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Syntech/Chroma Cult Manual

This is the manual for the Syntech/Chroma Cult/KMX MIDI interface, the best and most popular of the retrofits available for the Chroma. It is still available!

Chroma MIDI Converter User's Manual VERSION 1.0, November 12, 1985



The Chroma Cult reserves the right to make improvements in the product described in this manual at any time and without notice.


The Chroma Cult makes no warranty with respect to this manual or to the product described herein, its quality, performance, merchantability, or application for a particular purpose, except as expressed herein.


First Edition - November, 1985 by The Minister of Information, © copyright 1985 The Chroma Cult. International, distribution and marketing rights are the property of the Chroma Cult. The information contained in this manual is subject to change without notice.

*Chroma is a registered trademark of Fender Corporation.


The Chroma Cult warrants the original purchaser of the product described herein, that the product will be free from defects in material and workmanship for ninety days from the date of purchase.

Defective product returned by purchaser within the ninety day warranty period will be replaced or repaired without charge, providing the purchaser has returned the product along with a copy of the invoice, and provided that the product has not been subjected to any unusual damage, wear, or tear.

Defective product should be returned, postage and/or shipping prepaid, to: [see MIDI Retrofits: Syntech for contact information]

Please be sure that any returned product is shipped in a protective package, along with a brief description of the problem.

The warranty does not apply to the firmware itself, firmware is sold AS IS.

This warranty is in lieu of any other warranty; oral, written, expressed or implied.

Any warranty is expressly limited to ninety days from date of purchase. This includes any implied warranty of merchantability and fitness for a particular purpose. The Chroma Cult is not responsible for any incidental, consequential, or collateral damages resulting from use and/or operation of its products, or for the breach of any expressed or implied warranty.


Before attaching the Chroma to MIDI Converter to your Chroma or Apple, make sure they are turned off. Never plug your converter box into a Chroma or Apple that is already turned on. Also take care not to allow static electricity to enter the converter box through the plug on the end of the ribbon cable. The components are all CMOS and are sensitive to static discharges.

The converter box gets its current from the Chroma or Apple that its plugged into, so no external power supply is required. If you intend to use the converter with the Fender/Apple Music System you'll have to install a jumper wire on your Apple card to supply +5 volts to the Chroma or Expander port. Unfortunately this was omitted from the design of the card but is easy to remedy. Consult the section on using the Fender Music System in this manual on how to install the jumper.

If you have the pressure sensor installed in your Chroma and you wish to transmit pressure over MIDI, you must turn on the pressure switch from the front panel of the Chroma. This is done by pressing set split then number 35. Set split 34 turns the pressure switch off.

The MIDI connections are labeled "IN" and "OUT". The "OUT" can also function as a MIDI through port when programmed as such. Consult the programming section in this manual for instructions on how to do that.

This manual assumes that you already know a little about MIDI already. At least enough to hook up your MIDI cables and start playing.

The converter powers up the first time in a very usable fashion. Omni is on (which means all MIDI channels are received), the MIDI send channel is set to channel 1, lever 1 transmits and receives mod wheel information, lever 2 transmits and receives pitch bend, and all other programmable MIDI functions are disabled. If this satisfies all your needs then you don't have to read any further. But if you wish to access all of the powerful programmable functions of this device, please continue.

The Special Functions

There are five special functions that you can activate from the Chroma panel whenever the converter box is plugged in. They are activated by pressing set split then 20, 46, 47, 48, or 49. If you happen to have a Chroma or Expander with the older Rev 12 Eproms in it, you access the last four functions (set split 46-49) by pressing the program numbers 46-49 directly, without first pressing set split. Unfortunately this prevents you from using the programs that reside at those four locations. If this is an inconvenience I suggest getting the newer Rev 14 Eproms for your Chroma. They are available from Fender (Tel. 714-990-0909), ask for Steve Grom.

Set split - 20 transmits the currently selected program as a MIDI system exclusive file over the MIDI port. Use this to copy the current program from one MIDI'd Chroma to another or to a computer for storage. Consult the section in this manual on sending and receiving Chroma programs over MIDI for more information on the system exclusive format.

Set split - 46 puts the Chroma to MIDI Converter into program mode. From there you can access all of its programmable MIDI functions. Consult the programming section in this manual for more on this.

Set split - 47 outputs the current configuration of the converter box's MIDI parameters as a system exclusive file. Use this with a MIDI sequencer to store the MIDI parameters at the start of a sequence, so you won't have to re-program the converter box each time you play a new sequence. Note: Not all sequencers allow you to record or play system exclusive messages.

Set split - 48 sends all fifty Chroma programs out over the MIDI port as a system exclusive file. Use this to save Chroma programs to a computer or to transfer programs from one MIDI'd Chroma to another. Consult the section in this manual on sending and receiving Chroma programs through MIDI for more on this.

Set split - 49 transmits a MIDI program 0 command. This is MIDI change program command requesting program number 0. When received, this is translated by the converter to a Chroma undefine command. Use this feature with a MIDI sequencer to initiate a Chroma undefine command at the end of a track. Consult the section in this manual on using the Chroma with a MIDI sequencer for more information on this.

Programming the MIDI Converter from the Chroma

Enter program mode by hitting set split then 46 (just hit 46 if you have Rev 12 Eproms). The converter tells you you're in program mode by displaying "Pr" in the program number display on the Chroma. While in program mode, all MIDI transmission and reception is temporarily disabled. To exit program mode, hit 46 again and The Chroma will be restored. The Chroma will remember the MIDI parameters after leaving program mode and will always power up with the parameters set to their last used settings. While in program mode, the Chroma must be set to program select not param select. The converter will put the Chroma in program select for you upon entering MIDI program mode.

To program one of the sixteen MIDI parameters, you first select the one you want by pressing its number on the Chroma panel (1 - 16). You then use the parameter slider to select the value, just as you would change a Chroma parameter. The converter box takes over the parameter display while in program mode. The parameter window will display "P", followed by the MIDI parameter number you have selected. The last four spaces on the window will display the parameter value, either an abbreviated word message or a number, depending on the parameter. The following is a description of each MIDI parameter.

