,
>>
>>1) E-SEQ to a Disklavier diskette
>>
>>and
>>
>>2) to a DAT with microphones connected.
>>
>>Using Sound Forge, I determined to within a millisecond the time 
>>differences between the starts of the notes that I played.  (With the 
>>notes separated by about a second, it was easy to read the time where 
>>each started.)  I then played the Disklavier diskette (Volume = 0), 
>>recorded the audio again with the DAT, and compared the note initiation 
>>time differences as reproduced with that as originally played.  Here's 
>>what I found:
>>
>>1) At note velocities between 80 and 100, 90% of the timing errors were 
>>within plus or minus 5 milliseconds.
>>
>>2) At note velocities between 20 and 40, 90% of the timing errors were 
>>within plus or minus 15 milliseconds.
>>
>>Those results don't apply directly to your question, but suppose the 
>>timing errors within a chord did run 5 to 15 milliseconds.  Would it be 
>>possible to hear unwanted arpeggiation?  Here's my opinion based on a 
>>short experiment using Sound Forge:  As one approaches 10 milliseconds 
>>time difference between two notes that are supposed to be played 
>>simultaneously, the playing does begin to sound a little sloppy. 
>>(Anyone is free to disagree with me.)
>>
>>Based on the foregoing, I would expect that if you are experiencing 
>>arpeggiation of chords, you may be able to improve things by raising the 
>>velocity of the notes in the chord or by operating the Disklavier at a 
>>higher volume setting.
>>
>>In summary, there are timing errors introduced by:
>>
>>1) the pianist (as Mike pointed out)
>>
>>2) the Disklavier recording process
>>
>>3) the Disklavier reproduction process
>>
>>In the design of the Disklavier, there are surely many engineering 
>>compromises.  For example, the keyboard and hammer motions are serially 
>>sampled; even at very high speed, timing errors, however small, must 
>>occur.  The important issue is: Overall, does the Disklavier, despite 
>>its engineering compromises, perform to your satisfaction?  Any 
>>detractor can rant about the engineering compromises inherent to the 
>>Disklavier and to the MIDI protocol, but do those compromises 
>>significantly--even noticeably--impair performance as you hear it?  And, 
>>could you afford a better alternative if there were one?
>>
>>
>>>(and what
>>>speed is the Disklavier's MIDI-in interface capable of?)
>>>
>>+++ All MIDI interfaces transmit and receive at 31,250 baud.  That's in 
>>the MIDI specification.
>>
>>
>>>3.  Does the Disklavier buffer the MIDI playback signal so that the
>>>output to the solenoids is parallel when it needs to be?
>>>
>>+++ The Disklavier does buffer playback for about 0.5 seconds.  I don't 
>>know how closely in time two or more solenoids can be driven.  What does 
>>it matter to the listener if a timing error is present but is too small 
>>to be aurally detected?
>>
>>
>>>4.  Does conversion of MIDI files to ESEQ format eliminate the
>>>problem?
>>>
>>+++ I've never been able to detect any difference in performance (as 
>>recorded on DAT and observed with Sound Forge) between a MIDI file and 
>>its corresponding E-SEQ file.
>>
>>Be aware, however, that in playing the same E-SEQ file (or MIDI, for 
>>that matter) twice in a row (on my Mark II anyway), you will find 
>>differences in note timing betwen the two successive playings.  The 
>>errors are on the order of 5 milliseconds for note velocities of 40 to 
>>100, and up to 15 milliseconds at note velocities of about 20.  I can 
>>measure those errors using Sound Forge, but I could never hope to detect 
>>them by ear.
>>
>>
>>>5.  Relative to this problem, does it matter whether the MIDI output
>>>is from an I/O device within the Disklavier control unit, vs. a
>>>signal from an external PC?
>>>
>>+++ It depends.  An old PC I once had (running Windows 3.1) would 
>>lug-down, with Cakewalk used as a sequencer, if I started using Windows 
>>Explorer (or whatever it was then).  Now, with the commonly used 
>>machines and OS's, and with reasonable care, I wouldn't expect a problem.
>>
>>
> 
> 
> 
> 
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-- 
Robert Welcyng
Anchorage, Alaska

Dear Robert and Winfried,


Thank you so much for your thoughtful answers to my questions about 
MIDI limitations.  Who would have thought that answers would have 
originated from both the "frozen north" and from the tropics.  Lest 
I give offense, I hasten to add that I have not visited either spot, 
and also that I have heard glowing reports about life in both places.

