Category Archives: Music technology

Through a gap in the curtain…

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Another day, another brief slip. The following Yamaha Montage information is taken from a credible posting at the gearslutz.com web site. It adds to the information that was inadvertently revealed earlier. Of course, all news before the official unveiling is unverified! If I’m all wrong about this, I will be the first one to have a good laugh! A good laugh is healthy. 🙂

  • AWM2: 128-note, stereo polyphony.
  • New AWM2 waveforms: Yamaha CFX Premium Grand Piano, Bösendorfer Imperial Premium Grand Piano, strings, woodwinds.
  • FM-X: 128-note polyphony, 8-operator voice architecture.
  • FM voices taken from the DX and TX series.
  • DX-to-FM-X conversion utility is in development.
  • Seamless Sound Switching (SSS) for Performances with 8 or fewer parts; no more sound cut-off when changing performances.
  • Envelope follower to extract a routable, control envelope.
  • 1.75GByte of internal user flash memory.
  • Class compliant USB with multiple audio channels back to a DAW.
  • Sampling rate up to 192 kHz.
  • VCM effects including a compressor with sidechain; damper resonance.
  • Pure Analog Circuit (PAC) postprocesses after-DAC audio.
  • Eight rotary encoders and eight sliders.
  • Direct Control Assignment for convenient assignment of parameters to physical controls.
  • 61- and 76-note models have FSX action and aftertouch.
  • 88-key model has fully-weighted balanced hammer action and aftertouch.

Thank you, thank you, for SSS!

The 128 stereo polyphony for AWM2 is interesting given the way Yamaha assigns voice generation elements on the fly. Also, given Yamaha’s tone generation scheme, this is true polyphony. Not to diss the Kronos, but Korg have to publish a lot of fine print about voice/effect trade-offs because the Kronos synthesis engines and effects share the same x86 cores.

Hopefully, the stereo polyphony spec implies a greater use of stereo waveforms for AWM2 voices. Improved woodwinds would really be a God-send for me, not to mention the new acoustic pianos. No word on the electric pianos or B3 organ emulation, though, so I’m still holding my breath. SCM, where are you? The latest reveal mentions “synth libraries from yamahasynth.com.” It would be cool (and useful!) if Yamaha follows the path taken by Nord with their downloadable sound libraries. Aftermarket accessories and sounds drive sales as well as a thriving environment for third party developers. I hope the Montage ecosystem ramps up fast.

One poster noted that 1.75 GBytes of user flash memory is kind of an odd amount. The Montage uses the flash memory scheme that is employed in the most recent arrangers. The flash memory feeding the tone generator holds both the factory voice samples and user samples. Users basically get whatever space is left over from the factory set. Yamaha essentially reserves this much space in the physical memory for your own use.

The motion control and motion sequencer appear to be similar to features implemented in the old Yamaha AN200 and DX200 table-top groove boxes. These allow dynamic control of multiple parameters for sound “morphing.”

The Motion Control Synthesis Engine “unifies” the treatment of AWM2 and FM-X voices across zones and layers in a Performance. Transparency of operation is good.

The visual styling is very nice! Rakish. (Always wanted to use that word.) The Montage appears to be physically smaller than the Motif. Hopefully, the Montage weighs less, too. Yamaha may get slagged for the lack of readable panel markings in low stage light.

Overall, pretty good stuff and I can’t wait to hear more!

Yamaha has now released the official Montage teaser video. If you’re on their mailing list, check your in-box. Otherwise, cruise on over to Youtube. (I don’t usually post Youtube links. You know how to use the Interwebs.) The video confirms the images that we have seen so far.

Yamaha has also opened up the Montage forum on yamahasynth.com. No manuals, yet. 🙂

More than a few people noticed that sequencing capabilities have not been mentioned in the leaked promotional material. Right now, it’s hard to read anything into the absence of this information. We’ll need to stay tuned, but don’t Bogart that Motif/MOX yet! It’s still an incredible time to buy a Motif XF, BTW, with the “Fully Loaded” package and all.

In case you missed them, here are links to two of my earlier posts speculating about the Montage:

New Yamaha workstation at NAMM 2016?
(Re)take the stage

Some hits, some misses.

Yamaha Montage: First (leaked) glimpse

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Looks like the first credible leak about the Yamaha Montage has appeared on the gearslutz.com web site. There is a post taken from the February 2016 issue of the Music Trades NAMM Show special edition, including a small amount of text paraphrased from a Yamaha press release. Here is a short list of product features taken from the leaked text:

  • 61-, 76- and 88-key models
  • New user interface with color touch screen
  • Two sound engines: AWM2 and FM-X
  • Ten times more wave memory
  • Two times the effects as Motif XF
  • Two times the polyphony
  • Motion Control Synthesizer Engine
  • Super Knob: A single knob to control multiple parameters at once
  • Integrated flash

The blurb has the link http://4wrd.it/Montage which leads to a page that is not yet enabled.

YamahaMontage

This information is consistent with my earlier analysis. The Montage uses integrated NAND flash (no more DIMMs!). Ten times the wave memory puts total wave memory around 8GBytes (compressed? uncompressed?). This memory will be shared between the factory sound set, libraries and user samples. Polyphony is 256 voices. The XF supports 16 effect units, so the Montage should have 32 effect units (reverb, chorus and insert) total.

