Category Archives: Music

Motif styles for your arranger!

Posted on by

I’m pleased to announce my collection of Motif performance styles for the Yamaha PSR-S950 arranger and its close cousins: Tyros 5, PSR-S770 and PSR-S970.

Motif and MOX are great song-writing machines with thousands of built-in musical phrases. In Motif-speak, these phrases are called “arpeggios.” Motif/MOX also have built-in “Performances” which combine these musical phrases into jam-along song starters. Although Motif-series workstations are not arranger keyboards, the Performances are fun for live jams, covering many modern genres (contemporary jazz, funk and R&B) which are underserved by arranger workstations.

To fill this gap, I translated 23 Motif performances to PSR/Tyros styles. In keeping with the original source material, these styles are stripped down and lean. No orchestration to get in the way! Some styles use only bass and drum. INTROs and ENDINGs are short and basic. Depending upon the source performance, a translated style may have only three MAIN sections. However, all styles bring the groove.

Many of the styles use Megavoice bass and guitar. Plus, I’ve added appropriate OTS voices. Of course, you’re welcome to ditch the OTS voices and replace them with your own.

Here is the link to the ZIP file: perf_for_s950.zip. The file unzips into a directory named “PERF_for_S950”. The ZIP file includes a short READ ME file with more information.

If you would like to know how I translate a Motif/MOX performance to a PSR/Tyros style, please read the following articles:

Montage: The hardware platform

Posted on by

The Yamaha Montage is one heck of a fine keyboard! Let’s take a quick look inside.

The Montage hardware is a new platform. Sure, there are a few things borrowed from older products, but that’s like blaming Apple for reusing a USB controller. The digital and analog electronics are all new.

There are several printed circuit boards and I will only cover the main PCBs.

  • PNL/PNR: Handles the front panel buttons, knobs, sliders, master volume and gain.
  • LCD: Bridge between the LCD controller in the main CPU and the 7inch TFT WVGA LCD touch panel.
  • DJK: Digital jacks (foot controllers, foot switch, sustain, MIDI)
  • AJK: Analog electronics and jacks (DACs, ADC, balanced/unbalanced outputs, analog input, phones).
  • DM: Digital electronics (main CPU, tone generators, external USB and Ethernet interfaces).

A few ports and connections are “Debug only” and are not populated or used in normal operation. The Ethernet port to the main CPU is debug only, for example.

The separation of the digital and analog electronics and jacks is significant. When the Montage was first introduced, I mentioned that “Pure Analog Circuit (PAC)” appeared to be an exercise in old school engineering that pays careful attention to board layout, component selection and clean power. The AJK board bears this out. The AJK board contains the stereo DAC and ADC components:

  • Audio ADC: Asahi Kasei AK5381VT-E2 24-bit ADC (96KHz max)
  • Audio DAC assignable output: Asahi Kasei AK4393VM-E2 24-bit DAC (96KHz max)
  • Audio DAC main output and phones: Asahi Kasei AK4393VM-E2 24-bit DAC

The ADC and DACs communicate with the DM board over an audio backbone. Physical separation keeps digital circuits (with fast rise/fall times) away from analog signal paths. The AJK board also has its own voltage regulators. They ain’t kiddin’ about PAC!

Yamaha adopted ARM architecture processors for the first time in the Reface series. (See my article about the Reface CS and Reface DX internals). Montage continues this trend.

  • The PNL board contains an MB9AF141NA ARM microcontroller with a 40MHz internal clock. The ARM microcontroller is assisted by a Toshiba TMP89FW24AFG microcontroller (SOC) operating at 10MHz. In Yamaha’s terminology, this ARM is a “sub CPU.”
  • The main CPU is an AM3352BZCZ80 ARM microprocessor with an 800MHz CPU clock. It is a Texas Instruments Sitara ARM Cortex-A8 single core MPU.

The ARM Cortex-A8 is a major departure from the Motif line which employed MIPS architecture microprocessors (such as the Toshiba TX4939C) as the main CPU.

We first saw the new SWP70 tone generator in the Yamaha PSR-S970 arranger workstation. The SWP70 replaces the SWP51L which has been the mainstay in mid- to upper-tier Yamaha products for several years. Top-tier products (e.g., Motif XF and Tyros 5) have two SWP51L tone generator chips which together share a common wave memory. The two SWP51Ls split AWM2 voice and DSP duties.

So, it isn’t any surprise to see two SWP70s in the Montage. What is suprising, however, is how the Montage’s two SWP70s are deployed. The two SWP70s are not connected in the “classic” structure. Instead, the microarchitecture is assymetric.

  • TG Master: The TG Master is connected to wave ROM (flash), wave RAM (SDRAM), and DSP RAM (SDRAM).
  • TG Slave: The TG Slave is connected to DSP RAM (SDRAM) and an SSP2 processor (through an ASIC gate array bridge).

I’ll have more to say about the SSP2 in a moment. The bridge connects the TG Slave’s serial audio interface to the SSP2 and the bridge carries several channels of digital audio (I2S format) to/from the TG Slave and the SSP2.

