Akai MPK Mini Play MIDI mod (1)

Posted on August 9, 2022 by pj

Yesterday, I took a quick look inside the Akai MPK Mini Play MIDI controller and synthesizer. I would like to discover a way to drive fully the Dream S.A.S. SAM2635 synthesizer chip without interference by the Arm microcontroller.

My initial investigation concentrated on the set of test points connected to key SAM2695 inputs and outputs:

    Pad Signal        Dream function 
    --- -----------   --------------------------- 
     1  STIN          Serial test input 
     2  STOUT         Serial test output  
     3  SAM2635_RST   Master reset and power down  
     4  SAM2635_TX    MIDI OUT  
     5  SAM2635_RX    MIDI IN  
     6  D GND         Digital ground  
     7  D +3.3V       Digital +3.3V

If I can read and drive the SAM2635 MIDI IN and OUT, it should be possible to control the Dream synthesizer directly.

First, I need easy access to the relevant test points. I started with a 4-wire ribbon cable with male prototyping pins at both ends. These ribbon cables are easy to find and are generally used to connect a group of signals from one prototyping connector to another. In this case, I cut off the pins at one end with the intention of soldering the wires to the test points on the Mini Play main printed circuit board.

Ribbon cable to Akai Mini Play test points

The picture above shows the test points after soldering. The soldering job ain’t pretty, but the joints are functional. The color coded connections are:

    Pad Signal        Dream function  Color 
    --- -----------   --------------  -----  
     4  SAM2635_TX    MIDI OUT        Black  
     5  SAM2635_RX    MIDI IN         White  
     6  D GND         Digital ground  Grey  
     7  D +3.3V       Digital +3.3V   Purple

After inspection, I took a deep breath and powered up. The Mini Play functioned correctly, thank goodness.

I created a small, unobtrusive notch in the plastic top panel and routed the ribbon cable through the gap above the high C key. If I ever go to sell or trade the Mini Play, I should be able to unsolder and remove the cable while leaving the case visibly intact. As you can see in the picture above, the ribbon cable terminates at four male prototyping pins.

Next up, I assembled a UBLD.IT MIDI breakout board and interface. I bought the UBLD.IT board from Amazon. Unfortunately, the board is now out of stock. Bummer, cuz it’s a nice one.

The UBLD.IT has a 4-pin female header:

    Pin   Function 
    ----  -------------- 
    Xmit  MIDI OUT 
    Recv  MIDI IN 
    Vcc   Positive voltage rail 
    GND   Ground

I connected the ribbon cable to the UBLD.IT board and connected the UBLD.IT to a Windows PC through a 5-pin Roland MIDI interface.

Power up. No joy. The Mini Play worked properly, but I wasn’t able to monitor the MIDI traffic from the Arm microcontroller to the Dream SAM2635 synthesizer via MIDI-OX. Nor was I able to drive the SAM2635. So much for the quickest and dirtiest solution!

Since nothing smoked and the Mini Play is healthy, it’s time for methodical investigation. First goal, I would really like to monitor the MIDI traffic from the Arm to the SAM2635. It might help me figure out what the heck the Akai software is doing to incoming USB MIDI messages. Once I ace this problem, I’ll try driving the SAM2635, again.

One further observation. I attached SAM2635_RX and SAM2635_TX to a Gabotronics USB oscilloscope. After futzing with the scope controls, I observed what looks like serial data bytes (MIDI) on the SAM2635_RX line. The Arm drives this line when it sends MIDI messages to the SAM2635. Serial bytes are sent in response to note ON/OFF, control knobs, and the joystick. Ooooo, so close!

By golly, there ought to be a way to monitor this MIDI traffic! I conjecture that the logic signal is inverted. Another possibility is a non-standard data rate, that is, something other than 31,250 baud. Probably ought to test the UBLD.IT in isolation, too.

Inside Akai MPK Mini Play (mk1)

Posted on August 8, 2022 by pj

Akai MPK Mini Play (first generation). Let’s take a look inside.

The Akai MPK Mini Play splays open just like an Akai MPK Mini. Check out one of the fine MPK Mini disassembly videos if you want to crack open your MPK Mini Play. Here are a few quick tips:

Gently remove the knobs from the pots. You will need to pry under each knob with a super small screwdriver or some other flat blade.
You need to remove the red rubber cap from the center of the joystick. The rubber cap is held on by adhesive.
Once the red rubber cap is removed, unscrew the joystick knob and set it aside along with the cap.
Remove all twelve screws from the bottom. These screws hold the bottom to the top.
Pry up the back of the Mini Play first and expect to sneak the top past the underside of the keys.
Mind the ribbon and battery cables when opening the chassis. Be slow and gentle. Do not aggressively flip the case open!

Splaying the case is good enough to expose the main electronics. Unless you are going to fix or mod the pads, you do not need to remove the main printed circuit board (PCB).

As you can see in the picture, the keybed is mounted on the bottom tray. The battery compartment is molded into the bottom. A ribbon cable connects the keybed switch matrix (rows and columns) to the main PCB. In the future, I’d like to personalize my Mini Play by replacing the standard black on white keybed with a white on black keybed — Vox Continental envy. 🙂

The main PCB has left, middle and right parts. The middle looks empty, but the rhythm pads are on the other side in this region. The rubbery black pad in the case bottom provides mechanical support to the PCB beneath the rhythm pads.

The right part of the main PCB has the arpeggiator switches and joystick subassembly. The legend on the integrated circuit (IC) is super faint and is barely readable with a strong light and magnifying glass. IC5 appears to be a CMOS 595D 8-bit serial-in, serial- or parallel-out shift register. Signals from the right part of the PCB travel over a gazillion traces to the left part.

