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ChromaTalk Archives: January 2015

Chroma videos

Eric Frampton [21030501]

HI all -

My friend Patrick Strawser, as part of an ongoing video series he calls The Keyboardist Blog, just finished cutting together two videos of me giving a quick tour of the Chroma - actually two different Chromas - and then two other videos of me demo’ing some sounds. Thought this might be of interest, since there isn't a whole lot of Chroma footage floating around out there.

A link to the Chroma playlist.

A link to Pat's main Keyboardist Blog page, where you can find me demo’ing a few other keyboards in my pile, as well as his interviews with some other folks.


Here's the first of the videos:

Dave Bradley [16330135]

Watching now, well done!


William Santana [21030244]

On the programmer, did you notice the threshold related params on outlined in green on the right hand side?

Jesper Ödemark [21010135]


And I couldn't help myself but had to comment (somewhat ironic) on the last one. :)

Eric Frampton [21030501]

Thanks, guys! It’s been a long time coming.

Enrico Dibennardo [21030494]

A fantastic job, Eric, I think everybody could enjoy and appreciate.

P.S. Maybe you remember me, we shared a neural agonizing story. But this is O.T.


Eric W. Mattei [21030443+]

I just learned about this today.

In the movie "Close Encounters of the Third Kind" (1977) [Cast]

"Real-life ARP technician Phil Dodds cameos as the operator of the ARP 2500 synthesizer communicating with the alien ship."

Chris Ryan [21030691]

I asked Phil Dodds about this; see his reply on the site.

Paul DeRocco [21030230]

Another bit of trivia that seems to be missing from your interview, and from the Wikipedia article: after all the effort to set up the 2500 and film that scene, Spielberg (or someone) decided to replace the sound with real orchestral sounds. That wasn't the 2500 we all heard. That was, however, Phil Dodds's voice wondering "What are we saying to each other?"

Paul Tillotson [21030218]

I've always found that scene unbearable because of this. Here you've got an amazing synth sitting there with Phillip Dodds at the helm and you hear this trite junk with a tuba and I'm not even going to look this up to verify but is it a piccolo or clarinet or oboe trading the trite little phases back and forth like dueling banjos except without any imagination or dexterity. Actually, I better keep quiet as I've never watched that movie from start to finish anyway in spite of it being about the only movie in history that shows an ARP 2500. A Pro Soloist could've filled in nicely with style to spare audio wise, and Phil could've stayed at home and changed out of the lab coat.

Dave Bradley [16330135]

For me, the unbearable was when the keys started moving after the (sequencer? recorder? conversation module?) was switched on.

I think the actual sound used was a pipe organ diapason stop, with tuba from the mother ship.

Brian McCully [21030361]

Come on, lighten up. It was a fun movie. Why shouldn't lip syncs apply to synths too? It's all marketing...and large lumps of mashed potatoes.

Patrick Stewart playing the Chapman Stick in the Dune movie wasn't bad press, even if he isn't apparently playing anything like the audio track. A major distraction was Sting's early acting skills...

Eric W. Mattei [21030443+]

An audience is supposed to suspend its disbelief. Having worked with computers for 35 years, I always noticed how, in many Sci-Fi movies from the 70's and 80's, as the letters would appear on the computer screen, you'd hear the sound of a printer. In the 1950's Sci-Fi classic, "Forbidden Planet", every time before Robby the Robot would talk, you'd hear the sound of a mechanical adding machine. Hollywood!

Meanwhile, while I respect everyone else's opinions, John Williams can do no wrong in my book.

Chris Smalt [21010280+]

Yeah, and nobody ever locks their cars after they get out!

Eric W. Mattei [21030443+]

I'm not saying you should believe everything Hollywood tells you. Quite the opposite. I expect Hollywood to lie, I never take it personally and I always lock my doors.

Digital Chroma & NAMM

See earlier threads What do people actually like about the Chroma?, July 2012; NAMM anyone?, January 2013; and Digital Chroma, January 2014.