P1 - MIDI BASE CHANNEL: When attached to a Chroma, the converter is capable of transmitting on up to two HIDI channels and receiving on up to eight channels simultaneously. The two transmitting sources are the "main" instrument and the "link" instrument inside the Chroma. The "main" transmits on the MIDI base channel and the "link" transmits on the base channel + 1. The only exception to this is when in omni mode. In omni, the "main" and "link" both transmit on the base channel. So, if you set the base channel to 1, omni to off, and you set the Chroma to "link upper", the left side of your keyboard split point will transmit on MIDI channel 1 and the right side will transmit on MIDI channel 2. If the Chroma is set to "link unison", each key and each performance control will transmit duplicate MIDI data on two channels, the base channel and the base channel + 1.

To understand how the Chroma can receive on up to eight channels you must first understand the concept of Chroma "instruments". The Chroma is capable of setting up eight instruments inside of itself. You can think of these as eight separate synthesizers each capable of producing a different sound. The instruments are numbered 0 through 7. The "main" is always instrument 0 and the "link" is always instrument 1. That leaves you six more instruments that you can only get at through the computer interface on the back of the Chroma. With the Chroma to MIDI Converter you can access these other instruments along with the "main" and "link" each from separate MIDI channels. Instrument 0 (main) will receive on the MIDI base channel. Instrument 1 (link) will receive on the MIDI base channel + 1. Instrument 2 through 7 will receive on the MIDI base channel + 2 through the MIDI base channel + 7. The channel assignment is circular so that if the base channel is 16, the base channel + 1 will be channel 1.

P2 - OMNI: This turns MIDI omni mode on or off. With omni on, the Chroma transmits only on the MIDI base channel and receives on all MIDI channels, regardless of the channel number. With omni off, the Chroma transmits and receives on the selected channels, as described in the previous section. One added feature of "omni on", is that the Chroma will play from MIDI exactly as its keyboard is set up to play. If you have a link upper, lower, or unison selected, the Chroma will play both sounds from MIDI. It will also play the transpositions. The link on the Chroma must be part of the stored program though. If you just temporarily set up a split point or transpose value, the converter won't know that you did this. This feature is useful if you want to control a Chroma or Expander from another keyboard, especially one that can't layer sounds or split the keys.

P3 - MIDI OUT PORT: This is the status of the MIDI output jack. You can configure it as a normal MIDI out or as a MIDI through. When set to out, the converter converts the Chroma information to MIDI and sends it on its way. When set to "thru", the out port acts as a MIDI through port and outputs the data that is coming in the in port. No MIDI performance data from the Chroma is mixed in. When the converter does a MIDI system exclusive dump, it temporarily overrides through mode and outputs the dump.

P4 - PROGRAM CHANGE SWITCH: If this MIDI parameter is set to on, the converter allows the receiving and sending of MIDI program change commands to and from the Chroma. A program change will be sent whenever a new program is selected from the Chroma. If off, program change commands are ignored and won't be sent from the Chroma. When received, MIDI program change commands are translated to Chroma "define" commands. A MIDI program change to program 0 is translated to a Chroma "undefine" command. Consult the section on using the Chroma with a MIDI sequencer for more on this topic.

It is interesting to note that some MIDI keyboards send a program change number that is one less than the actual number selected. They likewise select the program number that is one less than the one you sent it. The Yamaha DX-7 is one of these. NOTE: Selecting program 1 from one of these instruments will send a MIDI program 0 command. This may be interpreted by a Chroma as an "undefine". The end result would leave the Chroma with no "sound" on the Chroma instrument that received the MIDI program 0 command.

If omni is on, the Chroma will respond to a MIDI program change as if the program was selected from the Chroma panel. The program display will change, the tapper will tap, and all the panel parameters will reflect the selected program. This does not normally happen when a define command is received by a Chroma.

P5 - INSTRUMENTS AVAILABLE: This sets the number of Chroma instruments that you want to have listening to MIDI. The selection is a number from 0 to 7. If set to 0, only instrument 0 (main) will be listening to MIDI. If set to 1, instruments 0 and 1 will be listening, set to 7, all eight Chroma instruments will be active and listening for MIDI data on their respective MIDI channels. This feature is necessary to prevent Chroma instruments from being inadvertently defined and played when you've got other MIDI synthesizers on the same line, and the MIDI data is intended for them and not the Chroma.

Note: If omni is on, only the "main" and possibly the "link", if there is one, will be played, regardless of the setting of instruments available.

P6 - CHROMA PARAMETER SEND/RECEIVE SWITCH: This enables or disables the sending or receiving of Chroma parameter changes as MIDI controller changes. If set to "on", the converter will translate parameter changes to MIDI continuous controller commands. Unfortunately there weren't enough MIDI controller numbers available to cover all one hundred Chroma parameter numbers, so only the Chroma parameters you would most likely want to change while recording are translated. Any others will be ignored. Consult table 1 in the back of this manual for which ones are implemented and which MIDI controller numbers are assigned to them. You would set this MIDI parameter to "on" only if you wanted to record Chroma parameter changes with a MIDI sequencer or if you wanted to control Chroma parameters from a remote MIDI keyboard controller. If you examine table 1 you will see that the most commonly used Chroma parameters are assigned MIDI controller numbers 8 through 31. These are 24 of the MIDI continuous controller numbers most likely to be available from a MIDI keyboard controller. You may also notice that some of the undefined MIDI controller numbers were borrowed to cover some of the lesser used Chroma parameters.

When controlling a Chroma parameter from a slider on a MIDI controller, a Chroma parameter value of 0 will be sent when the MIDI slider is in its center position. This allows you to change the Chroma parameters that are bi-polar (plus and minus). Any values that the MIDI controller's slider sends to the Chroma that are outside the range of that particular Chroma parameter will be limited. NOTE: If you have assigned a MIDI controller number to one of the Chroma performance controls that is the same MIDI controller number assigned to a Chroma parameter, the Chroma performance control will take precedence over the parameter change when receiving MIDI. See the next parameter description for more on how the converter handles contention for MIDI controller numbers.