Akai Mini Play PCB (Arm and Dream synthesizer)

All the really fun stuff is on the left part of the main PCB. Here you will find the back panel components: battery/USB power switch, 3.5mm headphone jack, sustain pedal jack, and USB-B port. The sustain pedal jack is hidden beneath the ribbon cable in the picture. [You’re not really missing anything.]

The ribbon cable near the USB-B connector connects the OLED display to the main PCB. IC10 and IC11 are TI HJ4051 8:1 multiplexer/demultiplexers. Akai conveniently printed cable signal tables on the PCB. Signals for the OLED display (J2) are:

     Pin Signal       Pin Signal 
     --- ---------    --- --------- 
      1  NC             8 OLED_CS 
      2  NC             9 OLED_RST 
      3  NC            10 OLED_CD 
      4  NC            11 OLED_CLK 
      5  D +3.3V       12 OLED_DATA 
      6  D GND         13 D GND 
      7  D +3.3V       14 D GND 
                       15 D GND

The legends on IC4 and IC5 are quite faint. They are either 74HC595D or 74HC395D. My eyes are old and sore. 🙂 This logic is probably related to the rhythm pads and signals from the right side of the main PCB.

Signal assignments are given for the keybed ribbon cable (FCN1):

     Pin Signal       Pin Signal 
     --- ---------    --- --------- 
      1  KBD_COL8       9 KBD_COL4 
      2  KBD_ROW1      10 KBD_ROW5 
      3  KBD_COL7      11 KBD_COL3 
      4  KBD_ROW2      12 KBD_ROW6 
      5  KBD_COL6      13 KBD_COL2 
      6  KBD_ROW3      14 KBD_ROW7 
      7  KBD_COL5      15 KBD_COL1 
      8  KBD_ROW4      16 KBD_ROW8

Typical key scanning drives a row (or column) signal and reads back a column (or row) group. Holy smokes! The Mini Play PCB may support eight groups of eight keys. If the proper software support is implemented, one might be able to attach a 61-key keybed to the main PCB! (A big “IF”.)

The 64 pin surface mount (SMT) device near the two printed tables is the main CPU: an ST Microelectronics STM32F401RCT6 Arm Cortex-M4 microcontroller. This device has a single core, 64KB RAM and 256KB flash memory. The blue dot may indicate that the device was programmed before installation. (Dunno.) I can’t read the top of the crystal XTIM1, so I don’t know the clock speed.

Finally, we get to the synthesizer (IC2): a Dream S.A.S. SAM2635. The Macronix IC (IC3) at the left edge of the PCB is NOR flash containing the Dream waveforms. Again, the blue dot may signify preload status. Near the SAM2635, we find JST connectors for the battery and the speaker.

In my view, the most exciting and interesting part of the main board are the test points in the lower left corner. The signals are:

    Pad Signal        Dream function 
    --- -----------   --------------------------- 
     1  STIN          Serial test input 
     2  STOUT         Serial test output 
     3  SAM2635_RST   Master reset and power down 
     4  SAM2635_TX    MIDI OUT 
     5  SAM2635_RX    MIDI IN 
     6  D GND         Digital ground 
     7  D +3.3V       Digital +3.3V

I verified these connections using a continuity tester. The SAM2635_RX and SAM2635_TX pads are connected to the Arm microcontroller:

    Pin  Function       Test POINT  Pad 
    ---  ------------   ----------  --- 
     42  USART1_TX      SAM2635_RX   5  I/O 5V tolerant 
     43  USART1_RX      SAM2635_TX   4  I/O 5V tolerant

So, boys and girls, we may be in business!

In my opinion, Akai botched the MPK Mini Play by hiding the Dream synthesizer behind software on the Arm. The Arm makes the Mini Play look like a semi-crazed synth of its own, not the SAM2635. The test points may — may — provide a way to get at the Dream synthesizer directly. The INTERNAL SOUNDS button acts like a MIDI LOCAL CONTROL button. So, I’m hoping to disable internal sounds and hijack the MIDI IN and OUT test pads (signals) to the SAM2635.

Come for the teardown; Stay for the mods:

Review: Akai MPK Mini Play (Mk1)

Posted on August 5, 2022 by pj

Now that Akai have introduced the new Akai MPK Mini Play Mk3, original first generation Mini Plays are going on sale. Being a notorious bottom-feeder (doing the most with the least), I cashed in a few loyalty points and bought one.

Sound On Sound magazine recently reviewed the new mk3. Many of their comments apply to the original MPK Mini Play; basic functionality has not changed. The mk3 includes an improved second generation MPK Mini keybed, a bigger and better speaker, a different panel layout and different, narrower pads. Everything else is pretty much the same. Having an OLED in an inexpensive product like the MPK Mini Play is a luxury.

For the el cheapo price, the MPK Mini Play is surprisingly well-made. The keyboard and knobs don’t feel cheap although I doubt if they are very durable. All of the back connectors are mounted directly on the main printed circuit board (PCB) and should be treated with respect and care. There are numerous USB connector repair videos on-line (for the similar Akai MPK Mini), so beware when handling any of the Minis.

As to the Mk3 improvements, I get it. The original’s speaker is quite weak with limited frequency range. The original keybed is a little touchy. Keys need to be struck firmly to reliably trigger notes. One cannot play soft notes; forget nuance. The pads aren’t bad, however. Pads have always been Akai’s strong point.

The sound engine is the Dream S.A.S. SAM2635 with its 8MByte CleanWave® soundset. The Mini Play’s soundset has 128 General MIDI sounds, 9 drum sets and one sound effects (SFX) set. By and large, it’s a decent sounding GM set including the reverb and chorus. The front panel knobs let you tweak filter cut-off, resonance, attack time, release time, reverb level, chorus level, EQ low and EQ high. Edits can be saved to one of eight Favorite locations. In this regard, the Mini Play is one-up on the Yamaha PSS-A50. (The PSS-A50 price is in the same neighborhood as the Mini Play.)