Paul DeRocco [21030230]

Anyone going to NAMM? I'll be there, and I'll have a Digital Chroma nearby if anyone wants to try it out. Since last year, I've added Reverb, Distortion, mono envelopes (e.g., Hammond percussion), more modulation inputs to the pitch and cutoff, and an improved editor. If you're interested, contact me off-list.

Dave Bradley [16330135]

Not going, but would love to see and hear the Digital Chroma. Maybe someday!

Paul DeRocco [21030230]


From: Dave Blees

Hi, Paul! Would love to see it! If you (or anybody) could get me a pass, I'd be there... unfortunately, I've been out of "the industry" for a couple of years, so am having a hard time tracking down the badge.

(Dave's note appears to have been a personal email.)

I had to scrounge a badge, too, as usual, so I can't help you there. But the Digital Chroma won't be inside the show, so anyone in the neighborhood who isn't going to the show is welcome to drop by to see it, if you don't mind dealing with the mess of NAMM traffic and parking.

Brian McCully [21030361]

Hi Paul,

It'd be great if you could produce a Digital Chroma video for all of us "un-attendees".



Michael Di Francesco [21040001]

Ciao Paul ,,,How are you ,,, I have a questions ,,Hope you can help me


After i install a new CC+ bOARD AND a NEW psu,,,,Eveyithing is Ok ,,,,The only thing is that i can not aktive the set split function ,,, because at moment i can only use with an external Keyboard,,the internal Keybord dont work ,,,the Local off on is only possible to switch with the Set split ,,,,,Any idea ????

Saluti form Italy Michele

CC+ firmware 218 offers MIDI Syncable LFO/Sweep & Microtonal Tuning

David Clarke [21030085++]

Thank you all for your continuing participation in the Chroma CPU Plus (CC+) project.

The CC+ has now been produced for close to 9 years, is being used on 5 different continents and is still being actively maintained.

I normally would not announce a new version of firmware before it was available on the Rhodes Chroma site (and the on-line documentation was updated), but as I'm currently shipping some CC+ boards with the new firmware installed I felt I should introduce it before users receive it.

Firmware Release 218 adds:

  • MIDI Syncable LFO/Sweeps
  • The ability to assign arbitrary frequencies to each key of the keyboard (Microtonal Tuning)

The release also has the following specific changes:

  • [Set Split 36][P25] now returns 218
  • The 'performance tune' SYSEX response was corrected to return with a SYSEX preamble of F0 08 00 4B 59 01 37.
  • A minor update was made to ensure an appropriate MIDI program change will be sent if the same program button is pressed twice from the front panel.

Thanks go to Paul DeRocco [21030230] and Werner Schöenenberger [21010114] for their input on the MIDI sync topic - and thanks to Brian McCully [21030361] for noticing the behaviours addressed in the last two points.

There hasn't been an opportunity for rigourous evaluation of the new features - and as my schedule hasn't freed up in the past little while, it probably won't in the near future either. So - rather than holding on to the code even longer, hoping that my own availability may free up, the code is being released now such that others can use it and help identify if there are changes required.

This is the first release of the MIDI Sync capability. Testing of the gross Sync functionality was completed.

The Microtonal Tuning implementation is being provided in this release as an 'Evaluation' Feature. In most other cases, features have been added to the CC+ based on receiving several user requests and then there being discussion on the Chroma List. That wasn't the case for Microtonal Tuning; rather, an opportunity arose where I needed to investigate this feature - and since I had the functionality on hand, it is being provided here for your use. This is currently being called an 'Evalulation' feature since if the CC+ community decides that the feature is undesired, then it could be removed from future firmware releases. That said - based on the ease with which alternate tunings can be evaluated, I think others may find this to be an interesting/enjoyable feature.

Details and other notes on the Firmware 218 changes are below. [David's notes are available at The Chroma CPU Plus (CC+): Firmware - 218 (December 2014)] — Chris


  • Information on the new features will later be made available on the CC+ firmware page as well as in the CC+ User's Manual.
  • If someone wants the 218 EPROM image before it becomes available on the Chroma site, just let me know and I can provide it via e-mail.

Best regards,

David Clarke


thank you so much for your work and your involvement to make this instrument more alive with each update !

Al Tutlys [21030645]

Great stuff....thank you!