P7 - LEVER ONE SELECT: This allows you to select which MIDI function you wish to control from lever 1 on the Chroma. It will also be the same MIDI function that will control lever 1 when the Chroma receives MIDI data. The selections are "off", "ptch", and a number from 0 to 31. "Off" disables lever 1 from sending or receiving MIDI, "ptch" selects MIDI pitch bend, and a number represents one of 32 MIDI continuous controller numbers. See table 2 in the back of this manual for a list of some of the more commonly used MIDI controller numbers.

The first time you power up the converter box, lever 1 is set to MIDI controller 1. This is the MIDI standard for mod wheel. This assignment corresponds to most of the Chroma factory sounds, which use lever 1 as a modulation control.

When you assign your Chroma performance controls to MIDI controller numbers, it is possible to assign more than one Chroma control to the same MIDI controller number. When sending MIDI from the Chroma, both Chroma controls will send MIDI data to the same MIDI control. This may cause them to conflict if you were operating both Chroma controls simultaneously. In the other direction though, when receiving MIDI controller information, only one Chroma control will be controlled from MIDI at a time. If more than one Chroma control is set to the same MIDI controller number, the Chroma control with the highest priority will be controlled from MIDI. The priority from highest to lowest is as follows: lever 1, lever 2, pedal 1, pedal 2, volume (link balance not volume pedal), parameter change.

P8 - LEVER ONE POLARITY: This sets the polarity of lever 1 on the Chroma. The settings are either "PUSH" or "PULL". For example, if lever 1 is set to pitch bend and polarity is set to "PULL", the MIDI pitch goes higher when you pull on the Chroma lever. This is how most of the Chroma factory sounds are programmed. If lever one is set to control one of the MIDI continuous controllers and polarity is set to "PULL", pulling on the lever would be like incrementing the MIDI controller. Pushing the lever from center position will have no effect on MIDI since MIDI continuous controllers are not bi-polar. This setting is set to "PULL" the first time you power up your converter box. Like all of the other MIDI parameter settings it will be saved if you decide to change it.

P9 - LEVER TWO SELECT: This is identical to lever one select except that is affects lever two on the Chroma.

P10 - LEVER TWO POLARITY: This is identical to lever one polarity except that it affects lever two.

P11 - PEDAL ONE SELECT: This is the pedal marked "volume" on the rear panel of the Chroma. This does not necessarily mean that pedal one is set to control volume on every one of your Chroma programs though. This depends on how that particular program was programmed. The selections for pedal one select are "off" or one of 32 MIDI continuous controller numbers. If you want this pedal to control volume on another MIDI instrument from the Chroma, you would set this to the MIDI controller number that the other MIDI instrument recognizes as volume. The M.M.A. is trying to set the volume controller standard to controller number 7 (since this is what the DX-7 uses), but consult the manual for the particular instrument you're interfacing to.

If you are trying to control the volume on your Chroma from a MIDI keyboard, I would suggest setting MIDI parameter 14 (volume select) instead of pedal one select, to the volume controller number of your MIDI keyboard. Not all of your Chroma sounds may be set up to control volume from pedal 1.

P12 - PEDAL TWO SELECT: This is the pedal marked "effects" on the rear panel of your Chroma. The selections are the same as those of MIDI parameter 11. Set this if you want to have pedal 2 correspond to a MIDI controller on another MIDI instrument or if you want to record pedal 2 commands into a MIDI sequencer. When recording with a MIDI sequencer, set pedal two to any controller number that does not conflict with any other number you may have assigned to another Chroma control. Since the Chroma has no equivalent command for MIDI channel pressure (global aftertouch), it is sent to the Chroma as pedal 2 commands. This feature is fixed, so you should be aware that if you assign pedal 2 to a MIDI controller, it will contend with channel pressure if you try to send the Chroma both channel pressure and MIDI controller information that is destined for pedal two at the same time. If you intend to send channel pressure to a Chroma or Expander, the safest thing would be to set this to "off".

P13 - FOOTSWITCH TWO SELECT: Footswitch two is the left footswitch on your dual footswitch box, also called the latch pedal. This can be assigned to any of the MIDI switch numbers (64 - 95). Upon receiving whichever MIDI switch you select for footswitch two, the Chroma will react as if you pressed or released the latch pedal. Note: The right footswitch is always set to MIDI sustain (controller number 64).

P14 - VOLUME SELECT: This is true volume and not pedal 1, alias "the volume pedal". The Chroma will send volume commands whenever you move the link balance parameter. Note: There is a bug in the Chromas that have the Rev 12 Eproms, where the volume sent out over the computer interface is all messed up, (another good reason to get the Rev 14 Eproms for your Chroma).

This selection is most useful when you want to control the volume of the Chroma from another source like a MIDI keyboard controller. Set this to the MIDI controller number that corresponds to the MIDI keyboard controller's volume control.

P15 - PARAMETER SLIDER SELECT: This setting is different from the other MIDI parameters in that it only lets you send MIDI data and not receive it for a particular Chroma control. This will allow you to send parameter slider moves as MIDI controller changes, regardless of what Chroma parameter is in the parameter window at the time. If the MIDI parameter change switch is on, you will be sending parameter changes that are translated to MIDI as well as MIDI controller changes you assign to the parameter slider.

This essentially turns the parameter slider into an extra MIDI continuous controller. You could, for instance, set the controller number to 1 (mod wheel) and have a Chroma parameter in the parameter window such as filter tuning. Then whenever you changed the filter tuning on the Chroma, you would be sending mod wheel commands to a MIDI instrument at the same time.

P16 - PRESSURE MODE: This parameter is only relevant if you have a pressure sensor in your Chroma. This determines whether you want to transmit the pressure as poly key pressure or as channel pressure. Most keyboards only recognize channel pressure. The selections are "pol" and "chnl".

Using the Chroma with a MIDI Sequencer

Connect the "out" on the MIDI converter to the "in" on you're sequencer. Connect the "out" of the sequencer to the "in" of the MIDI converter. If the Chroma is to be only one of several slave keyboards driven by your sequencer, you can make it part of a MIDI chain by setting MIDI parameter number 3 to "thru". That way you can have other MIDI instruments all listening to the same MIDI information by connecting the MIDI input from the next MIDI instrument to the MIDI "thru" of the converter. In through mode, the Chroma only listens to the MIDI in port and plays information on the channels that it's set to listen to. No MIDI data will be generated from the Chroma. The MIDI data coming into the MIDI in port will be duplicated at the MIDI out port on the converter box.

