Foreword Welcome to the MPE Users Guide. Within these pages lurk the details you’ll need to twiddle every knob on your Rane MIDI Programmable Equalizer with full confidence and expertise. If a quick start is all that you desire, please refer to your MPE Operating/Service Manual. The MPE family consists of two models. The MPE 28 is a one channel, 1/3-octave, 28 band equalizer. The MPE 14 is a two channel, 2/3-octave, 14 bands per channel equalizer.
About This Users Guide Conventions A few words about the various conventions used in this document: Front panel LED and key names will be printed in capital letters and bold typeface. When pressing the FUNCTION key and another key ( OMNI, PRGCHG , KEY, etc.) simultaneously, we will write this as “ F-KEY NAME” (for example, F-OMNI ).
User Modes and Functions The MPE user interface is organized into three main user modes. These are: Normal Operating mode EQ Edit mode Expression Edit mode Each user mode can be thought of as a drawer containing a particular set of MPE parameters. To adjust an MPE parameter, you enter the corresponding mode (i.e., open the drawer), change the parameter, and then exit (close the drawer) when you’re done. As implied by its name, the Normal Operating mode is the mode in which you normally operate the MPE.
Notice that the MEMORY LED is lit, and the SYSTEM display has some sort of number in it. The EQ Edit mode can be recognized by the LEDs above the EQ button. If either of these LEDs is lit, (and not flashing) then you are in EQ Edit mode. The following figure shows what the MPE 14 looks like after a band is selected, the MPE 28 has a similar appearance: In the above example the MPE 14 is in Channel 1 EQ Edit mode, as shown by the CHANNEL 1 LED and number in the EQUALIZER display.
That’s all. The Stored Memory corresponding to the number you just typed in is immediately transferred to Working Memory. The rate at which the equalizer changes to these new parameters is determined by the ramp step size (more on this later). There are three variations to the process described above. These involve the bank hold/release option, the octal/decimal numerical base option, and scrolling with the UP and DOWN keys. Let’s take a look at each in detail.
The Secrets of Decimal and Octal Numbers The concepts behind decimal and octal numbers may be intimidating at first, but are really very simple. People count in base ten (decimal) because they have ten fingers and toes. A chicken has three toes on each foot, and would therefore naturally count in base six (if it used both feet). Snakes don't have toes, that's why they can't count. Anyway, ten is a very special number to us humans.
lower frequency bands (31.5-630 Hz) of the equalizer. Pressing EQ again selects the upper frequency bands (800-16 kHz). Pressing EQ a third time returns you to Normal Operating mode. The LED corresponding to the group of bands you choose illuminates, and a cursor flashes in the EQUALIZER display. 2. Select a band or overall level by pressing its key (31.5-16k , or LEVEL). The LED associated with this parameter lights. The parameters current value appears in the EQUALIZER display. 3.
Adjusting The Ramp Step Size One of the unfortunate laws of physics tells us that abrupt changes to audio signals cause “pops”. The bigger the change, the worse the pop. To combat this nemesis, the MPE ramps between curves, with a programmable step size. The slope of this ramp determines how much of a pop is output by the equalizer. The steeper the slope, the faster the change, and therefore—the louder the pop. The ramp step size is programmed in dB values.
Editing The Expression Parameters Expression is a feature of importance to musicians who use MIDI continuous controllers or channel pressure aftertouch. Expression assigns a vector (direction) to each band of the MPE, and specifies a MIDI continuous controller or channel pressure aftertouch to act as the expression controller. When the assigned expression controller sends MIDI data to the MPE, the current equalizer parameters boost, cut, or remain unchanged depending on the direction of each band’s vector.
2. Press the UP or DOWN keys to scroll to the desired expression controller. Any single MIDI continuous controller number ( 0-120) may be selected. Scrolling past number 120 selects channel pressure aftertouch (displayed as aft), aft or all controllers and aftertouch (displayed as all). all A third option is the auto-detect feature (displayed as det). det You may scroll to this option, or access it directly by pressing the UP and DOWN keys simultaneously.
The overall level adjustment has its own minimum and maximum values. There is a limit then, to how far this curve shifting can go before running out of room. If you know the resultant curve requires overall level compensation ahead of time, make sure the overall level is capable of supporting this change. The above curve is the final result of the curve weighting algorithm. What happens if we have both over and under ranges? For example: Sum: Level 50 125 315 800 2k 5k 12.
