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#1880164 - 04/15/12 07:26 PM "DIY" DP possible?
pandamonium Offline
Full Member

Registered: 12/10/09
Posts: 21
So in general it it seems that the holy grail is grand action and expressive sound reproduction. I'm totally okay with being tethered to my computer for playing. And while I like (but have not yet bought) PianoTeq, the on-board samples in my PX130 are sufficient for me. I haven't even thought of trying Galaxy.

But I started thinking about about it the other day. If true grand keybeds are somewhat easily removable and you can retrofit a piano (PianoDisc, PNOScan, and Doepfer come to mind) for MIDI output, why not combine the two?

I'll admit to not having looked around for salvage pianos, but I can't imagine that it's terribly difficult to find a grand piano keybed for sale. If you were to retrofit one with midi sensors and paired it to your VST of choice, wouldn't you basically have a N3 without the fancy case, speakers, and haptic feedback?

I mean, the only thing I could see as being a problem is if any of the retrofitting kits are prohibitively expensive. I can't find any reference to the price of a PNOScan or PianoDisc's midi strip.

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#1880175 - 04/15/12 07:52 PM Re: "DIY" DP possible? [Re: pandamonium]
piano_shark Offline
Full Member

Registered: 03/27/12
Posts: 201
good luck, but you know life is too short?...

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#1880229 - 04/15/12 09:29 PM Re: "DIY" DP possible? [Re: pandamonium]
gvfarns Offline
3000 Post Club Member

Registered: 04/16/07
Posts: 3480
Loc: Pennsylvania
I have actually looked into this extensively and actually arranged with a local piano tech to get an action. Here's a bunch of relevant info, in no particular order:

1. It is indeed difficult to find an action. Getting a new one will run you thousands of dollars, believe it or not. The best solution is to find a piano retailer or repair person and locate a dead grand. That is, one with a working action but otherwise unusable. The guy I talked with was willing to sell me such an action for $750 (regulation included) but it was not from a concert grand.

2. PNOscan will run you around $1000. It can only be had through piano retailers. Mine offered it to me for $1100. I bet I could have talked it down. Though the factory where it is made is driving distance from me, you can't find a way to get it in the US without going through a retailer. Apparently they don't like to sell their product for some reason. Terrible idea in my opinion.

3. Remember that you need to figure out a way to house it and something for the hammers to hit that is not too loud.

4. Here's a video of someone who did this on youtube. The guy is completely nonresponsive, though, so good luck getting more info out of him.

http://www.youtube.com/watch?v=korhxsv7xhw

5. PNOscan must be calibrated and it's apparently a painful process. You have to do key by key and it apparently isn't easy to get even. And some people paint the bottom of their keys to get better response.

6. PNOscan uses key movement only. As discussed in various places here, the right place to measure velocity is on the hammers (there are cases where it makes a difference). Thus I believe PNOscan does not provide a better sensor system than the hammer-based sensors in digitals.

7. PNOscan sends repeated notes (the ones without lifing the keys completely) in a nonstandard format. It sends a sequence of note-on, note-off, note-on, note-off, rather than note-on, note-on, note-one, like VST's expect. I think some VST's, especially PianoTeq, which is somehow connected to PNOscan, have overcome this hurdle somehow.

8. PNOscan has a single set of sensors. It's not 100% clear how they work, but I have never been able to determine whether they emulate three-sensor behavior (i.e., note calculation at the end of the stroke, damper disengagement half way through). No one seems to know or is willing to say.

9. You have to rig something for a pedal.

I was very serious about building one of these for myself. I finally gave up not because it would be too difficult or too expensive, but because after researching it, I decided that the finished product would be inferior to a regular digital piano. It would feel amazing, but I fear it would not be as responsive or work as well.

The AvantGrand N1 is more expensive, but it looks a lot nicer and probably works better, and it comes with its own speakers and sounds, as well as support.

On the plus side, I probably could have set it up such that there was an actual set of dampers that was lifted. That would cause the difference between up and down weight that is present in acoustics but not in any digital (including the AvantGrands).

Supposedly Petrof will build you a piano like the one we are thinking of. But they never answered my attempts to contact them. Jerks.

A thread about petrof's midi controller


Edited by gvfarns (04/15/12 09:45 PM)

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#1880245 - 04/15/12 09:53 PM Re: "DIY" DP possible? [Re: gvfarns]
Keegan Offline
Full Member

Registered: 05/22/09
Posts: 140
Loc: Canada (Ottawa, ON)
Originally Posted By: gvfarns


I was very serious about building one of these for myself. I finally gave up not because it would be too difficult or too expensive, but because after researching it, I decided that the finished product would be inferior to a regular digital piano. It would feel amazing, but I fear it would not be as responsive or work as well.