That’s the good news. Now the bad news. As mentioned in the Sound On Sound review, the incoming MIDI implementation is a nightmare. [I’m still figuring it out.] Foremost, the Akai Mini Play is not a multi-timbral GM module. The Akai software modifies (filters? blocks? mangles?) whatever MIDI you send to it before it sends its own internal MIDI stream to the SAM2635.

This is a shame and a lost opportunity for Akai and its customers. The Mini Play could be so much more if it allowed a direct path to the SAM2635. The Dream firmware is a complete GM/GS implementation. WTF, Akai? Akai would sell shed-loads more if the Mini Play was an actual GM module.

I’ve encountered Dream synthesis before in the Modern Device Fluxamasynth and the midiPlus miniEngine USB. Unlike the Akai, both devices suffer from noisy audio. I’m doubly disappointed because the Mini Play audio is relatively clean.

So, if you’re looking for a DAW-driven synth module, pass on both the original and Mk3.

As to the outgoing MIDI implementation — using the Mini Play as a controller — it is basic and functions well. The free software editor gives you access to everything configurable (pads, knobs and joystick), storing configurations into a Favorites slot. No complaints here although MPK Mini users might miss the four additional knobs provided by the plain ole Mini.

The Akai MPK Minis are the gateway drug to MPC production. Akai have always rolled out good value with their bundles. The Mini Play software bundle follows the path and includes:

Akai VIP VST instrument and effect host environment
AIR Hybrid 3 synthesizer
Wobble synthesizer
MPC Essentials (AKA tons of samples)
ProTools | First

And, of course, Akai’s free MPC Beats application. Download and installation, if you go for everything, is laborious due to partnership arrangements and different authorization and licensing procedures.

Bottomline. A MIDI module it is not. If you want a tiny, inexpensive MIDI controller with a limited in-built synthesizer and a serious stack of content, give it a go. If you expect to play live, go for the Mk3 and the better keybed and speaker.

After initial disappointment about the MIDI implementation, I took a screwdriver to the MPK Mini Play. Naturally, a device this small and inexpensive is mod fodder. I will discuss mod potential in a future post.

Update: If you intend to use the Akai MPK Mini Play as a MIDI module, you must read my analysis of its MIDI implementation. If you want to mod the MPK Mini Play, start here and here.

Like the review? Check out the teardown (disassembly) and mods:

2019 market data (NAMM)

Posted on August 1, 2022 by pj

The National Association of Music Merchants publishes the annual NAMM Global Report, a summary of market data from the USA and 28 countries and regions around the world. NAMM makes its best effort to collect market data, but there isn’t a single authoritative reporting mechanism or source.

I’m browsing through the 2020 NAMM Global Report which is a 306 page behemoth. Here are a few random observations. Even though the report says “2020,” the latest market data is from 2019.

The USA music market is estimated at $8 billion (USD) or 45.8% of the total global market. The US is roughly 5% of the world’s population. Yet, it purchases 40% of the world’s instruments and audio gear.

We keyboard players like to think we are a major segment. Wrong. Fretted instruments — AKA “guitars” of all kinds — are king:

    Fretted Products           $1,891M 
    Pro Audio                     853M 
    Wind Instruments              611M 
    Percussion                    374M 
    Acoustic Pianos               307M 
    DJ Gear                       264M 
    Digital Pianos                182M 
    Keyboard Synthesizer          159M 
    Portable Keyboards            127M 
    Stringed Instruments          125M 
    Electronic Player Pianos      100M

NAMM tracks many other product categories (e.g., accessories, cables, etc.), so I’ve been selective in what I have shown here. It’s enough to see, however, that our beloved synthesizer and arranger keyboards are minor players! No wonder brick and mortar stores have so few keyboards on the floor while the guitar section is stuffed.

Keyboard synthesizers had modest growth, 5.6% versus 9% growth in Fretted Instruments. (The Fretted Instrument category includes amps and effects, too.) Portable keyboards were off 18%. Yikes! Further proof that arranger keyboards in the US don’t get much love.

NAMM classifies Keyboard Synthesizers uder the Electronic Music market segment. This segment breaks down in the following way (by retail value):

    Keyboard Synthesizers        56.3% 
    Electronic Drums             24.3% 
    Controller Keyboards          9.8% 
    Electronic Piano/Organ        5.6% 
    Rhythm Machines/Production    3.7%

Oddly, NAMM does not include Portable Keyboards under Electronic Music. NAMM divides Portable Keyboards into two subsegments (by retail value):

    Keyboards under $199         41.3% 
    Keyboards over $199          58.7%

One could argue that portable keyboards under $199 are entry-level, beginner, educational instruments. Some of those portable keyboards over $199 are comparable to synthesizers. Without further data, one cannot make a stronger comparison. However, synths do out-sell mid- to high-end arrangers by retail value in the USA. Unit sales flip relative numbers the other way: 135,000 synthesizers versus 767,000 portable keyboards (total).

Higher tariffs are affecting the price of imported musical instruments, especially imports from China. By import value, 57% of imports are from China. No wonder manufacturers are shifting production to Indonesia, India and Malaysia. So much for using tariffs to move musical instrument manufacturing to the domestic US. Tariffs alone are a blunt instrument and the law of unintended consequences applies.