I am quite satisfied with the performance of my Disklavier, but I 
also am aware that (at least the non-pro models) do not capture all 
of the nuances of the original performances, and wanted to know more 
about the limitations. I will try listening at a louder volume and 
see if I detect a difference. (Generally, louder playback gives one 
a different, and usually more favorable, impression of audio 
recordings, so I suppose I will have to guard against that.)

I would like to mention one piano roll piece that contains a great 
number of chords that have many notes - the Duo-Art emulation of "An 
American In Paris."  The chords seem to be struck exactly at the 
same time.

Again, thanks for satisfying my curiosity.  One of the most 
significant new facts that I learned is that the Disklavier 
solenoids are serially activated. So making the inputs parallel 
would not fix everything.  

The Mark III solenoids are supposedly more powerful than those of 
the Mark II.  I wonder if that would make a difference.  (Mine is a 
Mark II.)

Mike McGregor

You're certainly welcome, Mike.

A couple of clarifications . . .

I was not advocating listening to the DKV at the the highest tolerable 
volume setting, but rather pointing out that the errors of reproduction 
do vary with note velocity.  Any interesting performance will encompass 
a range of note velocities; each note across that range will be 
reproduced with varying accuracy depending somewhat upon its individual 
velocity.  There is little you can do about that unless you happen to be 
the author of the file.  If you, as originator of the file, are having 
trouble reproducing trills and soft notes, for example, try increasing 
those note velocities.

The choice of the Volume setting is a whole other story, depending upon 
whether you're seeking the most accurate reproduction of the original or 
  just comfortable listening.  For critical auditioning of a performance 
recorded on a Mark II, set the Volume to "0" (and realize that there are 
still some inaccuracies in the reproduction).  For casual listening, set 
the Volume to a comfortable level; by doing so, you may sacrifice the 
original sound power and the dynamic range, but you will be able to 
enjoy the music.

For the record, I didn't state that "the Disklavier solenoids are 
serially activated".  Sixteen solenoids might well be driven in 
parallel.  I am reasonably certain that the keyboard and hammers are 
serially scanned, however.

It would be interesting to make measurements on both a Mark III and Pro 
and compare their accuracy of reproduction with the Mark II.

-- Bob Welcyng





mcgregor2play wrote:

> Dear Robert and Winfried,
> 
> 
> Thank you so much for your thoughtful answers to my questions about 
> MIDI limitations.  Who would have thought that answers would have 
> originated from both the "frozen north" and from the tropics.  Lest 
> I give offense, I hasten to add that I have not visited either spot, 
> and also that I have heard glowing reports about life in both places.
> 
> I am quite satisfied with the performance of my Disklavier, but I 
> also am aware that (at least the non-pro models) do not capture all 
> of the nuances of the original performances, and wanted to know more 
> about the limitations. I will try listening at a louder volume and 
> see if I detect a difference. (Generally, louder playback gives one 
> a different, and usually more favorable, impression of audio 
> recordings, so I suppose I will have to guard against that.)
> 
> I would like to mention one piano roll piece that contains a great 
> number of chords that have many notes - the Duo-Art emulation of "An 
> American In Paris."  The chords seem to be struck exactly at the 
> same time.
> 
> Again, thanks for satisfying my curiosity.  One of the most 
> significant new facts that I learned is that the Disklavier 
> solenoids are serially activated. So making the inputs parallel 
> would not fix everything.  
> 
> The Mark III solenoids are supposedly more powerful than those of 
> the Mark II.  I wonder if that would make a difference.  (Mine is a 
> Mark II.)
> 
> Mike McGregor
> 
> 
> 
> To Post a message to the group, send it to:   disklavier@...
> 
> To Post a private message to Todd Muncy, the group's founder and moderator, send it to:
> disklavier-owner@...
> 
> To reach our group's web site go to:
> http://Yahoogroups.com/group/disklavier
> 
> Todd's family web site was completely rewritten in June 2001 and contains some fun disklavier content and links to midi sites among other things, The url is:
> http://MuncyFamily.com
> 
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> 
> 
> 
> 