The picture shows a clean front panel where the touch screen has subsumed many of the front panel buttons on the XF. There are eight assignable part sliders and a master slider, along with (presumably assignable) eight knobs and buttons. The knobs and buttons are back-lit.

The Super Knob is also back-lit. It will be interesting to find out how this will be used in performance.

Of course, there are a zillion unknown details. Will the UI really be easy to use and navigate? Are there improved pianos and Spectral Component Modeling (SCM) electric pianos? Does the Montage continue phrase-oriented composition? How much internal flash memory is set aside for user samples? How much weight do we need to lug to the gig? What is the street price?

In case you missed them, here are links to two of my earlier posts speculating about the Montage:

New Yamaha workstation at NAMM 2016?
(Re)take the stage

(Re)take the stage

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A good show starts in the dressing room
And work its way to the stage
— “Get Dressed” by George Clinton

With Winter NAMM 2016 just a few weeks away, I started thinking about how Yamaha might position a new synthesizer workstation (rumored to have the name “Montage”).

Motif has had a long run as a stage instrument favored by many professional touring musicians. It makes a good master controller for a backstage rig and has a wealth of great native sounds. The synth- and piano-key actions are extremely playable with good key-to-sound response.

Over the last few years, Nord and more recently Korg have been taking the stage away from Yamaha. The Nord Stage and Electro series are firmly established as gig boards and the Korg Kronos is coming on strong. Korg products seem to be sprouting everywhere on The Late Night with Stephen Colbert thanks to John Batiste — who can really rock ’em.

I doubt if Yamaha is willing to surrender the stage. This news may disappoint those players who are hoping for a mind-blowing (virtual) analog synthesizer. As a business-person, I would say, “Hmm, we made good money on the stage and in the studio with Motif. Let’s build on that success. Besides, there are plenty of ’boutique’ vendors who make great instruments, like Dave Smith.” Yamaha even granted the name “Sequential” back to Dave Smith.

Yamaha may see the Nord Stage and Korg Kronos as their primary competition for the stage in the synth workstation space. Both instruments combine multiple synthesis techniques into a single integrated package:

  • Wavetable synthesis including sample playback
  • Analog synthesis
  • Frequency Modulation (FM) synthesis
  • Acoustic and electric piano emulation
  • B3 and combo organ emulation

So, which pieces are missing in the current Motif XF? Are you thinking “Reface” yet?

Let’s look at these aspects in turn.

Wavetable synthesis and sample playback

More than a few Internet posters slag AWM (Advanced Wave Memory). I suspect that many of these people would like real analog or modeled analog instead. That’s OK by me because they probably need those sounds for their music. However, there is a wide customer base who need “traditional” instruments (brass, strings, woodwinds, etc.) where sample-playback still rules. AWM is a very successful sample-playback engine and I don’t see Yamaha abandoning AWM.

Yamaha have a new tone generation engine, the SWP70 . The SWP70 is already at work in the PSR-S970 and PSR-S770 arranger workstations . The SWP70 is more than a sample-playback engine as it also performs programmable digital signal processing for effects and more. The S970 implements Motif-quality sounds and effects including Virtual Circuit Modeling (VCM) and the Real Distortion effects that were added to Motif XF in the v1.5 update.

Other posters feel that an SSD is essential for sample streaming. SSD is only one approach, however, and that approach requires a SATA interface for sample I/O. SSD is not necessarily the cheapest design nor does it minimize latency. Yamaha deconstructed the SSD functionality, threw away the SATA interface cost and latency, implemented an Open NAND Flash Interface (ONFI), and embedded sample data caching into the SWP70. The SWP70 has all of the extensibility of NAND flash without the cost of the SATA controller and without SATA bus latency.

As demonstrated by the S970 and S770, the SWP70 is ready to roll for sample-playback and effects processing.

Analog synthesis and FM synthesis

I contend that the Reface products are a field test for SWP70-based synthesis methods that are not tested by the S970 and S770. I have not yet seen absolute evidence that Reface keyboards use the SWP70, but my suspicion is strong.

The Reface CS and Reface DX demonstrate analog physical modeling and 4-operator FM sound synthesis, probably using the SWP70. Please remember that the SWP70 is not just sample-playback; there are digital signal processors in there. These DSP units can be programmed for effects (reverb, etc.) or sound generation. A computer is a computer whether it is an x86 architecture machine or an embedded DSP. Both the Reface CS and Reface DX implement VCM effects, too.

Two more general points about the Reface line. First, the Reface keyboards use an ARM architecture (FM3) processor for control and user interface. This is a major departure from past Yamaha practice. Next, all four keyboards operate on battery power (six “AA” batteries). Low power operation is a significant engineering accomplishment and means that the SWP70 could be deployed in a wide range of portable products — not true of the previous generation SWP51L tone generator.

Acoustic and electric piano emulation

Yamaha demonstrated its commitment to the stage when it introduced the CP1 stage piano and its siblings. The CP1 was well-received.

The CP1 is a bit of a breakthrough product technically. The acoustic piano is implemented mainly through sample-playback. The CP1 physical wave memory is only 128 MBytes. Yamaha eventually released the CP1 acoustic piano samples for Motif XF as part of the Motif XF Premium Collection. We should expect a CP1-level piano or better in the new workstation.