As mentioned earlier, the US has a 45.8% share of the global market. Here’s a table to fill out the world picture:

    United States      45.8% 
    China              10.8% 
    Germany             5.9% 
    Japan               5.4% 
    Canada              4.5% 
    France              3.5% 
    U.K.                3.3% 
    Australia           3.1% 
    Spain               2.0% 
    Italy               1.9% 
    S. Korea            1.9% 
    Mexico              1.3% 
    India               1.0% 
    Netherlands         1.0% 
    Belgium             0.9% 
    Hong Kong           0.8%

I’ve read other international music market studies wherein they decry abysmal reporting from certain world regions. Thus, one shouldn’t draw too many conclusions here. Data from South America, Africa and broader Asia are notably lacking. Systematic, consistent and complete? No.

Due to the lack of uniform reporting, it’s impossible to make any detailed comparisons against the US market. For example, I wanted to validate the conjecture that “arranger keyboards are more popular in region XYZ than the USA.” Only a few countries had data by market segment (Germany, the UK). Report subsegments just didn’t match up, preventing comparison.

As to the UK, guitars and effects dominate, but not to the extent as the US:

    Guitar and Effects   150M
    Pro Audio            112M 
    Keyboards             87M 
    Band and Orchestral   50M 
    Recording             50M 
    Accessories           45M 
    Percussion            42M

Retail value is expressed in British Pounds and is only an estimate (from a bar chart, argh). UK keyboard sales break down in the following way:

    Digital Pianos          31M 
    Grand Piano             14M 
    Keyboard Synthesizers   13M 
    Portable under $199     10M 
    Vertical Pianos          8M 
    Portable over $199       7M 
    Player Pianos            4M 
    Keyboard Controllers     3M

Again, these retail sales numbers are only approximate (British Pounds).

Well, have at it. If you have any quibbles about product categories, missing data, etc., please write to NAMM, not me. 🙂

You spin me right round

Posted on July 26, 2022 by pj

Spot product shortages have sparked speculation about discontinued products, new products, etc. Given the human propensity to look for and find patterns, it’s no wonder that conspiracy theories take hold!

The on-line inventory picture is mixed. Some retailers show Yamaha Montage/MODX, for example, in stock, some show them out of stock pending September availability and, in one case, discontinued.

Random “discontinued” tags seem to come and go. A month ago, the Yamaha Canada site marked the MX as discontinued. Now the marker is gone. Better indicators are blow-out pricing to move stock or a Yamaha spiff incentive to move old stock. So far, I haven’t seen any clearance pricing or promotions.

Yamaha’s mid- to upper-end keyboard products have a vulnerable supply dependency on Asahi Kasei Microdevices (AKM) DACs and ADCs. The AKM factory fire was worse than originally thought and production is still not back on-line. Renesas has offered to manufacture AKM devices. The Yamaha UK site has the disclaimer, “Due to the difficulty in procuring semiconductors and procuring parts worldwide, some of our product area deliveries may be delayed. Thank you for your understanding.”

AKM aren’t very public about their recovery and certainly haven’t released a public roadmap. A recent press release for VELVET SOUND DACs and ADCs mentions sampling (no pun intended) in January 2022 with “mass production scheduled for the third quarter of 2022.” Given that Toyota is a top AKM customer, who wins, Toyota or Yamaha? 😉

The AKM shortage inspires other conspiracy theories, too. Theory #1: Yamaha are using non-AKM DACs and ADCs in Montage — the analog/jack (AJK) board was redesigned or manufactured with inferior non-AKM devices. Theory #2: MODX is suspended in order to give preference to and ship the wider-margin Montage. Someone went so far as to ask about replacement DACs in Montage and got the usual non-response from Yamaha. (What did they expect?)

Some of the Yamaha boards use Yamaha proprietary ICs, e.g., SWL, SWX, or SSP2 processors, creating a different supply dependency. When production inventory is exhausted, Yamaha need to re-spin end product to use a newer part. The July 2016 MX refresh is one interesting example. I believe that was the case with the MX refresh.

I haven’t seen a new version of the heavy weight SWP70 tone generator. However, Yamaha have updated both the SWX and SSP lines:

The SWX08 is replaced by the SWX09.
The SSP3 — now appearing in Steinberg and Yamaha pro audio products — will likely replace the SSP2.

The SWX update would affect mid-range keyboards, notably the Yamaha Reface CP and YC. The SSP update would affect Montage, MODX, and Reface CS and DX.

Are new product spins in the works? Something is coming (eventually) given the CK61™/CK88™ and AN-X™ trademarks. Once again, only Yamaha really knows. 🙂

STEP EDIT → Chord Looper

Posted on July 15, 2022 by pj

Yamaha Genos and PSR-SX900 arranger workstations have a feature called “Chord Looper”. Chord Looper records your left hand chords and saves them in a memory slot. (8 slots per Chord Looper bank.) Once recorded and saved, you can play back the chord progression and play over the changes. Neat.

Obviously, one way to enter a chord progression is to play it in. Let’s say, that the chord progression is long and has jazz chords like the Coltrane changes (AKA “Giant Steps”). These changes are notoriously difficult to solo over because the changes come fast, furious, and in three different scales! On top of musical difficulty, Chord Looper does not allow edits. Make a mistake and you need to record the entire sequence over again. So, folks are looking for ways to create and edit Chord Looper progressions.

Chord Looper CLD files

Fortunately, Chord Looper let’s you import and export individual chord progressions (i.e., a slot). Chord Looper exports a progression into a file with the CLD extension. Henceforth, I will call these files “CLD files”.

A CLD file is actually a Type 0 Standard MIDI File (SMF) in disguise. You can examine (or possibly edit/create) a CLD file by renaming the extension to “MID”. Once renamed, conventional software tools (Cubase, SONAR, etc.) will recognize the renamed CLD file as a Type 0 SMF and import it.