Here's a very useful setup, especially in a live performance situation where the sequencer is only used for playback, the Chroma is the master keyboard, and you have several other MIDI instruments as slaves. Connect the MIDI out from the sequencer to the MIDI in on the Chroma. Connect the MIDI out on the Chroma to the MIDI in on the first MIDI slave instrument or to a through box, if you don't like to chain. Connect any other MIDI instruments via the through port of the second instrument or to the outputs of the through box. So now, whenever you want the sequencer to play the Chroma and the slaves, you would set MIDI parameter 3 to "thru" and the sequencer will be the source of the MIDI data. You can still play along on the Chroma keyboard, although it won't be transmitting MIDI to any of the slaves, the sequencer will. Then when you want to go back to having the Chroma keyboard as the master controller, set MIDI parameter 3 to "out". The sequencer will be disconnected from the slave instruments and the Chroma will generate the MIDI data.

MIDI CHANNELS: When played from a sequencer, the Chroma is capable of listening on up to eight MIDI channels simultaneously. Each of these eight MIDI channels will address one of the eight "instruments" inside the Chroma. You may recall that the eight Chroma instruments are numbered 0 through 7 and that the "main" is always instrument 0 and the link is always instrument 1. The MIDI channels are assigned to the Chroma instruments from the base channel (set from MIDI parameter 1), upwards. The "main" will always send and receive on the base channel, the "link" will send and receive on the base channel + 1, and instruments 2 through 7 will receive on the MIDI base channel +2 through the base channel +7. If omni is on, the "main" and "link" will receive on all MIDI channels indiscriminately and instruments 2 through 7 will be inaccessible.

Don't confuse Chroma instruments with voices. The Chroma has eight voices as well as eight instruments but the voices are divided up amongst however many instruments you are using at the time. If you are using two instruments, each gets four voices to play. This is obvious when you are in one of the link modes on the Chroma. One exception to this voice dividing scheme is when the Chroma program you have selected for an instrument is programmed with a "mono" keyboard algorithm. In that case it will eat only one voice. (You program a mono keyboard algorithm by setting Chroma parameter 3 to one of the values between 5 and 15). That way if you are using two instruments and one of them is a mono program, the mono one will get one voice and the poly one will get seven to play with. The same holds true when you start to define more and more instruments inside the Chroma. As you start adding more timbres to your sequence you will have fewer voices available to play the parts. That's why it's a good idea to use mono programs on the Chroma whenever possible, especially for bass parts and any other parts that require only one note to be played at a time.

SETTING THE MIDI PARAMETERS: If you only intend to have a sequencer play the program that you currently have selected on the Chroma, no special setup is required. Just remember that if you have a link, it will send and receive on its own channel if omni is off. If you want to access the upper instruments (2 through 7), you must first set several of the MIDI parameters. Set the base channel to whatever channel you want to record from, the Chroma keyboard's "main" instrument will transmit from this channel. It's a good idea to record your tracks from a Chroma program that has no link. That way you are only transmitting data on one channel and not duplicating data, as you would be if you were in "link unison". The link can always be edited into the sequence by copying tracks and channelizing, but more on that later.

Set omni (MIDI parameter 2) to "off". Set MIDI parameter 3 to "out" if you're recording, it can be set to "thru" on playback if you're chaining other MIDI instruments. Set MIDI parameter 4 (program changes) to "on". The converter box uses MIDI program changes to "define" the Chroma instruments. This requires further explanation. Normally the "main" (instrument 0) inside the Chroma is always defined. It is defined to the last program that you have selected from the Chroma front panel, the number that's in the display. The "link" (instrument 1) may also be defined if you have a program selected that is linked. So to set up more than just these two sounds in the Chroma you need to "define" more instruments (instruments 2 - 7). This is done through MIDI by sending the converter a MIDI change program command on the MIDI channel of the instrument that you want to define. If for instance you want to define instrument 7 and have it play the sound on program 50 of the Chroma, you would send a MIDI change program command 50 on the MIDI base channel + 7. If you had the base channel set to 1 this would be MIDI channel 8. So from this you can see that you must record a MIDI change program command at the beginning of a track on your MIDI sequence if that track is to play any of the upper instruments (2-7). This is done by simply selecting the Chroma program from the Chroma panel which in turn outputs a MIDI program change command, before you start to play. You can also edit the program change into the beginning of the sequence after you have recorded the part. NOTE: When selecting a program from the panel of the Chroma, the number in the display must be one that is different from the one you want to select. You may recall that if you press the same number as the one that's in the program display, the Chroma calls up the previous program.

The opposite of a "define" command for the Chroma, is an "undefine" command. When received, a Chroma will essentially turn the particular instrument that received the undefine, off, and relinquish the voices that were allocated to it. The converter box uses MIDI program change 0 commands as undefine commands. So from this you can see that it's desirable to record a MIDI program change 0 command at the end of a track. A MIDI program 0 change can be sent from the Chroma by pressing set split then 49 (just 49 for Rev 12 Chromas).

The next MIDI parameter you need to set is MIDI parameter 5 (instruments available). The purpose of this parameter is to tell the converter box how many Chroma instruments you intend to address. This is necessary to prevent Chroma instruments from being defined and played unintentionally. If you intend to address all eight of the Chroma instruments, you would set this MIDI parameter to 7. This tells the converter box that you want to be able to address instruments 0 through 7. If for instance, you set instruments available to 3, this would tell the converter to only recognize MIDI data destined for Chroma instruments 0 through 3, thus giving you four instruments and likewise four timbres to work with. If the Chroma is the only device connected to your sequencer, you can go ahead and just set instruments available to 7, giving you access to all instruments, if you decide to use them.

