Rainy day ramblings

A rainy New England day and the leaves and pine needles are piling up. Can’t do much of anything outdoors today, so off to GC. (Not that I really want to do yard work.)

No real agenda. I’ve been thinking about Yamaha Montage vs. Tyros 5++ vs. Nord Stage 2 ex vs. Electro 5d. That’s all “long term” as I’m having a lot of fun and staying busy with the S950 and MOX.

I really could use a “lap piano” for rehearsals. (A distant relative of “floor melodica?”) My body ached so much last Wednesday before rehearsal that even an eight pound Korg Triton Taktile was too much to schlep. So, I sang with the group, hoping to internalize the melodies of the new music for the week. This isn’t such a bad idea in any case, since it’s good form to sing along in one’s head while playing — improvisationally or not. A good reminder that, yes, hymns actually have words.

So, the issue of mini-keys rises from the grave like Joan Crawford. About one month ago, I sought and found a Yamaha Reface to try again. As it seems for most interesting music tech, one needs to drive a zillion miles or take two or more trains to find and play Reface, Montage, Korg Arp Odyssey and so forth. And thus it was to play a Reface DX. I had a fair chance to plink away and the DX provided a wide range of solid sounds. But, still, no love for the Reface mini-keys. I simply cannot imagine playing a Reface at rehearsals and even remotely enjoying the experience.

Today’s journey was inspired by a favorable review of the new Korg MicroKorg S in Sound On Sound magazine. What a pretty picture it is; Korg’s industrial design may ape Arturia, but they took the best! The review mentioned the larger mini-keys (what an oxymoron!) of the Microkorg XL+ and I decided to find a comparably equipped Korg.

Happily, today’s trial was the Minilogue, which proved to be a fun time indeed. It’s got a pretty sweet sound for an inexpensive polyphonic analog synth. With the right programming, I could even warp the Minilogue into a “lap piano” good enough for rehearsals. A built-in speaker a la the new Microkorg S would be nice. However, I could easily run it into the JBL Charge 2 that serves as the battery-powered amplifier for the Triton Taktile 49 (my usual rehearsal ax). It’s a shame that the Minilogue isn’t battery powered, too, as it would make a terrific portable instrument.

The Minilogue’s oscilloscope is a real treat and is totally entertaining. It’s also a reminder that I need to add a mini-/micro-oscilloscope to the dining room lab one of these days. The oscilloscope display is a small OLED screen much like the screen in the Triton Taktile.

The Minilogue’s keys are far more playable than the Reface. The keys are longer than typical mini-keys and the black keys (sharps and flats) are narrow. This combination makes for a surprisingly effective keyboard design. I wouldn’t want to play a gig with these, but they are suitable for plinking out melodies and such at rehearsal. (See this article at Synthtopia for a good analysis of the Minilogue’s key size.) Several other Korgs have the same key design: the Korg Arp Odyssey and the “Natural Touch” microKEY, to name two.

I’ll say this for Korg. They may miss the mark sometimes, but these folks are actively innovating at a fast pace!

After messing with the Minilogue, I revisited the Nord Stage 2 ex. This is a fine instrument and is in the same premium range as the Yamaha Montage. Having also revisited the Montage in recent weeks, the Nord’s string and woodwind voices just don’t come up to the same level as Montage. The Montage voices live and breath. Although the Nord is quite good, these voices sound like “sample playback.” Kudos to Yamaha.

I will have more to say about Montage in a forthcoming post. In short, is it time to spring for Montage or wait for the successor to the Tyros 5 (“Tyros++”)?

Time for a cuppa…

New Yamaha workstation at NAMM 2016?

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

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.