A CLD file recorded by Chord Looper is very simple inside. It contains a sequence of Yamaha XF chord events, one event for each chord change. Here are the metadata events for a simple progression (C-Am-F-G) played in by hand:

Chord Symbol   1.1.1.0     Metadata    Chord:  C/C 
Chord Symbol   1.4.4.112   Metadata    Chord:  Am/A 
Chord Symbol   3.1.1.34    Metadata    Chord:  F/F 
Chord Symbol   4.1.1.40    Metadata    Chord:  G/G

Each event specifies the chord root, chord type and alternate root bass. That’s it! A CLD file does not contain any other kind of event (notes, controller, time signature, tempo, etc.)

Each chord is a Yamaha XF Metadata chord event. The event time is the time of the chord event, i.e., when the player changed the chord and Genos recognized the chord. In the example above, the chord was changed at the beginning of each measure (sometimes a little early, sometimes a little late).

Chord STEP EDIT to CLD

Folks on the PSR Tutorial Forum have found a few ways of creating CLD files using existing software tools. Flip over to the forums and check out some of the Chord Looper threads.

Here’s a new method!

Yamaha arrangers have long supported a basic MIDI sequencer and editor. Like many software editors, the Yamaha sequencer supports step edit, letting you enter notes, control events, etc. with precise timing. One better, the Yamaha sequencer supports Chord STEP EDIT through which one can easily enter a chord sequence from a lead sheet into a separate chord track.

Thus, it’s possible to enter a chord progression easily using STEP EDIT and save the progression in a Type 0 Standard MIDI File. Initially, the progression is stored in a special part (Cds chunk) within the SMF. DAWs and so forth ignore the special proprietary data and typically delete it when writing the file back to MIDI. This kind of Chord STEP EDIT data does not contain the Yamaha XF chord events needed by Chord Looper. If you import one of these files into Chord Looper, Chord Looper comes up empty.

Once you EXPAND the step edit chord sequence, however, the expansion process creates Yamaha XF chord metadata events along with the notes and other MIDI events for the accompaniment parts. That’s the normal compositional process anyway — step edit the chord part, expand the chord part using the selected style, and save the expanded file as a Standard MIDI File.

One fly in the ointment. The Yamaha arranger software hides file extensions. This streamlines user workflow, but it inhibits interesting experiments! So, save the expanded MIDI file to a USB flash drive, take the flash drive to a personal computer, and rename the expanded SMF. Replace the “MID” extension with “CLD”. Copy the CLD file to the flash drive and reinsert the flash drive in the arranger workstation.

Import the newly renamed CLD file into Chord Looper. Voila! Chord Looper scans the file and produces a chord progression using the embedded Yamaha XF chord events. If you export the progression as a different CLD file, the exported data includes all of the other MIDI data, e.g., notes, etc. [I wouldn’t count on Chord Looper always doing this; software subject to change by Yamaha.)

Bottom line: If you pine to create and edit Chord Looper progressions with precision, use Chord STEP EDIT to create the progression, expand the backing, save as a Standard MIDI File, replace the file extension with CLD, and import into Chord Looper. Of course, you need to rename the MID file to a CLD file using a personal computer, but that’s a small hassle. Give it a try!

I tested this procedure on Genos with the Coltrane changes. Once the progression was captured in Chord Looper, I could try different tempos and different styles. Those changes do come fast and furious indeed!

Yamaha YC series: Tonewheels

Posted on June 30, 2022 by pj

overall Speculation about future Yamaha product reminded me of some unfinished business — analyzing the design of the Yamaha YC stage organ series.

Design of the YC series put some of Yamaha’s best minds to work including Dr. Toshifumi Kunimoto. “Dr. K” and his team are well-known for Virtual Circuit Modeling (VCM) and physical modeling (VL). Before reading ahead, it’s worth reviewing my post summarizing YC61 Developers’ comments. The article has link to a (subtitled) interview with Dr. K, Takashi Mori and Akinobu Shibuya. One big take-away is how the developers took a system-wide approach to emulation the Hammond sound.

The YC61 Owner’s Manual cites six specific innovations:

Natural, organic harmonies when playing chords — thanks to a matrix circuit that connects the keyboard, tone wheels, and drawbars.
Percussion sound with presence — based on vacuum tube circuit analysis.
Key clicks and leakage sounds — based on electrical circuit analysis.
Natural sound distortion — simulating vintage vacuum tube pre-amplifiers.
Vibrato/Chorus effect — from scanner-based vibrato circuitry.
Changes in frequency characteristics and drive amount that responds dynamically to operation of the expression pedal.

These innovations are all in the realm of VCM and are needed to re-create the overall Hammond sound.

I assumed that Yamaha modeled the tonewheels, too. Now, I’m not so sure. I think the tonewheel waveforms are sampled and a modified form of AWM2 synthesis generates the basic, uneffected tonewheel signal (in digital form, of course). Here is my justification.

The interview and YC-series documentation

Yamaha are always honest about what they say even if they don’t say everything. Neither the developers’ interview or Yamaha documentation mention modeled tonewheels.

The YC specifications provide an important clue. Yamaha specify YC polyphony as:

VCM Organ + AWM2: 128 (Total of VCM Organ and AWM2), FM: 128

YC series keyboards have a single SWP70 tone generator (TG) integrated circuit (IC). Like the MODX design, the YC splits AWM2 and FM-X tone generation duties. It’s clear from the polyphony spec that the “VCM Organ” and AWM2 voices split resources, i.e., the AWM2 tone generation channels.

In AWM2 synthesis, each active voice element is assigned to an SWP70 tone generation channel. Genos and the upper-end PSR — also AWM2- and SWP70-based — assign a single drawbar waveform to an element (so-called “Organ Flutes” mode). Organ emulation on MODX (Montage) is similar.

Clearly, the AWM2 pipeline is involved in “VCM Organ” synthesis in some way.

Oh, the complexity!

