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#2197793 - 12/15/13 12:11 AM Kawai F-10H pedal have too much latency/delay
Daniel Richter Online   content
Full Member

Registered: 10/09/13
Posts: 179
Loc: Venezuela
EDIT: At the end the problem was the ES100 all along. Kawai say they correct this for new ES100 that are produce, but for early buyers, you need to return your unit for a new one.



Now, my original post:

After buying the Kawai ES100 digital piano, I was (and still am) very happy about it. I have nothing bad to say about the ES100, except very minor things I will post on a full review.

But the pedal that came with it (F-10H) although looks very well made, with a lot of metal parts, heavy, stable, silent, apparently working well... but after some little time after using it was clear something was wrong about that pedal. Was a long story to figure out what was the problem, but now I know. Problem is latency (delay). When you press fully, the signal send to the digital piano have around 0.115 to 0.172 seconds of delay, and even 1 second in some circumstances I will explain later.

People that play an instrument like the piano know that 0.115 of a second of input delay is quite a lot. The pedal shows (with my ES100 digital piano) 6 to 7 steps in total. Each step has a delay that adds on, from full-press to release.

This is the delay between values:

Delay with F-10H pedal:
MIDI message from 10 to 30 = 0.012 seconds of delay
MIDI message from 30 to 55 = 0.014 seconds of delay
MIDI message from 55 to 84 = 0.021 seconds of delay
MIDI message from 84 to 116 = 0.032 seconds of delay
MIDI message from 116 to 127 = 0.093 seconds of delay

Total delay with F-10H pedal from 0 to 127: 0.172 seconds

Notes that delay is bigger the more the pedal is press.


Delay with a switch pedal:
MIDI message from 10 to 30 = 0.002 seconds of delay
MIDI message from 30 to 55 = 0.001 seconds of delay
MIDI message from 55 to 84 = 0.002 seconds of delay
MIDI message from 84 to 116 = 0.002 seconds of delay
MIDI message from 116 to 127 = 0.005 seconds of delay

Total delay with switch pedal from 0 to 127: 0.012 seconds



Note: For those who don't know about MIDI, values are 0, 1, 2, 3...until reach 127 (that is full)

Using a switch pedal proves the problem is the kawai F-10H pedal itself since is obvious the digital piano electronics can process pedal signal very fast (0.012 seconds maximum from 0 to full).




What problems in real life this cause?

Issue "late pedal": Is the most obvious problem I had that actually make me start investigating about all of this. Is quite important problem because when pressing a key, and releasing the key at the same time when pressing pedal, sound should sustain normally all the way. But because of the latency on the pedal, the key is partially damped (called "late pedalling"). As most of you should know, pedal usage is all about timing. This slight delay can really ruin a song quite often. Even pressing pedal a little earlier than releasing key, late pedalling issue is present dampening a little the sound. You are force to leave the key press for longer time, and this is not always possible, and is not realistic.



Issue "full pedal delay": Sometimes when fully pressing the pedal, the MIDI monitor (digital piano is connected to a computer) shows an important delay on sending the FULL (127) state. The delay is sometimes even over a second. It freeze on 116 value and after a while it sends 127 (full).


Here is a short video showing both issues in action: https://www.mediafire.com/?dp41hw2w3mm2w9a




Issue "pedal damper noise effect": The digital piano Kawai ES100 supports this effect. The pedal noise is louder the faster you move the pedal, like on an acoustic piano. But since the F-10H pedal sends data with such latency between steps, the digital piano always thinks the pedal is moving slowly so the damper noise is always too soft, no-matter how fast/hard the pedal is press. This issue is not super important, and that is why I mentioned last. But still, was something I notes even before I knew about all of this pedal-latency thing.



Obviously the delay also happens when releasing the pedal, but I didn't notes that when playing so I don't mention that as an "real life issue", although technically it is.



After I discover this, I remove the cover on the F-10H pedal, and looks like it use some kind of optic sensor. Not sure what cause the latency in there. My bet is the sensor itself, but the problem could be some other component.

Other kind of pedals like the Yamaha FC3 use potentiometers to send half-pedal position. Problem with potentiometers is that they wear out after some use. But at least potentiometers send data practically in real time (no delay). The initiative of kawai to use optic sensor is very good to prevent wearing (the pedal in theory could last dozens of years), but sadly they fail on making them latency-free. Everything about input on a instrument most have as little delay as possible. 0.001 of a second is very good; 0.01 of a second is acceptable; 0.1 of a second is terrible.