Yamaha “got away” with so few samples overall because the CP1 electric pianos are implemented using Spectral Component Modeling (SCM). “SCM” covers a family of technologies including spectral modeling synthesis (SMS). SMS replaces gobs of samples with computation (AKA “modeling”). SMS eliminates the nasty sonic artifacts due to velocity switched sample-playback because, well, there aren’t any samples, just lots of computations to be performed very quickly.

The Reface CP uses SCM to implement its electric pianos. The Reface CP sounds great. (See my Reface CP snap review.) The Reface CP re-introduces Formulated Digital Sound Processing (FDSP) to model the electric piano pickup. I expect to see SCM electric pianos and a subset of FDSP in the new workstation.

B3 and combo organ emulation

B3 emulation has never been Motif’s strong suit. Nord, in particular, excel at B3 and rotary speaker emulation. Hopefully, Yamaha have addressed this defficiency by incorporating the Reface YC technology into their new workstation.

The Reface YC provides a live front panel that lets a player control the B3 drawbars, percussion, vibrato and rotary speaker on the fly. The ability to play the bars, etc. is essential to B3 technique. A few important improvements include a rotary speaker brake (STOP) position as well as SLOW and FAST, a vibrato/chorus section, and a full percussion section. Hopefully, the vibrato/chorus section emulates the Hammond vibrato/chorus scanner — an effect that is lacking in the Motif (and Tyros/PSR, for that matter).

The Reface YC implements B3 tonewheels through AWM. Is sample-playback better than Nord’s modeling? Of course, a lot rides on rotary speaker simulation, too. I can’t wait to find out. So far, I haven’t been able to find a Reface YC to try one out! If Yamaha wants to take the stage, again, it needs to nail this one.

The bottom line

Yamaha surely have the basic technology to make a machine for stage performers. Hopefully, they have implemented a user interface that is easy to learn, responsive and fun to play — kind of like the live front panels in the Reface series.

The Tyros and the new S770/S970 arrangers sport large displays. The S770 and S970 wide-screens are really nice. Lately, Yamaha have placed greater emphasis on skeuomorphic user interfaces with virtual knobs, sliders, etc. Whether Yamaha goes for a touch panel, only Yamaha knows at this point. It would be kind of cool to have virtual Reface front panels with finger-tweaking controls. But, would it be playable?

Sixteen days to go to Winter NAMM 2016 …

If you liked this article, you might enjoy:

New Yamaha workstation at NAMM 2016?
Reface YC and DX teardowns
The SWP70 tone generator
PSR-S770 and S970 internal architecture
Reface CP: Yes, I played one!

Copyright (c) 2016 Paul J. Drongowski

Reface YC and DX teardowns

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Markus Fuller posted two Yamaha Reface teardowns (YC and DX) to Youtube:

In case you’re not familiar with the term “teardown,” think of a teardown as a casual tour through the insides of a keyboard.

Both Reface keyboards have an ARM FM3 handing the user interface panel. The switch to ARM is major news. In the past, Yamaha used Renesas H8 or SH4 microcontrollers for interface applications. They apparently have decided to ride the embedded cost curve and that curve leads to ARM, the current leader in low-power, high function embedded microcontrollers.

I wonder if Yamaha will adopt ARM in their entry-level keyboards? This would be a smart move. Yamaha currently use their own SWL01 processor in battery-powered entry-level products. Now that Yamaha have sold off their integrated circuit fabrication plant, they are free to move to off-the-shelf parts when it makes sense. ARM is the choice for battery-powered embedded devices. Further, the ARM-resident, XG-capable sound engine in Yamaha Mobile Music Sequencer has a better spec than the entry-level ‘boards. (MMS reference)

Both Reface keyboards have a large metal plate over one or more integrated circuits. This is the honey pot. 🙂 I understand Markus’s reluctance to remove the heat sink. This is, however, where the digital signal processing (DSP) is being performed. Apparently, Yamaha had a minor power dissipation problem and resolved it using a simple heat sink (no fan). Heat is an important product design problem; x86 fans take note. (More on x86 and instrument design.)

Here are some notes about the integrated circuits in the Reface YC:

Winbond W9864G6KH-6 SDRAM  (64Mbits)
    4Mx16 bits = 1M words x 4 banks x 16 bits (8MBytes equivalent)
    166MHz/CL3
    Parallel interface
    Burst-oriented accesses

Winbond W9812G6JH-6 SDRAM (128Mbits)
    8Mx16 bits = 2M words x 4 banks x 16 bits (16MBytes equivalent)
    Parallel interface
    166MHz/CL3
    Burst-oriented accesses

AKM AK4396VF (Asahi Kasei Microdevices Corporation)
    Digital-to-analog converter (DAC)
    24-bit 192KHz 128x oversampling
    I2S data interface
    Integrated digital filter

Texas Instruments / Burr Brown PCM1803A
    Stereo analog-to-digital converter
    24-bit, 64x or 128x oversampling
    I2S data interface

The circuits are all pretty typical for a Yamaha design. Not enough information here to indicate whether the SWP70 tone generator is in use or not. Yamaha have used W9864G6KH as DSP SDRAM in past designs.

I’m glad that Markus posts his teardowns. I like it when he zooms in and identifies the integrated circuits. One very small quibble with the YC teardown — I believe the “A” stands for “Acetone.”

While you’re here, catch my Reface CP snap review.

New Yamaha workstation at NAMM 2016?

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True gearheads are already making predictions and plans for 2016 Winter NAMM, January 21-24, 2016. Winter NAMM rumors abound including “Montage,” the rumored name for the rumored new Yamaha synthesizer workstation.