The remainder of the MIDI parameters should be set according to your needs. Assign the Chroma performance controls to MIDI controller numbers that correspond to any other MIDI devices you intend to have play the parts you record from the Chroma. If for instance you are recording a track from the Chroma keyboard that will later be played by a DX-7, set pedal one select (MIDI parameter 11) to 7 if you want to record volume pedal changes. MIDI controller 7 controls volume on a DX-7. If lever one is set to MIDI controller 1 (mod wheel), any lever one moves you record from the Chroma will be interpreted as mod wheel commands by another MIDI instrument playing that recorded part. This can be confusing, especially if the Chroma program you are recording from uses lever one for pitch changes instead of modulation changes. Also remember to set the MIDI polarity of your levers to the same polarity as the program in your Chroma. If the Chroma raises pitch by pulling lever two, set lever two select (MIDI parameter 9) to "ptch" and set lever two polarity (MIDI parameter 10) to pull.

If you want to record Chroma parameter changes as part of the MIDI sequence, set parameter changes (MIDI parameter 6) to "on". Be careful when using this feature. If you record parameter changes for the Chroma and then decide to send this information to another MIDI device other than a Chroma, the results could be unpredictable. Consult table 1 in the back of this manual to see which controller numbers are assigned each Chroma parameter.

If you have a pressure sensor in your Chroma and you want to record pressure, set the pressure send mode (MIDI parameter 16) to "p01" for polyphonic key pressure. This means that pressure information is sent separately for each key. If the part will later be played by a MIDI device that doesn't recognize polyphonic key pressure, set this MIDI parameter to "chan" for channel pressure. NOTE: Very few MIDI instruments can handle polyphonic key pressure. You will also have to turn on the Chroma's pressure switch by pressing set split then 35. Pressure can be disabled by pressing set split then 34.

AN EXAMPLE RUN-THROUGH: This example will assume that you have the MIDI base channel set to 1 and that all instruments are available (MIDI parameter 5 set to 7). The first musical part to record will be a bass line which will use a mono sound on the Chroma, lets say program 50. We'll set the sequencer up to record on track one. We'll also set the Chroma to a program other than 50 so when we press 50, 50 is what we'll get. So we start the sequencer recording then press 50 on the Chroma to store a MIDI program 50 change command at the head of the track then start playing the bass part. When the part is finished, we'll press set split 49 on the Chroma (press only 49 if you have a Chroma with Rev 12 Eproms) to record a MIDI program 0 change command at the end of the track. This will "undefine" the instrument on playback, after it's through playing its part, thereby freeing up the voice it was allocated when it was defined.

Now we'll edit this track so it will play instrument 7 on the Chroma. Since our base channel is set to 1, we recorded the track with MIDI channel 1 data. If we then "channelize" the track we just recorded to MIDI channel 8, on playback, Chroma instrument 7 will play the bass line and Chroma instrument 1, the "main" can play another timbre. If you have a primitive MIDI sequencer that doesn't have the ability to "channelize" a track, you'll have to do a few extra steps. What you'll have to do is record with the MIDI channel you intend the track to have. If you want the track to be on MIDI channel 8 as in our example, you must set MIDI base channel to 8 before recording. Then before playback, reset the MIDI base channel to 1 to have the track play instrument 7 on the Chroma. To record a series of tracks using this method, you would record your first track with the MIDI base channel set to 8 then reset the base channel to one number lower on each subsequent pass. This would make each previously recorded track play instrument 1 on the Chroma as you record from instrument 0 (main).

An alternative to the previous example would be to just record the musical part without the program change at the head of the track, then punch the program change in later. This may be necessary if you have to start playing immediately. You can also record the program change on another track and merge it into your performance track or just leave it on its own track if you have plenty of tracks to spare. If you give program changes their own tracks, just make sure they're set to the same MIDI channel as the musical parts that go with them. Another way to handle all of your defines, is to have a measure of setup at the beginning of the sequence. This is where you record all of your program change commands that will set up the timbres for the following tracks. This works nicely with sequencers that allow you to chain smaller sequences together to make one big sequence.

So to continue with our example, recording more tracks is just a matter of recording from the "main" Chroma instrument and then reassigning the "sound" to a higher instrument number by channelizing. When planning a large multi-timbral sequence using only one Chroma, you'll want to map out how many voices will be needed. Remember that the voices will be divided equally amongst the instruments that are defined at any one point in time. Don't forget that these instruments also include the "main" and also the "link", if one is in effect. You may want to have your last track play inst 0 (the "main") so that instrument-a won't be sitting there eating voices and not playing a part. Using mono sounds obviously helps with voice shortage problems. Also storing MIDI program 0 commands at the end of a part will free up voices as well. You will remember from the special functions section of this manual, that pressing set split then 49 will output a MIDI change program 0 command which when received, will be translated by the converter to a Chroma "undefine" command. You can also undefine all of the "extra" Chroma instruments by doing a reset from the Chroma panel (set split 50). I would recommend doing this only if you're too lazy to record MIDI program 0 commands. The Chroma goes into an auto tune and sits there flashing its lights at you for a while during reset.

If you want to play along with a sequence that's playing one or more timbres on the Chroma, assign the sequenced parts to any of Chroma instruments 2 through 7, then play along on the "main" and "link" (instruments 0 and 1). This works great when playing along with sequenced mono bass lines that only eat one voice. You still have seven voices on the Chroma left to play along with.

When you want to record a Chroma sound that requires a "link unison", you have several choices. You can record the part with the link temporarily turned off, then copy the track to an empty track, giving you two identical tracks. Then insert a program change for the main sound at the beginning of one track and a program change with the program number for the link at the beginning of the other track. Then set the two tracks to different MIDI channels so they'll be played by two different Chroma instruments. The second way is to record the track with the link in effect on the Chroma, thereby recording a track that contains information from two MIDI channels on it. With this scheme you won't be able to channelize the track since this would merge the MIDI data into one MIDI channel, so you'll have to record from the channels you intend to have the track play on. If for example, you want the main to be recorded as MIDI channel 6 data and the link as MIDI channel 7 data, set the MIDI base channel (MIDI parameter 1) to 6 before you start recording. Then if you reset the MIDI base channel to 1, the main sound you just recorded will play Chroma instrument 5 and the link will play Chroma instrument 6. The simplest solution though would be to record the link unison sound as the last track in your sequence, then let that track play instruments 0 and 1 on the Chroma, just as it was recorded.