Maybe I have a defected unit?

What about other pedals like the Kawai F-350 triple pedal unit?

I don't know since I didn't have a chance to test other pedals, and I don't have an answer from Kawai yet. I will post any news about this here in the future, if there is anything to report.




If any of you are interested on the schemat of the pedal, my friend dewster write it down here (thanks dewster):





For now, I will see how solve this problem for real. I want half pedal feature so will test with potentiometer pedals and see if any of them is compatible. Until then, switch pedal should be enough.

If any of you have the F-10H pedal, please do the test to see how much delay it has. Could be that I am just unlucky and got a defective unit. The way to test is connect the digital piano to the computer and install pianoteq (trial version works fine). In pianoteq there is a setup section where shows MIDI messages is receiving. That is what I use on the video I record. You simply write how much time it takes from having the pedal release to fully press.


Edited by Daniel Richter (01/11/14 02:18 PM)
_________________________
Long time piano player, with 7 years experience working in restaurants and doing gigs in random places.

My project: Comparison of Portable Digital Pianos under 1000 US$

Owner of Kawai ES100

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#2197868 - 12/15/13 08:21 AM Re: Kawai F-10H pedal have too much latency/delay [Re: Daniel Richter]
dewster Offline
4000 Post Club Member

Registered: 12/07/09
Posts: 4354
Loc: Northern NJ
Here is a warped/scaled/blended view of both sides of the PWB superimposed on one another:



U1 is probably an LED / phototransistor pair. Q1 is an emitter follower that buffers the output of the phototransistor. R2 & C1 form a low pass filter pullup, R5 and C3 form a low pass filter pulldown.

The phototransistor is more conductive the more light it gets. So when the pedal is up phototransistor is ON and pulling R2|C1 to ground. When the pedal is pressed quickly the phototransistor becomes a high impedance, and R2 must discharge C1 by itself, which can take 6800 x 0.000001 = 0.0068s or 6.8ms to reach 63% of the final value. Hard to know how the ES100 interprets this, but having most of the action near the top of the pedal movement likely aggravates things.

My advice to Daniel was to remove C1 and see what happens. If there is an improvement then C1 should perhaps be replaced with a smaller value, such as 0.1uF.

VR1 is marked "105" which usually means 1M Ohms, but that can't be right (way too high).

The "right" way to do this kind of optical thing is with a pulsed beam, because ambient light can then be largely removed from the equation.

Daniel, you might also try adjusting the potentiometer on the board, but first mark it so you can return it to the factory calibration point.
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#2198258 - 12/15/13 10:50 PM Re: Kawai F-10H pedal have too much latency/delay [Re: dewster]
Daniel Richter Online   content
Full Member

Registered: 10/09/13
Posts: 179
Loc: Venezuela
Thanks dewster for the suggestions, but I remove C1 and no change. Exactly the same latency, even with temporal freeze on 116 value like I mention before.

I also try to move the potentiometer on the board (VR1). Is clear is use to calibrate the position of the pedal. When move clockwise (reducing ohms) the pedal starts sending signal of press after pressing half-way or more. If move potentiometer too far on that direction, pedal always sends data as released, even when pressing fully the pedal. The opposite happens when moving the potentiometer counterclockwise (increasing ohms), sending signal like is press, but is actually released.

BTW I don't recommend relaying on marking the potentiometer so you can return it to the factory calibration point. Is not very accurate that way. Even a fraction of mm make a lot of difference on the ohms is setup. I prefer measure the ohms with a multimeter, write it down somewhere, and later when trying to restore to original position just move until is the same number.

I think I will stick with the idea of using a potentiometer as a pedal, like Yamaha FC3 pedal do. Tricky part will be adjust ohms and pedal-position to be realistically calibrated.

Question still remains: This latency is on every F-10H pedal or only on mine?
_________________________
Long time piano player, with 7 years experience working in restaurants and doing gigs in random places.

My project: Comparison of Portable Digital Pianos under 1000 US$

Owner of Kawai ES100

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#2198341 - 12/16/13 03:50 AM Re: Kawai F-10H pedal have too much latency/delay [Re: Daniel Richter]
spanishbuddha Offline
2000 Post Club Member

Registered: 11/08/09
Posts: 2434
Loc: UK
How do you know it's the pedal, and not delayed processing in the DP? Can you try another OEM pedal or visit a store and try another ES100 with pedal.