See the list of new waveforms in the Montage and read my initial review of the Montage8. Update: May 10, 2016.

Find the latest links, pictures, rumors and facts here . Update: January 21, 2016.

Check out some new thoughts about the rumored workstation and preliminary comments . Update: January 18, 2016.

Many folks — myself included — anticipate the release of a new Yamaha synthesizer workstation at the next NAMM. Much has been made of the registered trademark “Montage.” I don’t really care too much about what they call it, as I care about what it will do.

Last month, I posted two articles about the new Yamaha tone generation chip called “SWP70”:

This chip made its first appearance in the new PSR-S770 and PSR-S970 arranger workstations. Lest anyone scoff, the S770 and S970 produce Motif-caliber sounds including the REAL DISTORTION effects added to the Motif XF by the v1.5 update. The previous tone generator (SWP51L) is used throughout the mid- and upper-range Yamaha keyboard products including Clavinova, MOX/MOXF, Motif XS/XF, and Tyros 4/5. The number of tone generator chips varies by product specification and, most notably, sets the maximum available polyphony. A new tone generator chip is a pretty big deal since it will have an impact on all mid- and high-grade electronic instruments across product lines.

My earlier article about the SWP70 is written from the perspective of a computer architect and is way too nerdy for normal people. 🙂 Let me break it down.

Musicians using VST plug-ins within a PC-based DAW are familiar with the concept of sample streaming. In the quest for greater realism and articulation, sample libraries have become huge. These libraries simply cannot fit into fast random access memory (RAM) for playback. As a work-around, a software instrument reads samples from a drive-based library on demand and only a small part of the entire library is resident in RAM at any given time. The process is often called “sample streaming” because the software instrument streams in the samples on demand from a large fast secondary memory like a Solid-State Drive (SSD). The Korg Kronos workstation caught everyone’s attention because it incorporates an x86-based software system that streams samples from an SSD. (For Kronos-related articles, look here and here.)

The SWP70 combines streaming with tone generation. It does not, however, use an SSD for storage. Rather, it subsumes the functionality of the SSD. A moment to explain…

An SSD consists of three major subsystems: SATA controller, temporary storage cache (RAM) and one or more NAND flash memory chips. The NAND flash memory chips typically adhere to the Open NAND Flash Interface (ONFI) standard. This allows expansion and standardized configurability. The SATA controller exchanges commands and data with a computer using the SATA bus protocol. The temporary storage cache holds data which is pre-read (cached) from the NAND flash chips. Caching is required because random access read to NAND flash is too slow; sequential paged access is much faster. Data must be prefetched in order to achieve anything like SATA 1 (2 or 3) transfer speed.

The SWP70 subsumes the SSD functionality. It has its own memory controller and has a side memory port to its own RAM for caching samples. The SWP70 reads samples from its ONFI-compatible NAND flash memory bus and stores the samples in its cache. The tone generation circuitry reads the samples from the cache when it needs them. The SWP70 solution is, effectively, sample streaming without the added cost and latency of SATA bus transfers. The samples coming into the SWP70 from flash are compressed, by the way, and the SWP70 decompresses them.

The SWP70 will very likely make an appearance in the new Yamaha synthesizer workstation. The S770 and S970 do not make full use of the SWP70, so we have yet to see what this chip is fully capable of. We can definitely expect:

  • Much larger wave memory (4GBytes minimum)
  • Greater polyphony (256 voices or more)
  • More simultaneous DSP effects (32 units or more)
  • The demise of the expensive expansion flash DIMMs

I would simply love it if the new workstation implemented some form of Super Articulation 2 voices (now supported by Tyros 5). The raw resources are there.

User-installed expansion memory may be a thing of the past. The current DIMMs plug into a two channel, full parallel memory interface. That interface is gone and the SWP70 communicates with flash NAND through an ONFI-compatible interface. The Motif and Tyros follow-ons will likely reserve space for user samples and expansion packs in built-in flash memory just like the new mid-range PSRs.

What does Yamaha intend to do with all of this polyphony? Current high-end models like the Tyros 5 use two tone generation chips. Yamaha could replace both chips with a single SWP70 and pocket the savings.

Another possibility is to provide advanced features for musical composition that combine MIDI and audio phrases. Here is a list of technologies covered by recent Yamaha patents and patent applications:

  • Beat detection and tracking
  • Chord detection
  • Synchronized playback of MIDI and audio
  • Combined audio/MIDI accompaniment (time-stretch and pitch-shift)
  • Object-oriented phrase-based composition on a time-line
  • Accompaniment generation from chord chart
  • Display musical score synchronized with audio accompaniment
  • Phrase analysis and selection (via similarity index)
  • Near ultra-sonic communication of control information
  • Search for rhythm pattern similar to reference pattern

A few of these technologies are covered by more than one patent — recurring themes, if you will. I could imagine a screen-based composition system that combines audio and MIDI phrases which are automatically selected from a database. The phrases are transparently time-stretched and pitch-shifted. Some of the compositional aids may be implemented in the workstation while others are tablet-based. The tablet communicates with the workstation over near ultra-sonic sound (no wires, no Bluetooth, no wi-fi, no time lag).

Sample-based tone generators already perform pitch-shifting. That’s how a single sample is stretched across multiple keys. A musical phrase can be pitch-shifted in the same way. As to time-stretching, stay tuned.