Placing The MPE In And Out Of Lockout Lockout disables the MPE front panel for those who wish to make their equalizer tamper-proof. The MPE provides two levels of lockout for maximum flexibility. Lockout level 1 ( l.O.1) allows users to recall Stored Memories, but that’s all. No alteration of any MPE parameters is allowed. Lockout level 2 (l.O.2) disables the MPE front panel completely, like it wasn’t even there. To change the lockout status, you must enter a password.
MIDI Operation The MPE has very powerful MIDI capabilities. If you are not exactly bursting with MIDI knowledge, you might find it beneficial to take a break from the MPE at this time and read a few of the MIDI references listed in Appendix C. The MPE uses MIDI system exclusive messages (SYSEX) to transmit information—lots of it. To harness this power, without nuking your MIDI system with loads of MIDI data, you should be aware of which MPE SYSEX functions are necessary for your particular need.
Turning Omni Mode On And Off Sometimes it is necessary to instruct the MPE to listen to all MIDI channels, but to only transmit on one particular channel. This is useful, for example, if you want the MPE to listen to another MIDI device but don’t know what channel the device is transmitting on. It is also useful when more than one MIDI device is speaking to the MPE, and each is assigned to a different MIDI channel. Omni mode forces the MPE to accept messages on all MIDI channels.
In the above table, a received program change 1 recalls Stored Memory 10. Program change 2 also recalls Stored Memory 10. Program change 3 recalls Stored Memory 3, and so on. In general, any program change command can recall any Stored Memory. Multiple program change commands can recall the same Stored Memory, but a single program change command can only recall one Stored Memory. To program the MIDI map: 1.
Key Scan Messages Key scan messages carry the status of the MPE front panel. If the Key Scan Echo option is enabled, any time you press or release a key on the MPE, it sends a number corresponding to that key out the MIDI OUT port. Any MPE of the same model, as long as the MIDI channel and device ID match properly, accepts these messages and processes them as if those keys are pressed its own front panel. In this way, one MPE can be configured as the master controller over any number of slaves.
Enabling Parameter Echo 1. Make sure you’re in Normal Operating mode, then enter the Set Parameter Echo function by pressing F-PARAM . The FUNCTION LED illuminates, and the PARAM LED flashes to verify that you are in this function. The current Parameter Echo status occupies the SYSTEM display ( on or off). off 2. Use the UP or DOWN key to toggle the status of Parameter Echo on or off. 3. Press F-PARAM to return to Memory mode when you are finished. The FUNCTION and PARAM LED’s turn off.
RPS 4 Remote Program Selector In some applications, it may be desirable to switch the MPE programs from a remote location, without the use of a computer or MIDI controller. A simple switch to change programs can also make operation a lot easier for the non-technical person who may be responsible for operating the sound system. The RPS 4 comes to the rescue. Simply, the RPS 4 converts contact closures to MIDI program changes.
Here is a wiring diagram to use with momentary contact pushbuttons with optional LED indicators. This idea can be used for 2, 3 or 4 program changes. Using a binary encoded switch, 16 MIDI program changes can be activated. A four pole, sixteen throw switch can also be used. A switch with fewer positions (such as an eight throw switch) may be used by omitting the extra connections. Use of the RPS 4 is pretty obvious and shouldn’t present any problems. Here is a short check list: 1.
MPE Computer Software There are some advantages to programming the MPE's from a computer. Programs can be saved on disk and backed up for security, and the MPE front panel controls locked out if necessary. Because of the compact rack height of the MPE, it is difficult to provide a readable graphic display of the total response curve as found on normal graphic equalizers. A computer allows you to see the actual response of the entire graph you are working on.
Rane MPE Users Guide 21
Applications Now for the fun part, using the MPE. The MPE hooks up to other audio equipment just like a standard graphic equalizer. Audio goes in the audio input and comes back out the audio output. Don’t forget to connect power to the MPE. There are an endless variety of MIDI setups that could accommodate the MPE. A few simple ones appear below. In all cases, the MIDI OUT of one device connects to the MIDI IN of another device.