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#2198397 - 12/16/13 08:47 AM Re: Kawai F-10H pedal have too much latency/delay [Re: spanishbuddha]
Daniel Richter Online   content
Full Member

Registered: 10/09/13
Posts: 179
Loc: Venezuela
As I say on the main post, I test with a switch pedal. No significant delay with switch pedal, so the DP is not the problem. Read the post, that there is more details there about this.

I am searching for someone that have the F-10H pedal to test this. When find it, I will post the result.
_________________________
Long time piano player, with 7 years experience working in restaurants and doing gigs in random places.

My project: Comparison of Portable Digital Pianos under 1000 US$

Owner of Kawai ES100

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#2198414 - 12/16/13 09:47 AM Re: Kawai F-10H pedal have too much latency/delay [Re: Daniel Richter]
joflah Offline
Full Member

Registered: 08/09/09
Posts: 325
Loc: St. Louis, MO, USA
Interesting post, and great analysis. It would be so tempting to just probe around in there with a scope, to see what's really going on. Maybe there's something wrong with some of the pedal components - like the 6.8k being open-circuited or, or Q1 not working as a transistor, with R3 open, so the voltage changes reach the output but only slowly. There's nothing I can see about the circuit that should make it so slow.
_________________________
Jack

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#2198416 - 12/16/13 09:52 AM Re: Kawai F-10H pedal have too much latency/delay [Re: joflah]
Daniel Richter Online   content
Full Member

Registered: 10/09/13
Posts: 179
Loc: Venezuela
If someone else test this pedal and there is no delay, then the problem is a damage component for sure. We'll see.
_________________________
Long time piano player, with 7 years experience working in restaurants and doing gigs in random places.

My project: Comparison of Portable Digital Pianos under 1000 US$

Owner of Kawai ES100

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#2198423 - 12/16/13 10:04 AM Re: Kawai F-10H pedal have too much latency/delay [Re: Daniel Richter]
dewster Offline
4000 Post Club Member

Registered: 12/07/09
Posts: 4354
Loc: Northern NJ
Daniel, there may be some kind of calibration going on at power-up in the ES100. This could confound your testing. You might try adjusting the potentiometer a bit and then powering down, then powering back up.

Anything beyond this probably requires a scope and some inside knowledge of the ES100. Access to the former is likely much easier than the latter.
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THE RD-700NX Thread!
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#2198431 - 12/16/13 10:13 AM Re: Kawai F-10H pedal have too much latency/delay [Re: dewster]
Daniel Richter Online   content
Full Member

Registered: 10/09/13
Posts: 179
Loc: Venezuela
Actually I test that. What I found out is that ES100 don't calibrate in that way. Is always expecting a value from the pedal to detect half positions. Also means I most find a specific potentiometer to substitute this pedal and make my own.

So what calibrates is the pedal, not the digital piano. The calibration is that potentiometer VR1
_________________________
Long time piano player, with 7 years experience working in restaurants and doing gigs in random places.

My project: Comparison of Portable Digital Pianos under 1000 US$

Owner of Kawai ES100

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#2198817 - 12/16/13 08:57 PM Re: Kawai F-10H pedal have too much latency/delay [Re: Daniel Richter]
Squall21 Offline
Full Member

Registered: 12/06/13
Posts: 25
Very interesting especially since I've been wanting to get this p. I really hope this is just a defective unit.

Would it be possible for you to replace the pedal through warranty? Perhaps the store you bought the dp from can do it. If the replaced pedal is still the same, then it's likely every F10H pedals are like that, Also, have you tried with a different digital piano?

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#2198973 - 12/17/13 06:49 AM Re: Kawai F-10H pedal have too much latency/delay [Re: Squall21]
Daniel Richter Online   content
Full Member

Registered: 10/09/13
Posts: 179
Loc: Venezuela
First I most know if my pedal is defective or is a design problem, before considering sending it back for the warranty. I live in Venezuela so is not cheap ship things to US.

Can't try on different digital piano because no-one here have one. At least not Kawai. Anyway I know (from my test) that the ES100 is not the problem, so my focus is on the pedal itself.

I already contact the Kawai dealer and they contact kawai directly. Also James had inform this to kawai too. A response from them could take a lot of time, if there is any response.

I contact a friend that bought a Kawai ES100 and she will make the test. I have more hope on that to know if I have a defective unit or all F-10H pedals are like this.

"Stay tuned" for more news about this
_________________________
Long time piano player, with 7 years experience working in restaurants and doing gigs in random places.