Loading and Saving Sounds Via MIDI

The Chroma to MIDI converter utilizes several MIDI system exclusive messages for the sending and receiving of MIDI data that only pertains to a Chroma or Expander that is connected to a converter. The system exclusive format is designed to allow the transfer of data from one MIDI'd Chroma to another and to be compatible with any of the generic MIDI dump programs that run on the popular personal computers. The system exclusive for the Chroma to MIDI converter was developed using "Sys.Ex", a generic MIDI dump program by Key Clique, but any of the others should work fine.

The Chroma to MIDI converter recognizes six MIDI system exclusive messages. They are as follows: single program dump, request for single program dump, 50 program dump, request for 50 program dump, MIDI parameter dump, and request for MIDI parameter dump. The three types of dumps can be initiated from the front panel of the Chroma as well as by requesting them through MIDI.

TRANSFERRING PROGRAMS FROM ONE CHROMA TO ANOTHER: Connect the MIDI out from the source Chroma to the MIDI in of the destination Chroma. To transfer just one program, select the program on the source Chroma that you want to transfer, then press set split then 20. The program will be transferred to instrument 0 of the destination Chroma. If you then wish to save it on the destination Chroma, you'll have to do a store. Only single programs are sent this way, links must be sent separately. To send all fifty programs, press set split then 48 (just press 48 if you are using a Rev 12 Chroma). All fifty programs will be copied from the source Chroma to the destination Chroma. There is no need to do a store operation.

USING A MIDI DUMP PROGRAM FROM A COMPUTER: The following instructions apply to using "Sys.Ex", but should pertain to any other generic MIDI dump program.

To transfer one Chroma program or all fifty programs to a computer, you can either initiate the dump from the Chroma panel as described in the previous section, or you can have the computer request the program dump by having it send a request message. If your computer is always listening for MIDI system exclusive messages, as Sys.Ex is when MIDI input is set to on, it's probably easiest to initiate the dump from the Chroma panel. So when you send it the dump, the computer will store it in its buffer where you can then transfer it to your computer disk. If your computer program requires you to first construct a "request for dump" message, here is what you tell it to send your Chroma to initiate a dump.

To request a single program dump from a Chroma or Expander, send the following string of decimal numbers: 8, 0, 75, 89, 0, 0-50 (this last number is the Chroma program you are requesting, Program 0 is the current program on the Chroma keyboard, possibly an edited version of another program, 1-50 would be one of the programs in the Chroma memory). ROTE: Sys.Ex allows you to send a series of single program dump requests, incrementing the program number with each request. To request a small a group of programs, let's say programs 1 through 5, you would tell Sys.Ex to send the first request with the sixth value of the string (the program number) set to 1, then increment that value each time it sends the single program request message, until it reaches 6.

To request all fifty programs from a Chroma or Expander, send the following string of decimal numbers: 8, 0, 75, 89, 0, 51. The converter box will respond with a fifty program dump. When you later send this same dump back to a Chroma or Expander, it will replace all fifty programs with the fifty that make up the dump. The program dump that the converter responds with upon receiving a dump request, is in the same form as the one that is sent when you initiate the dump from the Chroma panel.

SYSTEM EXCLUSIVE FORMAT: The following information would be useful for someone who wants to write their own sound filer program. All six system exclusive messages implemented by the converter will start with the following hex ID bytes: $08 (Fender ID), $00, $4B, $59 (converter box's ID). The next byte will denote whether the message is a request for a dump or a dump itself, $00 denotes request, S7F (non-zero) denotes dump. The next byte will denote the file type, $00-$32 (decimal 0-50) denotes a single program file, (the value is the program number, program number 0 is the program currently on the Chroma front panel, possibly an edited version of one of the fifty programs). File type $33 (51 decimal), denotes a fifty program file. File type $34 (52 decimal) notes a MIDI parameter file. A MIDI parameter file describes the current configuration of the converter box's sixteen MIDI parameters.

A request doesn't require any more bytes. A dump will be followed by data bytes in the following form: single program file: 118 (dec) data bytes which are the normal 59 (dec) data bytes that make up a Chroma program, nibblized and sent high nibble first. Fifty program file: fifty separate program packets are sent with each packet containing the program number as the first byte followed by 118 nibblized data bytes. MIDI parameter file: 19 (dec) data bytes which describe the current MIDI parameter configuration.

If at any time when receiving a dump, the data stream is interrupted or invalid data is received, the tapper will tap on the Chroma and "DP ERROR" will appear in the parameter display.

Using the Converter with the Fender Music System

Before you can attach the converter box to the Chroma or Expander port of your Fender Apple card, you must install a jumper wire from +5 volts to pin 5 of the port jacks. Following is an illustration showing where on the Fender Apple card to solder the wires [click for larger image].

Fender Apple card

For a high resolution scan of the original schematic, along with the component layout diagram, see Hardware Description and Specifications.

This illustration shows the easiest places to connect to, on the component side of the card. If you're good with a soldering iron, you can put the jumpers on the circuit side of the card from pin 20 of Z6 to pin 5 of the Chroma and Expander port. If you only intend to use the box on one of the ports, of course you only need to connect 5 volts to that port.

When attached to the Fender Music System, the converter will essentially turn it into a MIDI sequencer and also allow you to use some of the other utilities provided with the system as well. When a converter is attached to a port, the system will be fooled into thinking that there is a Chroma on line at that port. The box is designed to respond, whenever possible, with valid data whenever the system asks for information. Unfortunately the Chroma language provides for more functions than are implemented by 141D1, so in some cases the box will respond with "dummy" data. The box will always respond though, and not cause the system to hang. Several cases of "dummy" data that you should be aware of are program numbers and program data. If you are trying to record a MIDI keyboard from the Chroma port, the converter will always tell the system that it's recording a Chroma with program number 1 as the current program. MIDI provides no means of inquiring the current patch number of the device that's on line. So this means you'll have to set the program number (if you want it to be part of the sequence) from the "change program" feature of the sequencer.