Yep, this is the deal breaker for me as well...I guess the only was to find out is to travel to a dealer that sells pianos with PNOscan already installed, bring in your laptop / midi interface and give it a shot (assuming that would be ok with them!). My biggest fear about the strip is having to release the key fully to "resting position" as calibrated before being able to strike another note, but perhaps lowering the "resting position" on the sensors would eliminate this problem? Man, so many mysteries about the strip...whoever decides to pull the trigger on one and go for the pianoworldforums dream setup (for those who can't afford an AvantGrand) will be a true hero to post meticulous details about this whole ordeal!
_________________________
Kawai CA-65, AKG K702, M-Audio Fast Track Pro
Pianoteq, VI Labs Ravenscroft
Macbook Pro 15-inch 2010

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#1880253 - 04/15/12 09:59 PM Re: "DIY" DP possible? [Re: gvfarns]
Keegan Offline
Full Member

Registered: 05/22/09
Posts: 140
Loc: Canada (Ottawa, ON)
Other things I fear in the strip:

- Not having triple sensor like response

- Having notes sound without full key depression

- Having notes sound FF when pressing a key with a fast initial movement but a soft landing (difficult to explain what I mean)

- Never being able to find a good calibration

- Being stuck with a $1000 piece of hardware useless for anything else if I decide I don't like it / can't get it to do what I want it to do

- Wasting an incredible amount of my time!
_________________________
Kawai CA-65, AKG K702, M-Audio Fast Track Pro
Pianoteq, VI Labs Ravenscroft
Macbook Pro 15-inch 2010

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#1880328 - 04/16/12 12:54 AM Re: "DIY" DP possible? [Re: pandamonium]
erichlof Offline
Full Member

Registered: 04/26/10
Posts: 367
Hi Pandamonium and all,
Is it possible to go the route that Infinite Response has, but cheaper? To be more precise, instead of retrofitting a grand action with hundreds of moving wooden parts that are susceptible to road wear-and-tear and humidity especially, would it be more satisfying, reliable, and less expensive to emulate the Vax77 midi controller somehow?

I have always dreamed of owning a light, portable, consistent, and most importantly - *accurate* action that I could carry under my arm and hook up to a laptop for gigs and home use. Could one start out with just the keys of a piano, or even the plastic keys of an old Yamaha keyboard or something, and somehow put sensors on those? The Vax77 has spring-loaded mechanisms I understand, and Stevie Wonder has called it the best action he has ever played in his life. The only caveat being that it doesn't have the escapement feel of a grand piano. But who needs that when you have much more midi resolution and accuracy, even more than a well-maintained concert grand action?

Then you would say, why not just buy the Vax77 - well there is only one problem with that - the price tag! $$$$ Is it possible to make something like the Vax77, but for around a 1000 dollars instead of 3-freakin'-thousand dollars?

Maybe there is a reason for that insane price tag for a midi controller - be it parts, labor, patented sensor/spring mechanisms - but I find it hard to justify putting a $3000 price tag on it.

Can it be done more cheaply, or is this a pipe dream?



Edited by erichlof (04/16/12 12:56 AM)

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#1880335 - 04/16/12 01:29 AM Re: "DIY" DP possible? [Re: pandamonium]
pandamonium Offline
Full Member

Registered: 12/10/09
Posts: 21
Hmmm okay so let's say that finding action is the limiting factor. What about making your own? There are plenty of CNC cutting outfits that let you send them designs. I'm googling images of some actions, but the best I've been able to find is http://www.rennerusa.com/VirtualActionModel.asp - it looks like a ton of parts for each key, but looking at it from a perspective of "what would I need to do to make this CNC-friendly?" and "where could I build a laser sensor system to handle input to MIDI duty?" and "how could this accomodate a case design that we find palatable?"

To that end, I've got my hands tied right now because I don't have access to any acoustics at the moment.

A laser system looks like it's possible but would definitely need some more googling on my part.

But as for a design that would be acceptable, I have a thought. The whole mechanism could be turned into a rather handsome parsons style desk. You could lift up the edge (much like a Roland DP-990) in order to expose the keys and a built-in music stand. When not in use, it would look like a long console table. I'm not sure how the pedals could be worked into it, but I'm thinking something that telescopes would work. That way you could retract it close enough to the bottom of the piano that an unaware passerby would probably not be able to see them.