Some of these features, like accompaniment generation from a textual chord chart, are more likely to appear in a future arranger workstation product. Making product-specific predictions is a risky business, especially if you want to get it right!

Yamaha — the business — is keenly interested in growth and expanding markets. Management sees opportunity in growth markets like China. The need to combine audio phrases with MIDI is driven by non-Western music: time signatures other than 3/4 or 4/4, different scales, different playing techniques and articulations. These concerns are perhaps more relevant to the arranger product lines. However, phrase-based composition that manipulates and warps audio and MIDI transparently is a basic feature of many DAWs. (Think “Ableton Live.”)

One final theme seems to recur. Yamaha appear to be interested in analyzing and accompanying non-keyboard instruments. The market for guitar-driven accompaniment is much wider and deeper than today’s arranger workstations and is a lucrative target.

Here are links to a few earlier articles, including speculation about the new Yamaha synthesizer workstation:

These articles link to further background information. Of course, we’ll know a lot more once Winter NAMM 2016 is underway!

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

The SWP70 tone generator

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As I mentioned in an earlier post, the Yamaha PSR-S770 and PSR-S970 arranger workstations have a new tone generator (TG) integrated circuit (IC) — the SWP70. (“SWP” stands for “Standard Wave Processor.”) The SWP70 is a new TG family in a long line of Yamaha tone generators. The SWP70 replaces the SWP51L, which has been the mainstay in recent generations of Tyros, upper range PSR, Motif, and MOX series workstations.

The SWP70 has much in common with the SWP51L, but also some very significant differences. The SWP70’s external clock crystal frequency is 22.5792 MHz versus 11.2896 MHz for the SWP51L. This funky looking clock rate is a multiple of 44,100 Hz:

    22.5792MHz = 44,100Hz * 512

Samples are transferred to the DAC, etc. at a multiple of 44,100 Hz (Fs). Thus, it makes sense to derive Fs and its multiples from the chip-level master clock. The higher crystal frequency and faster memory read clocks lead me to believe that the SWP70 is clocked twice as fast as the SWP51L.

I am comparing SWP characteristics as deployed in the S970 (SWP70) and the S950 (SWP51L) workstations. This keeps the basis of comparison even although many characteristics (clock rates, DSP RAM size) are the same in higher end models like Tyros 5 or Motif. Higher end models employ two SWPs in master/slave relationship and both SWPs share the same wave memory. For more information about the PSR-S970 internal design, look here.

Five interfaces are essentially the same as the SWP51L:

  1. CPU interface: Communicate with the Main CPU (e.g., Renesas SH7731) via the parallel CPU bus.
  2. Serial audio: Send/receive audio data to/from the DAC, audio ADCs, and main CPU.
  3. Clock interface: Synchronize serial audio data transfers (generate multiples of Fs).
  4. DSP SDRAM interface: Store working data for effect processing.
  5. EBUS interface: Receive controller data messages (e.g., pedal input, keyboard input, pitch bend, modulation, live knobs, etc.) from front panel processors.

The DSP SDRAM is the same size: 4Mx16bits (8MBytes). The SWP70 read clock is 95.9616 MHz, while the SWP51L read clock is 45.1584 MHz. This is more evidence for a higher internal clock frequency.

The Tyros 4, Tyros 5 and S950 have an auxiliary DSP processor for vocal harmony. The microphone analog-to-digital (ADC) converter is routed directly to the auxiliary processor. Prior to these models, the microphone ADC is connected to the tone generator. With the SWP70, the S970’s microphone ADC is once again routed to the SWP70 and the auxiliary processor disappears from the design. Thus, vocal harmony processing (fully or partially) is located in the SWP70. See my post about SSP1 and SSP2 for further details.

The biggest change is the wave memory interface.

A little history is in order. The SWP51L (and its ancestors) were designed in the era of mask programmable ROM. I contend that tone generation is memory bandwidth limited and the earlier interface design is driven by the need for speed. The SWP51L (due to its evolved history) has two independent wave memory channels (HIGH and LOW). Each channel has a parallel address bus (32 bits) and a parallel data bus (16 bits). The two channels account for over 100 pins. (System cost is proportional to pin count.) The user-installed, 512/1024MB flash DIMMs plug directly onto the two channels.

The SWP70 wave memory interface takes advantage of new NAND flash memory technology. The interface is described in US patent application 2014/0123835 and is covered by Japanese patent 2012-244002. I analyzed the US patent application in an earlier post.

The SWP70 retains the HIGH port and LOW port structure. Each port communicates with an 8Gbit Spansion S34ML08G101TFI000 NAND flash device. Address and data are both communicated over an 8-bit serialized bus. This technique substantially decreases pin count and the resulting board-/system-level costs. Smart work.

I did not anticipate, however, the introduction of a new parallel memory interface called “wave-work”. The wave work interface communicates with a 16Mx16bit (32MBytes) Winbond W9825G6JH-6 SDRAM. The read clock is 95.9616 MHz.