The other dummy data, program data, is used when you try to save the programs from the port the converter is attached to. If you have a converter box on one of the ports, and try to save its programs, you will only store dummy programs that won't sound like anything, if they were later returned to a Chroma. One thing you can do, is send a group of Chroma programs from disk, through a converter box attached to the Fender Apple card, to another Chroma that is attached to its own converter box. The only time this might be useful would be if you chain several MIDI instruments to the Expander port, one of which is a MIDI'd Chroma or Expander.

Included on the latest revision of Fender Music System software (released in November of 1985), is a utility for programming the MIDI parameters of the converter box. The utility resides on user bank 1, number 7. You call it up by pressing <cntrl> U then 7. From the utility you can change the MIDI parameters, selecting the one you want by moving the arrow cursor. You can then select the parameter value by pressing the return key. The value will circulate each time you press "return". What follows is a description of how each parameter affects how the system relates to MIDI.

OMNI: With omni on, all data received by the converter box from the Fender system will be sent on the MIDI base channel. All MIDI data coming into the converter will be sent to the Fender system as Chroma instrument 1 data, regardless of the MIDI channel it was received on. If you're recording from a MIDI instrument, this means that it doesn't matter what MIDI channel your MIDI instrument sends on. During playback, this means all tracks sent to the converter's port will play the MIDI base channel.

With omni off, each track will be assigned its own MIDI channel on playback, and you will only be able to record MIDI data on the MIDI base channel and the MIDI base channel + 1 if "Link Record" is turned on. On playback, the MIDI channels are assigned in ascending order from the MIDI base channel up, to each track as it is "defined" in the sequence. As each new track is defined and sent out a particular port, it will be given the next MIDI channel available starting with the MIDI base channel. You may have to go into the editor of the sequencer to see what order the tracks are defined in for that particular sequence. If a track becomes "undefined" in the course of a sequence, that MIDI channel will become available for another track later in the sequence. What this MIDI channel assignment scheme corresponds to, is how the Fender sequencer assigns sequencer tracks to Chroma instruments. If the sequencer is sending data to instrument 0 out the port the converter is attached to, the converter will translate that data to the MIDI base channel. Data destined for instruments 1 through 7 is likewise assigned to the MIDI base channel + 1 through the MIDI base channel + 7. The exception to this is when you have the converter attached to the Chroma port and you are recording or have selected "W-Play along" from the system menu. In this case the sequencer assigns the first track to instrument 1 or to instrument 2 if there is a link. What this means to you is that if you are recording a MIDI instrument into the Chroma port, and this isn't your first track, or if you selected "W-Play along", the previously recorded tracks being played back through the Chroma port will be assigned starting with the MIDI base channel + 1 or the MIDI base channel + 2 if Link Record is set to on.

LINK RECORD: This can be turned on only if omni is off. When on, the converter makes the system think that there is a Chroma on the port that has a linked program selected. When the system is recording a linked Chroma, it sets up another track to record the link. Turn link record on only if you want to record two tracks from two separate MIDI channels at once from a MIDI keyboard connected to the Chroma port. This is only useful if you have a splitable MIDI keyboard that is capable of transmitting on two MIDI channels. The system will only record MIDI data that is on the MIDI base channel and the MIDI base channel + 1.

BASE CHANNEL: This is the MIDI channel assigned to Chroma instrument 0 when the system is transmitting or receiving. The next 7 consecutive MIDI channels are assigned to instruments 1 through 7 in ascending order. The assignment is circular so that the next consecutive channel after MIDI channel 16 is MIDI channel 1. The system assigns tracks to Chroma instruments in the order that they are defined in the sequence, starting with instrument 0. This means that tracks will come out of the converter, assigned to MIDI channels, starting with the base channel and in the order that the tracks are defined. The system keeps a separate instrument assignment for each port, so you only need to look at tracks that are going to the converter's port when figuring the order of track defines. Remember also that the system will assign the first track on the Chroma port to instrument 1 or possibly instrument 2 (if it thinks there is a link), whenever you are in the process of recording or if you are in "play along" mode.

PROGRAM CHANGES: Set this to on if you want the sequencer to send a MIDI program change at the start of the track. The program number sent will be the one that you assign the track from the "change program" selection of the sequencer.

LEVER 1 CONTROLLER: This is the MIDI control that will correspond to lever 1 changes that you record into the sequencer. It can be set to pitch bend or any of the 32 MIDI continuous controllers. It defaults to MIDI controller 1 (mod wheel) when you first turn the system on. When recording from a MIDI instrument other than a Chroma, the MIDI controller assigned to lever 1 will be recorded as lever 1 changes.

LEVER 1 POLARITY: This is the polarity of lever 1 as it is translated to MIDI commands. If set to pitch bend, "PULL" means the MIDI pitch bend information will go higher when lever 1 is pulled towards you. When recording a MIDI keyboard, "PULL" means that the MIDI data will be recorded as lever 1 commands that correspond to lever 1 being pulled towards you whenever the MIDI control is incremented. "PULL" corresponds to most of the Chroma factory sounds which usually have you pull a lever to raise pitch or modulate a sound.

LEVER 2 CONTROLLER: This is identical to lever 1 controller only it affects lever 2 instead. It is set to pitch bend on power up which corresponds to most of the factory sounds.

LEVER 2 POLARITY: This is identical to lever 1 polarity only it affects lever 2 instead.

PEDAL 1 CONTROLLER: This is the MIDI controller assigned to the pedal marked "volume" on the back of the Chroma. It can be assigned to any of the 32 MIDI continuous controllers or it can be disabled. If you use the pedal to record volume changes from your Chroma, assign it to the MIDI controller number that controls volume on the MIDI instrument that you intend to have play the part.

PEDAL 2 CONTROLLER: This is the pedal marked "effects" on the back of your Chroma. You can assign it to any of the MIDI continuous controllers or you can assign it to transmit MIDI channel pressure. Since the Chroma recognizes individual key pressure, MIDI channel pressure is always sent to the Chroma as pedal 2 commands. So if you are recording a MIDI keyboard from the Chroma port and you want to record channel pressure (this is the kind of pressure most keyboards use), set this parameter to "CHPR". The sequencer will record the pressure as pedal 2 commands and send them back as MIDI channel pressure commands.