My project: Comparison of Portable Digital Pianos under 1000 US$

Owner of Kawai ES100

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#2199011 - 12/17/13 08:29 AM Re: Kawai F-10H pedal have too much latency/delay [Re: Daniel Richter]
dewster Offline
4000 Post Club Member

Registered: 12/07/09
Posts: 4354
Loc: Northern NJ
Originally Posted By: Daniel Richter
Anyway I know (from my test) that the ES100 is not the problem, so my focus is on the pedal itself.

My hunch is the pedal is not defective, and that the circuitry or software that interfaces with the pedal in the ES100 is the issue.
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THE RD-700NX Thread!
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#2199016 - 12/17/13 08:36 AM Re: Kawai F-10H pedal have too much latency/delay [Re: dewster]
Daniel Richter Online   content
Full Member

Registered: 10/09/13
Posts: 179
Loc: Venezuela
My hunch is that the problem is the optic sensor itself that is too slow, and that all F-10H pedals have the same problem.

Let's see.
_________________________
Long time piano player, with 7 years experience working in restaurants and doing gigs in random places.

My project: Comparison of Portable Digital Pianos under 1000 US$

Owner of Kawai ES100

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#2199778 - 12/18/13 03:45 PM Re: Kawai F-10H pedal have too much latency/delay [Re: dewster]
Daniel Richter Online   content
Full Member

Registered: 10/09/13
Posts: 179
Loc: Venezuela
Confirmed. All F-10H pedals have basically the same delay.

I ask a friend "therightmoment" to do the test with pianoteq showing the midi messages and when she press the pedal fast she get 0.116 seconds of delay from 0 to 127. Although the issue "full pedal delay" is not present. She only get "normal" delay of 0.116 seconds.




Her pedal shows 16 steps. Mine only 6 to 7 steps. But that don't bother me at all. What bothers me is that if I return this pedal I will have the same delay. Well, the "full pedal delay" would be solve, but I don't care if I still get 0.1 delay. So returning pedal is out of the question.

I have two options:
- Modify my kawai pedal to use switch, because I love the mechanics of this pedal, and the feel. My current switch pedal feels too artificial (what you expect from a cheap pedal). I want keep using this pedal. I only need to change what is inside.
- Or modify the pedal to use a potentiometer to send half positions. I assume the digital piano should read a potentiometer values like it was on the pedal. As far I know, that is basically what this pedal do, but digitally. I will try to make the same but analog.

I am not sure when I am going to do this mod. Is christmas and I don't have much rush to do this since I already am using a switch pedal. But when I get the time I will do it and report here how is going.

There is in theory one other option and is buy a F-350 3-pedal unit for the ES100. I am not sure yet, but I bet it doesn't have the same latency issues of the F-10H pedal. But F-350 pedal is too expensive for me. And overkill in a way because I don't use the other 2 pedals. It is problematic fit that pedal unit on a stand. Would need to buy the official kawai stand, or do a mod on my stand. But main reason is just too expensive, the unit and the shipping to my country.

If any of you have the F-350 pedal, would be great if you can test latency on that pedal.

Thank you "therightmoment" for doing the test.

Happy holidays everybody.
_________________________
Long time piano player, with 7 years experience working in restaurants and doing gigs in random places.

My project: Comparison of Portable Digital Pianos under 1000 US$

Owner of Kawai ES100

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#2199826 - 12/18/13 06:18 PM Re: Kawai F-10H pedal have too much latency/delay [Re: Daniel Richter]
MacMacMac Offline
3000 Post Club Member

Registered: 09/24/09
Posts: 3871
Loc: North Carolina
I would not assume this:
Originally Posted By: Daniel Richter
Or modify the pedal to use a potentiometer to send half positions. I assume the digital piano should read a potentiometer values like it was on the pedal.

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#2199858 - 12/18/13 08:24 PM Re: Kawai F-10H pedal have too much latency/delay [Re: MacMacMac]
joflah Offline
Full Member

Registered: 08/09/09
Posts: 325
Loc: St. Louis, MO, USA
Originally Posted By: MacMacMac
I would not assume this:
Originally Posted By: Daniel Richter
Or modify the pedal to use a potentiometer to send half positions. I assume the digital piano should read a potentiometer values like it was on the pedal.