Example 4: Master-slave configuration with 3 slaves, using a MIDI Thru box. This setup is similar to example 3, with the addition of a MIDI Thru box to increase the number of possible slaves. Although only three slaves are shown, any number may be used (limited by the number of outputs on the MIDI Thru box). Example 6: Computer-controlled system with MIDI Merger. The computer sends data to both MPE’s. The MIDI OUT of each MPE is merged and returned to the computer’s MIDI IN.
Battery Maintenance The MPE contains a battery to keep the memory alive during power down. The battery should last five years, as long as you abide by the following tips: Keep your MPE in a cool place. Battery life takes a dive when it gets hot. Keep your MPE powered from the power supply as much as possible. As long as the MPE has power, it doesn’t use the battery. The battery should be checked every year or so. This can be carried out at any Rane warranty station.
Problem: The MPE doesn’t receive MIDI program change commands. Troubleshooting: 1. Is the MIDI cable plugged in correctly? The MIDI Out of the transmitting device should be connected to the MIDI IN of the MPE. MIDI cables should not exceed 50 feet in length. If your cable is longer than this, try a shorter one. Problem: The MPE doesn’t communicate with another MPE via MIDI SYSEX. Troubleshooting: 1.
Appendix A: Error Codes Appendix B: Ramp Details The MPE scolds you with error codes (on the SYSTEM display) whenever you enter a key press that is invalid. These error codes are defined below. (For advanced users only, not necessary for normal operation) Any instantaneous change to the level of a bandlimited audio signal is accompanied by a small overshoot. Aurally, this reveals itself as a “pop”. This is a fact of life, as dependable as taxes and death.
Computing EQ Ramp Transition Time In the figure below an MPE 14 is in transition between two curves (the heavy lines). The Ramp is set for 2 dB steps, resulting in intermediate curves 15. To compute the total time required for the EQ change you must add up the time required for each step. The number of steps is determined from the band (or overall level) that makes the largest change, divided by the Ramp step size. In this example, the 16 kHz band makes the largest change of 12 dB.
Real World Example Let’s put this into MIDI studio language. Suppose we use the ramp as an effect to cross fade into a new section of a song. We want the fade to end on a given beat. For this example the tempo is 120bpm (beats per minute). Therefore one beat of 4/4 will be 1/2 second (500ms). The sequencer resolves into bar:beat:ticks with 120 ticks per beat (4.2ms between ticks). We determined that EQ changes take 3ms to 200ms, depending on the details given above. At 4.
Appendix D: MPE 14 Factory Presets Preset Ch Level 40 63 100 160 1 0 0 0 0 0 1 2 0 0 0 0 0 Comment: Stereo Flat 1 -12 6 6 6 6 2 2 -12 6 6 6 6 Comment: Stereo All 6dB Boost 1 0 -15 -15 -15 -15 3 2 0 -15 -15 -15 -15 Comment: Stereo All Full Cut 1 0 -15 8 1 1 4 2 0 -15 8 1 1 Comment: Stereo Low Cut 1 0 0 0 0 0 5 2 0 0 0 0 0 Comment: Stereo High Cut 1 0 6 2 -1 0 6 2 0 6 2 -1 0 Comment: Stereo Low End Punch 1 0 0 0 0 0 7 2 0 0 0 0 0 Comment: Stereo High End Rolloff 1 0 8 -15 10 -15 8 2 0 8 -15 10 -15 Comment: St
Preset Ch Level 40 63 100 160 250 400 630 1k 1.6k 2.
Appendix E: MPE 28 Factory Presets Preset Level 31.
Index A Adding two curves ................................................ 10 Aftertouch ............................................................. 22 editing ................................................................. 9 Applications .......................................................... 22 Assigning MIDI Channel ...................................... 13 Auto-Detect ............................................................ 9 B Bank ...........................................................
K M Key scan ............................................................... 16 Keys BANK ................................................................. 5 BYPASS ............................................................. 4 CURVE WEIGHT ............................................. 10 definition of ......................................................... 2 DEVICE ............................................................ 15 DUMP ...............................................................
P V Parameter echo ..................................................... 16 Patch ....................................................................... 2 Pops ........................................................................ 8 Preset MPE 14 ............................................................. 29 MPE 28 ............................................................. 31 recalling factory .................................................. 8 stored memory ......................................