The purpose of the wave work SDRAM is revealed by US Patent 9,040,800. This patent discloses a compression algorithm that is compatible with serialized access to the wave memory. The wave work SDRAM is a cache for compressed samples. The characteristics of the Spansion memory device give us a clue as to why a cache is required:

    Block erase time               3.5ms    Horrible (relative to SDRAM)
    Write time                     200us    Terrible
    Random access read time         30us    Bad
    Sequential access read time     25ns    Very good

As the patent explains, two (or more) samples are required to perform the interpolation while pitch-shifting. If there is only one tone generation channel, access is paged sequential. However, random access is required when there are multiple tone generation channels. (The patent mentions 256 channels.) Each channel may be playing a different voice or a different multi-sample within the same voice. One simply cannot sustain high polyphony through random access alone. The cache speeds up access to recently used pages of uncompressed samples.

The wave work interface takes additional pins, thus adding to board- and system-level costs. The overall pin count is still lower when compared to SWP51L. The penalty must be paid in order to use contemporary NAND flash devices with a serialized bus. This is the price for catching the current (and future) memory technology curve.

A few SWP70-related printed circuit board (PCB) positions are unpopulated (i.e., IC not installed) in the PSR-S970. There is an unpopulated position for a second Winbond W9825G6JH-6 wave work SDRAM which would expand the wave work memory to 32Mx16bit (64MBytes). A larger cache would be needed to support additional tone generation channels. Perhaps only half of the tone generation channels are enabled in the mid-grade PSR-S970 workstation.

There is what appears to a second separate wave work interface that is completely unpopulated. The intended memory device is a Winbond W9825G6JH-6, which is consistent with the existing wave work interface.

The PSR-S970 also has a stubbed out interface that is similar to the DSP SDRAM interface. The existing DSP SDRAM signals are labeled “H” for HIGH while the unused interface is labeled “L” for LOW. Perhaps only half of the hardware DSP processors are enabled for the mid-grade S970, waiting to be activated in future high-end Tyros and Motif products.

I refer to future high end products by the names of the current product lines. Yamaha may choose to rebrand future products (e.g., the much-rumored “Montage” trademark).

The Spansion S34ML08G2 8-Gb NAND device is Open NAND Flash Interface (ONFI) 1.0 compliant. The S34ML08G2 device is a dual-die stack of two S34ML04G2 die. The 8-bit I/O bus is tri-state allowing expansion e.g., multiple memory devices sharing the same I/O bus and control signals with at most device enabled at any time. The SWP70 has additional chip select pins that would support this kind of expansion. The current expansion flash DIMMs will no longer be needed or used.

In this note, I concentrated on observations and fact, not speculation about future products. I’ll leave that fun for another day!

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

SSP1 and SSP2: Designated hitter

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One notable absence from the Yamaha PSR-S970 design is the “SSP2” integrated circuit (IC) which handles vocal harmony processing. The SSP1 and SSP2 appeared in the Tyros series and PSR series coincident with Vocal Harmony 2.

For you signal sleuths, the PSR-S950 and Tyros 5 microphone input is routed to an analog-to-digital converter (ADC) where the analog signal is sampled and digitized. The digital sample stream is sent to the SSP2 IC. The firmware munges on the samples and voila, the SSP2 produces a vocal harmony signal that is mixed with samples from the tone generator, etc. The SSP2 sends its results to the TG where effects and mixing are performed. The TG sends its output to the digital-to-analog converters (DAC) and digital amplifiers. The Tyros 4 has the same signal flow using an earlier model “SSP1” processor instead.

Previous machines with vocal harmony (e.g., Tyros 3 and earlier, PSR-S910 and earlier), routed the digitized microphone stream to a tone generator (TG) IC such as the SWP51L. Presumably, vocal harmony processing was performed in the TG IC. With the brand new SWP70 tone generator in the S970, the digitized microphone stream is sent to the SWP70. Looks like vocal harmony processing is folded into the SWP70 TG.

I didn’t give the SSP2 much thought or investigation, and just assumed that it was a gate array or something. On inspection, the pin-out resembles a Renesas embedded DSP processor with analog inputs and outputs, digital I/O, USB and all of the usual suspects. The SSP2 in the S950 has 2MBytes of NOR flash program ROM (organized 1Mx16bits) and 2MBytes of SDRAM (organized 1Mx16bits). The clock crystal is a leisurely 12.2884MHz although the SDRAM read clock is 84.7872MHz.

Mysteriously, a web search on the part numbers doesn’t turn up much information. The part numbers are:

    Schematic ID  Manufacturer?       Yamaha
    ------------  ------------------  --------
    SSP1          MB87S1280YHE        X6363A00
    SSP2          UPD800500F1-011-KN  YC706A0

The PSR-S950 parts list does not give a Yamaha order number for the SSP2. If the SSP2 fails, you’ll need to call Yamaha 24×7 directly.

A web search does turn up a few of the interesting places where the SSP has been seen. In addition to Tyros 4, Tyros 5 and S950, the SSP and SSP2 are featured in:

    PSR-S500 arranger (probable role: effects processor)
    EMX5016CF mixer (role: SPX effects and user interface)
    Steinberg UR22 audio interface
    Steinberg MR816 Firewire audio interface
    Yamaha THR modeling guitar amplifier

The SSP is Yamaha’s designated hitter when they need an odd bit of DSP work done.

PSR-S770 and S970 internal architecture

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Yamaha just recently introduced the new PSR-S770 and PSR-S970 arranger workstations. As usual, I’m always anxious to dive into the service manual and see what’s up.

First, I’d like to thank Uli and capriz68 on the PSR Tutorial Forum for their help. Uli made a very nice table from my ramblings, so be sure to check it out there.