Right. If it's looking for a voltage, you'd have to rig the pot to produce the expected output voltage range, which would probably be a subrange of the supply voltage range applied to the pedal.
I think it's very unlikely that any lags are due to the optical devices.
_________________________
Jack

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#2199877 - 12/18/13 09:17 PM Re: Kawai F-10H pedal have too much latency/delay [Re: Daniel Richter]
Squall21 Offline
Full Member

Registered: 12/06/13
Posts: 25
Uh oh. Daniel, how big of an impact do you think this will be for people who have this pedal? Will it affect the playing experience or is it minor?

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#2200031 - 12/19/13 07:39 AM Re: Kawai F-10H pedal have too much latency/delay [Re: Squall21]
Daniel Richter Online   content
Full Member

Registered: 10/09/13
Posts: 179
Loc: Venezuela
Originally Posted By: joflah
I think it's very unlikely that any lags are due to the optical devices.


Actually many light sensors are quite slow. Depends on the type of sensor they use.

Originally Posted By: Squall21
Uh oh. Daniel, how big of an impact do you think this will be for people who have this pedal? Will it affect the playing experience or is it minor?


I think 0.1 seconds of latency on the pedal is notable for players that already play real songs on real pianos. If you are a learner that press pedal all the time or don't use pedal in the same way you would do in a song, don't see a problem. But I am experienced piano-player and notes this latency in day 1 since I got the digital piano.

I could still play songs fairly well. It doesn't make impossible play songs. But late pedalling happen quite often and normally that happens as a mistake of the player for pressing pedal too late. With this pedal happens even if you didn't make mistake.

So basically if you press pedal too near the limit, you will have late-pedalling even though you did it inside the limit. For complicated songs can happen all the time.

Any latency on input is bad, in my opinion. For instruments or video game controllers or computer screens, etc. Each 0.001 second count.

My recommendation for other owners of this F-10H pedal is buy a switch pedal. There are great ones like the M-Audio SP-2. Another option is buy the Kawai F-350 3-pedal unit, that I suspect should not have this issue. That one is expensive but at least you get half pedalling feature.

Of course, with a switch pedal you lose the half pedal capability, but having 0.1 seconds of latency is a lot worst.

I will explore the potentiometer pedal later to have half pedallling feature without latency.
_________________________
Long time piano player, with 7 years experience working in restaurants and doing gigs in random places.

My project: Comparison of Portable Digital Pianos under 1000 US$

Owner of Kawai ES100

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#2200090 - 12/19/13 10:18 AM Re: Kawai F-10H pedal have too much latency/delay [Re: Daniel Richter]
dewster Offline
4000 Post Club Member

Registered: 12/07/09
Posts: 4354
Loc: Northern NJ
Daniel:

I poked around DigiKey for a bit. Here is a datasheet of a part that may be similar to the one in the pedal (Omron EE-SY125):

www.components.omron.com/components/web/pdflib.nsf/0/3DF7E7E37F4CF53185257201007DD6AB/$file/D21EESY1250305.pdf

Response time is pretty quick, but can be improved by increasing the collector current. I would try lowering R2 somewhat and see what that does. Solder a 4.7k ohm resistor in parallel with the 6.8k resistor (4.7k || 6.8k = 2.8k) and recalibrate the potentiometer for correct range of operation. If that noticeably improves the response you can lower the resistance more, but not too much or the photo transistor could be destroyed.

It would help to know what the voltage being supplied to the pedal is. There is very likely a resistor or other current limiting device within the ES100 on the supply which could be playing into the equation.
_________________________
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THE RD-700NX Thread!
DPs Exposed! (nekid pichures!)

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#2200175 - 12/19/13 01:14 PM Re: Kawai F-10H pedal have too much latency/delay [Re: dewster]
joflah Offline
Full Member

Registered: 08/09/09
Posts: 325
Loc: St. Louis, MO, USA
Originally Posted By: dewster
Daniel:

I poked around DigiKey for a bit. Here is a datasheet of a part that may be similar to the one in the pedal (Omron EE-SY125):

www.components.omron.com/components/web/pdflib.nsf/0/3DF7E7E37F4CF53185257201007DD6AB/$file/D21EESY1250305.pdf

Response time is pretty quick, but can be improved by increasing the collector current.