Of course, one’s first thought is to presume that the TG Master handles AWM2 voices and the TG Slave handles FM-X voices. There’s a lot of generation and DSP resources within an SWP70, so I doubt if they are left idle in the TG Slave even though the TG Slave does not have memory memory! There is a sixteen bit wide bus between the TG Master and Slave — not really sufficient to carry the sample bandwidth needed for AWM2 tone generation, however.

Each SWP70 has 16MBytes of SDRAM for DSP working memory. The TG Master has 32MB of Wave RAM. The Wave RAM is a cache for samples that are read from wave flash. (See my earlier article about the SWP70 and U.S. Patent 9,040,800.) Commodity NAND flash (as one would find in an SSD) favors sequential access; random access is horribly slow. The Wave RAM caches samples that are read from NAND flash.

Now, the big question: How much wave memory? The Montage wave memory consists of four Spansion (Cypress) S34ML08G101TFI000 8Gbit, ONFI-compliant devices with a total physical capacity of 4GBytes. In classic fashion, the memory is separated into upper and lower bytes. The Yamaha specifications state wave size as, “Preset: 5.67 GB (when converted to 16 bit linear format), User: 1.75 GB.” Assuming a 2.52 aggregate compression factor, the arithmetic works out in the following way:

    4GB physical = (5.67GB / 2.52) preset + 1.75GB user

The Motif series has an aggregate compression factor in this ballpark.

The Montage has a common multi-channel serial audio bus (I2S format) that interconnects the main CPU, TG Master, TG Slave, SSP2, ADC and audio DACs. This is the digital audio backbone. The bus conveys digital audio from the generators and effects on the DM board to (from) the converters on the AJK board.

The SSP2 is a Yamaha proprietary processor which is used in many products: Reface CS, Reface DX, PSR-S950 workstation, etc. The SSP2 integrates signal processing, USB, serial audio, and more. It is the “designated hitter” for Yamaha designs. When Yamaha needs a flexible chip with DSP and interfacing skills, it calls on the SSP2. (Roland have a similar jack of all trades called the “ESC2.”)

The Montage’s SSP2 has only 2MBytes of NOR flash memory on its CPU bus. That’s not a lot of program space! The SSP2’s USB port is connected to the external “USB TO HOST” interface. The SSP’s other interfaces convey digital audio to/from the digital audio backbone and the TG Slave. Thus, the SSP2’s main role is to route digital audio. The Montage can send 16 channels and receive 3 channels of stereo 24 bit/44.1 kHz digital audio to/from an external computer or iOS device

Commentary and opinion

I hope you find this quick overview to be informative and helpful. I try to present the system structure objectively without too much speculation.

Please discuss the Montage responsibly! Yamaha have a definite design style which exploits their expertise in very large scale integration (VLSI) as a strategic advantage. When Yamaha specify maximum polyphony as “128 AWM2 and 128 FM-X”, that’s 128 each all day long without any dependencies on the number of effects in use, etc. Some people lament this approach and wish that Yamaha would base their systems on x86 even though x86 is not always the best choice for embedded systems. Yamaha are no strangers to x86 having obtained many patents covering x86-based tone generation back in the 1990s and early 2000s.

Before anyone carries on about SSDs and SATA, please study the design of the SWP70. The SWP70 memory interface has all of the power, flexibility and Open NAND Flash Interface (ONFI) compatibility as an SSD without the need for SATA bus protocol.

Users may rightfully be disappointed at the lack of user-installable expansion memory. Yamaha are not evil; they simply do not have a convenient way to provide user-installable memory at the chip level. I think users should lobby for more built-in expansion memory, but they shouldn’t delve into conspiracy theories about Yamaha’s engineering or managerial practice.

Some wag will undoubtably complain about “memory parts cost only $10,” “my jump drive is 32GBytes,” “the need to stream 100s of gigabytes,” etc. Fine. But, an instrument design is a just one design. It is what it is is. One should listen to the Montage with their ears, then question whether gobs of samples would improve the playability, sound or expression of the Montage. Also, if you really believe that you can build a better instrument at the same price point, by all means, line up the VCs and engineers, go to work, and compete.

The final result is what we hear with our ears. The hardware is important, but it is simply a platform for the “soft content” — the algorithms, code, waveforms and sound design. In the long run, the soft content is the biggest development expense and is the most important element in a successful digital musical instrument product.

Perspective. Chill. Peace.

Here are links to related articles on this site:

All site content is Copyright © Paul J. Drongowski

Beat Box at littleBits!

Posted on by

Apologies in advance as I spend more time remembering to be a musician, not a technology blogger. I bought a few MIDI files during the last Yamaha Musicsoft sale and I’m massaging them into PJ-approved backing tracks. Plus, I’m learning about the joys of the key of D-flat!