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#1880346 - 04/16/12 02:28 AM Re: "DIY" DP possible? [Re: pandamonium]
ando Offline
3000 Post Club Member

Registered: 11/23/10
Posts: 3508
Loc: Melbourne, Australia
Make your own grand action? Now we really are going of into a land where unicorns roam freely... wink

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#1880351 - 04/16/12 02:57 AM Re: "DIY" DP possible? [Re: ando]
Gigantoad Offline
Full Member

Registered: 01/02/12
Posts: 336
Originally Posted By: ando
Make your own grand action? Now we really are going of into a land where unicorns roam freely... wink


Would have to agree. A grand action is such a complex beast it is very likely impossible to make for mere mortals.

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#1880357 - 04/16/12 03:24 AM Re: "DIY" DP possible? [Re: pandamonium]
Aidan Offline
Full Member

Registered: 01/23/08
Posts: 372
Loc: UK
As others have already pointed out, the trouble is that to come up with anything decent, you're going to have spend a great deal of your own time and probably more money than an Avant Grand, which will do that particular job far better, look nicer and have some resale value (I guarantee you, your home project will have a resale value of virtually nil).

Life is one long compromise. I'd love a Steinway D but I'm never going to be able to afford one. The important thing is to find something you can live with, at a price you can afford, and then get on with making some great music on it. Don't confuse the tools with the product.
_________________________
Yamaha CP40 | Hammond SK1-61 | Kurzweil PC361

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#1880359 - 04/16/12 03:34 AM Re: "DIY" DP possible? [Re: Aidan]
Manolios Offline
Full Member

Registered: 11/19/10
Posts: 128
Loc: Germany
Originally Posted By: Aidan
The important thing is to find something you can live with, at a price you can afford, and then get on with making some great music on it. Don't confuse the tools with the product.


+1

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#1880372 - 04/16/12 04:17 AM Re: "DIY" DP possible? [Re: ando]
piano_shark Offline
Full Member

Registered: 03/27/12
Posts: 201
Originally Posted By: ando
Make your own grand action? Now we really are going of into a land where unicorns roam freely... wink


laugh exactly where we are in this thread...
But i agree, musicians should dream.

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#1880413 - 04/16/12 08:10 AM Re: "DIY" DP possible? [Re: Keegan]
dewster Offline
4000 Post Club Member

Registered: 12/07/09
Posts: 4338
Loc: Northern NJ
Originally Posted By: Keegan
Other things I fear in the strip:

- Not having triple sensor like response

- Having notes sound without full key depression

- Having notes sound FF when pressing a key with a fast initial movement but a soft landing (difficult to explain what I mean)

- Never being able to find a good calibration

- Being stuck with a $1000 piece of hardware useless for anything else if I decide I don't like it / can't get it to do what I want it to do

- Wasting an incredible amount of my time!

I don't have any hands-on experience with PNOScan, but have looked into it a tiny bit. It obviously uses the changing optical reflectivity of the key underside due to angular movement to sense key position. It seems to be a clever way to retrofit, but I'm not sure it's the best for new construction. Positional sensing is ideal because it allows you to go way beyond triple sensor, but of course the devil is in the details of exactly how it is implemented.

The VAX uses magnets and linear Hall-effect sensors to sense key position, which is likely more reliable and less interference prone. Someone should take a VAX apart and measure critical distances, weights, and spring constants. My guess is they have the weight located near the end of the played side of the key, the spring could be almost anywhere and still feel the same. I applaud the direction they have taken with this product.
_________________________
The DPBSD Project!
THE RD-700NX Thread!
DPs Exposed! (nekid pichures!)

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#1880423 - 04/16/12 08:32 AM Re: "DIY" DP possible? [Re: ando]
ryanct Offline
Junior Member

Registered: 03/16/12
Posts: 19
Originally Posted By: ando
Make your own grand action? Now we really are going of into a land where unicorns roam freely... wink

Oh come on, it's just a 3D printer away smile

(Kidding... but, maybe one day...)

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#1880894 - 04/17/12 01:38 AM Re: "DIY" DP possible? [Re: pandamonium]
erichlof Offline
Full Member

Registered: 04/26/10
Posts: 367
Hi Dewster,

Thanks for clarifying the sensor types in the Vax77 by Infinite Response. I have enjoyed and appreciated your DPBSD thread and your time and effort into exposing DP's and giving us here at PW an honest and unbiased look at them.

Do you feel that the Vax77 price point is right? I realize they have to make a buck like everyone else, but the price seems high (like doubly high) for a midi controller without sounds.

In keeping with the spirit of the OP, would it be possible to go this route and make something with magnets and linear Hall-effect sensors, but for less money? Are these parts inherently expensive? Is the labor too hard? There must be a reason for Infinite Response's $3,000 price tag other than profit margin (at least I would hope so).

When we talk of starting from scratch and buying and assembling all the parts of a keyboard like this, are we indeed wandering into la-la land? Or do you think it can be done more cheaply, if one is willing to put in the hours?