-- 
Robert Welcyng
Anchorage, Alaska

Hello all,

I think that Robert has got the limitations of the Disklavier just about
right. Some academic researchers published a paper on the accuracy of
the (Mark II) Disklavier last year. They found that the accuracy of the
recording was better than the accuracy of the playback. In particular
the timing accuracy of the playback of soft notes was poor and the
solenoids did not reproduce high midi velocities (there's no audible
difference between a midi velocity of 100 and 120). 
        If anyone's interested in the full details there's a paper
online with full details of their measurements at http://ftp.ai.univie.a
c.at/papers/oefai-tr-2001-27.pdf.
        The original query related to piano roll conversions played back
on the Disklavier. Piano rolls had their own timing problems and I'd
have thought that timing problems are much more likely to be a function
of the original roll (and its conversion to midi) than errors produced
by the Disklavier.
Hope this is helpful
Mick
>
>You are quite correct that there are measurable errors in the recording 
>and reproduction of the Disklavier Mark II.  At least that is what I 
>have found on mine.  The regulation of my Mark II has been maintained to 
>the satisfaction of my RPT and the keyboard and pedal calibrations have 
>been  periodically performed.  The measurable discrepancies between what 
>is played and what is reproduced are not limited to timing, but also 
>include loudness.
>
>Also, the same file played twice or more consecutively, reproduces 
>slightly differently each time, both in loudness and timing.
>
>The magnitude of the errors (that I have found on mine) is generally 
>dependent on the note velocity.  For example, with the Volume control 
>set to "0", notes that were recorded at a velocity of about 100 are 
>reproduced with a sound power from 1 to 4 dB softer than what was 
>played; notes that were recorded at a velocity of about 25 are 
>reproduced at a sound power of from 1 to 5 dB louder than what was 
>played; notes that were recorded at a velocity of about 60 are 
>reproduced at a sound power of from 0.5 to 2 dB louder than what was 
>played.
>
>With the Volume control set to "0", the sound output limits for note 
>velocity values from 93 to 127--that is, there will be no difference in 
>the loudness of a particular note whether its velocity is 93, 110, or 
>127.  In order to hear those gradations in dynamics, you would need to 
>set the Volume control to "-4".
>
>Once again, the magnitude of error may or may not be noticeable, 
>depending upon what is being played and who is listening.  Maximizing 
>the profit of a product evidently doesn't require satisfying the most 
>astute consumer.
>
>Unfortunately, judging accuracy by ear is a very subjective process. If 
>you are going to try that, and if you wish to approach the truth, I 
>suggest a "blind" test wherein the evaluators do not know whether they 
>are listening to an original performance or to a reproduction and can 
>only sort them out later through coded names.
>
>A comment on playing the old PianoSoft disks on the Pro:  The 
>information that a Pro recording includes--that is the fine continuous 
>time record of the key and pedal positions--is absent in an old 
>PianoSoft disk.  Without the benefit of that information, the Pro's 
>potential for accurate reproduction cannot be exploited.  To truly 
>evaluate the Pro, you must listen to a Pro with a Pro recording.  A 
>PianoSoft file cannot do it justice.
>
>Yamaha surely knows its market which is probably why they have focused 
>on the XG and now the CD features.  However, why, after developing the 
>Pro and bringing it to market several years ago, Yamaha has not 
>commissioned solo re-recordings targeted at Pro owners simply confounds me.
>
>--Bob Welcyng
>
>
>
-- 
mick hamer

Thank you Mick for pointing out this paper.  Although the authors did 
not fully answer their title question, "Are computer-controlled pianos a 
reliable tool in music performance research?", I thought their approach 
and exposition of the timing and sound power errors were excellent. 
What is now needed to complete the answer to their question are 
measurements on human perception:  How much of a timing error or sound 
power error is perceptible?