I posted the Beat Box drum machine project to the littleBits invention site. The littleBits project format is more “step-by-step” than the document that I post on this site. The step-by-step directions should help anyone interested in building the Beat Box without diving into the details of the design. Of course, you can still check out the Beat Box design at this site, too. (MP3 Demo)

Just so you don’t think I’ve been totally idle, I tried adapting the code to sing “Do-Re-Mi” solfege. This involved recording and editing my voice. I used my old trick of singing through the Yamaha PSR-S950 vocoder in order to pitch correct my rocky intonation. I had to lower the sample rate to 11,025Hz in order fit all eight syllables into the very small Arduino program memory (PROGMEM). Unfortunately, I cannot get clear audio at 11,025Hz. There is this raucous buzz which cannot be eliminated through filtering. I suspect that the problem is in the PWM generation itself. The waveforms play back fine at 22,050Hz, sounding like chipmunk solfege.

After hitting that brick wall, I’ve decided to take a different approach which has better long term possibilities. I’ve ordered a handful of MCP4921 12-bit SPI DAC ICs and intend to try them with the littleBits Arduino module. The littleBits Arduino is a Leonardo where the SPI interface is the (unpopulated) ICSP pads. The new approach requires soldering, but it should be worth the effort. Stay tuned.

Still tempted by the Reface CP and YC. But, $400USD street? C’mon, Yamaha!

Inside Reface DX and Reface CS

Posted on by

With so much to do and learn, it’s been a long while since I’ve taken a peek below the hood of an electronic musical instrument.

Yamaha caught the world by surprise with its Reface series of portable keyboards. So far, there are four models in the series: Reface YC (organ), Reface CP (electric piano), Reface CS (analog modeling synthesizer), and Reface DX (4-op FM synthesizer).

Before I get to the DX and CS, here’s a few thoughts about the YC and CP. According to Yamaha specifications, the Reface YC tone generation engine is “AWM (Organ Flutes)”. This suggests to me that the YC uses a standard AWM tone generation integrated circuit (IC) like the SWP70. Hammond-like “Organ Flutes” have been part of the mid- and upper-tier arranger workstations like Tyros for a very long time. Thus, I suspect that the YC implementation is an updated implementation of the arranger technology.

The Reface CP tone generation engine is specified as “SCM + AWM2”. SCM or “Spectral Component Modeling” is the modeling technique first employed in the flagship CP-1 stage piano. SCM and AWM2 are also used in the CP-4 and CP-40 models. The CP-1 uses three tried-and-true SWP51L tone generation ICs: master, slave and effects. The master and slave generate the base piano tones and the two ICs share the same WAVE ROM. Total WAVE ROM size is 1024Mbits or 128MBytes (organized as 16-bit words) which is a ridiculously small amount of memory for a top quality piano. Such is the power of SCM!

The CP-1’s samples are stored in two Lapis Semiconductor MR26V51252R devices (32M by 16-bit words each). The processor is a Yamaha SWX02 (SH-2A CPU core operating at 135.4752MHz). There’s not much to the CP-1 user interface, so a relatively light-weight, low-cost processor is enough for the job. The SWP51Ls handle all of the heavy computation.

Thus, the Reface YC and Reface CP are relatively uninteresting from a technologist’s point of view. The YC and CP use proven technology from other Yamaha products. That leaves the Reface CS and Reface DX.

Although the CS and DX implement two different tone generation techniques — analog physical modeling vs. frequency modulation (FM) — they are fraternal twins at the hardware level. They share much of the same base hardware design with a few variations to handle their unique user interface requirements.

The CS and DX both use a Fujitsu MB9AF141LAPMC1 processor to handle key and panel scanning. Here’s a quick summary of its characteristics:

    CPU                 Cortex-M3
    CPU Frequency       40MHz

    On-chip flash memory   Main area   64KBytes
    On-chip flash memory   Work area   32KBytes
    On-chip SRAM           SRAM0        8KBytes
    On-chip SRAM           SRAM1        8KBytes

    Peripheral interfaces:
        DMAC            8 channel
        Serial I/F      8 channel
        Base timer      8 channel
        Dual timer      1
        Realtime clock  1
        Watch counter   1
        12-bit A/D      12 channel

This processor is a good choice for embedded control applications where low power and low cost are important. To my knowledge, this is the first product line using an ARM embedded microcontroller.

The Reface CS and Reface DX both use the proprietary Yamaha SSP2 (uPD800500F1-011-KN9-A) for tone generation. The SSP2 is Yamaha’s designated hitter for DSP tasks and is incorporated into many products. The SSP2 has an SH-2A CPU core operating at an internal clock speed of 135.4752MHz. The SSP2 has its own ADC, GPIO, UART, USB and serial audio interfaces. The SSP2 UART handles 5-pin MIDI communications. The SSP2 USB interface handles external USB communications.

The SSP2 has two memory interfaces:

  • DSP RAM: Connecting to 8MBytes of DSP SDRAM.
  • CPU bus: Connecting to 8MBytes of program ROM and 16MBytes of SDRAM.

Memory sizes and devices are the same in both products.