The response times mentioned on that data sheet are 10 to 100 us, or 0.1 ms max. That's about 1000 times faster than the 100 ms lag times that are a problem.
_________________________
Jack

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#2200187 - 12/19/13 01:42 PM Re: Kawai F-10H pedal have too much latency/delay [Re: dewster]
joflah Offline
Full Member

Registered: 08/09/09
Posts: 325
Loc: St. Louis, MO, USA
Originally Posted By: dewster
Daniel:

I poked around DigiKey for a bit. Here is a datasheet of a part that may be similar to the one in the pedal (Omron EE-SY125):

www.components.omron.com/components/web/pdflib.nsf/0/3DF7E7E37F4CF53185257201007DD6AB/$file/D21EESY1250305.pdf

Response time is pretty quick, but can be improved by increasing the collector current. I would try lowering R2 somewhat and see what that does. Solder a 4.7k ohm resistor in parallel with the 6.8k resistor (4.7k || 6.8k = 2.8k) and recalibrate the potentiometer for correct range of operation. If that noticeably improves the response you can lower the resistance more, but not too much or the photo transistor could be destroyed.

It would help to know what the voltage being supplied to the pedal is. There is very likely a resistor or other current limiting device within the ES100 on the supply which could be playing into the equation.


Just to look closer, I ran a simulation of the circuit (after the optical parts) in LTSpice. Assuming a supply of 12 V, and taking 5 steps to zero in 0.5 seconds, there was about 20 ms lag on each step, which is pretty gross. Lowering the 1.0 uF to 0.1 uF cut the lags by a factor of 10.
If anyone uses LTspice (a free program from Linear Technology), I can share the circuit file.
_________________________
Jack

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#2200190 - 12/19/13 01:55 PM Re: Kawai F-10H pedal have too much latency/delay [Re: joflah]
dewster Offline
4000 Post Club Member

Registered: 12/07/09
Posts: 4354
Loc: Northern NJ
Originally Posted By: joflah
The response times mentioned on that data sheet are 10 to 100 us, or 0.1 ms max. That's about 1000 times faster than the 100 ms lag times that are a problem.

I agree, with this part (who knows if it is even remotely like the one in the datasheet) and for the way they test response time in the datasheet (across emitter resistor rather than from collector).

Originally Posted By: joflah
Just to look closer, I ran a simulation of the circuit (after the optical parts) in LTSpice. Assuming a supply of 12 V, and taking 5 steps to zero in 0.5 seconds, there was about 20 ms lag on each step, which is pretty gross. Lowering the 1.0 uF to 0.1 uF cut the lags by a factor of 10.

This is why my first suggestion was to remove C1, which Daniel reported makes no difference.

I'm wondering if SW is involved. Maybe it's looking for a certain amount of change on the pedal before updating, and this watching and updating process has a certain amount of latency for each step. That could explain why a switch pedal works fine and the variable pedal doesn't work so well. One test would be to stick a potentiometer pedal on there and see if it does the same thing.
_________________________
The DPBSD Project!
THE RD-700NX Thread!
DPs Exposed! (nekid pichures!)

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#2200220 - 12/19/13 02:38 PM Re: Kawai F-10H pedal have too much latency/delay [Re: dewster]
joflah Offline
Full Member

Registered: 08/09/09
Posts: 325
Loc: St. Louis, MO, USA
Originally Posted By: dewster
Originally Posted By: joflah
The response times mentioned on that data sheet are 10 to 100 us, or 0.1 ms max. That's about 1000 times faster than the 100 ms lag times that are a problem.

I agree, with this part (who knows if it is even remotely like the one in the datasheet) and for the way they test response time in the datasheet (across emitter resistor rather than from collector).

Originally Posted By: joflah
Just to look closer, I ran a simulation of the circuit (after the optical parts) in LTSpice. Assuming a supply of 12 V, and taking 5 steps to zero in 0.5 seconds, there was about 20 ms lag on each step, which is pretty gross. Lowering the 1.0 uF to 0.1 uF cut the lags by a factor of 10.

This is why my first suggestion was to remove C1, which Daniel reported makes no difference.

I'm wondering if SW is involved. Maybe it's looking for a certain amount of change on the pedal before updating, and this watching and updating process has a certain amount of latency for each step. That could explain why a switch pedal works fine and the variable pedal doesn't work so well. One test would be to stick a potentiometer pedal on there and see if it does the same thing.


That'd be a good test. You could even get a 10k pot, jumper it in, and operate it by hand.
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#2200381 - 12/19/13 07:30 PM Re: Kawai F-10H pedal have too much latency/delay [Re: joflah]
Daniel Richter Online   content
Full Member

Registered: 10/09/13
Posts: 179
Loc: Venezuela
Like dewster mention, I already try removing C1, with no change in delay.