Thanks for your input. smile
-Erich

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#1880981 - 04/17/12 07:52 AM Re: "DIY" DP possible? [Re: pandamonium]
MacMacMac Offline
3000 Post Club Member

Registered: 09/24/09
Posts: 3786
Loc: North Carolina
The manufacturer puts in thousands of hours doing these things. Do you have the time? Even if you work for "free"? Do you think you could ferret out all of the design, build, and reliability problems?

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#1881022 - 04/17/12 09:23 AM Re: "DIY" DP possible? [Re: pandamonium]
erichlof Offline
Full Member

Registered: 04/26/10
Posts: 367
Precisely MacMacMac. Is this why you think the price tag is $3,000? If it ain't the parts, it's the labor. I was looking at this problem like one would look at purchasing a desktop computer. Sure, you can order a pre-made, pre-configured Dell or Powerbook - at a certain cost. Or you can order the individual parts online for less money and put the computer together yourself.

Certainly people DO have the time and willingness to make their own computer. Is it the same for DP's, or is it too cost-prohibitive (price of Hall-effect sensors / keys), or lack of knowledge and too time consuming on piecing the different elements into a portable keyboard package?

There are plans on the internet to build electronics such as computers and radios, but I'm not sure there's plans on how to build your own DP. smile

Edit: Found some "plans" - I stand corrected smile
https://docs.google.com/viewer?url=http%3A%2F%2Fece.uprm.edu%2F~pol%2Fpdf%2Ficee04CruzPol.pdf


Edited by erichlof (04/17/12 09:29 AM)

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#1881080 - 04/17/12 10:41 AM Re: "DIY" DP possible? [Re: pandamonium]
MacMacMac Offline
3000 Post Club Member

Registered: 09/24/09
Posts: 3786
Loc: North Carolina
Building a computer is trivial. Pile of parts, plug them in, load the software. You're really not inventing anything. Nothing at all. The parts are MEANT to work together.

Building a piano is far from trivial. I presume we're not talking about buying a pile of parts and then assembling them, right? (That would be pointless, yes?)

So you have to invent lots of things. And test them. And repeat the cycle. Thousands of hours ... with no assurance that your result will be any better than (or even as good as) the pianos sold at your local dealer.

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#1881103 - 04/17/12 11:11 AM Re: "DIY" DP possible? [Re: pandamonium]
joflah Offline
Full Member

Registered: 08/09/09
Posts: 276
Loc: St. Louis, MO, USA
I would think the reason for the high price is the relatively low demand. They have to write off their development and manufacturing costs with something less than mass production.

Jack
_________________________
Jack

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#1881111 - 04/17/12 11:19 AM Re: "DIY" DP possible? [Re: erichlof]
dewster Offline
4000 Post Club Member

Registered: 12/07/09
Posts: 4338
Loc: Northern NJ
Originally Posted By: erichlof
Do you feel that the Vax77 price point is right? I realize they have to make a buck like everyone else, but the price seems high (like doubly high) for a midi controller without sounds.

I've never seen one so I can't vouch for the quality. But for something that they maybe sell 100 to 1000 of a year (total guess) they have to charge a lot to recoup all the up-front costs. With that $3k you're paying for several people sitting around and thinking.

I personally don't like the way it folds, and would prefer a unit that didn't do that.

Originally Posted By: erichlof
In keeping with the spirit of the OP, would it be possible to go this route and make something with magnets and linear Hall-effect sensors, but for less money? Are these parts inherently expensive? Is the labor too hard? There must be a reason for Infinite Response's $3,000 price tag other than profit margin (at least I would hope so).

I see linear Hall Effect sensors at DigiKey for around $1 each in quantity. You could multiplex the outputs into a high speed 10 or 12 bit A/D converter. The rest could be in a small FPGA (state machines) or processor (program). MIDI is fairly stone age at this point.

Originally Posted By: erichlof
When we talk of starting from scratch and buying and assembling all the parts of a keyboard like this, are we indeed wandering into la-la land? Or do you think it can be done more cheaply, if one is willing to put in the hours?

Certainly as a one-off for yourself it is doable. People obviously build their own harpsichords and clavichords, I don't think a MIDI keyboard controller could be any more difficult than that - particularly if you don't want to specifically emulate the "hammer feel" of a piano - though the skill set would obviously be somewhat different. For the base of the keys you could use aluminum channel or tubing, or basswood / poplar, or maybe even flakeboard on edge. If you go with aluminum U channel you could perhaps orient the channel opening down and use it to guide the key. All the black keys could be identical, but there may be ~6 different types of white keys. I'd go with a really long distance from the played end to the fulcrum (250mm white / 200mm black) and use a return spring rather than a counterweight.
_________________________
The DPBSD Project!
THE RD-700NX Thread!
DPs Exposed! (nekid pichures!)