The AUX IN and audio out hardware design is also the same across the two products:

  • PCM1803ADBR ADC: AUX IN analog-to-digital converstion
  • AK4396: Digital-to-analog conversion for OUTPUT L/R and PHONES OUT
  • YDA176 D-Amp: DAC and amplification for internal speakers

This shouldn’t be any surprise. All of the Reface series products ahare the same external jack, power and key switch boards.

Digital audio is transfered serially between the SSP2, the ADC, the DAC and the digital amplifier. The SSP2 generates the master clock (MCLK) and bit clock (BCLK) to synchronize data transfers. MCLK and BCLK are derived from the SSP2 clock, in case you’re wondering about those odd-looking CPU clock frequencies. MCLK is 256*fs and BCLK is 64*fs, where fs is the sampling frequency, 44.1KHz. MCLK operates the AK4396’s digital interpolation filter and delta signal modulator. Data format is I2S and is probably 24-bit as it is in workstation products.

Aside from the other front panel controls, the Reface DX has two major additions: Capacitive sensors for the front panel touch strips and the LCD panel display. The printed circuit board positions for the LCD interface are not populated (i.e., no mount) in the Reface CS as it has no LCD display.

There you have it — two more examples of solid and conservative Yamaha hardware design.

Now, you may find the SSP2 to be incredibly boring. It is, however, a good choice for a low-cost, compact product. The Reface CS and DX need a metal shield over the SSP2, perhaps to control RF emissions, perhaps to radiate heat, or maybe both purposes together. Low power is a vital concern throughout the Reface series due to battery power concerns.

I’m a little hesitant to draw any inferences about future products. The Yamaha Montage supports 128 note, 8 operator FM polyphony. The Reface DX provides a relatively meager 8 note, 4 operator FM polyphony. Thus, there must be considerable hardware resources at work in the Montage. Well-worth the price, one hopes! And speaking of hopes, many people would like an analog modeling extension to the Montage. That would depend, of course, on the availability of spare computational horsepower.

Copyright © 2016 Paul J. Drongowski

Arduino lo-fi beat box

Posted on by

Here’s another Arduino-based music project for ya — the Beat Box — a lo-fi, TR-808 drum machine. If you ever wanted to try your hand at DIY electronics, this one is a good starting point. Here is a short list of features:

  • 16 grungy, TR808-like rhythm instruments
  • Up to eight instruments per pattern
  • Up to five selectable patterns
  • Adjustable tempo (60 BPM to 188 BPM)
  • Full source code available including waveforms (samples)
  • Write and compile your own patterns, drum kits and waveforms
  • Built-in PWM signal generation into an external low pass filter
  • 22,050Hz, 8-bit signed, mono waveforms for true lo-fi grunge

The Beat Box uses the Arduino’s internal high resolution timer (TIMER1) to produce audio. The timer converts samples to a pulse-width modulated (PWM) bit stream which is sent into a simple low pass filter. The filter converts the PWM bit stream into an audio signal to be sent to a powered speaker, LINE IN, or what have you. This is absolutely the cheapest way to generate digital audio with an Arduino and it only requires four simple components, a solderless breadboard and a few jumper wires.

If you want to make assembly even easier, start with the littleBits Arduino Coding Kit, a Proto module and a Synth Speaker Module. I built the Beat Box using the littleBits Arduino Coding Hit and assembly was, literally, a snap.

The Beat Box source code includes drum waveforms and several classic drum patterns. With a 22,050Hz sampling rate and 8-bit samples, you get genuine lo-fi, bit-crunched TR-808 grunge. Purely optional, I added a littleBits synth Filter module and Delay module to the audio signal chain. Listen to the MP3 demo. In the demo, I sweep the filter frequency from low to open. At about 10 seconds in, you hear what is essentially the unfiltered sound of the Beat Box. Then, I increase the delay feedback level which adds echoes in time with the original pattern.

This pattern forever reminds me of riding the RTA #48 bus to work in Cleveland circa 1982.

Per standard operating procedure, I have provided the full design and source code.

Get your beat on! Build it now!

Add a filter and envelope to the tone sequencer

Posted on by

The tones produced by my littleBits tone sequencer are too basic. So, I decided to add a littleBits filter module and envelope module to spice things up. I built the Arduino part of the project on one mounting board and built the synthy part of the project on a separate board. Three wire modules connect the two subsystems together as shown in the picture below.

gatemodseq

Of course, since the whole thing is Arduino-based, it makes sense to drive filter modulation and envelope trigger (gate) from the Arduino. The trigger signal is turned on at the beginning of a note and is turned off at the end of a note. Nothing could be simpler.

The filter modulation signal is more fun. The dimmers connected to the Arduino control the attack and release time and the sustain level. Here is a simple diagram showing the shape of the filter modulation signal.

filter_mod_signal

One dimmer controls both the attack time and the release time. Close enough for rock and roll. I suppose that I could have added a third dimmer and controlled these times separately. A project for you perhaps?

Per standard operating procedure, I posted the design and code. The code is explained in detail. I also posted this project to the littleBits project site. The littleBits page has the source code, too, and has simple directions for building the project.

Have fun and keep on experimenting!