Kawai contact me, so I am also waiting to see what they say about this, before messing too much on the pedal. They are investigating.

Thank you joflah for the simulation. I didn't even know those electronic sims exist. Fascinating that you get a lot of latency too in there. But sadly removing C1 didn't work as we could expect.

I think next test should be just use a potentiometer directly connected to the DP.
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#2200418 - 12/19/13 08:28 PM Re: Kawai F-10H pedal have too much latency/delay [Re: Daniel Richter]
Amaruk Offline
500 Post Club Member

Registered: 12/02/11
Posts: 813
Loc: New England, USA
Daniel,
I am impressed by the level of effort you put into this! May I ask how you time events to determine the delays? I assume MIDI is involved but it is not clear how to me how you do this.

I don't know about the details involved here but if I had to guess I would also suspect the software to be the problem.
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#2200472 - 12/19/13 10:59 PM Re: Kawai F-10H pedal have too much latency/delay [Re: Daniel Richter]
dewster Offline
4000 Post Club Member

Registered: 12/07/09
Posts: 4354
Loc: Northern NJ
Originally Posted By: Daniel Richter
Kawai contact me, so I am also waiting to see what they say about this, before messing too much on the pedal. They are investigating.

Good on them that they contacted you. But you're doing the right thing by shouting the problem from the rooftops.
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#2200516 - 12/20/13 02:35 AM Re: Kawai F-10H pedal have too much latency/delay [Re: dewster]
pwl Offline
Full Member

Registered: 05/31/13
Posts: 204
Loc: Bay Area CA
I hope, with Kawai's help, this issue gets resolved. I'm ready to buy an ES100 after playing one today, but am going to put this purchase on hold for now.

For whatever reason I wasn't having much luck half-pedaling the ES100 today. Seemed to be on or off - but could well have been pilot error.

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#2200558 - 12/20/13 07:18 AM Re: Kawai F-10H pedal have too much latency/delay [Re: pwl]
Daniel Richter Online   content
Full Member

Registered: 10/09/13
Posts: 179
Loc: Venezuela
Originally Posted By: Amaruk
how you time events to determine the delays? I assume MIDI is involved but it is not clear how to me how you do this.

I don't know about the details involved here but if I had to guess I would also suspect the software to be the problem.

I know how much is the delays because MIDI shows times. I use Pianoteq to see MIDI messages. In the option section there is a window that shows time, values, controller and channel. The time is right there in 0.001 resolution. You can see how much time takes from one value to the other.

Why I think problem is not software nor MIDI adapter nor the digital piano? Because when I try with a switch pedal the delay is a lot less (between 0.009 and 0.012 seconds)

Also, I notes this delay while playing so obviously the delay happens on the source (the pedal). And when replace pedal to a switch, in real life is notable that there is no delay. 0.012 of a second for me is real-time, in practical terms.


Originally Posted By: pwl
I'm ready to buy an ES100 after playing one today, but am going to put this purchase on hold for now.

For whatever reason I wasn't having much luck half-pedaling the ES100 today. Seemed to be on or off - but could well have been pilot error.

Half pedal function can't be disable. Only way to disable is by plugin a switch pedal.

I would still recommend buying the ES100 because the problem is not the digital piano. The problem is the pedal. Maybe buy also the F-350 3-pedal unit would be a good way to don't have this issue. I bet don't have this problem because even use another connector. Is a speculation, thought.

But if you can wait a few months, then wait.

The half pedal position do work, though. Make sure on the store the F-10H pedal is connected, and not another pedal. Also is very sensitive. Half positions are very close together. Maybe around 2 or 4 mm.



I did another test with foil paper on the part of the pedal that reflect light back to the sensor, that normally is a white plastic. I find that the latency improve only for releasing pedal, but not for pressing.

EDIT: I can't replicate results of this test, so delete results.





Thanks for the help, you guys. Is good to have some great minds supporting my search for the problem, since my knowledge about electronics is very limited.

Maybe some of you can do a simulation in LTSpice following the suggestion of dewster of replacing R1 with a 4.7k ohm resistor. If show improvement I will do a real-live test.


Edited by Daniel Richter (12/21/13 06:43 AM)
Edit Reason: test can't be replicated
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#2200592 - 12/20/13 09:41 AM Re: Kawai F-10H pedal have too much latency/delay [Re: Daniel Richter]
Daniel Richter Online   content
Full Member

Registered: 10/09/13
Posts: 179
Loc: Venezuela
Another test I did. Not sure what it means but here it goes.