Everyone is familiar with the 100,000 foot view of the Hammond tonewheel generator. A synchronous motor drives an assembly which spins the tonewheels. Each tonewheel has a pick-up that produces a fluctuating sine-like waveform. The waveforms pass through a key switching matrix and drawbars producing a mixed-down, composite organ tone. The tone is sent to the vibrato scanner, reverb, Leslie speaker, etc.

When it comes to modeling, the devil is in the details. I highly recommend reading one of the excellent Hammond tonewheel deep-dives on the Web:

When reading, please think about what is would take to write a mathematical model of this wonderful electro-mechanical contraption! It ain’t as trivial as summing up a bunch of sine waves. 🙂

The tonewheel assembly itself is closer to Charles Babbage’s mechanical Analytical Engine, than it is to an electronic home organ. The twelve (24, really) fundamental pitches are determined by integer gear ratios which approximate equal temperment. The tone wheels themselves have 2, 4, 8, 16, 32, 64, 128, 192 notches, producing subpitches at (near) octave intervals, derived from the fundamental scale pitches.

We know from our own experience that other aspects of the Hammond and Leslie organ system affect the final sound more than the basic tonewheel tones. If I were a developer, I would say, “Memory is cheap,” sample the tonewheels, move on and concentrate on the scanner, vacuum tube distortion, rotary speaker, etc.

Patents

Except, there is the issue of phase relationships when samples are played back. The Hammond tonewheel generator is a mechanical system with fixed relationships between tonewheel positions. This must be taken into account. Naive sample playback moves phase all over the place in an un-Hammond-like manner. Sample playback should be positionally aligned to preserve the fixed relationships present in a real, physical Hammond tonewheel generator.

Dr. K refers to “phase interference:”

“While collecting a range of different pitch waveforms, combining them, and including some non-linear additions, we also had to deal with phase interference between them. It turns out that this interference is not constant, and while balanced over the entire pitch of the instrument, the pitches do shift in subtle and inconsistent ways. … [T]his disordered yet harmonious behavior” is essential and necessary.

I believe that Yamaha have solved this problem by fetching and combining sampled tonewheel waveforms in a different way than everyday AWM2. Here are some patents to consider:

US Patent 10,388,290 B2 Multifunctional audio signal generation apparatus, August 20, 2019, Inventor: Taro Shirahama, Yamaha.
Japanese Patent 6360692 B2, Audio signal generation apparatus, July 4, 2018.

Yamaha could be aligning tonewheel waveforms when samples are fetched, thereby eliminating phase errors with respect to Hammond behavior. The sampled waveforms, of course, must also preserve the near-equal temperment of integer Hammond gear ratios. The end result is “Natural, organic harmonies when playing chords.”

I also want to draw attention to:

European patent application 20214572.8, Rotary speaker emulation — Device, musical instrument, method and program, December 16, 2020, Inventors: Yuji YAMADA and Takashi MORI, Yamaha.

This patent may summarizes Yamaha’s most recent work on rotary speaker emulation although the patent seems to be written as to obfuscate its intent. Yamaha has covered this territory before including:

US Patent 9,899,016 B2, Time stretching applied to rotary speaker sound, February 20, 2018, Inventors: Masatsugu Okazaki and Taro Shirahama, Yamaha.

Please note the inventors!

Guess again: AN-X ™

Posted on June 23, 2022 by pj

Various forums are buzzing about Yamaha’s latest trademark application: AN-X™. The application was filed 9 June 2022 and must go through several steps before approval.

Like “CK61™” and “CK88™”, the primary class is “Musical Instruments” and the trademark registration is “intended to cover the categories of musical instruments, namely, electronic musical keyboards, electronic pianos, music synthesizers.”

Although Yamaha submitted a drawing (below), the “mark is presented in standard character format without claim to any particular font style, size or color.” So, keep your fingers offa those characters! 🙂

Update: Yamaha have filed for a stylized (figurative) trademark in the European Union. See image below.

Yamaha ANX trademark (European Union, filing: 018741845)

Of course, everyone is deconstructing the proposed mark. “AN” is known as Yamaha’s Analog Physical Modeling Synthesis as embodied in products like the AN200 Desktop Control Synthesizer. I’ve still got my AN200 and it’s a keeper. The AN200 consists of an SWX00B host processor and a PLG150-AN daugherboard. The PLG150-AN itself has a Renesas H8/300H 16-bit microcontroller and two Yamaha custom integrated circuits: VOP3 and MDSP. The custom circuits implement the VA synthesis and digital effects.

Yamaha AN200 analog physical modeling synthesis

It’s worth mentioning that VOP3 appears in the Yamaha FS1r — the inspiration for today’s FM-X. The FS1r does both 8-op FM and Formant Shaping Synthesis. Internally, two custom FS1-AB integrated circuits perform FM and formant shaping synthesis. Two VOP3 integrated circuits implement the filters (the first VOP3) and effects (the second VOP3).

Yep, I’ve mused about adding VA synthesis to Montage before and was skeptical about adding it to the existing SWP70-based Montage pipeline. I remain doubtful about adding VA synthesis to the existing Montage/MODX platform.

It’s worth noting, again, that Yamaha have never published nor described the actual data processing pipeline and signal paths within the SWP70 tone generator. I don’t have any formal relationship with Yamaha nor does Yamaha engineering ring me up regarding the internal details of their tone generation hardware. 😉 Do I have a right to change my mind in light of new information and analysis? Yes. Do I hope for a surprise from Yamaha? Yes.

The question is whether the SWP70 is capable of subsuming VOP3-like DSP functionality for VA synthesis. ~~It’s how the YC series implements its Virtual Circuitry Modeling (VCM) organ engine. Clearly, if you can model drawbars, you can model an analog oscillator.~~ Lest anyone forget, the Montage V3.0 upgrade (MODX V2.0) added the VCM Mini Filter, VCM Mini Booster and Wave Folder DSP effects.