Montage review: Yes, I’ve played one!

Posted on by

The Yamaha Montage synthesizer is now hitting stores in North America. One of the local retailers (GC in Natick) have a Montage set up for demo. Let’s go!

The demo unit is a Montage8 with the 88-key balanced hammer effect keyboard. I have always liked Yamaha’s upper-end “piano” actions and the Montage8 is no exception. I primarily play lighter “synth” action keyboards like the MOX and the PSR-S950. Fortunately, I spent the previous week working out on the Nord Elecro 2 waterfall keyboard, which requires a slightly heavier touch. I played the Montage8 for a little bit more than an hour without my hands wilting — a good sign.

First off, the demo unit was plugged into two Yamaha HS7 monitors and a Yamaha HS8S subwoofer. GC usually patches keyboards through grotty keyboard amplifiers, so I suspect that Yamaha provided the monitors in order to create the best impression of the Montage. I was dismayed when I started off with a few B-3 organ patches and could not contain the low end. The front panel EQ simply didn’t do the job. Time to check the monitor settings. The HS7s were flat, but the HS8S subwoofer level was cranked. After backing off the sub, all was right with the world.

Yes, some people like to simulate small earthquakes with subsonic frequencies. This, however, is not conducive for acoustic music. It’s not conducive for peaceful co-existence with your bass player either. If you encounter a Montage in the wild, check the EQ before proceeding!

So, as you may have gathered already, this is not a review of Montage for EDM. I took along my church audition folder (covering gospel to contemporary Christian to traditional and semi-classical music) and a small binder of rock, jazz, soul and everything in between. I’d like to think that this is the first time anyone has played “Jesu, Joy of Man’s Desiring” on the Montage, however poorly.

The electric pianos are terrific. I had a fine old time playing soul jazz and what not. Great connection between keys and sound. Comparing against Nord Stage, I would say that the Montage is top notch in this department and definitely a cut above the old Nord Electro 2. Yamaha did not put the Reface CP (Spectral Component Modeling) technology into Montage; they didn’t need to.

Tonewheel organ is still Yamaha’s Achilles’ heel. There is some modest improvement, but the Montage is not in clone territory. In this area, I would say, “Advantage Nord.” If I can cover B-3 with the MOX on Sunday, I’m sure that the Montage is up for medium duty. However, the tonewheel organs lack the visceral thrill of the EPs. I will say that the 88-key action did not inhibit my playing style too much. (If I was going to buy a Montage, tho’, it would be a 6.)

The pipe organs got some tweaks, mainly by enhancing the Motif pipe organ sounds via FM. There are a few lovely patches, but I will still look to the Tyros (and the PSR expansion pack) for true realism. The Nord Electro 5d has modeled principal organ pipes where the drawbars change the registration. Ummm, here, I would give the edge to Nord. Plus, the pipe organs in the Nord sample library are more on par with the Tyros and PSR expansion pack. Hate to say it: Montage pipe organs are good “synthesizer pipe organs,” and that ain’t entirely a compliment.

The new strings are wonderfully realistic, especially for solo/melody lines. I really enjoyed bringing sections in and out dynamically. (The expression pedal was sync’ed to the SuperKnob.) With the changes in our music ministry group, I’ve been playing more melodic and exposed parts. I could really dig playing a reflective improvisation for meditation using the strings and woodwinds under Motion Control.

The classical woodwinds got a boost in Montage, too. The woodwinds are all excellent although the sonic delta above Motif XF (MOXF and MOX, too) was not as “Wow” as the strings. Most likely, my ears were getting tired at that point…

Since I was losing objectivity, I just briefly touched on brass. I need good French horns and Montage did not disappoint. I wish that I had spent time with the solo trumpets and trombones, but my ears were telling me to knock it off.

The new Telecaster (TC) is quite a treat. The “Real Distortion” effects (Motif XF update 1.50) are now standard and the programmers made good use of them. I wish that the Montage had the voice INFO screen from the PSR/Tyros series. The INFO screen displays playing tips and articulations for each voice. This makes it a lot easier to find and exploit the sonic “Easter eggs” in the patches. (“Play AF1 to get a slide. Play AF2 to get a hammer on.”)

Fortunately, it was a rainy Saturday afternoon and the store was empty — disturbed only by the occasional uncontrolled rugrat pounding on some poor defenseless keyboard. Overall, I felt like I really heard the Montage and could make a fair evaluation.

I did not dive into editing, arpeggios, motion sequencing, recording, etc., so this is surely not a comprehensive review. Anyone spending less than one month with this ax cannot claim “comprehensive.” It just ain’t possible, so I would call my initial opinion, “first impressions.” That said, I can see why the Live Sets are important. I mainly dove in through Category Search where some of the touch buttons are a wee too small. Punching up a sound in full combat requires BIG buttons.

Montage looks, feels and sounds like a luxury good. Montage is also priced like a luxury good. The Montage8 MAP is $4000 USD. It is quite a beast physically and I would most likely go for the Montage6 at a “mere” 33 pounds and $3000 USD. None of the Montage line would be an easy schlep, especially when I have to buzz in and out of my church gig fast.