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#1881135 - 04/17/12 11:43 AM Re: "DIY" DP possible? [Re: pandamonium]
KHen Offline
Full Member

Registered: 09/18/09
Posts: 183
Loc: North America
I don't know if you've seen this or not, but this guy is able to make the PNOScan work very well on his DIY piano.

http://www.ltecmusic.com/

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#1881176 - 04/17/12 12:41 PM Re: "DIY" DP possible? [Re: pandamonium]
erichlof Offline
Full Member

Registered: 04/26/10
Posts: 367
Dewster, thanks for the info and the keybed suggestions.

@Jack and Dewster,
Yes, I suppose the Vax77 price point is in relation to low demand and small-scale production.

Dewster, one more question for you, please. In theory, if I had the Hall-effect sensors and a decent key and keybed, would the MIDI data be as accurate coming out of my contraption as the Vax77? In other words, if I had similar sensor equipment, would I be able to get HD or high resolution MIDI data like the Vax77 supposedly gets, or is there more at work here in your opinion?

Thanks for all the info and leads.

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#1881200 - 04/17/12 01:36 PM Re: "DIY" DP possible? [Re: erichlof]
dewster Offline
4000 Post Club Member

Registered: 12/07/09
Posts: 4338
Loc: Northern NJ
Originally Posted By: erichlof
In theory, if I had the Hall-effect sensors and a decent key and keybed, would the MIDI data be as accurate coming out of my contraption as the Vax77? In other words, if I had similar sensor equipment, would I be able to get HD or high resolution MIDI data like the Vax77 supposedly gets, or is there more at work here in your opinion?

I don't have experience with Hall Effect devices, so I can't say for sure. I'd buy a few (or request free samples) and play around with them in a key mockup with a magnet, spring, and weight. The response time or bandwidth of the device may be the key feature.

The resolution depends on the noise coming from the device, the specs of the A/D converter, and how many bits you would end up throwing out due to them being outside of the normal operating range. You're looking for velocity, or change in position with respect to change in time, at a positional trigger point. If you can determine position accurately enough and quickly enough you might be able to use multiple averaged samples to increase resolution. You could also look for peak velocity over the entire travel. Normal MIDI velocity is only 7 bits and you would have to do better than that in order to be able to apply curves and offsets without experiencing missing codes. Kicking out higher resolution might produce missing codes but maybe that isn't a big deal. Whatever device noise there is might not be a big deal either if its effect on velocity isn't noticeable during a normal performance.
_________________________
The DPBSD Project!
THE RD-700NX Thread!
DPs Exposed! (nekid pichures!)

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#1881236 - 04/17/12 02:30 PM Re: "DIY" DP possible? [Re: KHen]
gvfarns Offline
3000 Post Club Member

Registered: 04/16/07
Posts: 3480
Loc: Pennsylvania
Originally Posted By: KHen
I don't know if you've seen this or not, but this guy is able to make the PNOScan work very well on his DIY piano.

http://www.ltecmusic.com/


I think that product is vaporware. The site has been just as it is now for a long time and no one has ever seen the real beast.

But anyway, how do we know it works well? Obviously it works, but for example the difference between key movement and hammer movement is a little to subtle to be detectable in a video like that. Building our own digital would definitely work too, but the problem is that we are worried that it would not work well.


Edited by gvfarns (04/17/12 02:32 PM)

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#1881257 - 04/17/12 03:09 PM Re: "DIY" DP possible? [Re: pandamonium]
erichlof Offline
Full Member

Registered: 04/26/10
Posts: 367
Thanks dewster for the helpful information. I may try a mock-up like you said with one 'pseudo-key' and some sample parts and see if I can get anywhere. Your insight is much appreciated - thanks again.
-Erich

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#1881266 - 04/17/12 03:34 PM Re: "DIY" DP possible? [Re: erichlof]
dewster Offline
4000 Post Club Member

Registered: 12/07/09
Posts: 4338
Loc: Northern NJ
Originally Posted By: erichlof
I may try a mock-up like you said with one 'pseudo-key' and some sample parts and see if I can get anywhere.

If I were doing this seriously I'd probably strive to deviate from the "velocity at a given position" paradigm of the two and three sensor DP actions and go more for "total energy imparted to the key over its downward travel" type thing. This could give you a better calculated pseudo final hammer velocity. I think this is why most hammer action DPs use the hammer rather than the key to actuate the position switches.