Without further introduction, here is a table comparing previous generation models (PSR-S750 and PSR-S950) against the new models.

                    PSR-S750  PSR-S950   PSR-S770  PSR-S970
                    --------  ---------  --------  ---------
Main CPU            SWX08     SH7731     SH7731    SH7731
Clock rate (MHz)    135.4752  256        320       320
Tone generator      SWP51L    SWP51L     SWP70     SWP70
Ext clock (MHz)     11.2896   11.2896    22.5792   22.5792
DSP SDRAM (MBytes)  8         8          8         8
DSP RCLK (MHz)      45.1584   45.1584    95.9616   95.9616
Mic ADC                       AK5381     PCM1803   AK5357
AUX IN ADC          AK5357    AK5381     AK5357    AK5381
DAC                 AK4396    AK4396     AK4396    AK4396
Digital amp         YDA164C   2*YDA164C  YDA164C   2*YDA164C
Wave ROM (MBytes)   256       256        512       2048
Wave SDRAM          N/A       N/A        32MBytes  32MBytes
SSP2 chip           No        Yes        No        No

The main CPU remains a Renasas SH4AL-DSP CPU. The clock speed is increased from 256MHz to the 320MHz, which is just shy of the rated maximum for the SH7731.

Wave memory is increased from 256MBytes (S950) to 512MBytes (S770) and 2GBytes (S970). Part of the S770 and S970 wave memory is reserved for expansion pack voices: 160 MBytes (S770) and 512 MBytes (S950). How Yamaha uses the rest of the memory is up to Yamaha. However, we are now in an era when we cannot compare products solely on the basis of physical wave memory size. Our ears and performance experience are more important than mere byte counts!

The S970 has two NAND flash memory devices labelled “audio style.” The devices are:

    4Gbit NAND flash = 512MBytes
    2GBit NAND flash = 256MBytes
                       ---------
    Total audio style  768MBytes

Yamaha specifies memory size in bits, so one must be careful to convert during analysis. The PSR-S950 has a NAND flash device labelled “Program ROM,” which presumably served the same purpose as well as holding the operating system image that is loaded at boot time. The S950 device capacity is 512MBytes (4Gbits). The S970 reserves 128MBytes for audio style expansion.

The upper mid-range model, i.e., the S970, is biamplified with two digital power amps. The older S950 is also biamplified. Not much change here.

The big news is that Yamaha have a new tone generator integrated circuit (IC), the SWP70. The SWP70 uses the serialized wave memory interface that I described in an earlier post. The SWP70 appears to operate at twice the speed of the older SWP51L. The SWP70 has implications for other future products, so I will analyze it in a separate post.

With respect to the PSR-S970, however, there is another evolutionary step. With the appearance of the new SWP70, there is also the disappearance of the SSP2 IC. The introduction of the SSP2 IC coincided with the introduction of Vocal Harmony 2 in both the Tyros line and the PSR-S950. It is reasonable to infer, then, that vocal harmony is implemented on board SSP2. With the PSR-S970, there are two possibilites.

  1. Vocal harmony is assigned to the now faster main CPU, or
  2. SSP2 functionality is integrated into the new SWP70.

The SWP70 is beefed up in other ways including a new wave working memory.

The future looks interesting as always!

Here are links to my articles on other members of the PSR and Tyros product families:
What’s inside of a Yamaha arranger?
A follow-up on the Yamaha SWP51
Yamaha arranger product family

All site content is Copyright © Paul J. Drongowski unless otherwise noted.

Sending performance data via audio

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It’s a challenge to get one’s head around the recent patents filed and obtained by Yamaha. In this post, I concentrate on one kind of communication technology that pops up in several patents.

Most people would like to get rid of the cables in their studio or living room. Radio-based communication technology like wi-fi (e.g. IEEE 802.11), Bluetooth, or Bluetooth Low Energy (BLE) seems like a no brainer for wireless communication. Radio is a bit of a regulatory nightmare for a global electronics corporation, however, because radio gear needs type acceptance and approval from governmental authorities. On a functional level, both wi-fi and Bluetooth communications are subject to interference, conflict and latency.

If Yamaha knows anything, it knows about latency and how latency can adversely affect the generation/transmission of data and sound.

US Patent 8,779,267 describes an approach to CDMA-like (code division multiple access) communication via near-ultrasonic sound (18KHz). Pseudo-random spreading codes allow multiple transmitters to operate within the same frequency band. Thus, multiple musical devices in your living room or studio can communicate with each other at the same time. The sound of ongoing communication — “control tones” in the terminology of the patent — are sufficiently high as to be inaudible to humans. (I wonder what dogs will hear and think? Seriously.)

The patent deals specifically with the modulation and generation of control tones by a synthesizer. The synth CPU borrows one of 32 tone generator channels to generate the control tones to be transmitted. The waveforms for the tones are stored, ta-da!, in wave ROM. Amplitude is constant (no ADSR for you) and the tone is sent only through the left channel to avoid sonic interference with itself through the right channel (avoiding phase cancellation, no doubt).

All in all, this is quite clever. Using a tone generation channel keeps cost low — no specialized modulator. The symbol rate is about 400.9 symbols per second, so transmission speed is not blazing fast. However, the ultra-sonic approach avoids the regulatory hassles and latency of consumer data radio technology.