The switch pedal have some delay if not connected in the right connectors. The jack have 3 connectors. Tip, middle and big. That is the way I will call them.

Normal switch pedals have the big contact and the middle always together. And they together do the switch with the tip. In that configuration I get this delay:

Tip and middle+big (meaning middle and big are always together)
Press 0.010
Release 0.062

0.062 seconds of delay I think is kinda acceptable. But I am curious that there is a difference in pressing vs releasing.




And gets more interesting. When I put the tip and the middle always together, making them switch with big contact, then the delay is this:

Tip+middle and big
Press 0.020
Release 0.004


This time there is practically no delay in releasing and pressing.




Now with tip and big only making the switch, leaving the middle alone, delay is like this:

Tip and big alone
Press 0.012
Release 0.063


The same delay with "Tip and middle+big".




What all this means? Don't know for sure, but I mod my switch pedal to have the tip and middle always together. That way I get the less delay possible, and is quite acceptable (only 0.020 seconds pressing and 0.003 releasing)





Another test I did was connect a potentiometer on the tip and big connector. Was 10K ohms. Half pedal work, but reach a limit with 10K giving a MIDI value of 64, so obviously i need a 20K potentiometer to have a full release in that configuration. Was full press or half press, and the 1 value in between. Not sure if I will do the potentiometer mod, though. They wear fast. But at least we know this concept work.

It would be great test with F-350 pedal. I would consider buy that to have the half pedal and don't have the head-ache of modding with a potentiometer. That pedal is expensive so I would not make that investment if I am not sure work without the delay.

As I say before, for now I am happy with switch pedal.
_________________________
Long time piano player, with 7 years experience working in restaurants and doing gigs in random places.

My project: Comparison of Portable Digital Pianos under 1000 US$

Owner of Kawai ES100

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#2200701 - 12/20/13 08:27 PM Re: Kawai F-10H pedal have too much latency/delay [Re: Daniel Richter]
joflah Offline
Full Member

Registered: 08/09/09
Posts: 325
Loc: St. Louis, MO, USA
Originally Posted By: Daniel Richter
Another test I did. Not sure what it means but here it goes.

The switch pedal have some delay if not connected in the right connectors. The jack have 3 connectors. Tip, middle and big. That is the way I will call them.

Normal switch pedals have the big contact and the middle always together. And they together do the switch with the tip. In that configuration I get this delay:

Tip and middle+big (meaning middle and big are always together)
Press 0.010
Release 0.062

0.062 seconds of delay I think is kinda acceptable. But I am curious that there is a difference in pressing vs releasing.

And gets more interesting. When I put the tip and the middle always together, making them switch with big contact, then the delay is this:

Tip+middle and big
Press 0.020
Release 0.004


This time there is practically no delay in releasing and pressing.

Now with tip and big only making the switch, leaving the middle alone, delay is like this:

Tip and big alone
Press 0.012
Release 0.063


The same delay with "Tip and middle+big".

What all this means? Don't know for sure, but I mod my switch pedal to have the tip and middle always together. That way I get the less delay possible, and is quite acceptable (only 0.020 seconds pressing and 0.003 releasing)


For reference, in English the phone jack contacts that you've called tip, middle and big are called tip, ring and sleeve respectively. In the pedal you have, I imagine they might be the ground, the plus supply, and the pedal position output, Usually the sleeve is the ground. You might measure the voltage of the other two with respect to ground to see what the plus supply voltage is and which contact it's on.
I didn't try to figure out what your results meant, because it's getting a little hard to visualize, without a diagram of what you have, and what it's supposed to be.
Quote:

Another test I did was connect a potentiometer on the tip and big connector. Was 10K ohms. Half pedal work, but reach a limit with 10K giving a MIDI value of 64, so obviously i need a 20K potentiometer to have a full release in that configuration. Was full press or half press, and the 1 value in between. Not sure if I will do the potentiometer mod, though. They wear fast. But at least we know this concept work.

It would be great test with F-350 pedal. I would consider buy that to have the half pedal and don't have the head-ache of modding with a potentiometer. That pedal is expensive so I would not make that investment if I am not sure work without the delay.

As I say before, for now I am happy with switch pedal.


A fairer test of an external potentiometer would have the two outside contacts connected to the two wires with the ground and plus voltage, and the wiper connected to the third sensing terminal, rather than a two-wire setup.
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