You could maybe strip out the action in a decent Kawai DP and retrofit it with your sensors, but I think I'd avoid the hammer mechanism altogether. It may feel somewhat more piano-like, but for me it's overlapping the non-ideal / gimmick category (like graded hammer weighting). Hammers add complexity and weight, I would ditch them and their crazy mechanisms if at all possible.
_________________________
The DPBSD Project!
THE RD-700NX Thread!
DPs Exposed! (nekid pichures!)

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#1881276 - 04/17/12 03:54 PM Re: "DIY" DP possible? [Re: erichlof]
gvfarns Offline
3000 Post Club Member

Registered: 04/16/07
Posts: 3480
Loc: Pennsylvania
Originally Posted By: erichlof
In other words, if I had similar sensor equipment, would I be able to get HD or high resolution MIDI data like the Vax77 supposedly gets


I guess I don't understand how higher resolution velocity data is useful unless you are also designing your own tone generator. If you will use it to drive a VST, you will be limited to the 128 MIDI velocities anyway.

Not that I want to discourage you in any way. If you can figure out how to DIY a better piano, I'd be all over that.

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#1881288 - 04/17/12 04:11 PM Re: "DIY" DP possible? [Re: pandamonium]
erichlof Offline
Full Member

Registered: 04/26/10
Posts: 367
Dewster, yes, I agree - the hammer mechanism is a necessity in acoustic pianos, but in our opinion a liability in DP's. More wooden parts, more moving parts = more $$$ spent, more weight, more things that can go wrong over time.

I like the spring resistance solution of the Vax77, but is there a device for measuring "total energy imparted" as you mentioned? Is this what the Hall-effect sensors are doing, or are they of the "velocity at a given position" variety?

The reason I'm asking all this is I play and teach piano but I'm not tech-savvy - but my brother (who does not play keyboards) is technically-minded. He's into woodworking, computers and such - he built a controller for vintage arcade emulation with lots of buttons, wheels, and sliders, that sends data out to a laptop so you can use arcade emulators such as MAME. He's always looking for a new project to start. Maybe I will show up at his doorstep one day unannounced with a box full of keys, magnets, and sensors! Haha.





Edited by erichlof (04/17/12 04:11 PM)

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#1881292 - 04/17/12 04:22 PM Re: "DIY" DP possible? [Re: pandamonium]
erichlof Offline
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Registered: 04/26/10
Posts: 367
Hi gvfarns,
I own Pianoteq PRO which I believe utilizes HD MIDI resolution.

Also, here's a blurb taken from the Supreme Pianos 2 website:

"Supreme Piano 2 gives you absolute control over every aspect of a piano. You can adjust hammer actions, microphone positions, sympathetic resonances, dynamics and more. You can even design your own piano! *

True Piano Dynamic System with flexible controls *

HD Velocity Layer supports up to 65,536 Velocity Layers! *"


Here's the website link (you have to click on the "Learn More" button by the "See detailed features of Supreme Piano 2" line).:
http://www.supremepiano.com/product/sp.htm

Unless I'm mistaken, aren't these software pianos using more than the standard 0-127 values?

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#1881295 - 04/17/12 04:31 PM Re: "DIY" DP possible? [Re: pandamonium]
gvfarns Offline
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Registered: 04/16/07
Posts: 3480
Loc: Pennsylvania
Ahh I didn't know PT would support HD MIDI. That's great! I wish all DP's and VST's did. It would make me less leery about messing with the velocity curve (kind of like 8 bit JPEG is fine for looking but if you edit it multiple times you start to lose a lot of information).

I'm not sure how to interpret the quote from supreme pianos. If you are right, that would be neat too.

Actually, is HD MIDI a real standard? I thought there hadn't really been a standardized non-proprietary way of transmitting MIDI-like data since the original MIDI. The Wikipedia page doesn't indicate what that standard would be, and it knows more about MIDI than I do. smile

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#1881300 - 04/17/12 04:50 PM Re: "DIY" DP possible? [Re: pandamonium]
erichlof Offline
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Registered: 04/26/10
Posts: 367
Hi gvfarns, like I said I am not too electronics-savvy, but here is a link to the Pianoteq news/updates:

http://www.pianoteq.com/pianoteq3_changes

Look under version 3.6.6

Unless I am misreading this, it looks like if you have a Vax77 or the 'fabled DIY keyboard with similar sensors'(haha), you will be able to utilize the extra resolution inside these piano programs.

As I understand it, the MIDI standard is 7 bit 0-127 for velocity like dewster stated before. I don't know how the software developers magically tap into the unused higher resolution values, while still sending standard MIDI data (if you don't have a Vax77), but like you said - it would be great if everything worked this way, or MIDI upped their standards. laugh

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#1881309 - 04/17/12 05:11 PM Re: "DIY" DP possible? [Re: gvfarns]
MacMacMac Offline
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Registered: 09/24/09
Posts: 3786
Loc: North Carolina
I don't understand. How does HD MIDI help in this area?
Originally Posted By: gvfarns
HD MIDI ... It would make me less leery about messing with the velocity curve.