Would I buy one? Tough call. On the same field trip, I got to sit in a Tesla Model S ($71,000 USD) — a luxury car built around a computer monitor or two. I just recently bought a Scion iM (AKA Toyota Auris, Levin, Blade, whatever) for about $20,000 USD. Both cars could get me to the gym and back. I like my iM. What does that say about me as a customer? Do you think I would buy a Montage? Enigmatic.

See the list of new waveforms in the Montage. Also, check out the latest blog posts! Update: May 10, 2016.

We need “code-able” MIDI controllers!

Posted on by

All MIDI controllers for sale are rubbish!

Eh?

OK, here comes a rant. I’ve been working on two Arduino-based MIDI controllers in order to try out a few ideas for real time control. I’m using homebrew microcontrollers because I need the flexibility offered by code in order to prototype these ideas.

None of the commercial available MIDI controllers from Novation, Korg, AKAI, Alesis and the rest of the usual suspects support user coding or true executable scripts. Nada. I would love it if one of these vendors made a MIDI controller with an Arduino-compatible development interface. Connect the MIDI controller to a Mac or PC running the Arduino IDE, write your code, download it, and use it in real time control heaven! Fatal coding mistakes are inevitable, so provide an “Oops” button that automatically resets program memory and returns the unit to its factory-fresh state.

Commercial MIDI controllers have a few substantial advantages over home-brew. Commercial controllers are nicely packaged, are physically robust and do a good job of integrating keyboard, knob, slider, LED, display, etc. hardware resources into a compact space. Do I need to mention that they look good? Your average punter (like me) stinks at hole drilling and chassis building.

Commercial controllers, on the other hand, stink at flexibility and extensibility. Sure, the current crop of controllers support easy assignment of standard MIDI messages — usually control change (CC), program change (PC), and note ON/OFF. Maybe (non-)registered parameter number messages (RPN or NRPN messages) are supported. System exclusive (SysEx) most certainly is not supported other than maybe a fixed string of HEX — if you’re incredibly fortunate to have it.

The old JL Cooper FaderMaster knew how to insert control values into simple SysEx messages. This is now lost art.

Here are a few use cases for a fully user-programmable MIDI controller.

The first use case is drawbar control. Most tone-wheel clones use MIDI CC messages for drawbar control, but not all. The Yamaha Tyros/PSR “Organ Flutes” are controlled by a single SysEx message. That SysEx message sets everything at once: all the drawbar levels, percussion parameters and vibrato. Drawbar control requires sensing and sending all of the controller’s knob and switch settings in one fell swoop. None of the commercially available MIDI controllers can handle this.

If you’re interested in this project, check out these links: Dangershield Drawbars, design and code.

The second use case is to fix what shouldn’t have been broken in the first place. The Korg Triton Taktile is a good MIDI controller. I like it and enjoy playing it. However, it’s brain-damaged in crazy ways. The function buttons cannot send program change messages! Even worse, the Taktile cannot send a full program change: bank select MSB followed by bank select LSB followed by program change. This makes the Taktile useless as a stage instrument in control of a modern, multi-bank synthesizer or tone module. If the Taktile allowed user scripting, I would have fixed this nonsense in a minute.

The third use case is sending a pre-determined sequence of pitch bend messages to a tone generator. Yes, for example, you can twiddle a controller’s pitch bender wheel (or whatever) to send pitch bend. However, you cannot hit a button and send a long sequence of pitch bend messages to automatically bend a virtual guitar string or to play a convincing guitar vibrato. Punters (like me) have trouble playing good guitar articulations, but we do know how to hit buttons at the right time. Why not store and send decent sounding pitch bend and controller values in real time as the result of a simple button press?

The fourth use case is an example of the “heavy lifting” potential of user code. Many sample players and libraries (like the Vienna Symphonic Library) assign a range of keys to articulations or other methods of dynamically altering the sound of a notes played elsewhere on the keyboard (i.e., the actual melody or chord). I claim that it’s a more natural gesture to control articulations through the keyboard than to reach for a special function button on the front panel. User coding would allow the redefinition of key presses to articulations — possibly playing a different sample or sending a sequence of controller messages.

Let me give you a more specific example, which is an experiment that I have in progress. Yamaha instruments have Megavoices. A Megavoice is selected as a single patch. However, different samples are mapped to different velocity ranges and different key ranges. As such, Megavoices are nearly impossible to play through the keyboard. Nobody can be that precise consistently in their playing.

I’m prototyping a MIDI controller that implements articulation keys to control the mapping of melody notes to the individual Megavoice samples. This involves mapping MIDI notes and velocities according to a somewhat complicated set of rules. Code and scripting is made for this kind of work!

Finally, the Yamaha Montage demonstrates how today’s MIDI controllers are functionally limited. Yamaha have created excitement promoting the “Superknob” macro control. Basically, the Superknob is a single knob that — among other things — spins the parameters which have been assigned to individual small knobs. Please note “parameters” is plural in that last sentence.