An earlier version of this port stated the YC series uses modeled tonewheels. Further analysis makes me believe otherwise.

As to filtering, what is a hardware or software digital filter other than a mathematical model of an analog filter — even if its cold and heartless? What is a digital amplitude envelope other than a model of an analog envelope generator and VCA? Distinction due to implementation technology is nearly moot; it comes down to the characteristics of the particular models.

What does all this portend for the future? If I were Yamaha and I could add VA to the Montage (MODX) platform, I would sell it as an upgrade. Many people want VA on Montage and there is money to be made.

I’m willing to go a step further. Yamaha could and should offer a VCM organ upgrade, too. The SWP70 can support it. I’ll put money where my mouth is — I will pay real money for a YC upgrade on MODX (Montage). BTW, there’s no technical reason to not offer the FM-based YC organs on MODX/Montage already — it’s FM-X, after all.

Now, what are “CK61” and “CK88”? 🙂

Review: Arturia Keylab Essential

Posted on June 21, 2022 by pj

Oh, did I fail to mention, I added an Arturia Keylab Essential 49 to my iPad rig. I wanted a super light-weight MIDI controller with knobs, sliders, and a minimum of 49 keys with good action. The Keylab Essential 49 fits the bill at 6.6 pounds (3kg), eight pads, nine encoders and nine faders (sliders). The street price is attractive, too: $229 USD. I had a good experience with the Arturia Keystep 32 and decided to give the Keylab Essential a go.

I use the Keystep mainly for control voltage (CV) and gate with littleBits synth modules. Mini-keys are OK for experiments, but not for real playing. If your Keystep keys get dirty, here’s a guide to Keystep teardown and cleaning.

Why the Keylab Essential after Korg Microkey Air joy? I gave the Air’s mini-keys the old college try and then some. First off, most mini-key instruments are three octaves and too short for two-fisted playing. The Microkey Air 49 has four octaves, making it much easier to play most tunes without finger gymnastics. [If you’re a pianist, we’re not even having this conversation!] Although the Microkey Air has Bluetooth MIDI built-in and is battery-powered — genuine plusses — it doesn’t have knobs/sliders for VST control. And, well, it still has those mini-keys.

The Keylab Essential 49 is only three inches longer than the Microkey Air: 30.9″ versus 27.9″. Sure, the Keylab Essential is twice as deep, but them encoders and 30mm faders have to go somewhere! I will admit, the Keylab Essential is not a “lap board” like the Air; it needs a proper stand and power source.

The Keylab Essential key action is decent enough. Like the Keystep, it feels a bit soft. If you want a fast, crisp action, this isn’t the droid you’re looking for. Even though the Keylab Essentials are Arturia’s budget line, the encoders and faders feel sturdy with a reasonable amount of resistance.

I’m happy with the Keylab Essential and, yes, I’ll be keeping the Microkey Air, too. Here’s my short Keylab Essential wish list:

Battery power
Bluetooth MIDI
Expression input, not simply sustain (on/off)

Then again, the price would be higher and/or the build quality would be lower. No free lunch.

Analog Lab

I’m mainly interested in iPad (IK BX-3) and hardware (YC and Skulpt SE) control, not PC-based VSTs. However, Analog Lab is a fun leisure destination. Analog Lab and its integration with Keylab Essential are simply brilliant. Prepare to waste long hours jamming away with the best sounds of yester-year with lots of knob twisting and fader slamming.

Controlling Yamaha Reface YC

Yamaha Reface YC is one of my keeper keyboards. It’s been a handy companion at rehearsals and even a few church services. You’ve already heard my gripe about three octave mini-keyboards and Reface YC occupies that doghouse. No need to repeat.

Fortunately, Keylab Essential is almost made for Reface YC. [Dreamers, Yamaha has a full-size YC; forget a Reface re-issue.] Keylab Essential has a 5-pin MIDI OUT which links to the Reface YC dongle MIDI IN. Thank heavens for 5-pin MIDI.

Arturia provide their MIDI Control Center (MCC) app for configuration. The Keylab Essential has eight configuration slots: Analog Lab, DAW and six user slots. MCC communicates with Keylab Essential over USB. Fortunately, the 5-pin MIDI OUT operates concurrently with a USB connection back — no either/or.

Obviously, the faders map to the YC drawbars. Fortunately, the Keylab Essential faders have a drawbar mode, flipping low and high values. The Reface YC drawbars are controlled by MIDI continuous controller (CC) messages CC#102 to CC#110. It’s all right there in the Reface Data List PDF available on the Yamaha Web site.

Amazing how many people will ask a forum for such info. Please RTFM.

The rest of the front panel controls — waveform, rotary speed, vibrato/chorus, percussion, and effects — are under MIDI CC control, too. Keylab Essential has three switches (Part 1, Part 2, Live) which are mapped in the following way:

Vibrato/chorus select (CC#79)
Percussion on/off (CC#77)
Percussion harmonic (CC#112)

The switches are configured as toggles, so that the switch LEDs indicate individual switch state.

Rotary speed is interesting because Reface YC has four states: OFF, STOP, SLOW and FAST. By default, Reface YC modulation (CC#0) switches between SLOW and FAST. As an alternative to the wheel, I assigned OFF, STOP, SLOW and FAST to pads 5 through 8. It’s a shame that Keylab Essential doesn’t support radio buttons. If it did, one could make each pad in the group a toggle showing the current rotary speed state.