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#1881316 - 04/17/12 05:20 PM Re: "DIY" DP possible? [Re: gvfarns]
Kawai James Online   content
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Registered: 09/06/07
Posts: 8866
Loc: Hamamatsu, Japan
Originally Posted By: gvfarns
..8 bit JPEG


8 bit JPEG?
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#1881325 - 04/17/12 05:32 PM Re: "DIY" DP possible? [Re: erichlof]
dewster Offline
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Registered: 12/07/09
Posts: 4338
Loc: Northern NJ
Originally Posted By: erichlof
I like the spring resistance solution of the Vax77, but is there a device for measuring "total energy imparted" as you mentioned? Is this what the Hall-effect sensors are doing, or are they of the "velocity at a given position" variety?

Hall-effect devices measure magnetic field strength, and are fairly linear in this regard. But the field strength of a magnet is inversely proportional to the square of the distance. So a magnet embedded in the key interacting with the sensor will tell you non-linear position, and you will have to linearize these readings before using them to calculate energy. Software can do this, as can dedicated hardware in an FPGA. The linearized positional info can be used directly for damping.

If you know how much energy it takes to accelerate (change the velocity) of your key (something you can calculate based on the mass of the key, the distribution of the mass, and the spring force) then you can take the instantaneous positional information from the sensor and through further calculation find the energy being imparted to the key. Integrating (summing) this over time gives the work done on the key to move it.

An alternative to Hall-effect sensors and magnets might be infra-red LEDs. If you can shield them well enough from ambient light, it's pretty easy to use LEDs as both emitter and detector - you would need two LEDs per key. If you modulate the emitter and measure both lit and dark at the detector you might be able to tolerate a fair amount ambient light.
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#1881353 - 04/17/12 06:14 PM Re: "DIY" DP possible? [Re: dewster]
sullivang Online   blank
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Registered: 07/05/09
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Originally Posted By: dewster

If I were doing this seriously I'd probably strive to deviate from the "velocity at a given position" paradigm of the two and three sensor DP actions and go more for "total energy imparted to the key over its downward travel" type thing. This could give you a better calculated pseudo final hammer velocity. I think this is why most hammer action DPs use the hammer rather than the key to actuate the position switches.


Yes, and it appears that the VAX actually does something along these lines. Quote from http://www.infiniteresponse.com/expr.html :
Quote:

A sophisticated digital signal-processing algorithm (DSP) analyzes the slightest key movement thousands of times a second. It delivers MIDI messages based on acceleration vectors, not just key speed at the bottom. Its more about how you play the note than how you hit the note. For example, you can play trills without fully depressing the keys. Many of the best keyboard players in the world play the VAX77 and find it to be the most expressive keyboard instrument ever. Never before could you play a MIDI keyboard so softly. And no matter how strongly you attack the keys, it always feels like you can dig down and get a little more out of it.


Unforunately though, the VAX doesn't feel much like a real piano.

Greg.

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#1881489 - 04/17/12 11:00 PM Re: "DIY" DP possible? [Re: MacMacMac]
gvfarns Offline
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Registered: 04/16/07
Posts: 3480
Loc: Pennsylvania
Originally Posted By: MacMacMac
I don't understand. How does HD MIDI help in this area?
Originally Posted By: gvfarns
HD MIDI ... It would make me less leery about messing with the velocity curve.


Velocity curves on the software side are a mapping from 1-127 into a function that is not those values, so it necessarily causes some rarification in areas where a few values are mapped into a larger number of values.

It's not as serious as the problem with the jpegs (which are all 8 bits per channel). If you edit a jpeg and adjust the colors, then save, then open it, make changes, open, make changes, etc., the quality goes down and you start to see the levels of the colors. Irrecoverable information loss. Not such a problem with higher color resolution formats.

There are other people who can explain both phenomena better than I can, but that's the general idea.


Edited by gvfarns (04/17/12 11:02 PM)

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#1881490 - 04/17/12 11:03 PM Re: "DIY" DP possible? [Re: pandamonium]
Kawai James Online   content
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Registered: 09/06/07
Posts: 8866
Loc: Hamamatsu, Japan
I believe the degradation in quality experienced with repeated saving of JPEGs is due to lossy compression, not colour depth.

Cheers,
James
x
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Nord Electro 3 fan & occasional rare groove player.