Today’s MIDI controllers and their limited configuration paradigm typically allow only one MIDI message to be assigned to a knob at a time. The target VST or whatever must route that incoming MIDI value to one or more parameters. (The controllers’ engineers have shifted the mapping problem to the software developers at the other end.) Wouldn’t it be cool if you could configure a controller knob to send multiple MIDI messages at once from the source? Then, wouldn’t it be cool if you could yoke two or more knobs together into a single macro knob?

If you had user coding, you would be there already.

All site content Copyright © Paul J. Drongowski unless otherwise indicated

Inside the DGX digital pianos

Posted on by

Thanks to SeaGtGruff in the PSR Tutorial Forum, I took a chance to deep dive a few members of the Yamaha DGX portable grand family. The DGX is a “value” line of electronic keyboards offering a digital piano experience at affordable prices.

Polyphony depends on the available processing power and memory bandwidth (i.e., the ability to transfer samples from wave memory to the processing elements).

Here is a small table for some models in the DGX product line. I took a look at the service manual for models with distinctive features, e.g., DSP effects or no DSP effects. The analysis came out rather nice, so I decided to post it here, too.

           Poly Panel XGlite Kits REV CHO DSP IntMem  Processor
           ---- ----- ------ ---- --- --- --- ------  ------------------
DGX-200     32   108   480    12    8   4   0  352KB
DGX-300     32   122   480    12    8   4  38
DGX-500     32   122   480    12    8   4  38         HG73C205AFD SWX00B
DGX-520     32   127   361    12    9   4   0  875KB
DGX-530     32   127   361    12    9   4   0  875KB  YMW767-VTZ  SWL01T
DGX-620     32   127   361    12    9   4   0  875KB
DGX-630     64   130   361    12   29  24 182 1895KB
DGX-640     64   142   381    12   35  44 238 1895KB  R8A02032BG  SWX02
DGX-650    128   147   381    15   35  44 237  1.7MB  R8A02042BG  SWX08
DGX-660    192   151   388    15   41  44 237  1.7MB

Yamaha has several proprietary processors. The least powerful are the SWLs, which are normally used in the entry-level portables. The SWL does not have DSP support for variation/insert effects. Samples are transfered on the same bus as CPU instructions — low bandwidth. SWLs make for inexpensive products, but no DSP effects and relatively low polyphony.

The PSR E-series typically uses SWL01 variants such as the SWL01U in the PSR-E443. It’s interesting that the DGX members using the same SWL01 processor do not have DSP effects. The SWX processors have integrated DSP capability; the SWLs do not.

The SWX family of processors have dedicated buses/memories and a hardware digital signal processor for effects. (I deliberately avoided the acronym “DSP” here to avoid confusion with the way “DSP” is used in arranger terminology.) The SWX08 has three dedicated buses and memories:

  • SHA2 CPU bus and memory (CPU program and data)
  • Wave ROM bus and memory (voice samples)
  • DSP RAM bus and memory (working memory for digital signal processing)

The extra memory and external connections increase cost. However, this is a lot more processing power and memory bandwidth than the lowly SWL!

The SWX00 and SWX02 are earlier members of the family and aren’t used in new designs anymore. It’s too soon to see a service manual for the DGX-660, so any further comment is an educated guess. I suspect an SWX08 operating at a higher clock rate.

The SWX08 is used in the PSR-S750 and the SWX02 is used in the MOX. In both of these cases, the SWX is the main CPU and tone generation is handled by a single SWP51L tone generator chip, not the SWX. Because Yamaha had its own internal IC fab then these products were designed, Yamaha incorporated its own proprietary processor instead of an off-the-shelf Renesas R8. This is an effort to increase Yamaha’s own fab volume. Yamaha may even be using SWX chips in which the processor is good and the DSP is faulty and fused out!

Analysis isn’t complete without looking at wave memory size:

Model   Wave memory                Size         Description
------- -------------------------- ------------ ------------------------
DGX-500 K3N7V402GB-DC10            64Mbit  8MB  Mask ROM 64Mbit (wave)
DGX-530 Lapis Semi MR27V12852L     128Mbit 16MB 8Mx16b P2ROM (prog+wave)
DGX-640 Lapis Semi MR27V12852L     128Mbit 16MB 8Mx16b P2ROM (wave)
DGX-650 Spansion S29GL256S90TFI020 256Mbit 32MB 16Mx16b NOR flash (wave)

Memory size affects the number and quality of the voices. More memory allows more voices, more samples per voice, longer samples per voice, etc. Pianos are especially memory hungry. So, improvements in piano voices usually require significantly more wave memory. SWX wave memory is 16-bits, data parallel.

Now that Yamaha have sold off their IC fabrication capability, they aren’t under the same pressure to use proprietary processors. It’ll be interesting to see if Yamaha adopt ARM for tone generation and/or effects in value product lines. In the Reface line, they have adopted ARM for user interface and control. Yamaha’s Mobile Music Sequencer on iPad has a fairly completely XG engine, so Yamaha certainly aren’t strangers to tone generation on ARM!