The application discussed in the patent is the synchronization or display of “musical score data” on a tablet. The synthesizer sends control tones to the tablet telling notation software where it is in a musical score. The low symbol rate should be OK for this kind of application. If you’re curious about this application, then check out US Patent 9,029,676 (“Musical score device that identifies and displays a musical score from emitted sound and a method thereof”).

Six futher “embodiments” of theses idea are described in US Patent 9,006,551. The object of this invention is a musical performance information output device and system which superimposes musical performance-related information (e.g., notes, tempo, expression, etc.) on an analog audio signal without damaging the “general versatility” of the the audio data. The embodiments include:

  • A guitar that derives MIDI messages from string sensors and imposes the MIDI data on the audio signal.
  • A guitar that determines fingering information and sends it.
  • An electronic piano that sends tempo clock by imposing it on the audio.
  • A guitar that controls an effect unit.

And so forth.

Data is superimposed onto an audio signal. The signal can be sent in either free-air (patent ‘267) or over an audio cable (patent ‘551). There are probably limits and restrictions on free-air transmission such as signal strength, interference from ambient noise and so forth. Patent ‘267 assumes that the tablet and keyboard are in close proximity (speaker to microphone). In the case of ‘551, combining audio and data communication over an audio cable at least eliminates the need for a separate parallel data cable.

The normal disclaimers apply: Who knows if this technology will make it into product, how, or when?

Why not high-end x86?

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Last time around, I broke down the computational core of the Korg Kronos and Krome workstations. The Kronos is one of the few (only?) current synthesizer workstations based on the x86. The Kronos 2 is built around an Intel mini-ITX motherboard with a 1.86GHz dual-core Atom running a custom version of Linux. Since the x86+Linux combination is flexible and versatile, it hosts a wide variety of software-based synthesizers, including the ever popular sample-based synthesis used in so many other products from Korg, Roland and Yamaha (to name a few manufacturers).

Learning this, some folks may be disappointed to find a “lowly” Atom instead of high-end processor such as a honking 4.0GHz Core i7-4790K. It’s a quad-core processor (8 processing threads) with 1MB L2 cache, 8MB L3 cache, and integrated Intel HD Graphics 4600. Sounds like a positive screamer when compared against the D2550 Atom in the Kronos 2.

Before any fanbois freak out, I didn’t have any particular reason for choosing this particular CPU as the example. Yes, it was released in 2014, blah, blah.

First and foremost, please consider power consumption. The i7 is rated at 88W total power dissipation (TDP) while the Atom is rate at 10W TDP. High clock speed and high functionality come at a cost, specifically, power.

  • On the consumption side, the i7 needs a power supply with 8 times the capacity of the Atom-based solution.
  • On the dissipation side, the i7 solution needs to dissipate and remove 8 times the heat of the Atom solution.

It’s the laws of physics, folks. Silicon CMOS circuits at high clock speed consume gobs of power. If you want to save dynamic power, then reduce the clock speed and/or throw away unneeded functionality.

High power consumption and dissipation lead to difficult design problems at the product system level. The power supply (PSU) must be bigger and heavier. An ATX power supply is 2.5 to 5 pounds of dead weight. The PSU also generates heat of its own no matter how efficient it may be. CPU cooling requires both a heavy heat sink and a fan. Further, the heat produced by the heat sink and power supply must be removed from the product chassis by exhaust fans. Great, additional weight and fan noise. Ultimately, the musical instrument designer becomes a desktop computer designer.

Customers already complain about the weight of workstation products. Heavy synthesizer workstations are “studio queens.” If a workstation is too heavy to take to gigs, then why not use a high performance desktop or server solution in the studio to begin with?

One must take the CPU support infrastructure into account, too. Mid- and high-end x86 processors cannot stand alone — they need a companion chipset. The x86 processor and the chipset integrated circuit (IC) are the Mario and Luigi of computer design. You don’t see one without the other. The chipset IC implements the I/O ports: PCIe, USB and most importantly, the SATA interface to bulk storage. The chipset IC consumes and dissipates power, too, and must have its own heat sink.

x86 system design requires specialized expertise in high frequency electronics, thermal design and mechanical design. You’re unlikely to find this specific expertise at Korg, Roland and Yamaha. It’s not their core competence or value added. That’s why Korg very wisely adopted an existing mini-ITX solution for the Kronos. Korg design and manufacture the ARM-based user/audio interface board. Embedded electronics like that are a core competence and value-added component. The mini-ITX motherboard plus user/audio interface board solution is smart, system-level engineering.

So, in the end, we have the “good enough” solution that is appropriate for the product space. Korg build musical instruments, not desktop computers. The D2550 Atom has enough computational horsepower to deliver a range of synthesis techniques with adequate polyphony. The solution fits into a conventional keyboard chassis without noisy fans, without becoming dangerously hot to the touch, and at a tolerable weight.

You may think that I’ve conceded higher performance at this point, but here is one more idea for consideration — laptop technology. This solution will not deliver the absolute highest level of performance, but it might be the next step up from the mini-ITX solution. From the systems point of view, it might make sense to design a portable keyboard product around an OEM laptop motherboard, cooling system and processor. Laptop fans are generally quiet and heat could be vented through a modest port in the chassis. One could power the instrument from lithium ion batteries for relatively short periods of time or leave the batteries out for lighter weight. Perhaps Korg engineers considered this solution, too. They’ve clearly demonstrated their skill in the design of the Kronos.