As I mentioned, Keylab Essential does not have an expression pedal input. Thus, I route a Yamaha FC-7 expression pedal to Reface YC directly. The Keylab Essential sustain input is still useful, however. I attach a sustain pedal and assign the sustain input to rotary speed (CC#19: SLOW and FAST). Momentary switch mode allows quick changes and speed bumps.

It’s worth noting here that rotary speed has four settings:

     CC#19       Value 
     ----------  ----- 
     0 - OFF         0 
     1 - STOP       42 
     2 - SLOW       85 
     3 - FAST      127

Switching between SLOW and FAST means changing CC#19 between 85 and 127.

Making the rest of the story short, the remaining Reface YC parameters are assigned to the encoders. Waveform, vibrato/chorus depth and percussion length have five discrete settings each, i.e., they do not sweep continuously across 1 to 127. Expect to hear discrete changes (steps). The step values are: 0, 32, 64, 95, 127.

Vibrato/chorus does not have a Reface on/off switch. Vibrato or chorus are OFF when the vibrato/chorus depth is zero.

Here is a table which summarizes the control mappings:

--------------------------------  ---------------------------------------- 
Reface YC                         Arturia Essential 49 
--------------------------------  ---------------------------------------- 
Rotary speed  19    0-127         Mod wheel, Pad 5-8 OFF, STOP, SLOW, FAST 
Wave          80    0-127         Knob 1
 
16'           102   0-127         Slider 1 
5 1/3'        103   0-127         Slider 2 
8'            104   0-127         Slider 3 
4'            105   0-127         Slider 4 
2 2/3'        106   0-127         Slider 5 
2'            107   0-127         Slider 6 
1 3/5'        108   0-127         Slider 7 
1 1/3'        109   0-127         Slider 8 
1'            110   0-127         Slider Master 

V/C type       79   0-63, 64-127  Switch Part 1 
V/C depth      77   0-127         Knob 2 
Perc on/off   111   0-63, 64-127  Switch Part 2 
Perc harm     112   0-63, 64-127  Switch Part 3 
Perc length   113   0-127         Knob 3 

Effect Dist    18   0-127         Knob 7 
Effect Reverb  91   0-127         Knob 8 
Volume          7   0-127         Knob 9

Oh, yeah, don’t forget volume! With the Keylab Essential at hand, you’ll probably have the Reface YC out of reach at the end of its MIDI tether.

I intend to get into good trouble with the Arturia Keylab Essential. Expect future experiments with iPad, IK Multimedia BX-3 and Modal Skulpt SE.

New toys: Roland E-X50 and Moog Mavis

Posted on June 14, 2022 by pj

While Sud Claviers are teasing the release of a new arranger keyboard, Roland — of all manufacturers — have announced a new entry-level ($400) arranger: the Roland E-X50 arranger keyboard. And a new synth kit from Moog.

Arranger forums are anticipating a new Korg flagship arranger, the Korg Pa5x, on 30 June 2022. Sud Claviers France have taken the lead for European introductions before, as arranger keyboards are more popular in Europe and Asia than North America. Various Korg (and Yamaha!) forums have leaked images and video — a lot of it blurry. Fans are usually good at spotting fakes, but this time it looks to be real.

You’ll pay a high price for the Pa5x jewelry. The Roland E-X50 is for punters having an estimated $400 USD price. (The Pa5x will cost 10x that amount.)

The E-X50 has a sleek, professional, squarish look to it, weighing 9.6kg (21.3 pounds). The new arranger kits out with 256 polyphony, 433 regular tones plus 256 GM2 tones and a total of 18 drum sets. Effects include equalization, chorus, reverb and delay. The stereo audio system is 10 Watts per side through a 12cm speaker and 3cm tweeter. With a 30 Watt power draw, it’s an AC adaptor; no battery power.

Bluetooth is built-in. The E-X50 has fixed formet LCD display which is typical for entry-level keyboards.

Auto-accompaniment and registration memory are on par with Yamaha, Casio, and Korg. Roland have not broken any new ground, here. The most novel feature is AUDIO PAD playback. The Scale Tune buttons are linked to WAV (or MP3) files on a USB drive. Striking one of the buttons plays back the associated audio file (one shot or loop). Unlike Yamaha arrangers which are notoriously picky about audio file format (16-bit, 44kHz stereo), the E-X50 supports a broad range of bit rates and sampling frequencies. (You’re still stuck with 16-bit samples, tho’.)

The E-X50 is supported by a free E-X Style Converter application (Windows and Macintosh), which converts a MIDI file to a style file compatible with the Roland E-X series.

Bottom line, the E-X50 offers an alternative to similar units from Korg and Yamaha. Every vendor has its own sound and this Roland may float your boat more so than Korg or Yamaha.

Moog Mavis is a new build-it-yourself monophonic analog synth kit from Moog. I rather like the looks of Mavis right off the top. The front panel screams “Moog”. It has a mess o’patch points (24-point CV controllable) on the left hand side of the front panel. The module is 44HP in case you want to rack it up. The Mavis form factor is compatible with earlier units like the DFAM.

Moog Mavis monophonic analog synth module

Mavis boasts the Moog “legendary oscillator and filter circuits,” adding a diode wave folder. The filter spec is -24 dB Moog Low Pass Ladder filter. Mavis has a built-in courtesy keyboard. Serious folk will be driving Mavis from external, 1 V/oct gear.

“Build-it-yourself” is more like assemble it yourself as the mainboard is fully wave soldered, etc. No soldering required.

Mavis is $349 USD. That seems a little price-y, but you get an entire monophonic synth signal chain. Near as I can tell, Mavis avoids the shortcomings of the Werkstatt-01. I almost bit on a Werkstatt-01 until I realized its interfacing limitations. And guess what? Mavis is already in stock at a few on-line retailers! Nice work, Moog.

Sand, software and sound

Electronics and computing for the fun of it

Category Archives: Music technology