Chris Smalt [21010280+]

Firmware Release 218 adds:

  • The ability to assign arbitrary frequencies to each key of the keyboard (Microtonal Tuning)


David Hobson [21030506]

Great news! Thank you very much, David.

Roel D. [21010092]

Hi David,

Thanks for the great work!

I have a suggestion for a future update: is there a possibility to make a 3rd setting for the external LCD which sends just raw data that can be decoded by an external display processor? I have programmed a serial receiver on arduino for my LCD, as that was a quicker and cheaper solution than ordering one. Since I already have that code, I was planning on building a simple (arduino based) serial display convertor that allows for oled displays to be used. At the moment I would have to write the received data in a buffer and have the software interpret that if I want to use any graphics or whatever on the display. If it's implemented with lookup tables for the text, this option would be fairly easy to implement.

If I get to program this, I will gladly share the code and assembly details for the website. There is however no rush, as I'm also reprogramming parts of my house....



that would be awesome ! :)

David Clarke [21030085++]

... is there a possibility to make a 3rd setting for the external LCD which sends just raw data that can be decoded by an external display processor?...

Roel - by 'raw data' do you mean that instead of ASCII text that the serial stream would (for instance) just send a parameter number and a parameter value?

If so, then even if that serial stream was available, you may not be able to show as much data on the display as is currently done by the ASCII serial stream. The reason for that is that the current display doesn't just decode a single parameter/value pair, but in some cases it will re-interpret the data based on other settings. In other cases, more than one parameter is shown on a given display.

For instance - the 'glide rate' value (Parameter 6) is decoded differently depending on whether the 'glide shape' value (Parameter 7) is set to Portamento or Glissando - meaning it isn't sufficient to know parameter 6, but you also need to know parameter 7 at the same time.

For parameters that that different mod sources, the current display will simultaneously show the setting being changed, plus the 3 mod select sources and the mod depth amounts, xref:


An external serial display using raw data wouldn't be able to achieve that same sort of representation unless it actually had a bi-directional communication path so that the external device could ask for other settings from the Chroma in support of what it is looking to display.

If that sort of 'enhanced' display was desired, it would likely be easier to simply create a small adapter that plugged into the Chroma port - since then the attached device would actually have full bi-direction communications and could dynamically request the details of the on-card values (xref: Interface Manual: Command Descriptions).

David C.

Lawrence Eldridge [21010100]

Morning David,

Would it be possible to send a copy of Firemware 218? Been having the Rhodes Chroma repaired for a while now but syncable LFO's is something that would add so much to the unit... I'll send it to the engineer and hopefully get the updated included in the repair job.

All the best,
Lawrence Eldridge

Roel D. [21010092]

Thanks David,

That clarifies a lot. You're right about the enhanced display. I had no idea that the computer interface would make this possible. If I start working on this, using the computer interface would make it a more flexible system that can be changed on it's own without changing the CC+ firmware.

However, this will require more chroma-studying as I intended at first and I might need some help figuring out the lower layer protocol. Other than that, I like the idea. Anyone know a place with a good price for spare time?


David Clarke [21030085++]

... If I start working on this, using the computer interface would make it a more flexible system that can be changed on it's own without changing the CC+ firmware.

Another plus to using the computer interface is that the display could be used with Chromas that still have the original CPU too (since the computer interface is a basic functionality of the board).

One down-side though (at least for some) is that the Syntech, EES and JL Cooper MIDI interfaces use the Computer Interface - meaning if someone was still using those, then the display wouldn't have a place to hook up (unless you wanted to get fancy with your electronics).

However, this will require more chroma-studying as I intended at first and might need some help figuring out the lower layer protocol.

In software you wouldn't have to worry about any protocol - instead it is a message-based interface (e.g., send an opcode, get a reply back, etc.)

On the hardware site, it's an 8-bit parallel interface. It can be implemented with some basic hardware. There is some handshaking to do to - but it isn't bad. I have an old implementation that used a PIC18F4320, a few resistors and an 74HC74 - and so if you ever find you want to do this you're more than welcome to the code I had used as a starting point.

David C.

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