FOOTSWITCH 2 CONTROLLER: footswitch box. It can numbers 64 through 95. always sends MIDI sustain This is the left footswitch on the dual be assigned to any of the MIDI switch The right footswitch (footswitch one) pedal commands (MIDI controller 64).

VOLUME CONTROLLER: This is the MIDI controller that will correspond to Chroma volume commands. The system will send volume commands when a track is defined and if you record link balance changes. The most useful way to use this would be to assign the MIDI controller number that controls volume on the MIDI instrument you attach to the system. That way if you use the "change volume" feature of the sequencer, it will set the volume accordingly on your MIDI instrument at the start of a track.

PRESSURE SEND MODE: This only applies if you have a pressure sensor in your Chroma or if you record poly key pressure from a MIDI keyboard. If set to "CHAN", on playback, the polyphonic key pressure will be converted to MIDI channel pressure. The conversion from poly to channel is only implemented for Chroma instruments 0 and 1.

MIDI OUT JACK: This determines whether the MIDI out is an "out" or a "through". This is only useful when you are only interested in sending data into the system since the system can't output MIDI when the port is set to through.

THIS PORT: If for some perverted reason you have a converter box connected to both the Chroma and Expander port, this allows you to select which one you want to set the parameters on.

Also included with the utility is the ability to save your favorite setup on disk. That way you don't need to go through a lengthy setup procedure each time you boot up the system. "5" saves the current setup to disk and "L" retrieves it. Only one setup can be saved, so there is no selection process. The setup is not loaded automatically when you first turn on the system. You must first call this utility then load your setup each time you power up.

You can see from the previous paragraphs that you will have to do some investigation into your sequence to determine which tracks will be assigned to which MIDI channels. The text editor utility that is part of the Fender Music System can be helpful for finding the order that the tracks are defined in. If a track is muted, it will probably also affect the MIDI channel assignment as well.

Some of the other utilities that can be used with the MIDI converter are "H-Expander", the Multi-Instrument program, and the Arpeggiator. The only feature that "H" can't implement is copy tuning. The multi-instrument program will assign MIDI channels to the Chroma instruments in ascending order, starting with the MIDI base channel. The arpeggiator is a little strange. It receives its key information from instrument 0 and instrument 1 if there is a link. It transmits the arpeggiated notes on instrument 2 for the main and instrument 3 for the link. That means that the arpeggiation will play on the MIDI base channel + 2 for the "main" keys that are played and on the MIDI base channel + 3 for the "link" keys.

TABLE 1: Chroma Parameters to MIDI Controller Translations

Params Group Name MIDI controller number
1 Panel Patch
2 Control Fsw Mode
3 Control Kybd Alg
4 Control Detune 112
5 Control Output Select

6, 56 Glide Rate
7, 57 Glide Shape

8, 58 Sweep Mode
9, 59 Sweep Rate 8, 9
10, 60 Sweep Rate Mod
11, 61 Sweep Wave Shape 113, 114
12, 62 Sweep Ampl Mod

13, 63 Env 1 Ampl Touch
14, 64 Env 1 Attack 96, 97
15, 65 Env 1 Attack Mod
16, 66 Env 1 Decay 98, 99
17, 67 Env 1 Decay Mod
18, 68 Env 1 Release 100, 101

19, 69 Env 2 Delay
20, 70 Env 2 Ampl Touch
21, 71 Env 2 Attack 102, 103
22, 72 Env 2 Attack Mod
23, 73 Env 2 Decay 104, 105
24, 74 Env 2 Decay Mod
25, 75 Env 2 Release 106, 107

26, 76 Pitch Tune 10, 11
27, 77 Pitch Mod 1 Select
28, 78 Pitch Mod 1 Depth 12, 13
29, 79 Pitch Mod 2 Select
30, 80 Pitch Mod 2 Depth 14, 15
31, 81 Pitch Mod 3 Select
32, 82 Pitch Mod 3 Depth 108, 109

33, 83 Wave Wave Shape
34, 84 Wave Width 16, 17
35, 85 Wave Mod Select
36, 86 Wave Mod Depth 18, 19

37, 87 Cutoff LP/HP
38, 88 Cutoff Resonance 20, 21
39, 89 Cutoff Tune 22, 23
40, 90 Cutoff Mod 1 Select
41, 91 Cutoff Mod 1 Depth 24, 25
42, 92 Cutoff Mod 2 Select
43, 93 Cutoff Mod 2 Depth 26, 27
44, 94 Cutoff Mod 3 Select
45, 95 Cutoff Mod 3 Depth 110, 111

46, 96 Volume Mod 1 Select
47, 97 Volume Mod 1 Depth 28, 29
48, 98 Volume Mod 2 Select
49, 99 Volume Mod 2 Depth 30, 31
50, 100 Volume Mod 3 Select

NOTE: The first column is the Chroma parameter number. The first number is the "A", the second the "B" parameter. If the MIDI controller column contains a blank, that parameter is unimplemented.

TABLE 2: Some common uses of MIDI controller numbers

Controller Number Function
1 Mod wheel or lever (standard)
2 Breath controller
4 Foot controller
5 Portamento time
6 Data Entry
7 Main Volume
64 Sustain pedal (standard)
65 Portamento
66 Sustenuto
67 Soft pedal
96 Data increment
97 Data decrement

NOTE: Most of these values pertain to Yamaha products.


Set Split 20: Send current program

Set Split 46: Enter MIDI programming mode

Set Split 47: Send MIDI parameter file

Set Split 48: Send 50 programs

Set Split 49: Send MIDI change program 0

MIDI Parmaters Quick Reference

P1: Base Channel

P2: Omni on, off

P3: MIDI out, through

P4: Program changes

P5: Instruments available

P6: Parameter changes

P7: Lever 1 select

P8: Lever 1 polarity

P9: Lever 2 select

P10: Lever 2 polarity

P11: Pedal 1 select

P12: Pedal 2 select

P13: Footswitch 2 select

P14: Volume select

P15: Param slider select

P16: MIDI pressure mode