If you enjoyed this article, you might also like this overview of the Tyros/PSR arranger family architecture.

Nord Stage 2 ex: Test Drive

Posted on by

The Yamaha Montage announcement got me thinking about the kind of “all-in-one” keyboard that I would like to play. I still enjoy playing my Nord Electro 2, but the NE2 falls short as an all-in-one. My all-in-one needs to be strong in B3 organ, pipe organ, acoustic sounds, and to a lesser extent, electric pianos. Ideally, the action would be a waterfall keyboard or a good quality “synth action” keyboard. I do not need the weight or expense of a hammer action keyboard. And speaking of weight, the all-in-one should be as far under 20 pounds (about 10 kg) as possible.

The current Nord Electro 5d has gotten very favorable reviews. As one would expect of Nord, it is one of the leading clonewheels, has very good electric pianos, and plays back sampled acoustic instruments from the Nord Sample Library. The 5d has a waterfall keyboard, sliding drawbars, and a nice clear OLED display. The 5d can layer and split voices with a few limitations. Finally, musicians can create sample-based voices of their own using the Nord Sample Editor.

Looks great and the on-line demos sound good! Now, where can I find one to try? This is a dilemma faced by many musicians today and it’s not only trying to find Nord products on display in store. Brick and mortar stores cannot afford to keep a wide spectrum of keyboards on the floor just in case someone feels the urge to try out a new ax. Keyboard sales are not that hot — guitars out-sell keyboards by 5 to 1 when measured in dollar sales volume. Plus, pro-level keyboards are expensive and that’s a lot of money to tie up in inventory.

Fortunately, the nearest GC (the store whose name I dare not speak) had a Nord Stage 2 ex 88 on the floor. So, I grabbed my audition folder and took a drive. I’m glad that I did. (Wednesday night at 8PM is a good time. No shredders and head cases.)

Most NE5 reviews focus on the clonewheel and electric piano sounds. Nord Stage reviews put the synthesizer section to the test, too. My review is different because I decided to concentrate on the quality of the sampled acoustic instruments. One leap of faith is needed: the acoustic instruments on the Stage are not doctored up by the synthesizer when compared to the NE5. Still, a favorable response to the Stage has encouraged me to look for an NE5d to try, possibly by going to the downtown Boston store. (A day trip for me.)

I scrolled through the Stage’s presets and pulled an appropriate lead sheet from my audition folder whenever I found a voice that I wanted to try. I played mainly hymns and liturgical service music from our repetoire: contemporary hymns, traditional hymns, gospel hymns, etc. Yeah, some B3 got in there. I’m weak.

Without being long-winded, here’s a quick rundown.

  • The handfull of pipe organ sounds (big church and chapel) are pleasing and useful. The big cathedral sounds are not overdone, one of my biggest complaints with typical synth “church organs.”
  • Strings? You got ’em. Big, small, sections, solo. The majority of the string voices are very playable. Big strings that are rich without getting screechy in the high end.
  • The orchestra brass ensembles are generally darned good. The trombone section is too loud and brash for church. Softer French horn voices are needed, too. The few horn voices are borderline bright and loud — I need mellow. The pop brass ensembles sound terrific. (“Knock On Wood,” anyone?)
  • Woodwinds, too, are a mixed bag. The woodwind sections are good and playable. The orchestra solo winds (except the flute) are terrible. If I bought an NE5d today, I would cobble together my own solo oboe and clarinet. Although it wasn’t a focus, I played one sax patch that was pretty decent and I wouldn’t be embarrassed to play it in public.
  • B3. Nord groovy as usual. The B sounded darker compared to my memory of the NE2. The Stage has the fast/slow switch on the left where it should be. Nord needs to make the switch BIGGER as it is really difficult to find and hit. (I switch speeds via foot pedal normally, so this is a minor niggle.)
  • Electric pianos, thumbs up.

The Nord Stage 2 ex 88 has a hammer action keyboard. I was pleasantly surprised to find it easy to play organ with this action. The keys did not cut my hand when doing palm swipes and I didn’t have too much trouble playing with a legato touch. Nice work, Nord.

You might reasonable ask, “Why use sampled pipe organ when the NE5d has modeled pipe organ?” The modeled organ solely consists of principal pipes. I think I could use the modeled organ to lead congregational singing as principals are a clear, supportive voice. However, after listening to the demos, the principal pipes alone get “same-y, same-y” fast. I hope Nord continues their work on modeled pipes as the current implementation needs a more varied sound (e.g., reed voices, and so forth).

Overall, the Nord Stage 2 88 left me with a very favorable impression. Despite the shortcomings mentioned above, the acoustic instruments are pro-quality and suitable for liturgical music. I will seek and find a Nord Electro 5d for trial. It’s worth the effort. The Nord Stage 2 ex Compact (73-key waterfall) has a street price around $3,600 USD. The Yamaha Montage 7 (FSX action) has a street price around $3,500 USD. I see a shoot-out on the horizon…