"Richard, none of us could forget you have a CLP-990." - EssBrace, 2014

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#1881493 - 04/17/12 11:07 PM Re: "DIY" DP possible? [Re: Kawai James]
gvfarns Offline
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Registered: 04/16/07
Posts: 3480
Loc: Pennsylvania
Originally Posted By: Kawai James
I believe the degradation in quality experienced with repeated saving of JPEGs is due to lossy compression, not colour depth.


Both cause problems (completely different ones).

The lossy compression issue causes characteristic jpeg artifacts (blocks, a certain kind of noise, etc) similar to the look if the compression was set to very aggressive.

The bit depth thing causes a different problem where relatively large areas have the exact same color, similar to the way it would look if you had downgraded it to a 256 color image or something. They call this posterization. It happens on lossless files as well if the bit depth is not high enough and the file is edited.

Actually I guess it always happens when you do certain types of edits (adjusting the white balance, for example) but with a large number of colors in a deeper palette to choose from, it's not typically visible.

The latter effect is the visual equivalent of what happens with MIDI when it is remapped. Not a problem if you start with thousands of MIDI levels.


Edited by gvfarns (04/17/12 11:43 PM)

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#1881507 - 04/17/12 11:42 PM Re: "DIY" DP possible? [Re: pandamonium]
Keegan Offline
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Registered: 05/22/09
Posts: 140
Loc: Canada (Ottawa, ON)
Funny how a topic of discussion can shift from installing an optical sensor into a grand piano action, to visual artifacts in compression of digital photos :P
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#1881511 - 04/17/12 11:57 PM Re: "DIY" DP possible? [Re: gvfarns]
Kawai James Online   content
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Registered: 09/06/07
Posts: 8866
Loc: Hamamatsu, Japan
Originally Posted By: gvfarns
The bit depth thing causes a different problem where relatively large areas have the exact same color, similar to the way it would look if you had downgraded it to a 256 color image or something. They call this posterization. It happens on lossless files as well if the bit depth is not high enough and the file is edited.


I'm afraid I still don't follow how this relates to JPEG compression.
I skimmed through the Wikipedia entry about JPEG to refresh my knowledge, but could not find any mention of posterisation or colour banding.

Are you perhaps comparing JPG to RAW (12/14/16-bit per channel)? Or possibly moving in the other direction and comparing to GIF (8-bit colour, 256 indexed values)?

Apologies to everyone else for the off-topic - gvfarns, you can PM if preferable.

Cheers,
James
x
_________________________
Employed by Kawai Japan, however the opinions I express are my own.
Nord Electro 3 fan & occasional rare groove player.

"Richard, none of us could forget you have a CLP-990." - EssBrace, 2014

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#1881523 - 04/18/12 12:57 AM Re: "DIY" DP possible? [Re: Kawai James]
gvfarns Offline
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Registered: 04/16/07
Posts: 3480
Loc: Pennsylvania
Originally Posted By: Kawai James
I'm afraid I still don't follow how this relates to JPEG compression.
I skimmed through the Wikipedia entry about JPEG to refresh my knowledge, but could not find any mention of posterisation or colour banding.


It doesn't. Compression is a separate issue. The JPEG standard happens to be limited to 8 bits per channel, which is the part that's similar to MIDI. When you have that many or fewer colors to choose from, image enhancements start to cause posterization. It happens with all formats with low bit depth, but JPEG is the most common case.

Modifying the MIDI touch response curve is similar to adjusting the color balance or something in an image, and can lead to the MIDI equivalent of posterization.

The phenomenon is not mentioned on the wikipedia page because it's not actually JPEG specific. Photography forums or photoshop forums are the place to look, where they discuss bit depth issues associated with editing. I first ran into this while discussing the gimp. The gimp can only do 8 bit color (and has for years), which causes many people to say it's not the right software to use for image enhancement. For that reason, people who edit photos seriously start with high bit depth images when they can, and edit them in photoshop.

Notice that RAW files contain more information than can be displayed in any single image, but that's a separate issue as well. Even if you first render the RAW to an image, and then take that image into an editor and tweak it like crazy, you want the image to be a higher color depth than JPEG allows or the editing will start to make it look bad.


Edited by gvfarns (04/18/12 01:04 AM)

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#1881533 - 04/18/12 01:33 AM Re: "DIY" DP possible? [Re: pandamonium]
Kawai James Online   content
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Registered: 09/06/07
Posts: 8866
Loc: Hamamatsu, Japan
Okay, I see where you're coming from now. wink

So this is really a discussion about the limitations of using 8-bits per channel when performing image manipulation.

Cheers,
James
x
_________________________
Employed by Kawai Japan, however the opinions I express are my own.
Nord Electro 3 fan & occasional rare groove player.

"Richard, none of us could forget you have a CLP-990." - EssBrace, 2014

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