I am looking forward to one day reading a parallel paper on the Mark III 
and Pro.

--Bob Welcyng

mick hamer wrote:

> Hello all,
> 
> I think that Robert has got the limitations of the Disklavier just about
> right. Some academic researchers published a paper on the accuracy of
> the (Mark II) Disklavier last year. They found that the accuracy of the
> recording was better than the accuracy of the playback. In particular
> the timing accuracy of the playback of soft notes was poor and the
> solenoids did not reproduce high midi velocities (there's no audible
> difference between a midi velocity of 100 and 120). 
>         If anyone's interested in the full details there's a paper
> online with full details of their measurements at http://ftp.ai.univie.a
> c.at/papers/oefai-tr-2001-27.pdf.
>         The original query related to piano roll conversions played back
> on the Disklavier. Piano rolls had their own timing problems and I'd
> have thought that timing problems are much more likely to be a function
> of the original roll (and its conversion to midi) than errors produced
> by the Disklavier.
> Hope this is helpful
> Mick
> 
>>You are quite correct that there are measurable errors in the recording 
>>and reproduction of the Disklavier Mark II.  At least that is what I 
>>have found on mine.  The regulation of my Mark II has been maintained to 
>>the satisfaction of my RPT and the keyboard and pedal calibrations have 
>>been  periodically performed.  The measurable discrepancies between what 
>>is played and what is reproduced are not limited to timing, but also 
>>include loudness.
>>
>>Also, the same file played twice or more consecutively, reproduces 
>>slightly differently each time, both in loudness and timing.
>>
>>The magnitude of the errors (that I have found on mine) is generally 
>>dependent on the note velocity.  For example, with the Volume control 
>>set to "0", notes that were recorded at a velocity of about 100 are 
>>reproduced with a sound power from 1 to 4 dB softer than what was 
>>played; notes that were recorded at a velocity of about 25 are 
>>reproduced at a sound power of from 1 to 5 dB louder than what was 
>>played; notes that were recorded at a velocity of about 60 are 
>>reproduced at a sound power of from 0.5 to 2 dB louder than what was 
>>played.
>>
>>With the Volume control set to "0", the sound output limits for note 
>>velocity values from 93 to 127--that is, there will be no difference in 
>>the loudness of a particular note whether its velocity is 93, 110, or 
>>127.  In order to hear those gradations in dynamics, you would need to 
>>set the Volume control to "-4".
>>
>>Once again, the magnitude of error may or may not be noticeable, 
>>depending upon what is being played and who is listening.  Maximizing 
>>the profit of a product evidently doesn't require satisfying the most 
>>astute consumer.
>>
>>Unfortunately, judging accuracy by ear is a very subjective process. If 
>>you are going to try that, and if you wish to approach the truth, I 
>>suggest a "blind" test wherein the evaluators do not know whether they 
>>are listening to an original performance or to a reproduction and can 
>>only sort them out later through coded names.
>>
>>A comment on playing the old PianoSoft disks on the Pro:  The 
>>information that a Pro recording includes--that is the fine continuous 
>>time record of the key and pedal positions--is absent in an old 
>>PianoSoft disk.  Without the benefit of that information, the Pro's 
>>potential for accurate reproduction cannot be exploited.  To truly 
>>evaluate the Pro, you must listen to a Pro with a Pro recording.  A 
>>PianoSoft file cannot do it justice.
>>
>>Yamaha surely knows its market which is probably why they have focused 
>>on the XG and now the CD features.  However, why, after developing the 
>>Pro and bringing it to market several years ago, Yamaha has not 
>>commissioned solo re-recordings targeted at Pro owners simply confounds me.
>>
>>--Bob Welcyng
>>
>>
>>
>>


-- 
Robert Welcyng
Anchorage, Alaska